Category Archives: Agriculture

There are few published studies on the genetics of tolerance to chilling temperatures in tomato

Our results reveal that BrpHMA2 could be activated by Cd2+ , which is similar to the results found for HMA2 in Arabidopsis. Results suggest that BrpHMA2 is involved in the Cd response of plants. BrpHMA2 was also found to be expressed explicitly in the vascular tissues of roots, stems, leaves, flowers, siliques, and carpopodia, and its protein was localized in the plasma membrane . These results are consistent with previous findings for HMA2 in Arabidopsis, OsHMA2 in rice, and TaHMA2 in wheat. The protein plasma membrane localization and the vascular-specific expression pattern of the genes revealed that HMA2 might function as a membrane transporter in long-distance transport in plants. In recent years, some studies have investigated the function of HMA2. Most of these studies demonstrated that HMA2 is involved in Zn2+ and Cd2+ transmembrane transport and influences root-to-shoot Zn/Cd translocation. For example, HMA2 in Arabidopsis is thought to be involved in the outward transport of Zn2+ and Cd2+ from the cell cytoplasm, and HMA2 mutants are more sensitive to Cd stress and exhibit higher Zn or Cd accumulation than wild-type plants in the presence of high levels of Zn2+ or Cd2+ 14,15. The over expression of OsHMA2 in wheat, rice, and Arabidopsis improves root-to-shoot Zn/Cd translocation. In addition, the transformation of TaHMA2 in yeast enhances the resistance of cells to Zn/Cd. In rice, the suppression of OsHMA2 decreases the Zn and Cd concentrations in leaves, increases the retention of Zn in roots and reduces the translocation of Cd and Zn from roots to shoots compared with the results obtained with wild type plants. According to the literature, HMA2 is responsible for Zn2+/Cd2+ efflux from cells, plays roles in Zn and Cd loading to the xylem,procona buckets and participates in the root-to-shoot translocation of Zn/Cd. However, Yamaji et al. found that OsHMA2 is localized at the pericycle of the roots and in the phloem of enlarged and diffuse vascular bundles in the nodes. Their insertion lines of rice showed decreased concentrations of Zn and Cd in the upper nodes and reproductive organs.

The study revealed that the heterologous expression of OsHMA2 in yeast is associated with the influx transport of Zn and Cd. These researchers suggested that OsHMA2in the nodes plays an important role in the preferential distribution of Zn and Cd through the phloem to the developing tissues. Our results also revealed that, in the presence of Cd2+, transgenic Arabidopsis seedlings and yeast over expressing BrpHMA2 showed higher concentrations of Cd and enhanced Cd2+ sensitivity compared with the controls . Thus, we propose that BrpHMA2 functions in Cd2+ transport in the phloem tissue of vascular systems through influx into cells, and the efflux from phloem cells during long-distance transport may be performed by other transporters. The differential function of HMA2 from various plants might come from the tiny difference in amino acids in their function domains; this puzzle requires further investigation.In this study, we identified the NAC TF gene BrpNAC895, a homolog of Arabidopsis ANAC087 , which could be induced by Cd2+ stress . We confirmed that BrpNAC895 has a role in the response of B. parachinensis to Cd2+ stress by upregulating BrpHMA2 expression through direct binding to the BrpHMA2 promoter using EMSA, ChIP–qPCR, and the transient transformation method with B. parachinensis protoplasts . Previous studies have demonstrated that Arabidopsis ANAC087 is associated with plant programmed cell death . It functions along with the TF ANAC046 to show partial redundancy in coregulating the expression of some PCD genes in the root columella, including ZEN1, BFN1, and RNS3. Whether ANAC087 could participate in regulating Cd transporters in plants has not been reported. Our findings on BrpNAC895 show that this NAC TF has a novel role in upregulating BrpHMA2 expression in response to Cd2+ stress. We also identified the Cd-responsive AREB TF BrpABI 449 , which is a homolog of Arabidopsis ABF3 and can bind to the promoter of BrpHMA2 . ABF3 modulates the response to drought, salt, and other osmotic stresses as a master component in ABA signaling. This TF can also regulate the expression of multiple genes, such as the AGAMOUS like MADS-box TF family gene SOC1, which is a floralintegrator regulating flowering in response to drought, and the AREB TF ABI5, which is a core component in the ABA signaling pathway in the regulation of seed germination and early seedling growth during exposure to ABA and abiotic stresses .

In general, ABF3 can form protein complexes with other TFs. For example, ABF3 forms homodimers or heterodimers with AREB1/AREB2 and acts cooperatively to regulate ABRE dependent gene expression. ABF3 forms a complex with NF-YC3 to promote the expression of the SOC1 gene and thus accelerate flowering and drought-escape responses; ABF3 interacts with NAC072 to regulate RD29A and RD29B expression in response to ABA. Thus, complex formation might be the important functional mechanism by which ABF3 regulates gene transcription. Using EMSAs and ChIP–qPCR assays, we found that BrpABI449 could directly bind to regions of the BrpHMA2 promoter . The interaction of BrpABI449 and BrpNAC895 was further confirmed by pull-down and BiFC assays . The inhibition of BrpABI449 on the transcriptional regulatory role of BrpNAC895 was detected in the B. parachinensis protoplast transient system . The inhibition by BrpABI449 of the transcriptional regulatory role of BrpNAC895 complex, likely interferes with BrpNAC895’s activity in the transcriptional activation of BrpHMA2 in response to Cd stress. It has also been reported that Cd stress can induce a stress response via ABA signaling. Our results showing that BrpNAC895 and BrpABI449 are upregulated by Cd stress also support this point. The uptake or homeostatic regulation of heavy metals needs proper modulation to ensure plant health. Previous studies have shown that Cd stress induces the MYB TF gene MYB49 in Arabidopsis. This TF may further positively regulate the downstream TF gene bHLH38 and bHLH101 by directly binding to their promoters, and activate iron-regulated transporter 1 to enhance Cduptake. In contrast, Cd stress upregulates the expression of ABI5. ABI5 interacts with MYB49, prevents its binding to the promoters of downstream genes, and functions as a negative regulator to control Cd uptake and accumulation. Our present results also demonstrate a mechanism for controlling the expression of the heavy metal transporter gene BrpHMA2 under Cd stress. We propose that Cd2+ induces the expression of BrpNAC895 and BrpABI449, which might be mediated by ABA signaling. BrpNAC895 then promotes the transcription of BrpHMA2 by binding directly to its promoter . The activation of BrpHMA2 enhances Cd2+ uptake and may induce cell damage. Negative regulation of BrpHMA2 is then achieved by the upregulation of another AREB TF, BrpABI449, which interacts with BrpNAC895 and forms BrpNAC895-BrpABI449 protein complexes to inhibit the BrpHMA2 transcription activated by BrpNAC895 .

BrpABI449 could also bind to the promoter of BrpHMA2 directly to compete with BrpNAC895 in binding to the BrpHMA2 promoter. This negative regulation may play a supplementary role in the uptake and transport of Cd.Many plant species of Brassicaceae, including Arabidopsis, turnip, and oil seed rape, can be genetically modified, but the creation of transgenic B. parachinensis remains difficult. Therefore, we over expressed BrpHMA2 in Arabidopsis to investigate the function of BrpHMA2 and established a transient transformation system in B. parachinensis protoplasts to perform gene regulatory network analysis. Protoplasts have been widely used for sub-cellular protein localization and gene regulation analyses. In this study,procona florida container the transient transformation of B. parachinensis protoplasts was demonstrated to be a powerful system for ChIP–qPCR analysis. Previous studies have applied a similar approach to Populus trichocarpa and Brassica napus. Although the transient transformation system of B. parachinensis protoplasts was successfully used in this study of molecular mechanisms, the system cannot be easily used for phenotype and physiological analyses. The lack of BrpNAC895 and BrpABI449 transgenic B. parachinensis is a problem that severely limits research on this plant. New techniques, such as the transient reprogramming of plant traits via the transfection of RNA based viral vectors using Agrobacterium and gene editing combined with fast-treated Agrobacterium coculture, may be useful approaches for comprehending gene function concerning physiology and for the further application of modifications of gene function to effectively control the accumulation of Cd in B. parachinensis.Abiotic stresses, especially those which affect the water relations of the plant such as low temperatures, may decrease plant growth and yield. The majority of plants will suffer damage when exposed to freezing temperatures , but plants of tropical or sub-tropical origin also suffer damage when exposed to chilling temperatures . Exposure of roots to chilling temperatures decreases root hydraulic conductance , and can result in water stress and chilling injury within a few hours of exposure . The susceptibility to water stress induced by root chilling in species of tropical and sub-tropical origin is a concern for agricultural production in Mediterranean climates such as California, where exposure to cold soils in the spring can affect seedling establishment because soil temperatures under an open canopy may be colder than air temperatures . Cultivated tomato is a classic example of a chilling-sensitive crop . It was domesticated from the wild cherry tomato, which is native to mesic, tropical environments . A related wild tomato species, S. habrochaites, grows in the Peruvian Andes at altitudes up to 3300 m and thrives in xeric habitats and at chilling temperatures detrimental to S. lycopersicum . Upon exposure to root chilling conditions, the root hydraulic conductance of both tomato species decreases, but S. habrochaites closes its stomata rapidly in response to chilling stress, thereby maintaining water potential and shoot turgor, whereas the stomata of S. lycopersicum remains open and the shoots wilt . Other agronomically important crops of tropical or sub-tropical origin such as maize and rice respond to root chilling in a manner consistent with that of cultivated tomato . An improved understanding of the underlying mechanisms of root chilling tolerance in wild S. habrochaites would contribute to a better general understanding of chilling sensitivity in crops of tropical and sub-tropical origins.A review by Venema et al. focused on physiological effects of chilling and noted that wild tomato species were promising sources of genetic tolerance to chilling.

Oyanedel et al. evaluated a back cross inbred line population derived from S. habrochaites acc. LA1777 for growth traits under chilling temperatures and reported QTL for higher biomass accumulation on chromosomes 2, 3, and 9. Elizondo and Oyanedel evaluated tomato introgression lines containing S. habrochaites acc. LA1777 introgressions on chromosomes 2 and 3 in the field under low temperatures . The ILs had higher growth rates but lower fruit set than the parental lines in response to an increase in the number of hours of chilling temperatures. To investigate the genetic basis of shoot turgor maintenance under root chilling, Truco et al. used an interspecific BC1 population derived from chilling-susceptible S. lycopersicum cv. T5 and chilling-tolerant wild S. habrochaites acc. LA1778 to map QTL for this trait. Three QTL for shoot turgor maintenance under root chilling were identified on chromosomes 5, 6, and 9. The largest effect QTL located on chromosome 9 accounted for 33 % of the trait phenotypic variance . We designated this QTL stm9 for shoot turgor maintenance, chromosome 9. Subsequently, QTL stm9 was fine-mapped to a 2.7-cM region on the short arm of chromosome 9 between markers T1670 and T1673 . Easlon et al. determined that tomato ILs containing the short arm of chromosome 9 from chilling-tolerant S. lycopersicoides and S. habrochaites maintained shoot turgor under root chilling. Here we high-resolution mapped QTL stm9 using recombinant sub-near-isogenic lines and compared high resolution mapped QTL stm9 to the S. lycopersicum reference genome for initial identification of potential candidate genes and regulatory sequences . Our longer term goal is to identify and functionally test candidate genes and regulatory sequences from S. habrochaites and determine the causal gene or polymorphisms for QTL stm9.A population of near-isogenic lines containing the chromosome 9 region from S. habrochaites acc. LA1778 in an otherwise completely S. lycopersicum cv. T5 background was marker-selected and used for fine-mapping, as described in Goodstal et al. . For high-resolution mapping of stm9, we created and marker selected recombinant sub-near-isogenic lines as follows.

Reliance on biotechnology can increase the risk of forward biological contamination

Trace elements and small-usage compounds can be transported from Earth, or in some cases extracted from the Martian regolith. In the case where power is provided from photocollection or photovoltaics, light energy will vary with location and season, and may be critical to power our bioreactors. Although photosynthetic organisms are attractive for FPS, a higher demand for carbon-rich feedstocks and other chemicals necessitates a more rapid and efficient CO2 fixation strategy. Physicochemical conversion is inefficient due to high temperature and pressure requirements. Microbial electrosynthesis , whereby reducing power is passed from abiotic electrodes to microbes to power CO2 reduction, can offer rapid and efficient CO2 fixation at ambient temperature and pressure . MES can produce a variety of chemicals including acetate , isobutanol , PHB , and sucrose , and therefore represents a filexible and highly promising ISRU platform technology . Biological N2-fixation offers power- and resource-efficient ammonium production. Although photoautotrophic N2 fixation with, for example, purple non-sulfur bacteria, is possible, slow growth rates due to the high energetic demand of nitrogenase limit throughput . Therefore, heterotrophic production with similar bacteria using acetate or sucrose as a feed stock sourced from electromicrobial CO2-fixation represents the most promising production scheme, and additionally benefits from a high degree of process redundancy with heterotrophic bioplastic production. Regolith provides a significant inventory for trace elements and, when mixed with the substantial cellulosic biomass waste from FPS processes, can facilitate recycling organic matter into fertilizer to support crop growth. However, regolith use is hampered by widespread perchlorate , indicating that decontamination is necessary prior to enrichment or use. Dechlorination can be achieved via biological perchlorate reduction using one of many dissimilatory perchlorate reducing organisms . Efforts to reduce perchlorate biologically have been explored independently and in combination with a more wholistic biological platform . Such efforts to integrate synthetic biology into human exploration missions suggest that a number of approaches should be considered within a surface bio-manufactory.

