The institutional framework advanced in Rausser and Johnson are satisfied by a constitutional smart contract . When structuring the constitutional design, any prescription must essentially define: the degree of centralization; the balance of power; identifying interest groups; the space of issues over which those interests can negotiate; the degree of consensus that is sufficient to conclude negotiations; and the appropriate course if negotiations break down .Second, smart contracts can provide legal and regulatory infrastructure that allow for the strict reinforcement of the constitution. In particular, the security or private property, enforcement of contracts, and assignment of liability for wrongful damage must be established . This is consistent with the Institutional Analysis and Development framework’s scope and payoff rules . This allows DAO partnerships to have greater transparency and “prescriptive force,” or the knowledge and acceptance of a rule leads individuals to recognize that if they break the rule, other individuals may hold them accountable .Third, DAOs, by design, admit that the collective interest of the PPRDP is able, for crucial matters, to rise above immediate self-interest of any particular participants . This is accomplished by allocating the majority of tokens to public sector agents, who have internal incentives and mechanisms to preserve the advancements of fundamental knowledge. Fourth, provisions that discourage collusive activities coupled with policies that provide opportunities to partners who have a comparative advantage are key in achieving sustainable economic growth . The transparency and accurate logging of data using block chain technology allows for these provisions to be fulfilled.

While DAOs have a systemic risk of shadow centralization, in which a cabal of rent-seeking interest groups will collude to gain majority decision-making power, a governance provision of the constitutional smart contract will provide the public sector partner, or universities,vertical grow rack system with 51% of all voting rights to order to assure the partnership will ultimately be to conduct fundamental research with positive spillovers in the space industry. One possible approach to structure the partnership is summarized here. After the PPRDP fee is paid, partners will receive “soul bound” governance tokens , or irrevocable tokens that cannot be sold or transferred to another wallet, to join the DAO. Because of its unique attributes, SBTs can accurately represent and store an entity’s credentials, history with the PPRDP , as well as implement reputation-based voting, which reduces the occurrence of Sybil attacks and can incentivize active and meaningful participation. Because SBTs can create “novel markets with decomposable, shared rights, and permissions” , control rights for IP are less susceptible to IP theft and administrative transaction costs. With these tokens, PPRDP partners have an active say into the governance structure and process. The amount of tokens unlocked will decrease over time; a company who joins the PPRDP in the first year will be allocated more tokens in comparison to a company who joins in the fourth year. The university partner would allocate its governance tokens to researchers, professors, and staff members in order to satisfy the decentralization requirement. Other than governance power, a key utility in holding SBTs is the eligibility to buy security tokens for research projects that are in progress within the PPRDP. Security tokens reflect the potential market value of research discoveries that may well lead to patents and/or commercial applications; such tokens are akin to equity shares of startup companies. During the inception phase, an initial coin offering will be conducted with a valuation that estimates what an investor would be willing to spend on an IP of a similar type. Based on the market share percentage and choice, a PPRDP partner would own either: a proportionate percentage of the patent’s income streams ; right of first refusals; exclusive licensing rights or proportionate payout from another PPRDP partner.

Ultimately, a PPRDP in which the sharing and structure for sharing any value of discoveries are determined by the PPRDP.PPRDP participants can sell security tokens with one another at market prices or sell it back to the university at a 25% discounted price should they lose faith or have high opportunity costs for other research projects. In other words, liquidity is provided for all PPRDP partners with mechanisms to prevent premature investment retractions, mitigating liquidity concerns industry partners are burdened with while hedging financial risk for public partners. In fact, PPRDP partners are incentivized to provide research personnel or in-kind services in exchange for additional security tokens and increased probability of research discoveries. No more than 51% of total security tokens offering should be sold before the maturity of IPs; the public sector would collectively maintain a majority stake in all holdings to protect the public sector interest and research agenda by prohibiting collusive action from participating private firms.Engineering resistance for agricultural improvement presently incorporates diverse strategies to mitigate the crop losses imposed by pathogens. For instance, traditional breeding has been strengthened and streamlined with the advent of new molecular markers for rapid selection of desired traits. Transgenic technology provides a complement to some of the weaknesses inherent in traditional breeding. This includes altering the expression of endogenous components from specific and broad-based pathogen resistance signaling pathways as well as utilizing genes from other species. Further analyses are providing insight into other means of inducing inherent plant defense responses through refined chemical and hormone treatments. The control of viruses and a bacterial pathogen using transgene expression in planta to initiate RNA silencing has also shown great promise.Shortly after the re-discovery of Mendel’s laws of heritability, qualitative traits were identified in wheat that conferred resistance to the rust pathogen Puccinia striiformis . Subsequently, numerous qualitative loci have been identified in diverse plant species that confer resistance .