A biomanufactory must be able to produce and utilize feed stocks along three axes as depicted in Figure 5: CO2-fixation to supply a carbon and energy source for downstream heterotrophic organisms or to generate commodity chemicals directly, N2-fixation to provide ammonium and nitrate for plants and non-diazotrophic microbes,macetas para viveros and regolith decontamination and enrichment for soil-based agriculture and trace nutrient provision. ISRU inputs are sub-module and organism dependent, with all sub-modules requiring water and power. For the carbon fixation sub-module , CO2 is supplied as the carbon source, and electrons are supplied as H2 or directly via a cathode. Our proposed bio-catalysts are the lithoautotrophic Cupriavidus necator for longer-chain carbon production [e.g., sucrose ] and the acetogen Sporomusa ovata for acetate production. C. necator is a promising chassis for metabolic engineering and scale-up , with S. ovata having one of the highest current consumptions for acetogens characterized to date . The fixed-carbon outputs of this sub-module are then used as inputs for the other ISRU sub-modules in addition to the ISM module . The inputs to the nitrogen fixation sub-module include fixed carbon feed stocks, N2, and light. The diazotrophic purple-non sulfur bacterium Rhodopseudomonas palustris is the proposed bio-catalyst, as this bacterium is capable of anaerobic, light-driven N2 fixation utilizing acetate as the carbon source, and has a robust genetic system allowing for rapid manipulation . The output product is fixed nitrogen inthe form of ammonium, which is used as a feed stock for the carbon-fixation sub-module of ISRU along with the FPS and ISM modules. The inputs for the regolith enrichment sub-module include regolith, fixed carbon feedstocks, and N2. Azospira suillum is a possible bio-catalyst of choice due to its dual use in perchlorate reduction and nitrogen fixation . Regolith enrichment outputs include soil for the FPS module , H2 that can be fed back into the carbon fixation sub-module and the ISM module, chlorine gas from perchlorate reduction, and waste products. Replicate ISRU bioreactors operating continuously in parallel with back-up operations lines can ensure a constant supply of the chemical feed stocks, commodity chemicals, and biomass for downstream processing in ISM and FPS operations. Integration of ISRU technologies with other biomanufactory elements, especially anaerobic digestion reactors, may enable complete recyclability of raw materials, minimizing resource consumption and impact on the Martian environment .

Waste stream processing to recycle essential elements will reduce material requirements in the biomanufactory. Typical feed stocks include inedible crop mass, human excreta, and other mission wastes. Space mission waste management traditionally focuses on water recovery and efficient waste storage through warm air drying and lyophilization . Mission trash can be incinerated to produce CO2, CO, and H2O . Pyrolysis, another abiotic technique, yields CO and H2 alongside CH4 . The Sabatier process converts CO2 and CO to CH4 by reacting with H2. An alternate thermal degradation reactor , operating under varying conditions that promote pyrolysis, gasification, or incineration, yields various liquid and gaseous products. The fact remains however, that abiotic carbon recycling is inefficient with respect to desired product CH4, and is highly energy-intensive. Microbes that recover resources from mission wastes are a viable option to facilitate loop closure. Aerobic composting produces CO2 and a nutrient-rich extract for plant and microbial growth . However, this process requires O2, which will likely be a limited resource. Hence, anaerobic digestion, a multi-step microbial process that can produce a suite of endproducts at lower temperature than abiotic techniques , is the most promising approach for a Mars biomanufactory to recycle streams for the ISM and FPS processes. Digestion products CH4 and volatile fatty acids can be substrates for polymer-producing microbes . Digestate, with nutrients of N, P, and K, can be ideal for plant and microbial growth , as shown in Figure 6. Additionally, a CH4 and CO2 mixture serves as a biogas energy source, and byproduct H2 is also an energy source . Because additional infrastructure and utilities are necessary for waste processing, the extent of loop closure that is obtainable from a treatment route must be analyzed to balance yield with its infrastructure and logistic costs. Anaerobic digestion performance is a function of the composition and pretreatment of input waste streams , as well as reaction strategies like batch or continuous, number of stages, and operation conditions such as organic loading rate, solids retention time, operating temperature, pH, toxic levels of inhibitors and trace metal requirements . Many of these process parameters exhibit trade-offs between product yield and necessary resources. For example, a higher waste loading reduces water demand, albeit at the cost of process efficiency. There is also a potential for multiple co-benefits of anaerobic digestion within the biomanufactory. Anaerobic biodegradation of nitrogen-rich protein feed stocks, for example, releases free NH3 by ammonification. While NH3 is toxic to anaerobic digestion and must thus be managed , it reacts with carbonic acid to produce bicarbonate buffer and ammonium, decreasing CO2 levels in the biogas and buffering against low pH.

The resulting digestate ammonium can serve as a fertilizer for crops and nutrient for microbial cultures.FPS and ISM waste as well as human waste are inputs for an anaerobic digester, with output recycled products supplementing the ISRU unit. Depending on the configuration of the waste streams from the biomanufactory and other mission elements, the operating conditions of the process can be varied to alter the efficiency and output profile. Open problems include the design and optimization of waste processing configurations and operations, and the identification of optimal end-product distributions based on a loop closure metric against mission production profiles, mission horizon, biomanufacturing feedstock needs, and the possible use of leftover products by other mission elements beyond the bio-manufactory. A comparison with abiotic waste treatment strategies is also needed, checking power demand, risk, autonomy, and modularity benefits.Biomanufactory development must be done in concert with planned NASA missions that can provide critical opportunities to test subsystems and models necessary to evaluate efficacy and technology readiness levels . Figure 7 is our attempt to place critical elements of a biomanufactory road map into this context. We label critical mission stages using Reference Mission Architecture -S and RMA-L,macetas por mayor which refer to Mars surface missions with short and long durations, respectively.Beyond contamination, there are ethical issues that concern both the act of colonizing a new land and justifying the cost and benefits of a mission given needs of the many here on earth. Our road map begins with the call for an extensive and ongoing discussion of ethics . Planetary protection policies can provide answers or frameworks to address extant ethical questions surrounding deep-space exploration, especially on Mars . Critically, scientists and engineers developing these technologies cannot be separate or immune to such policy development.We have outlined the design and future deployment of a biomanufactory to support human surface operations during a 500 days manned Mars mission. We extended previous stand-alone biological elements with space use potential into an integrated biomanufacturing system by bringing together the important systems of ISRU, synthesis, and recycling, to yield food, pharmaceuticals, and bio-materials. We also provided an envelope of future design, testing, and biomanufactory element deployment in a road map that spans Earth-based system development, testing on the ISS, integration with lunar missions, and initial construction during shorter-term initial human forays on Mars. The innovations necessary to meet the challenges of low-cost, energy and mass efficient, closed-loop, and regenerable bio-manufacturing for space will undoubtedly yield important contributions to forwarding sustainable bio-manufacturing on Earth. We anticipate that the path towards instantiating a biomanufactory will be replete with science, engineering, and ethical challenges. But that is the excitement—part-and-parcel—of the journey to Mars.Rose production is currently the largest component of California’s $300 million cut-flower industry. In 2001, California growers produced 66% of the U.S. rose crop, with a wholesale value of $45 million . The key pests of cut roses are two spotted spider mites , western flower thrips and rose powdery mildew . The two spotted spider mite is a foliage feeder that extracts the cell contents from leaves. This feeding causes foliar stippling and can disrupt the plant’s photosynthetic and water balance mechanisms . The western flower thrips is both a foliage and flower feeder, although it feeds primarily on flowers in the cut-rose system . Powdery mildew is probably the most widespread and best-known disease of roses. The fungus produces a white, powdery-appearing growth of mycelium and conidia on leaves, which can cause distortion, discoloration and premature senescence. Although it causes some disruption of photosynthesis and transpiration control, the key impact of powdery mildew is reduced aesthetic value caused by the white, powdery spots and leaf distortion. Fresh cut roses are often harvested twice daily, so revised reentry intervals imposed by the U.S. Environmental Protection Agency after pesticide application limit the number of pesticides that are useful in this production system . In addition, the typical number of pesticide sprays applied to roses grown for cut flowers has impeded the implementation of integrated pest management procedures, particularly the use of biological controls. The IPM approach to pest management incorporates all cost-effective control tactics appropriate for the crop, including biological, cultural and chemical controls. Pesticides that target hard-to-kill floriculture pests frequently kill natural enemies as well, which favors continued reliance on conventional pesticides while discouraging the adoption of biological control. Heavy pesticide use against key pests in the greenhouse has resulted in the widespread development of pesticide resistance in western flower thrips , mites , white flies , aphids and leaf miners . The heavy use of pesticides in cut roses is also a worker safety concern in global and local production. California rose growers reached a crisis point about 8 years ago, when pesticide resistance, costs and limited pesticide availability threatened the growers’ ability to effectively manage two spotted spider mites. At the same time, a new cut-rose production system that favors the success of IPM was gaining widespread acceptance. Roses were traditionally grown in soil with a hedgerow training system, where flowers are cut in a manner that gradually creates a 7-foot or taller hedge. The hedges are pruned back annually to about a 3-foot height and the process is begun again.

The far side is occupied by community and government facilities

Most of the search results involved tourist agencies in Nanjing and Shanghai who were advertising the theme park by means of a detailed tourist itinerary. Second, I found a limited number of advertisements for the sale of resettlement houses in the Jinhu New Village. Third, I found accounts from urbanites who had traveled to Jinhu and were commenting on their experiences at the theme park. Most of them seem to have enjoyed themselves and left only very short comments. Last but not least, I encountered one informed and detailed online report by a local resident—entitled “Jinhu New Countryside is a Gambling Game and a Fraud”. Although I have used the internet as an extra source to understand what is going on at the Jinhu site, it is worth noting that the internet has also served as an important arena used by actors involved with Jinhu to gain legitimacy, to voice complaints, to vent anger, and to advertise for economic profit. Jinhu New Village is located in southern Anhui Province about 30 kilometers south of Wuhu City. Altogether it occupies an area of 189 hectares , on a stretch of land running along the east side of the national road G205. G205 is a two-lane paved road built before China’s highway construction boom of the last ten years. The site is situated on a broad plain traversed by numerous canals and lakes. These lakes are the reason why this area would also be chosen as the site for a theme park. Given the relatively high average temperatures and annual precipitation, two harvests are possible each year . The rich agricultural fields in the Jinhu new countryside construction zone once supported twelve traditional villages . Residents of these villages have now all been relocated to Jinhu New Village on the southwest corner of the development zone. Both the Jinhu New Village and the associated theme park are separated from the national G205 road by a stretch of landscaping composed of a long canal, green lawns, and willow trees. As with many New Countryside projects now under construction in China—projects often readily visible to drivers rushing along the gleaming new freeways crisscrossing the country—the Jinhu site is a veritable monument to a particular notion of rural modernization and development.

When driving north along the national highway,maceta 5 litros one encounters first a large billboard explaining that one is approaching China’s “first low-carbon national tourist site.” Behind the billboard, one sees the new houses arranged in a perfect grid, quite distinct from the more haphazard arrangement of farmhouses and fields in the traditional villages . Less than a kilometer beyond the New Village, one reaches the entrance to Jinhu Rural World theme park, situated on the east side of the highway. Here two large billboards announce: “National AAAA tourist site—National modern technology agricultural experimental site—National agricultural tourist demonstration site—Welcome to Jinhu experimental site!” According to the master plan—which appears on one of the billboards— the rural world theme park will eventually have 41 attractions. However, as of June 2012, only 16 projects were finished and open to tourists. Below I analyze the built environment of Jinhu New Village and Jinhu Rural World theme park, paying particular attention to how rural space is undergoing transformation and to how the “New Countryside” contrasts with the old countryside and traditional rural society.One’s first impression of Jinhu New Village is of a modern suburb imported from somewhere in the United States. It is a large housing complex, with houses that are remarkably uniform in structure and physical appearance laid out on a grid consisting of alleyways running either perpendicular or parallel to the national highway. The residences nearest to the highway are two- or three-story townhouses; further from the highway are several rows of new apartment buildings. The aesthetics of the new residences stand in stark contrast to the vernacular architectural style of the old red brick peasant houses, a few of which still stood undemolished just southeast of the New Village. This aesthetic of the New Village is a curious mimicry of American “streetcar” and “sitcom” suburbs, those suburbs that Dolores Hayden describes as refilecting the American “idealized life in single-family houses with generous yards”. More specifically, the dwellings in the New Village, with their white stucco walls, their grey-tile roofs, and their uniformity of appearance, resemble in remarkable ways tract housing in American suburbia—such as in the Los Angeles Basin . As in any American suburb, each house also has a garage, with additional parking available in clearly marked parking spaces along the alleyways. Many aspects of this new Chinese suburbia seem out of place in the Chinese context.

Grass lawns may have particular symbolic significance in American urban and suburban environments , but from a Chinese peasant’s perspective, grass is a weed that infects one’s fields, the last thing one would think of deliberately planting beside one’s home. The garages and parking lots are also curiosities given that very few peasant households in Jinhu own a car. Many peasants currently use their garages to store their agricultural tools. The New Village does not merely emulate American suburbia; it also contains elements of a China-specific vision of the urban modern, as represented by an orderly but dense arrangement of tall buildings. In American suburbia, the ideal consists of single detached family houses placed in a landscaping that tries to imitate the natural environment. However, in Jinhu New Village, one experiences a much greater feeling of density, highlighted by the concentration of residences, including both rows of two- to three-story stucco houses—called bieshu in Chinese—and blocks of six- to seven-story apartment buildings. The term bieshu ordinarily refers to detached houses. At Jinhu, however, they are not free-standing; they are much more like townhouses or row houses than detached single-family houses. One way to explain this preference for a densely built environment is to consider the perceived ecological limitations of Chinese agricultural land. The central government has in recent years expressed concern for China’s “national food security,” leading to various strategies to maximize available arable land, a point I will address later in detail. However, there is another equally plausible explanation. For the Chinese urban elites, tall buildings and uniform orderliness symbolize modern life. For example, many Chinese government officials and nouveaux riches traveling to the U.S. are quite disappointed by their experience—if the U.S. is so modern, why do the vast dense expanses of awe-inspiring skyscrapers exist only in New York City and Chicago, and not in other American cities and towns?10 The orderliness and density of Jinhu New Village, then, is a public advertisement of how fortunate the displaced peasants are to be living in a new modern environment. Besides the modern architectural styles and the orderly arrangement of buildings,cultivo de la frambuesa the modern environment of Jinhu New Village is also refilected inside the homes. Here, one finds a variety of conveniences unavailable in the old villages, including flush toilets, solar powered water heaters, running water, reliable plumbing, built-in gas stoves, garbage collection, and even high-speed internet.

Although my host Mrs. Tang had only a second grade education, she was adamant about the importance of using computers and accessing the internet, by means of which she learned a great deal chatting with other netizens. Indeed, computers and the internet seem generally to be welcome by most peasants in rural China. Other particularly appreciated modern conveniences are showers and hot water, made possible by the solar-powered water heaters installed on the roofs of the houses. I have observed these new water heaters in New Countryside housing projects . Much like the entire Jinhu development site, the space of the New Village is clearly compartmentalized with well-delineated commercial, communal, governmental, and private residential zones. The core of the New Village is organized around a T-shaped axis . Immediately after entering the New Village by the main gate, one faces a two-lane street with commercial shops on both sides . At the far end of this street is a perpendicular street that forms the top of the T. One side of this second street is also occupied by commercial space. A multi-story building houses the police station, the community administrative office , and a “petition office” that handles grievances.Beside the government building is a three-story pre-school and kindergarten, a basketball court, and an indoor market place . Further from the T-shaped axis and on all sides are the private residences. The two- or three-story townhouses stand closer to the national highway; the apartment blocks lie just beyond the community and administration buildings. Throughout the New Village, iron fences separate public spaces from private residential yards, and curbs demarcate the boundaries between pedestrian and vehicular zones of circulation. None of these various ways of compartmentalizing space—derived from Western urban models—were present in the old natural villages. Despite the orderliness and the conveniences of the modern built environment, all is not as it seems, since the new houses come with a variety of extra costs that peasants were not burdened with in their old villages.

The cost of high-speed internet access is roughly USD $25 per month, a fee that also includes unlimited local phone calls. Peasants accept this fee more readily than some of the other charges they face, as it provides a service they did not formerly enjoy. By contrast, from the peasant’s perspective, the cost of water and natural gas are more difficult to accept. In the old villages, water was freely drawn from wells; and they used gathered firewood rather than gas for cooking. Most significant of all, however, their cost of living is now much higher because food has to be purchased instead of being produced on their land, a concept utterly alien to the peasants. While staying in the village, the most common complaint I heard was that residents no longer had land for cultivating vegetables and raising domestic animals. Now they had to buy food from supermarkets. Inevitably, village residents have found ways to cut living expenditures by a variety of means. To avoid using running water, women wash vegetables and laundry in the canal built next to the main road. For drinking water, many households invest in a well, which they dig in their small backyards. Not only is well water free, peasants also consider it to be cleaner than tap water. In a similar fashion, to minimize natural gas usage, many households have purchased portable pre-made cylinder-shaped aluminum stoves. Around 5 am every morning, in order to boil water, Mrs. Tang’s father-in-law got up to start a fire in the aluminum stove, using wood collected from demolished houses. This was a common practice: with the stove set right outside the garage door, he would chat—sometimes standing and sometimes sitting on a stool—with two other neighbors who were also doing the same thing. Another way to save on cooking expense is to build an old-style firewood stove in one’s backyard. One couple running a majiang parlor out of their home did just this, despite warnings from the New Village management, who has ordered them to demolish it, on the grounds that it was ugly and damaged the orderly and neat image of the New Village. There are other ways in which, in order to save money, residents resist the management’s efforts to maintain a neat appearance. To mitigate the daily cost of food, residents in Jinhu New Village utilize all sorts of marginal land around the edge of the complex. In some cases, they have gotten rid of the lawn near their houses by spreading herbicides left over from their farming days. Another less destructive way is to dig a hole just large enough to plant pumpkins or other vegetables that grow vertically, plants that can more discretely blend into the lawn and tree landscaping. Chickens are also allowed to roam freely on and around the landscaping . All of these various survival strategies constitute continuities with common practices in the old villages; all are very much part of the peasants’ familiar habitus.But the “landless” peasants residing in the New Village have also turned to other more novel strategies to help them make ends meet. Numerous residents have converted their townhouses for commercial purposes, something they would not have done in their old villages. One common small business is a restaurant.

A representative quality control sample run was used as the reference file to align peaks

After the fusion of Tic20-proteoliposomes with a lipid bilayer, ion channel activity was observed . The total conductance under symmetrical buffer conditions , 250 mM KCl was dependent on the direction of the applied potential: 1260 pS and 1010 pS under negative and positive voltage values, respectively. The channel was mostly in the completely open state, however, individual single gating events were also frequently observed, varying in a broad range between 25 pS to 600 pS . All detected gating events were depicted in two histograms . Two conductance classes were defined both at negative and positive voltage values with thresholds of 220 pS and 180 pS, respectively . Note that gating events belonging to the smaller conductance classes occurred more frequently. The observed pore seems to be asymmetric, since higher conductance classes notably differ under positive and negative voltages. This is probably due to interactions of the permeating ions with the channel, which presumably exhibits an asymmetric potential profile along the pore. Since small and large opening events were simultaneously observed in all experiments, it is very unlikely that they belong to two different pores. The selectivity of Tic20 was investigated under asymmetric salt conditions , 250/20 mM KCl. Similarly to the conductance values, the channel is intrinsically rectifying ,supporting asymmetric channel properties. The obtained reverse potential is 37.0 ± 1.4 mV . According to the Goldman-Hodgkin-Katz approach, this corresponds to a selectivity of 6.5:1 for K+ :Cl- -ions, thus indicating cation selectivity similar to Tic110. To determine the channel’s orientation within the bilayer, two side-specific characteristics were taken into account: the highest total conductance under symmetrical buffer conditions was measured under negative voltage values, and the channel rectifies in the same direction under asymmetrical buffer conditions . Therefore, it seems that the protein is randomly inserted into the bilayer. The pore size was roughly estimated according to Hille et al.. Considering the highest conductance class , a channel length of 1-5 nm and a resistivity of 247.5 Ω cm for a solution containing 250 mM KCl,frambueso maceta taking into account that the conductivity of the electrolyte solution within the pore is ~5 times lower than in the bulk solution, the pore size was estimated to vary between 7.8-14.1 Å.

This is in good agreement with the size of protein translocation channels such as Toc75 in the outer envelope membrane and Tic110 in the IE. Thus, the size of the Tic20 pore would be sufficient for the translocation of precursor proteins through the membrane. NtTic110, as a negative control, did not show any channel activity during electrophysiological measurements, indicating that the measured channel is not the result of a possible bacterial contamination . Considering our data presented here and those published in previous studies, we can conclude that the Tic translocon consists of distinct translocation channels: On the one hand, Tic110 forms the main translocation pore and therefore facilitates import of most of the chloroplast-targeted preproteins; on the other hand, Tic20 might facilitate the translocation of a subset of proteins. This scenario would match the one found in the inner mitochondrial membrane, where specific translocases exist for defined groups of precursor proteins: the import pathway of mitochondrial carrier proteins being clearly separated from that of matrix targeted preproteins. The situation in chloroplasts does not seem as clear-cut, but an analogous separation determined by the final destination and/or intrinsic properties of translocated proteins is feasible. The severe phenotype of attic20-I mutants prompts us to hypothesize that Tic20 might be specifically required for the translocation of some essential proteins. According to cross-linking results, Tic20 is connected to Toc translocon components. Therefore, after entering the intermembrane space via the Toc complex, some preproteins might be transported through the IE via Tic20. On the contrary, Kikuchi et al.presented that Tic20 migrates on BN-PAGE at the same molecular weight as the imported precursor of the small subunit of Rubisco and that tic20-I mutants display a reduced rate of the artificial precursor protein RbcS-nt: GFP. The authors interpreted these results in a way that Tic20 might function at an intermediate step between the Toc translocon and the channel of Tic110. However, being a substantial part of the general import pathway seems unlikely due to the very low abundance of Tic20. It is feasible to speculate that such abundant proteins as pSSU, which are imported at a very high rate, may interact incidentally with nearby proteins or indifferently use all available import channels.

To clarify this question, substrate proteins and interaction partners of Tic20 should be a matter of further investigation. Additionally, a very recent study suggested AtTic20-IV as an import channel working side by side with AtTic20-I. However, detailed characterization of the protein and experimental evidence for channel activity are still missing.Plants have pre-formed and inducible structural and biochemical mechanisms to prevent or arrest pathogen ingress and colonization. These defenses include barriers such as papillae and ligno-suberized layers to fortify cell walls, and low-molecular weight inhibitory chemicals . Plants undergo transcriptional changes upon perception of microbe associated molecular patterns or effectors to induce local and systemic resistance. The oomycete MAMPs, arachidonic acid and eicosapentaenoic acid , are potent elicitors of defense. These eicosapolyenoic acids were first identified as active components in Phytophthora infestans spore and mycelial extracts capable of eliciting a hypersensitive-like response, phytoalexin accumulation, lignin deposition, and protection against subsequent infection in potato tuber discs . Further work demonstrated root treatment with AA protects tomato and pepper seedlings from root and crown rot caused by Phytophthora capsici, with associated lignification at sites of attempted infection . AA has been shown to induce resistance, elicit production of reactive oxygen species, and trigger programmed cell death in members of the Solanaceae and other families . Phaeophyta and Rhodophyta members contain numerous bioactive chemicals that can elicit defense responses in plants . The brown alga, Ascophyllum nodosum, is a rich source of polyunsaturated fatty acids, including AA and EPA, which comprise nearly 25% of its total fatty acid composition . A. nodosum and oomycetes belong to the major eukaryotic lineage, the Stramenopila, and share other biochemical features . Commercial extracts of A. nodosum, used in organic and conventional agriculture as plant bio-stimulants, may also help plants cope with biotic and abiotic stresses. A proprietary A. nodosum extract, Acadian , has been shown to provide protection against bacterial and fungal pathogens . Studies in A. thaliana showed ANE induced systemic resistance to Pseudomonas syringae pv. tomato and Sclerotinia sclerotiorum . Investigation into ANE-induced resistance in A. thaliana and tomato suggest the role of ROS production, jasmonic acid signaling, and upregulation of defense-related genes and metabolites .

As a predominant polyunsaturated fatty acid in ANE, AA may contribute to ANE’s biological activity. In a parallel study we demonstrated AA’s ability to systemically induce resistance and ANE’s capacity to locally and systemically induce resistance in tomato to different pathogens . Further, we showed that AA and ANE altered the phytohormone profile of tomato by modulating the accumulation of defense-related phytohormones . Through RNA sequencing,cultivar frambuesas this same study revealed a striking level of transcriptional overlap in the gene expression profiles of AA- or ANEroot-treated tomato across tested time points . Gene ontology functional analysis of transcriptomic data revealed AA and ANE enriched similar categories of genes with nearly perfect overlap also observed in categories of under-represented genes. Both AA and ANE treatment protected seedings from challenge with pathogens with different parasitic strategies while eliciting expression of genes involved in immunity and secondary metabolism. The shared induced resistance phenotype and extensive transcriptional overlap of AA and ANE treatments suggested similar metabolic changes may be occurring in treated plants. In the current study, untargeted metabolomic analyses were conducted to assess global effects of root treatment with AA and the AA-containing complex extract, ANE, on the metabolome of tomato plants. Fatty acid sodium salts were prepared and stored as previously described . AA stock solution was prepared by dissolving 100 mg of fatty acid salt in 1 mL of 75% ethanol. AA stock solution was subsequently stored in a glass vial at −20°C flushed with N2 to minimize oxidation. A proprietary formulation of A. nodosum extract was diluted with deionized water to a 10% working concentration, which was used to prepare treatment dilutions. All chemicals were diluted to their treatment concentrations with sterile diH2O. Hydroponically reared, 3-weekold tomato seedlings with two fully expanded true leaves were transferred to 1 L darkened treatment containers with their respective root treatment solutions. Following 24, 48, 72, and 96 hours of root treatment, tomato seedlings were removed from treatment containers, and leaves and roots were excised from shoots and flash frozen in liquid nitrogen. Each sample was the pool of roots or leaves of two seedlings with four replications per tissue, treatment, and time point. Samples were transported on dry ice and stored at −70 °C until metabolite extraction. The issue samples were ground in liquid nitrogen using a mortar and pestle and 100 mg was weighed and transferred to a 2-ml bead-beating tube containing four 2.8-mm ceramic beads. All tools and consumables were pre-chilled in liquid nitrogen. After weighing, each sample was removed from liquid nitrogen and kept at −20 °C until addition of extraction solution.One ml of extraction solution was added to each sample which was then vortexed, followed by bead-beating in a bead mill at a speed of 2.9 m/s for one 3-min cycle. After bead-beating, samples were centrifuged at 12k × g for 10 min at 4 °C . Samples were diluted 5-fold using extraction solution and filtered into LC-MS-grade HPLC vials using 0.22-μm PTFE syringe filters. HPLC vials were kept at 4 °C until LC-MS analysis. A blank was prepared by adding 1 ml extraction solution to a bead-beating tube containing beads that was processed equivalently to the samples. In addition, a quality control sample was prepared by combining 20 μl of each of the extracted samples and processed equivalently.Samples were analyzed via high performance liquid chromatography and electrospray ionization quadrupole time-of-flight mass spectrometry controlled by MassHunter software in centroid data mode. Mobile phase A was ultrapure water with 0.05 % formic acid and mobile phase B was acetonitrile with 0.05 % formic acid. Before starting the run, the column , equipped with a guard column , was conditioned for 20 minutes with 95 % mobile phase A and 5 % B. Column temperature was maintained at 40 °C.

The sample injection order was randomized, with individual samples being run consecutively in positive and negative mode. The quality control sample was injected at the beginning and end of the run, as well as after every 12 samples throughout the run to check signal and elution stability. Source parameters were as follows: drying gas temperature of 325 °C and 350 °C , drying gas flow 12 l/min, nebulizer pressure 35 psi, sheath gas temp 375 °C and 400 °C , sheath gas flow 11 l/min, capillary voltage 3500 V and 3000 V , nozzle voltage 0 V and 1500 V , fragmentor 125 V, skimmer 65 V, and octopole 750 V. Acquisition was performed over a mass range of 50 to 1700 m/z using the all-ions MS/MS technique, cycling three different collision energies at an acquisition rate of 3 spectra/s. Simultaneous infusion of a solution of purine and hexakisphosphazine using the reference nebulizer was used throughout the runs for mass calibration. Positive and negative mode raw data files from MassHunter were analysed separately in MS-DIAL before downstream analysis. Tolerances for MS1 and MS2 were set to 0.025 and 0.075 Da respectively . For peak detection, the mass slice width was set to 0.1 DA and the minimum peak height was set to 15,000 which was approximately 3 times the noise level observed in the total ion chromatogram. A linear weighted moving average method was used for peak smoothing, with a smoothing level of 3 scans and a minimum peak width of 5 scans. Deconvolution was performed with a sigma window value of 0.5 and an MS/MS abundance cutoff of 10. The adducts permitted were [M+H]+, [M+NH4]+, [M+Na] +, [M+K]+, [M+H−H2O]+, and [2M+H]+ in positive mode, and [M−H]−, [M−H2O−H]−, [M+Cl]−, [M+Na−2H]−, and [M+K−2H]− in negative mode.MS-DIAL data was cleaned in MS-CleanR in RStudio using the following parameters: minimum blank ratio of 0.8, maximum relative standard deviation of 30, minimum relative mass deffect of 50, maximum RMD of 3000, maximum mass difference of 0.05 and maximum retention time difference of 0.15.

The variability in both stomatal conductance and shoot Fe concentration was considerably large

As aphid species rely heavily on the endosymbiont Buchnera species to grow and develop, many aphid populations treated with antibiotics will not survive. However, our treatments did not affect aphid microbial communities when treated with antibiotics and other CECs, which is possibly why there were no discernable effects on the aphid population as a whole. While treatments used in our study have previously been demonstrated to have negative effects for at least two other species of insects, this work suggests that aphids are either not exposed to CECs through their host plant, or their bacterial symbionts are not sensitive to, or depleted enough, to alter their basic biology. Plants treated with antibiotics typically have lower levels of intracellular calcium due to chelation. However, in our study we did not notice any obvious signs of calcium stress , possibly due to the use of a hydroponic solution which contains more than enough metal ions to provide adequate nutrients to the plants, even with some chelating. We did notice an overall decrease in mass for plants treated with antibiotics likely due to a slowed growth rate from direct action of the antibiotics on plant growth. Overall, there were no discernible effects of CECs on the aphids’ populations and or microbes. However, there were reductions in plant growth when treated with antibiotics. This could pose a problem to growers, especially as antibiotics tend to be reapplied with each watering especially with manure from antibiotic-treated animals. These antibiotics could also hinder the growth of the plant’s rhizosphere which would add another problem for growers who rotate crops to reintroduce nitrogen into the soil . More studies will need to be performed to determine how CECs will affect root microbial communities in soil,macetas de plastico 30 litros the roots themselves in soil, and degradation of CECs in soil.Drought, rising temperatures and expanding human populations are increasing water demands. Many countries are extending potable water supplies by irrigating crops with wastewater.

Unfortunately, wastewater contains biologically active, long-lived pharmaceuticals, even after treatment. Run-off from farms and wastewater treatment plant overflows contribute high concentrations of pharmaceuticals to the environment. These pharmaceuticals then can be either directly ingested by insects or translocated through plants and then ingested by insects. I have determined the effects of CECs on four different insects, all with different feeding styles and exposure risk. Culex quinquefasciatus larvae reared in water contaminated with environmentally relevant concentrations of common CECs were affected both directly and indirectly. Acetaminophen alone and a mixture of contaminants were found to increase developmental time of larvae. Susceptibility to Bacillus thuringiensis subsp. israelensis toxin increased in larvae exposed to antibiotics, acetaminophen, or a mixture of PPCPs. Overall there were significant differences in the microbial community of C. quinquefasciatus in treated water. Within control groups, the predominant families of bacterial symbionts change with each larval instar despite consistent diets and rearing conditions, an effect that has been described in older life stages but not in larvae. This trend was also seen in hormone treatments, but not in the antibiotic or the mixture treatments. Richness and evenness were reduced in both antibiotic and mixture treatments, suggesting that antibiotics remove certain bacteria or inhibit them from increasing to proportions seen in the control treatment. Interestingly, the mixture treatments had greater richness and evenness compared to antibiotic alone treatments, possibly due to the other contaminants facilitating growth of different bacteria. Megaselia scalaris larvae reared on artificial diets spiked with contaminants of emerging concern at environmentally relevant concentrations displayed no oviposition preference for treated or untreated diets. Larvae exposed to caffeine in diets showed increased mortality, and larvae fed antibiotics and hormones showed signs of slowed development, especially in females. The normal sex ratio observed in M. scalaris from control diets was affected by exposure to caffeine and the pharmaceutical mixture treatments. There was an overall effect of treatment on the flies’ microbial communities; notably, caffeine-fed insects displayed higher microbial variability.

Trichoplusia ni larvae showed increased developmental time and mortality when reared on artificial diets containing antibiotics, hormones, or a mixture of contaminants. Mortality was also increased when T. ni were reared on tomatoes grown hydroponically with the same concentrations of antibiotics. The antibiotic-treated plants translocated ciprofloxacin through their tissues to roots, shoots, and leaves. Microbial communities of T. ni changed substantially between developmental stages and when exposed to CECs in their diets. Myzus persicae reared on bell peppers treated with CECs displayed no effects in population growth over nearly three generations and no effects on the aphids’ microbial communities. The M. persicae retained their proportionately largest family Enterobacteriaceae across all life stages and across all treatment groups. Interestingly, the greatest effect was noticed in the bell peppers themselves, which had decreased root and leaf growth in treatments containing antibiotics. Overall, our findings indicate that at environmentally relevant concentrations, CECs in reclaimed water can have biologically important effects on important insects. They also, illuminate the complexity of the effects CECs can have on insects with different feeding methods. While the research reported in this dissertation suggests that CECs in reclaimed water could have positive effects on certain pests , they could have unintended negative effects on other insects and how humans interact with them. Effects described here have substantial potential consequences for forensics and IPM strategies. The results show increased developmental time and mortality in insects would alter biological time-clocks for forensic entomology and for dosage practices for IPM . Determining whether or not these PPCPs could influence pathogen transmission in insect-plant interactions is also of concern. Because many of the insects studied here are lower trophic level organisms, the potential for bio-magnification or unexpected chemical modification as CECs move through the food webs are serious concerns. There is also the possibility of pharmaceuticals affecting the rhizosphere of plants in soil and influencing plant health, but more research is still needed to determine precise effects.Soybean is an important biotech food, vegetable, and field crop that provides oil , protein , and carbohydrate to millions of people worldwide. Furthermore, soybean is a promising sustainable source of bio-fuels in North America, South America, and Europe . Zinc deficiency has been recognized globally as a major micro-nutrient stress that lowers crop yield and productivity around the world . Zn deficient soils occur in nearly 30% of the world’s arable lands. Selection and breeding of plant genotypes for Zn efficiency , defined as the ability of plants to maintain reasonable yield under Zn deficiency, is considered a sustainable approach to increase plant production on low Zn soils .

Considerable differences in response to low Zn stress are known to exist among genotypes of bread wheat , rye, triticale , rice, tomato , and common bean . Variations in shoot or leaf based parameters together with higher internal Zn utilization can be the principal factors in differential ZE in crop plants . Preliminary studies in common bean indicated that leaf physiological parameters such as leaf area are a useful criteria for ZE screening . Currently, there is little information regarding response of stomatal conductance to low Zn stress. Many earlier studies of low Zn stress focused on economically important cereal species. Few studies have been conducted in soybean,cultivo hidroponico and fewer have tested hydroponics as a growing media. It has been shown that critical Zn deficiency level for soybean leaves was 15 µg g-1 . In a field study in Central Turkey, Zn deficient calcareous soils were shown to reduce yield and cause the development of visual symptoms on young leaves of soybean plants . Many soybean genotypes are being developed in the U.S. but little is known about their reaction to low Zn stress. Therefore, the objectives of this study were to: develop a suitable hydroponics-based method for ZE screening of soybean plants to identify more Zn efficient and less Zn efficient genotypes; and detect genotypic ZE variation in soybean using physiological parameters such as leaf area, chlorophyll contents, stomatal conductance, nutrient concentration, and plant biomass. Available Zn concentrations around 1 to 2 pM has already been shown to induce Zn deficiency in bread wheat and common beans . Accordingly, our experiments successfully induced Zn deficiency at this concentration level in hydroponics. Based on our results, it appears that hydroponics with chelate buffers is feasible for screening soybean ZE trait. The soybean genotypes tested in this study had considerable variability and physiological responses to low Zn stress in hydroponics. Total leaf area, chlorophyll content, and leaf Zn concentration levels were all high in MZE genotypes. At the same time LZE soybean genotypes had various visible symptoms which indicated unfavorable Zn levels. This is consistent with previous findings that soybean plants showed chlorosis and brown leaf patches in calcareous soils . In terms of overall assessment genotypes “Williams” and “Hampton” were the most Zn efficient and inefficient, respectively . Although chlorosis is the most prominent symptom of low Zn stress, there is limited info on the effect of Zn deficiency on chlorophyll content levels. Leaf chlorophyll content was greater for MZE genotypes such as “Williams” and “Pella86” compared with LZE genotypes. Our results suggest that increased chlorosis was the cause of reduced SPAD levels. This is in agreement with the previous findings on wheat and common beans .It is interesting to note that Fe concentrations were considerably high for some genotypes such as “Thomas” . The lack of correlation with ZE trait across the genotypes tested may indicate that stomatal conductance could not be used for early detection of Zn stress in soybean.

Significant differences between soybean genotypes in shoot Zn and N concentration were observed in low-Zn grown plants in hydroponics. Although there was no significant correlation between shoot nutrient concentration and ZE trait, LZE genotypes were characterized by slightly lower concentration of Zn, Fe, and N . This data are in agreement with previous findings showing that Zn efficient wheat varieties transported more Zn from roots to shoots than Zn inefficient varieties under Zn deficiency in the early field growth stages in bread wheat . Pharmaceuticals have been increasingly prescribed for the past 30 y, and prescription rates have almost tripled in just the past 14 y . In 2013, animals grown for human consumption were treated with 9.1 × 106 kg of antibiotics; of those, 6.6 × 106 kg were used for the purpose of increasing production . Many antibiotics and other common contaminants of emerging concern  can be excreted by both humans and animals with little change in their chemical structure . Not surprisingly, pharmaceuticals have been appearing in wastewater, surface waters, and in some cases tap water, over the past few years . Standard wastewater treatment facilities are not equipped to completely remove pharmaceuticals , resulting in these compounds being found in effluent. In addition, even higher concentrations of many pharmaceuticals are released during heavy storms in the untreated wastewater overflow, which then directly contaminate the environment . These pharmaceuticals have been found at biologically active concentrations in surface waters around the world . There is also an increasing effort to use reclaimed wastewater in drought-affected areas, such as Southern California . In agriculture/livestock operations, pharmaceuticals are found in manure that is used as fertilizer, effectively compounding the pharmaceutical concentrations . Current research shows these chemicals tend to be both pseudopersistent in soil and detrimental to soil and rhizosphere microbes . Our recent studies of the effects of pharmaceuticals on aquatic insects show that, at concentrations found in reclaimed water, these CECs can alter development of the mosquito Culex quinquefasciatus, its susceptibility to a common larvicide, and its larval microbial communities . Watts et al. showed 17α- ethinylestradiol, a common birth control agent, and Bisphenol-A, a common plasticizer, can cause deformities in the midge Chironomus riparius. However, because larval forms of aquatic insects develop directly in the contaminated water, their constant exposure is likely greater than most terrestrial insects. Interestingly, many CECs, which were not designed specifically to impact microbes, have been shown to affect microbial communities. For example, caffeine, a common mental stimulant, can alter biofilm respiration, and diphenhydramine, an antihistamine, has been shown to modify the microbial community of lake biofilms .

Eggs are laid in rafts on the water’s surface and the larvae hatch directly into the water

Chitobiase plays a role in digestion of the cuticle during a molt. Ecdysone is an insect hormone important for initiating the molting process when larvae are transitioning between instars, and is structurally similar to estrone. Bisphenol A , a xenoestrogen, has the ability to bind and express not only the estrogenbinding proteins in mammals, but also to the ecdysone-binding protein in Chironomus riparius . Exposure of the non-biting midge, C. riparius, to estrogenic compounds has been shown to cause mouth deformities, decreased fecundity, and increased developmental time if administered over multiple generations. Culex quinquefasciatusare aquatic arthropods in their larval in stars, and terrestrial as adults. From their first to fourth instar, most mosquito larvae feed on detritus and thereby recycle nutrients back into the environment . Once they reach the fourth instar, larvae cease feeding and prepare to molt into a non-feeding pupal stage. Mosquitoes, like many insects, rely on endosymbionts to grow and develop. For example, bacteria in the genus Buchnera are commonly endosymbionts of aphids and provide the aphid with essential amino acids . Similarly, bacterial symbionts in the genus Asaia have been shown to be crucial in the development of the mosquito, Anopheles stephensi . Not surprisingly, mosquitoes treated with antibiotics to eliminate bacteria took significantly longer to develop than untreated control larvae. However mosquitoes “rescued” by a subsequent introduction of the bacteria following antibiotic exposure showed no difference in development . Currently, there is little information available on the effects of PPCPs at environmentally relevant concentrations on aquatic invertebrates, on the effects of PPCPs on the holobiome of insects, or on the effects of PPCPs on efficacy of Bacillus thuringiensis subsp. israelensis ,plastic plant pot a bacterial insecticide commonly used to control larvae of mosquitoes. Joint exposure to a pollutant and a microbial larvicide can be used to detect sublethal physiological stress .

Further, since 1997, 1000s of hectares of floodwater mosquito breeding sites have been treated with Bti . Thus Bti is likely to coexist with PPCPs in aqueous environments. Therefore, we used a series of bio-assays to evaluate the effects of PPCPs on development and mortality of the mosquito, Culex quinquefasciatus, which is a lower trophic level arthropod found worldwide and native to the Southern U.S.. This species is a vector of encephalitides including West Nile Virus and the nematode, Wuchereria bancrofti, which causes filariasis in the tropics and subtropics. Thus, any potential effects would have interesting implications from both ecological and medical perspectives.Culex quinquefasciatus mosquito egg rafts were obtained from a parental colony maintained at the University of California, Riverside using the procedures described by Wirth et al.. Rafts were maintained in shallow porcelain pans containing 3 L water or water and one of the PPCP treatments. Following emergence, larvae were kept in an incubator at 28°C, approximately 70% RH, and a light: dark cycle of 16:8. Second in stars were transferred individually by disposable pipette to a bio-assay container consisting of a 29.mL plastic cup with clear plastic lid containing 15 mL of CGSW. Each mosquito larva was given 67.0 µL of diet on day 1 and 33.5 µL of diet every other day thereafter. Diet was prepared as in Sorensen et al.; briefly a 3:1 mixture of ground mouse chow: brewers yeast was rehydrated by 50 mL of CGSW for 4 g of dry mixture. Bio-assay containers were treated with stock solutions to ensure environmentally relevant concentrations of PPCPs and/or the correct concentration of Bti before larvae were transferred. Volume was checked periodically throughout the experiments with no noticeable difference. This methodology was used for all experiments.To determine the chronic LC50 of Bti for C. quinquefasciatus, mosquito larvae were treated with one of seven concentrations and an untreated control. Initially, doses of Bti were chosen by dividing a 24-h acute LC50 , determined by Mogren et al., by ten. Based on the resulting mortalities, an eight-dose concentration range was developed to determine the chronic LC50 covering the time span from second instar through adult eclosion. Second in stars were transferred from pans to bio-assay cups and given an 8-h acclimation period. If a larva died before the end of the acclimation period, it was replaced. Sixty individuals were used for each replicate, with three replicates per treatment. This replication was used throughout all experiments.

After treatment, larvae were maintained in incubators as previously described. Larvae were monitored daily until all larvae died or eclosed. The resulting chronic LC50 of Bti on C. quinquefasciatus was then used as a standard Bti concentration in all subsequent treatments with Bti and/or PPCPs and Bti.In order to determine the effect of PPCPs on growth and development of C. quinquefasciatus, larvae were reared in CGSW treated with each of the five PPCP treatments, or an untreated control. Mosquito larvae were reared and transferred to their respective bio-assay containers as stated previously. Larvae were monitored daily for growth, developmental stage, mortality, and number of days to pupation. The endosymbiont microbial community of mosquitoes reared under the various PPCP regimes was sequenced and quantified. Mosquitoes were reared in pans as described previously. Three subsets of ten mosquitoes were collected when mosquitoes reached the second, third, and fourth instar. Mosquitoes were then twice washed with 95% ethanol to remove any external microorganisms. After washing, larvae were transferred to a sterile 2 mL micro-centrifuge tube with 95% ethanol and frozen at -60 ± 3°C in an ultra cold freezer until DNA extraction. DNA was extracted using a Qiagen DNeasy® Blood and Tissue Kit following the manufacturers protocols with the following amendments. Mosquitoes were crushed by micropestles in a sterile 2 mL micro-centrifuge tube and 20 µL of Buffer ATL. After thorough pulverization, 160 µL of the Buffer ATL and the 20 µL of proteinase K was added. Nucleic acid concentration was quantified using a Nanodrop ND- 2000c Spectrophotometer . A commercial sequencing facility performed Roche 454 bacteria barcoded amplicon pyrosequencing .After PCR, all amplicons were mixed in equal concentrations and purified using Agencourt Ampure beads . Samples were sequenced with Roche 454 FLX titanium instruments and reagents following the manufacturer’s guidelines.Statistical analyses were performed in R . The chronic LC50 was calculated using logistic regression, and a logit link function. Lethal concentrations at 95% confidence intervals were calculated using the dose.p function of the MASS package. Growth and development were examined using a generalized linear model with a Poisson probability distribution. Individual treatments were examined using linear contrasts with the untreated control.

In susceptibility assays, overall significance in mortality was determined using ANOVA; individual significances were determined using a binomial generalized linear model. Bacterial community data from bTEFAP® was examined with respect to instar and treatment using “permutational MANOVA” . PERMANOVA is analogous to MANOVA but is robust to non-normality that is commonly associated with count data. Microbial community data from pyrosequencing was further examined with principal component analysis performed in the FactoMineR package.When the microbiome of third and fourth instar larvae was examined with PCA, there were 17 dimensions with an Eigenvalue greater than one. However, the first two dimensions explained 23% of the total variation . When examined across the first and second principal components , bacterial communities treated with acetaminophen and caffeine and the controls cluster together,plastic planter pot suggesting they are similar. The micro-biomes of the mosquitoes in the mixture or antibiotic only treatments are similar to each other. The hormone treated mosquitoes are distinct from all other treatment groups. There were 30 bacterial families with non-zero contributions to one of the first two principal components. Twenty of these families account for at least 96% of the PPCP-treated mosquitoes’ bacterial community and cluster in three distinct groups . Eight bacterial families each contribute greater than 0.01% to the overall bacterial community in all treatment groups . The family Enterobacteriaceae is mostly described by the first dimension and is associated with the control, acetaminophen, and caffeine treatments . Rickettsiaceae is the most abundant bacterial family in all of the treatment groups except for the hormonetreated mosquitoes, where it is second most abundant. Wolbachia pipientis accounts for >99% of this family . Microbacteriaceae is the most represented bacterial family in the treatment groups and, like Rickettsiaceae, has > 9% abundance in all treatment groups . However, the Microbacteriaceae species vary among treatments, but Rickettsiaceae bacteria are consistently represented by Wolbachia pipientis . While the eight families presented in Table 2.1 account for at least 96% of the bacterial community, the total counts are reduced by 66% in the antibiotic treatment and reduced by 33% the mixture treatments. Thus, while Wolbachia pipientis has a relatively similar number of counts in all distinct treatments, this species accounts for 86.7% of all bacteria in the antibiotic-treated and 69.1% of bacteria in the mosquitoes exposed to mixtures of PPCP.Previous studies reporting LC50 values for C. quinquefasciatus exposed to B. thuringiensis subsp. israelensishave only reported acute values . The dosedependent toxicity of Bti to C. quinquefasciatus documented in our study was used to calculate the first chronic LC50 of Bti on C. quinquefasciatus. This value of 10.20 ng/mL is much lower than previously reported acute LC50s determined in 24 h tests. For example an acute LC50 value was reported at 140.0 ng/mL by Mogren et al.. Thus, although acute assays are faster to conduct, and can be compared against previously published reports, they overestimate the amounts of Bti needed to kill 50 percent of mosquito populations that are exposed over their entire life spans. Bechmann 88 noted that in lifetable experiments some toxicants, especially pesticides, can drive a population to extinction even at concentrations well below an acute LC50. However, effective mosquito control typically requires suppression of late instar larvae even with only an acute exposure and a relatively high dose of Bti is be needed to achieve that goal. Mosquitoes treated with PPCPs at environmentally relevant concentrations displayed increased developmental time in the acetaminophen and mixture treatments. As these two treatments were not significantly different, it is possible the effects on mixture treated mosquitoes could be from acetaminophen alone.

The majority of these two treatments pupated 1-2 days after the control group. The cause of this delay is difficult to determine and may be due to individual or joint actions of many factors including an effect on the nutrients during rearing, an effect of these specific PPCPs on the mosquito physiology, or some general stress. Stress has been shown to influence insect physiology and behavior 89,90. Regardless of the cause, increased developmental time would increase larval exposure to PPCPs and potentially to predation. All mosquitoes treated with Bti exhibited an increase in developmental time of 1-2 days, including those in the acetaminophen and mixture treatments. Since Bti is a larvicide that damages the gut lumen in certain mosquitoes 91, a reduced nutrient absorption could lead to increased developmental time. Longer developmental times caused by PPCPs would increase exposure to contaminants and exposure time to Bti. Increased mortality would almost certainly occur. Larvae in the acetaminophen, antibiotic, and mixture treatments were more susceptible to Bti than the larvae exposed to Bti alone. While the increased time to exposure described above may have played a role in the increased mortality, the pyrosequencing results indicated significant changes in the bacterial community of the mosquito. If some of the affected bacterial communities, especially those eliminated, have detoxifying abilities for Bti-toxin this could also play a role. However, more research in the area is warranted. Previous studies show the inability of Anopheles mosquitoes to fend off the malaria parasite Plasmodium falciparum following treatment with the antibiotic gentamycin. Contrary to our findings, Broderick et al. showed the gypsy moth had a reduced susceptibility to Bacillus thuringiensis after treatment with antibiotics, which was removed after reintroducing the Enterobacter sp. NAB3. As the mosquitoes in our study retained their Enterobacteria, the Bti was still activated and the mosquitoes were still susceptible.In our study, larvae exposed to hormones contained substantially different bacterial communities as compared to controls, suggesting that at least some hormones likely play a role in altering bacterial communities.

We hope that future fabrication designs can benefit and improve on designs that work well

Through our assessment of lab-based chamber systems, we identify unique advantages and challenges associated with each system .Lastly, we offer our perspectives on areas in which technological advances are needed to fill current knowledge gaps.In studying rhizosphere processes, the myriad of complex interactions among members of the rhizosphere are often dissected to two interacting variables such as root-and-soil or root-and-microbes, etc. Each of these interactions inherently operates under distinct parameters and requires specifically designed platforms to effectively answer different research questions. This review is structured in a way that first describes each rhizosphere process briefly and then reports on the specific growth chamber systems designed to facilitate experiments for answering related research questions. The major rhizosphere processes discussed below include root system architecture, physicochemical gradients in the soil, exudation patterns by the roots and interactions between roots and nematodes, fungi or bacteria. Root system architecture encompasses structural features that provide spatial configuration such as root length, width, spread and number and is an important rhizosphere parameter in regulating soil porosity, and nutrient and water uptake efficiency by plants . Plants have been observed to “sense” and direct root growth toward nutrient sources in soil, and the RSA of a plant exhibits great malleability in response to environmental stimuli which in turn, influences microbial communities . For instance, bean plants grew deeper roots under drought conditions to enhance water foraging capabilities while low phosphate conditions stimulated the formation of dense lateral roots involved in P uptake from upper soil layers . Given that most soils are heterogenous,black plastic nursery pots understanding the RSA of plants becomes critical in improving resource use efficiency and agricultural yields . Often, RSA in pot-grown plants is investigated by excising the roots via mechanical means such as root washing or blowing with compressed air . These methods are, however, time-consuming, cause inevitable damage of fine root hairs and result in loss of spatial and temporal information .

An appealing alternative for studying RSA is the use of rhizotrons. Rhizotrons were initially constructed as underground facilities designed for viewing and measuring roots in the field . In the lab, the rhizotron implies a chamber constructed using two vertical sheets with at least one or both of the sheets being transparent and/or removable . This allows repeated visual inspections of individual roots; a feature unachievable with destructive sampling. In some cases, the word “rhizobox” is used for a similar set up although this was first introduced in as compartmentalized systems to separate the root and soil compartments . Rhizotrons/rhizoboxes are often constructed with PVC or acrylic materials and come in many sizes to accommodate different plants with soil or soil-less substrates . Root growth and morphology in the rhizotron can be tracked by a variety of methods ranging from manual tracing onto a plastic sheet, using handheld or flatbed scanners to fully automated time-lapse imaging camera systems . Data can be subsequently analyzed with a wide range of software packages . Affordable and robust RSA imaging platforms using rhizotrons have also been developed for increased accessibility in low-income countries . The versatile construction of a rhizotron design for RSA studies has inspired many variations. For instance, ara-rhizotrons were designed to enable the study of 3D canopy competition with simultaneous root growth observation in an Arabidopsis plant population . The horizontal and radial design of HorhizotronTM and mini-Horhizotron consisting of transparent quadrants attached to a central chamber were developed to study lateral growth of roots in a semi-3D space and to perform post-transplant assessment . The separated quadrants can also be used with different soil substrates simultaneously to study substrate effects on root growth . A rhizotron fitted with water-tight gasket seals has also been used successfully to investigate the RSA of plants under water-logged conditions . Despite the continuous real-time visual read-out, most rhizotron designs suffer from inevitable loss of information from roots occluded by soil particles. The GLO-Roots system overcomes this by imaging from both sides of the rhizotron while using bio-luminescent roots to create higher contrast against the soil, enabling quantitative studies on RSA . Following advances in engineering and device fabrication, more rhizotron variants adapted to specific plant growth conditions can be envisioned. In a typical topsoil, approximately half is composed of solid minerals and organic matter while the rest is a fluctuating composition of water and gas filled spaces influenced by environmental conditions and uptake/release of solutes from plants . Changes in gaseous and hydrologic parameters, such as ions, O2 and moisture among others, create a spatially complex environment that influences microbial communities and overall plant health.

These physicochemical fluxes are heterogeneously distributed along roots and vary with root types and zones . Often, they exist as gradients in the rhizosphere , thus emphasizing the need for non-destructive sampling in order to accurately capture processes occurring at biologically relevant times and scales. Rhizotron chambers with a visually accessible rhizosphere allows in situ and continuous mapping of these gradients in the soil through the use of different types of imaging methods. For instance, photo luminescence-based optical sensors enable in situ, repeated detection of small molecule analytes in addition to pH , O2 and NH4 . Methods like zymography to detect enzyme activity and diffusive gradients in thin film can be used to map solute concentrations in the soil down to sub-mm scales with high spatial resolution more realistically than traditional destructive approaches. For example, transport and distribution of water in the rhizosphere soil has been imaged on both 2D and 3D planes by coupling a rhizotron with neutron radiography and tomography, respectively and showed varying moisture gradients along the root system with higher water uptake at the rhizosphere compared to bulk soil. On the other hand, if the rhizotron slabs are thin enough , even simple imaging solutions based on light transmission can be set up to capture water uptake by roots in sand . Despite trade-offs in method sensitivity between these two studies, a rhizotron set up is critical in both designs and illustrates its adaptability to multiple equipment. Roots exude a substantial amount of photosynthetically fixed organic carbon into the soil consisting of a wide variety of compounds such as sugars, organic acids, and primary and secondary metabolites . Together with mucilage and border cells , root exudates provide a major source of nutrients for the rhizosphere microbiome . Root exudation is regulated under genetic control  as well as in response to environmental conditions in the soil such as nutrient limitations or increase in toxicity . Exudate patterns are also recognized as one of the strongest drivers shaping the rhizosphere microbiome . As a central player in the rhizosphere ecosystem, it is imperative to understand root exudation patterns to unravel subsequent impacts to the surrounding soil and microbial community. Improvements in analytical instrumentation have made it possible to move from targeted to untargeted explorations with mass spectrometry to create root exudate fingerprints in its entire complexity . Regardless, the impact of such techniques relies partly on our exudate sampling techniques.

Detection of exudates in real-time is difficult due to rapid bio-transformation and sorption to the soil matrix. As such, common collection methods rely on root washing in hydroponic systems to overcome complications in the soil matrix and preserve native exudation profiles. However, a comparison between a soil-based collection method and hydroponic methods showed varied responses particularly in amino acid exudation although the underlying cause was not elucidated . It is possible that the differing growth conditions between hydroponics and soil,greenhouse pot which include differences in gas concentrations, mechanical impedance and microbial spatial composition, can elicit differing root exudation responses to the same environmental stimuli. Rhizoboxes offer the advantage of localized sampling in soil using sorption media such as paper and membrane filters, compound specific ion exchange binding resin or micro-suction cups placed closed to root zones of interest to collect exudates . Moreover, in a rhizobox fitted at the bottom with a porous rootimpenetrable membrane, a root mat is allowed to be formed which is then further transferred onto a collection compartment . The collection compartment containing soil could then be cut into thin slices parallel to the membrane to represent differing distances from the rhizosphere . While this approach can be used to investigate exudate release and sorption under soil conditions, the root mat growth generalizes exudate production in terms of the whole root system and occludes spatial exudation patterns. In a hybrid set up by Oburger et al. , the rhizobox is transplanted to a second specialized rhizobox for continued vertical root growth. This specialized rhizobox consists of a nylon membrane close to the transparent side to restrict root growth into the soil except for root hairs . This creates a vertical flat root mat onto which localized exudate samples can be collected. A comparison of this novel set up to conventional collection methods showed that amino acid exudation rates were most varied among the different methods , further highlighting the need for specialized chambers. Nonetheless, successful implementation of these chambers is still limited to fast-growing plants which can form active root mats. The high density of root mats could also lead to unnatural root exudate levels and an overestimation of rhizosphere effects. In addition, care has to be given to the choice of membrane as selective sorption of certain root exudates onto the membrane may also occur . Free-living nematodes are ubiquitous in the soil. They are beneficial to the plants by playing a role in nutrient cycling and in defense against insects and microbial infections through signaling interactions with the roots . Conversely, infections by parasitic nematodes in the roots increase the plant’s susceptibility to stress and other pathogenic bacteria, fungi, and viruses creating major losses in crop productivity . With an impending rise in nematode infections due to climate change, understanding nematode behavior and interactions in the rhizosphere becomes important to develop appropriate bio-control methods to ensure long term food security .

Traditional nematode studies are performed in petri dishes with agar or culture media . However, these substrates do not accurately emulate the physical textures and heterogeneity of soil and create homogenous solute and temperature gradients which could impact nematode behavior and interactions with the roots . Indeed, nematode motility speed and dispersal decreased in substrates more closely mimicking sand . On the other hand, studying nematode behavior in the soil is a difficult endeavor as its near-transparent body and small size makes it almost indistinguishable from soil particles. Cross-sectioning and staining infected roots make it possible for nematode visualization but they are destructive and provide only static snapshots of cellular changes or nematode behavior during infections . On the other hand, microscopy rhizosphere chambers provide non-invasive detection and observation of nematode activity in the rhizosphere . The roots in these chambers grow between a glass slide and a nylon membrane . The membrane restricts movement of roots except root hairs into the soil while the transparent glass enables microscopy of the roots at high resolution . Coupled with fluorescently stained nematodes, microscopy rhizosphere chambers allowed for non-destructive in situ observations of nematode infection in its host species over the entire life of the parasite . Nonetheless, staining nematodes is an additional challenge as nematode cuticles are impermeable to stains . This can, however, be alleviated by using advanced imaging technologies which eliminates the need for staining. A recent study demonstrated live screening of nematode-root interactions in a transparent soil-like substrate through the use of label-free light sheet imaging termed Bio-speckle Selective Plane Illumination Microscopy coupled with Confocal Laser Scanning Microscopy . Using this set up, researchers were able to monitor roots for nematode activity at high resolution and suggest its possible use in rapid testing of chemical control agents against parasitic nematodes in soil-like conditions . Fungal communities in the rhizosphere are involved in the degradation of organic matter in the soil and subsequent nutrient turnover affecting plant health as well as the microbial community . Fungal biomass often reaches a third of total microbial biomass carbon and almost all terrestrial plants are able to form symbiotic associations with mycorrhizal fungi .

The resulting NOx and SO2 pollutants need to be removed and recovered for reuse by a flue gas cleanup system

We believe that ample water and nutrients, mixed with the short lived, annual lifestyle of H. incana, led these plants to produce greater above ground biomass as compared to naturalized, or wild, H. incana found at the field sites. Conversely, native E. fasciculatum specimens showed more below ground root material than that of the invasive species. This is due to the perennial habit of the native, where a taproot and established root system would be necessary for survival. Because perennials such as E. fascicultum do not respond as quickly to increased nutrient availability, the species would not develop the same amount of biomass as that of H. incana during the exposure period. Overall, we observed complex movements of tracer within the individual PLS systems which may explain why we computed substantially different N deposition rates using sub-components of the modules than we computed with the module-average approach.Since Deployment 3 had aluminum foil installed 2 weeks after the exposure had begun, some nitrogen may have been lost to algal or microbial biofilms. In a few Hoagland Controls, there were also very small weeds that were also present. The small seedlings were included in the module calculations as they utilized module nitrogen during exposure, possibly adding a small source of error to deposition rates. Additionally, the prolonged time to senescence, 130 days, might have lowered the apparent N deposition rate as the winter season is not a time in which H. incana readily grows; instead H. incana sprouts with the last spring rains and grows primarily in the summer season. Because H. incana was grown out of season, we speculate that the plants were transpiring less water and therefore assimilating less gaseous N than plants exposed during the summer deployments , and therefore growing much slower. This is confirmed by the fact that Deployment 3 took 130 days for H. incana to reach senescence,growing raspberries in container but in Deployments 1 and 2 the species took approximately 70 days to senescence. I also noted that invasive treatments seemed to have smaller above ground plant structures than in previous deployments.

The AP 15N of below ground biomass had a relatively narrow compared to that of the above ground plant material . While this might be a physiological artifact, we speculate that nitrogen settling on the above ground plant surface directly from the atmosphere may have contributed to greater isotopic dilution and variability in the above ground biomass. Since below ground plant material is not exposed to direct nitrogen deposition, the roots did not experience the same depletion of the 15N tracer. In contrast, stomatal uptake of atmospheric N, and the subsequent allocation of this N to the root system, would be the major pathway in which root tissues would become depleted of 15N. The Control treatments, lacking a plant component but containing all other ITNI parts, resembled a passive nitrogen deposition collector, because there was no plant component in which to actively uptake gaseous nitrogen or deposition. Modules with plants had higher apparent N deposition because of active absorption of atmospheric N through leaf stomates and because of the larger surface area of plant canopies relative to the sand surface in the Control modules.In all deployments, and across all treatments, ITNI modules exhibited the following pattern of depositions rates using the different computation methods: Module Average> Plant> Above ground. This finding is explained by two factors. First, the plant is more isotopically enriched than the liquid and sand components of the ITNI modules so that the portion of Equation 1.3 in parentheses was lower when computed using only the plant than when it was computed using the module average; this smaller number was then multiplied by Ns to yield a smaller apparent N deposition. Secondly, the Ns value for the plant and the above ground plant are lower than the Ns for the entire module, further decreasing the value of N deposition in Equation 1.3. Thus our hope that the PLS would reach an internal isotopic equilibrium so that selecting only plant tissue for ITNI calculation could result in accurate N deposition failed. The high levels of tracer in the plant occurred because of early exponential growth when 15N tracer was abundant in the liquid reservoir. As the Deployment continued, the plant remained isotopically enriched compared to the other components of the module. The sand and liquid reservoirs, because of their small size, experienced higher levels of isotope dilution. This leaves the plant more enriched as the exposure continues as the plant does not appear to exude the 15N-labelled material back into the liquid and sand after it has been allocated to plant tissues.

Therefore, the different computational methods of Plant and Above ground are not helpful in determining the nitrogen deposition experienced by the modules. Module Averages are the only way to compute nitrogen deposition to ITNI modules. Module Average nitrogen deposition rates were greatest in Deployment 2, compared to Deployments 1 and 3, perhaps due to improved nitrogen recovery at harvest. As a consequence of calculating nitrogen deposition rate via the module average ITNI method, the rate is dependent on nitrogen recovery as represented by Ns. As Ns decreases, the nitrogen deposition rate experienced by the module also decreases, therefore underestimating true nitrogen deposition to the module over the exposure period. Since Deployments 1 and 3 lacked a foil barrier to deter algal/microbial growth in the module during the exponential growth of the plant, they recovered less nitrogen at harvest as a result. He et al., 2010, stated that plant detrital material was neglected in their ITNI measurements. In contrast, I included plant detritus during the harvest of the plants. Though the plant detritus was not actively taking up gaseous nitrogen, it derived from the ITNI plant and still experienced dry deposition to surfaces and therefore was included in the sampling for the respective modules. Plant detritus was most likely a conundrum for He et al. as the agricultural species that they utilized had plant organs that senesced during exposure. This senescence led to the volatilization of NH3, however our modules were harvested as soon as the plants senescenced, therefore reducing this nitrogen loss. In the case of E. fasciculatum treatments, there was no plant detritus to include, further supporting our suggestion that perennials, instead of agricultural or annual species, should be used as ITNI study specimens. Extrapolation methods were introduced by Russow and Bohme 2005 in which the plant density of the module was modified to match the field density of the same species. To correct for this in our own study, Bromus rubens, Hirschfeldia incana, and Eriogonum fasciculatum were sown in the ITNI modules at field density or very close to that of field density when sown a single seedling to a single module . Therefore, only the exposed sand surface was necessary for extrapolating ITNI calculations to the hectare level. Similarly to He et al. 2010, our study also experienced lower nitrogen deposition rates for species grown outside of their traditional growing season. He et al. Contributed this finding to less active uptake of gaseous nitrogen as compared to normal growing conditions. However, they found that despite this, the ITNI method produced higher deposition rates than traditional methods and concluded that this excess nitrogen deposition was active uptake by the plant.

According to the National Atmospheric Deposition Program, total nitrogen deposition for our study area ranged from 12 kg ha-1 yr -1 to 18- >20 kg ha-1 yr -1 . When extrapolated to an entire year, the ITNI method estimated total deposition to be approximately 38 ha-1 yr-1 , also exceeding NADP’s measurements. Since our study site was not dominated by wet deposition,raspberry container size as was He et al.’s, we attributed this excess deposition to the active uptake of gaseous nitrogen by the plant and improvements upon the shortcomings in dry deposition measurements in the region . Future ITNI experiments in arid and semi-arid regions should utilize a single or a very few, representative short-lived perennial species. We make this suggestion based on the considerable variability in biomass among individual specimens in the annual invasive treatments. If a short-lived perennial was used instead of an annual, we suspect there would be less influence from early senescence and less influence from a life history that promotes quick growth. Annual life history traits can increase the chance of biomass loss due to seeding events, flowering, pollen release, etc. By working with a perennial plant, ITNI operators can still grow a plant with enough aerial biomass to actively uptake nitrogen, but the plant is less likely to senesce or seed during the exposure period. Additionally, we suggest picking one, or just a few representative species, for the ITNI measurements across regions. Interspecies differences in life history, physiology, and aerial plant parts would interfere with a direct comparison across a region. However, if a single species were utilized across all habitats in question, spatial patterns in N deposition would be easier to detect. We also suggest that ITNI modules contain the same improvements as I have noted, such as the addition of a mechanism to prevent herbivory bird visitation and covering the modules to prevent light from entering the liquid reservoir to deter algal/microbial growth in the PLS system. Life support systems are what make human travel a possibility. In long range space travels, such as the travel to Mars, life support cannot depend upon storage alone, it requires a fully regenerative system as well, i.e. waste must be reclaimed for reuse. Steam reformation, supercritical water oxidation, electrochemical oxidation, and incineration are a few of the solid waste reclamation technologies that are being developed and tested for use in space travel. Currently though, it seems that incineration might be the best choice among the previously mentioned, in providing a fully regenerative system. Through rapid conversion, incineration of the inedible parts of wastes and crops produces carbon dioxide, water, and minerals. Incineration is already the most thoroughly developed technology for use in a terrestrial environment. However, with the use of incineration in a closed environment, there is the eventual buildup of pollutants that are emitted in the process. Important things to consider when developing a flue gas clean up technology for use in long range space travels are safety, energy requirements, sustainability, and doable under a micro-gravity condition.

Due to the sensitivity and restrictions of space missions, a flue gas clean up system lacking in any of these considerations can be hazardous and could potentially compromise the missions. Technologies requiring things such as expendables or the use of catalysts are unsuitable for space missions due to the loss of valuable resources and the possibility of catalyst poisoning thus limiting the life-span of a catalyst. Also, due to the micro-gravity, it is difficult to use wet processes that handle liquids, such as spray absorbers. Consequently, even though there are numerous flue gas clean up technologies developed , taking into consideration the limitation each provides, the number of reliable and applicable systems seem to be dwindling. Commercial activated carbon, made mostly from materials such as coconut shells and coal, has been studied for the adsorption and/or reduction of NOx and SO2 . In this paper, we study the use of the activated carbon prepared from hydroponic grown wheat straw and sweet potato stem for the control of air pollutants that are a result of incineration during space travel. Both wheat straw and sweet potato stalk are inedible biomass that can be continuously produced in the space vehicle. It was found that there is actually a minuscule amount of SO2 in the flue gas from the incineration of hydroponic biomass, and that most of the sulfur from the biomass ends up as sulfate in flyash. Since SO2 should have already reacted with the alkali metal, the technique entails the carbonization of the wheat straw and sweet potato stalk, resulting in an activated carbon for the adsorption of NOx and then a reduction of the adsorbed NOx by carbon to form N2. Since most NOx in flue gas from combustion is in the form of NO, and NO2 is readily adsorbed on the activated carbon, this paper concentrates on the removal of NO.

Activities of several vital antioxidant enzymes were determined after exposure to CECs

The continued observation of the formation of N4-acetylsulfamethoxazole, an acetyl conjugate, in the environment is of considerable interest because conjugates have the potential to maintain the biological activity of the parent compound . Further, because researchers traditionally only quantify parent compounds during environmental assessments, the formation and accumulation of conjugates implies that there may be an underestimation of environmental exposure to CECs such as pharmaceuticals and further incomplete environmental risk assessment of CECs . This is of particular concern for antibiotics, because of the rise of antimicrobial resistance . The major metabolite of methyl paraben, p-hydroxybenzoic acid, was observed in all soil samples, including the non-treated controls . This was likely due to the endogenous p-hydroxybenzoic acid in sphagnum peat . However, the concentration of p-hydroxybenzoic acid was higher in the spiked earthworm treatments than in the blank controls or non-earthworms chemical controls indicating that E. fetida was also capable of taking up and metabolizing methyl paraben and excreting of p-hydroxybenzoic acid into the soil. This was consistent with previous contact tests in which 70% of the initial methyl paraben was found to be metabolized to p-hydroxybenzoic acid and phenol within 48 h in E. fetida . The transformation products o-desmethylnaproxen and nordiazepam were not detected in earthworm tissues, but o-desmethylnaproxen was quantifiable in earthworm-CEC treated soils during the 21 d incubation , indicating active uptake, metabolism, and excretion. The quantification of the major metabolites for naproxen, sulfamethoxazole and methyl paraben, o-desmethylnaproxen, N4- acetylsulfamethoxazole, and p-hydroxybenzoic acid suggested a trend in the capabilities of E. fetida to take up, metabolize and excrete then transformation products of some CECs in the soil environment. Previous studies used radiolabeling and LC-FTMS analysis to assess potential metabolism of carbamazepine,blueberry plant pot diclofenac and fluoxetine in E. fetida but were unable to verify the presence of metabolites in earthworm tissues . Results from this and other studies indicated that metabolism may be chemical-specific.

To the best of knowledge, this was the first study to identify and quantify metabolites of these CECs in E. fetida dwelling in a soil. A significant increase in the activity of glutathione-S-transferase in the treatment samples over the controls was observed starting after 3 d into the incubation , and the GST activity continued to increase until the end of the 21 d incubation . This observation suggested that increased exposure time resulted in increased oxidative stress because glutathione is considered a critical antioxidant that acts to maintain redox homeostasis and signaling in cells . Further, GST is a crucial enzyme family for the detoxification of xenobiotics during Phase II metabolism . Thus, the observed increase in GST activity may indicate that there was a formation of additional Phase II metabolites. However, the detection of these potential metabolites was not attempted due to a lack of authentic standards. High GST activity was also observed at 0 h for both the controls and treated samples. However, this increase in activity is likely due to the initial stress of the earthworm being transferred into the test media, and the effect dissipated within the first day of exposure. No significant difference in catalase activity was observed between the treatment and controls until the end of the exposure period . At the 21 d time point a significant increase was seen in the treatment samples , indicating that extended exposure to CECs likely resulted in increased production of hydrogen peroxide in earthworm tissue . However, an increase in the CAT activity was also found in the control at 0 h. The increase in CAT activity was, again, likely due to the initial stress of the earthworms being transferred to different environmental conditions and the difference dissipated within 24 h. A significant increase in superoxide dismutase was observed at 1 d and 3 d . However, no significant differences were observed between the treatment and controls after 3 d . This trend was in accordance with SOD has the first line of defense against reactive oxygen species . SOD acts to catalyze the superoxide radical into oxygen molecules or hydrogen peroxide . As an increase in CAT was observed at the later time point it was likely that SOD activity increased initially, resulting in an increased production of hydrogen peroxide, which was then detoxified by CAT. Previous studies examining the biochemical effects of CEC exposure in earthworms showed somewhat similar trends.

For example, a study exploring the biochemical and genetic toxicity of triclosan in E. fetida showed a dose-dependent hormesis effect over time for both CAT and GST activity, with increasing activity being observed after a 2 d exposure at low doses and an inhibition of enzyme activity being observed after 14 d at high doses. Further, similar studies considering oxidative stress in E. fetida exposed to herbicides showed an increase in enzyme activities at lower concentrations and a suppression of enzyme activities at high concentrations . Thus, it is likely that the lower, environmentally relevant, concentrations of CECs used in this study resulted in the observed increase in enzyme activities while these concentrations were not high enough to cause an inhibition in enzyme activity. Currently we are experiencing a series of global trends that are creating unique challenges for the future of sustainable development. These trends include shifting precipitations patterns, rising temperatures, growing human populations, and rapid urbanization. In order to meet these challenges, traditionally under-utilized resources, such as treated wastewater and bio-solids, will have to be harnessed. These resources are derived from wastewater treatment plants and contain biologically active, pseudo-persistent, trace chemicals referred to as contaminants of emerging concern . Land application of TWW and bio-solids for agriculture and landscaping has the potential to introduce CECs into terrestrial ecosystems, from where they could accumulate, be metabolized and/or cause adverse effects in terrestrial organisms. This dissertation has described the ability of terrestrial plants and invertebrates to take up and metabolize CECs and highlighted the potential for these trace contaminants to induce biochemical changes in non-target terrestrial organisms. The findings of this project, overall conclusions, and recommendations for future work are summarized below. In arid and semi-arid areas, TWW reuse is becoming increasingly prevalent for agricultural irrigation. However, irrigation with TWW has the potential to introduce CECs including antibiotics into agroecosystems. One of the most commonly prescribed and environmentally relevant antibiotics is sulfamethoxazole. However, little is known about the fate of sulfamethoxazole in terrestrial plants. In this study, sulfamethoxazole was observed to be taken up and actively metabolized by Arabidopsis thaliana cells into six transformation products. The transformation products included oxidation of the amine group, producing Phase I metabolites, which was followed by conjugations with glutathione, glucuronic acid and leucine, producing Phase II metabolites.

Phase III metabolism was assessed by determining the mass balance of 14C-sulfamethoxazole in A. thaliana cells and cucumber seedlings. Non-extractable 14C-sulfamethoxazole increased over time in both A. thaliana cells and cucumber seedlings, indicating that Phase III metabolism significantly contributed to the fate of sulfamethoxazole in A. thaliana cells and cucumbers. Further, in A. thaliana cells and cucumber seedlings, the mass balances were calculated to range from 80-120% and 80-94%, suggesting a minor role of mineralization. The results from this study highlighted the potential of terrestrial plants to transform pharmaceuticals, forming both bioactive Phase I metabolites and Phase II conjugates, and store them as in the form of bound residues as Phase III metabolism. Plant uptake of CECs from TWW reuse and bio-solid application has been documented in agroecosystems. Previous studies suggested that plants were capable of metabolizing CECs after uptake. However, these studies often reported different results even with the same CECs,plastic gardening pots likely due to the use of different plant species and/or different laboratory conditions. In this study, the metabolism of the benzodiazepine diazepam was explored in three different plant species, A. thaliana, cucumber , and radish . The plants were exposed to diazepam in laboratory under three different laboratory exposure conditions that included a 6 d cell culture, an acute /high concentration hydroponic cultivation, and a chronic /low concentration hydroponic cultivation. 14C-Diazepam was incubated concurrently with non-labeled diazepam to determine the fractions of extractable and non-extractable radioactivity to quantify Phase III metabolism. Diazepam was taken up and metabolized in all plant species under the different exposure conditions. A. thaliana cells actively transformed diazepam into temazepam and nordiazepam via Phase I metabolism. This metabolism mimicked human metabolism, as temazepam and nordiazepam are the minor and major metabolites, respectively, formed during human metabolism of diazepam. Intriguingly, both of these metabolites are bioactive and prescribed pharmaceuticals in their own right, alluding to a potential for increased risk from consumption not considered in previous studies. The fraction of non-extractable residue increased over the 6 d incubation, indicating extensive Phase III metabolism over time in A. thaliana cells. In cucumber and radish seedlings, a similar Phase I metabolism pattern was observed, with nordiazepam being the most prevalent metabolite at the end of the 7 d and 28 d cultivations. However, significant differences in phase III metabolism were observed between the radish and cucumber plants. For example, after the acute exposure, diazepam mass balance was 99.3% for cucumber seedlings but only 58.1% for radish seedlings, indicating increased mineralization in the radish system. Diazepam induced changes in the regulation of glycosyltransferase activity in both cucumber and radish seedlings, indicating the formation of Phase II metabolites. The results from this study showed that exposure conditions and plant species can influence the metabolism of diazepam, and formation of bio-active transformation intermediates and different phases of metabolism should be considered in order to achieve a comprehensive understanding of risks of CECs in agroecosystems.

Exposure of terrestrial invertebrates to CECs will likely increase with increasing TWW reuse and bio-solid application. However, currently there is limited information on the fate and effects of CECs in terrestrial organisms. In this study, the earthworm E. fetida was exposed to three pharmaceuticals, i.e., sulfamethoxazole, diazepam, and naproxen, and one preservative, i.e., methyl paraben, for 21 d in an artificial soil. Methyl paraben did not accumulate in the earthworm tissue, likely due to its rapid degradation in the soil. The other CECs showed an accumulation in earthworm tissues from the soil/soil porewater. The presence of E. fetida did not significantly affect the adsorption of these CECs to the soil. The presence of primary metabolites in the treated soil suggested that E. fetida were capable of actively metabolizing the three pharmaceuticals and excreting the metabolites. However, the metabolism was chemical-specific, and only N4- acetylsulfamethoxazole was detected in earthworm tissues. Exposure to the four CECs also resulted in the up-regulation of several antioxidant enzymes, including glutathione-S-transferase, superoxide dismutase, and catalase, and an increase in malondialdehyde, indicating oxidative stress in the exposed E. fetida. Results from this study highlighted the need to consider the role of, and effects on terrestrial invertebrates when understanding risks of CECs in agroecosystems. Our findings illuminate the complexity of the interactions between contaminants of emerging concern and terrestrial organisms. The dissertation highlights the ability of terrestrial organisms to take up and transform CECs through metabolism, which results in both bio-activation and detoxification of the target contaminants. This project also demonstrates the ability of CECs to alter the biochemistry of the studied terrestrial organisms by changing the regulation of enzymes associated with oxidative stress and metabolism. The use of cell cultivations, hydroponic studies, and artificial soil allowed us to examine the metabolism and effects of CECs in terrestrial organisms with limited confounding factors. However, it is highly likely that similar studies conducted in soils may show low rates of uptake and different patterns in metabolism. Our research suggests that scientifically sound understanding of fate of, and risks from, CECs in the environment cannot solely rely on the assessment of the parent compound and/or only consider the potential for human exposure to CECs. One must also consider the potential for the formation of metabolites and the consequences of exposure to all non-target organisms in order to better understand the fate and risks of CECs in terrestrial environments. The results have potential implications for policy makers and other stakeholders attempting to assess the risks for the land application of treated wastewater and bio-solids.

Carbamazepine has been oftenreported to be taken up by plants in both field and laboratory settings

Arabidopsis thaliana, on the other hand, produced acyl-glutamatyl-diclofenac as the major Phase II metabolite via direct conjugation . Direct conjugation of naproxen and ibuprofen with glutamic acid and glutamine was also observed in Arabidopsis thaliana plants . The metabolism of acetaminophen has also been studied in multiple plant systems, including horseradish hairy root cultures and Indian mustard . In these studies, direct glucuronisation, glucosidation, and sulfation were observed along with the formation of a reactive metabolite N-acetyl-pbenzoquinoneimine . Taken together these studies have highlighted the ability of plants to uptake and transform NSAIDs. Several classes of psychiatric pharmaceuticals have been detected in TWW and bio-solids including antidepressants, mood stabilizers, and antianxiety agents . Of these compounds, carbamazepine has been likely considered in probably the most in the agroenvironment due to its stability during wastewater treatment and in the environment . In hydroponic systems, carbamazepine has been shown to accumulate in both roots and shoots of multiple plant species, including lettuce, spinach, cucumber, and peppers . Cucumber was found to readily translocate carbamazepine when cultivated in hydroponic systems . However, a high rate of translocation was not observed in cabbage plants cultivated in hydroponic systems . In greenhouse studies, carbamazepine was reported to be taken up by cucumbers and ryegrass grown in soils irrigated with TWW and urine . In addition, Shenker et al., reported that uptake into cucumbers was negatively correlated with soil organic matter content. In fields irrigated with TWW, trace levels of carbamazepine was found to accumulate in different parts of various vegetables . Carbamazepine was also reported to transfer to humans after consumption of contaminated vegetables . The metabolism of carbamazepine in plants has also been investigated . In carrot cell cultures five phase I metabolites of carbamazepine were observed to form over 22 d . Further, 10,11-epoxycarbamazepine and 10,11-dihydroxycarbamazepine have been reported in carrots and sweet potatoes grown in fields irrigated with CEC-spiked TWW . Fluoxetine is an antidepressant prescribed for both human and animal consumption ,blackberry container resulting in fluoxetine being commonly detected in environmental samples .

In hydroponic cultivations fluoxetine was taken up by cauliflower and accumulated in the stems and leaves . In a greenhouse study exploring plant uptake of fluoxetine from soils irrigated with TWW and amended with bio-solids fluoxetine accumulated in the roots , but, it was not translocated to the leaves . In addition, fluoxetine displayed an opposite uptake pattern to that for carbamazepine, and showed a greater accumulation in plants grown in bio-solid-amended soils as opposed to soil irrigated with TWW . Benzodiazepines, are one of the most prescribed classes of pharmaceuticals . Of these, diazepam is among the most commonly detected pharmaceuticals in TWW, with concentration ranging from ng L-1 to low µg L-1 . Benzodiazepines have been shown to be taken up and accumulate in tissues of plants grown in treated hydroponic solutions or soils . In hydroponic solutions, diazepam has been observed to accumulate in both the leaves and roots of lettuce, spinach, cucumber, and pepper with BCF of 10-100 ]. Further, in a greenhouse study exploring the uptake of seven benzodiazepines , both silverbeets and radish crops took up and accumulated all seven benzodiazepines from the treated-soil . Oxazepam was found to have the highest accumulation in both plants, with concentrations up to 14.2 µg g-1 in silverbeets and 5 µg g-1 in radishes . However, the fate of these pharmaceuticals in the agro-environment is still relatively unexplored, even though their physicochemical properties indicate a high potential for uptake by plants .A multitude of antimicrobials and preservatives are used in health and grooming products, collectively known as personal care products . Personal care products have garnered increased scientific attention due to their presence in surface waters and concerns that some of these antimicrobials and preservatives may be endocrine disruptors . Of these, triclocarban and triclosan have been amongst the best studied compounds in the terrestrial environment due to their ubiquitous occurrence in bio-solids and relative stability in soils after bio-solid application . Triclocarban and triclosan have been reported to be taken up by several crop species from hydroponic solutions. For example, after exposure to an aqueous solution mixture of triclocarban and triclosan 11 different food crops, cucumber, tomato, cabbage, okra , pepper , potato , beet, onion , broccoli, celery , and asparagus , were capable of taking up both compounds. However, translocation from roots to the aerial tissue was ≤1.9% for triclocarban and ≤ 3.7% for triclosan after 1 month of exposure . Similarly, Wu et al. found triclocarban and triclosan to have a translocation factor < 0.01 in four vegetables cultivated in a hydroponic solution with two initial exposure concentrations . In a greenhouse study, triclocarban and triclosan were taken up in radish, carrot, and soybeans from bio-solid-amended soils and, the greatest concentration was observed in the carrot root after 45 d of treatment and decreased thereafter .

However, in a three-year field study in which soils were amended with bio-solids in accordance with Ontario providence agricultural practices, the concentration of triclosan and triclocarban in the plant tissues was relatively steady and low . Plants have also been shown to metabolize triclosan, forming 33 metabolites in horseradish cell cultures with the majority being phase II conjugates . Further, one transformation product of the triclosan, methyl-triclosan, has been widely detected in environmental samples and is known to have greater toxicity than the parent compound . Parabens are common preservatives used in cosmetics, and among the most commonly detected CECs in TWW and bio-solid. Parabens are of concern due to their endocrine disrupting potential . Parabens have been widely detected in surface waters and sediments . However, knowledge of their behavior, uptake, and transformation in terrestrial systems is comparatively limited. Methyl paraben was unstable in soil after application of bio-solids, with the maximum concentration of 14.1 µg kg-1 reached after 5 h and decreasing to < 1 µg kg-1 after 35 d . In a bio-solid amended field, methyl paraben was the lone paraben detected in the bio-solids but was not quantifiable in tomatoes, sweet corn, carrot and potatoes . The above studies highlight the potential for CECs to enter the terrestrial environment, accumulate in plant tissues, and undergo transformations in plants. However, the wide variations in plant uptake and translocation rates under different soil and environmental conditions are currently not well understood and warrant further investigation. Further, it must be noted that the majority of currently published studies have focused on many of the same 20 or so CECs and explored their uptake in mostly the same plant species . There are over 1500 pharmaceutical compounds, alone, currently in circulation . Further, many of the current models have been shown to overestimate the concentration of CECs in plant tissues . In addition, no models have been able to take into account plant metabolism when determining the concentration and risk of CECs in terrestrial plants. More research is needed on a wider swath of CECs with different physicochemical properties in a wider range of plants to improve risk assessment. Transformation of CECs in the environment, including through plant metabolism also needs to be further investigated to better understand their fate and risks in the terrestrial environment. Antibiotic exposure in plants has been widely studied due to previously observed phenotypic toxicity. Several studies showed decreases in root length and changes in shoot development of various plants exposed to several different classes of antibiotics including sulfamides, fluoroquinolones, and penicillins .

Most of these studies were conducted at antibiotic concentrations greater than those of environmental relevance and/or utilized artificial or hydroponic growth media. For instance, shoot and root growth of pinto beans grown in a nutrient solution spiked with two antibiotics, chlortetracycline and oxytetracycline, significantly decreased in a dose-dependent manner . Enrofloxacin,planting blueberries in a pot a fluoroquinolone, induced hormetic and toxic effects on post-germination growth in lettuce, cucumber, radish and barley plants at concentrations ranging from 0.005 to 50 mg L-1 in laboratory conditions . Seed germination has also been studied as a potential biological end-point to assess toxicity to antibiotic exposure . The exposure effects on seed germination vary considerably by plant species and exposure chemical. In filter paper tests, sweet oat , rice and cucumber seeds were negatively impacted when the seeds were exposed to aqueous solutions of increasing concentrations of six antibiotics, i.e., chlortetracycline, tetracycline, tylosin, sulfamethoxazole, sulfamethazine, and trimethoprim . The EC10 and EC50 for seed germination were, however, significantly different depending on the antibiotic and the plant species. Rice seeds exposed to sulfamethoxazole were the most sensitive with an EC10 of 0.1 mg L-1 but tylosin had an EC10 > 500 mg L.-1 On the other hand, cucumber seeds exposed to sulfamethoxazole had an EC10 > 300 mg L-1 but an EC10 of 0.17 mg L-1 for chlortetracycline . Exposure to antibiotics can also change plant nutrient and chemical compositions. For example, irrigation with water spiked with sulfamethoxazole and trimethoprim increased production in carbohydrate and soluble solid contents in tomatoes as compared to the plants irrigated with untreated water . The mechanisms driving the phytotoxicity of antibiotics have also been explored. Antibiotics can be directly toxic to or indirectly affect plants. Indirect adverse effects can arise from antibiotic exposure that detrimentally affects mycorrhizal fungi, a vital plant-microbe interaction . Direct toxicity can result when antibiotics interfere with plant hormones or chemical synthesis pathways, or damage chloroplasts, etc. For example, sulfamethoxazole was shown to directly disrupt the folate synthesis pathway in plants by blocking the action of dihydropteroate synthase . Tetracyclines was shown to interrupt mitochondrial proteostasis and damage plant chloroplasts . Interactions with plant hormones may also play a role in the observed phenotypic phytotoxicity. Erythromycin and tetracycline can promote the production of abscisic acid in plants . Abscisic acid, a stress hormone, is crucial for plant responses to drought, salinity, heavy metals, among other stressors , but antibiotic-induced production of this hormone can cause premature leaf and fruit detachment and inhibit seed germination. Plants, depending upon species, can also detoxify antibiotics through reactions with phase II metabolic enzymes . However, studies so far have shown significant variations among plant species. For example, the antibiotic chlortetracycline was detoxified by glutathione conjugation via glutathione-Stransferase in maize , but glutathione-S-transferase did not efficiently catalyze the conjugation in pinto beans . These detoxification reactions, likely produce a series of conjugated metabolites that have yet to be characterized. Understanding the extent of such conjugation is crucial for estimating the total antibiotic uptake, accumulation, and translocation of antibiotics in plants as the formation of conjugates may mask the total concentration, even though some of these conjugates may retain biological activity . Several widely used NSAIDs, such as ibuprofen, acetaminophen, and diclofenac are amongst the most studied pharmaceuticals in the environment. Studies have shown that NSAIDs can induce toxicity to plants . Phytotoxicity, however, is often plant species and NSAID specific. For example, ibuprofen has been shown to inhibited root elongation in Sorghum bicolor at high concentrations, with EC50 of 232.64 mg L-1 . However, in seed germination tests exposure to a hydroponic solution containing 1 mg L-1 ibuprofen, along with other fenamic acid class NSAIDs, increased the length of the primary root in lettuce but had no effect on radish . In the same study, diclofenac was observed to decrease the root-to-shoot ratio in radish seedlings cultivated in a sand/spiked-nutrient solution , but did not significantly affect the seed germination. However, protein content was not affected in maize cultivated in soils irrigated twice with different concentrations of acetaminophen but grain yields and seed germination were negatively impacted in a dose dependent-manner . Plants can metabolize and detoxify NSAIDs. For example, plants were found to detoxify acetaminophen by conjugation with glutathione followed by conversion to cysteine and acetylcysteine conjugates . Similarly, diclofenac was found to be converted to glucose conjugates in barley and horseradish and glutamic acid conjugates in Arabidopsis thaliana . Arabidopsis thaliana cell cultures can detoxify ibuprofen via conjugation with sugars and amino acids .As mentioned above, pharmaceuticals used to treat psychiatric disorders are another group of frequently detected pharmaceuticals in environmental samples, particularly the anticonvulsant carbamazepine .