Most of these loci do not confer broad-spectrum resistance; rather, the resistance is limited to subgroups within pathogen species. Likewise, diverse isolates of a particular pathogen species have been shown to contain loci that prevent the pathogen from successfully causing disease on the host . Flor developed a model based upon classical genetics using flax, Linum ultissimom, and the fungal pathogen Melamspora lini. His ‘gene-for-gene’ theory states that the plant resistance locus [R] and the pathogen avirulence determinant [avr] must both be present toobserve phenotypic resistance in the host . For any given plant and potential pathogen pair, an incompatible interaction is the product of these two loci. If the plant lacks the R locus or the pathogen lacks the avr determinant, then a compatible interaction is the outcome. The R gene products are hypothesized to act as receptors for the products of the avirulence locus. Thus Flor’s findings demonstrate that for many host–pathogen relationships,vertical farming companies resistance [R] and avirulence [avr] loci dictate the outcome of varying combinations of host and pathogen genotypes. R gene-mediated resistance is an economical method to control losses in the field and breeders have mobilized R genes into virtually all improved lines. Often this genetic mechanism of resistance lacks long-lasting durability in the field. In terms of Flor’s ‘gene-for-gene’ theory, the pathogen responds to selection pressure by altering or eliminating the avirulence determinant. When the pathogen eliminates the cognate avr gene product, the R gene can no longer perceive the product of the avirulence locus. Plants have responded to these dynamic genetic changes of the pathogen by generating their own clusters of diverse resistance loci . Over the past decade,vertical farming compa a number of R loci and avr loci have been cloned from diverse species of plants and pathogens.As noted above, monogenic resistance frequently is not durable in the field when exposed to high levels of pathogen pressure. One strategy to control pathogen outbreaks in the field is to cultivate plants with diverse genetic backgrounds within a single field. This agricultural practice has been shown to dramatically reduce yield losses caused by the rice fungal pathogen Magnaporthe grisea in repeated field studies . For many crops, utilization of this approach may provide a mechanism for conferring long-term, durable resistance. For some crops, planting and harvesting a field planted with diverse germplasm may not always be practical. Thus it would be useful to develop disease control strategies that would benefit farming practices that still rely on monculture. The use of gene pyramiding offers an attractive mechanism by which multiple resistance loci, each recognizing a unique range of isolates of a pathogen species, may be incorporated into a single cultivar . The combined presence of these R loci ensures that only pathogens devoid of all cognate avirulence loci perceived by the R loci combination can cause disease and. With the advent of molecular markers tightly linked to resistance loci, simultaneous selection of multiple resistance loci has been facilitated. This strategy of marker assisted selection also allows for the selection against undesirable chromosomal segments known to carry unfavorable agronomic traits as well as the successful incorporation of recessive resistance genes.

The interaction of cultivated rice, Oryza sativa, and a bacterial pathogen, Xanthomonas oryzae pv. oryzae offers a clear example of the benefits of gene pyramiding. One set of gene pyramiding experiments was performed using two completely dominant resistance genes, Xa21 and Xa4, and two recessive genes, xa5 and xa13 . Each of these resistance genes confers resistance to distinct isolates of Xoo and individually these R genes have been overcome by known field isolates . The efficacy of the disease resistance conferred by combinations of these four different resistance loci was evaluated in controlled environments as well as in field studies.These results demonstrate the utility and efficacy of gene pyramiding for generating broad-spectrum resistance to Xoo, although this finding does not suggest that combinations of four genes will lead to durable resistance per se. One caveat in gene pyramiding is that any given resistance locus may have variable penetrance. It should not be assumed that each R gene introgressed into any genetic background will display full phenotypic resistance. Therefore each set of R genes incorporated into a cultivar must be evaluated systematically requiring a significant investment of time. However, it is clear that gene pyramiding offers an attractive mechanism for combining the individual specificities of R genes as well as taking advantage of their synergistic effects to generate broad-spectrum resistance.Occasionally, the loss or mutation of an avirulence locus is associated with reduced pathogen fitness. In pepper, bacterial spot disease has been controlled effectively using the Bs2 resistance locus in breeding programs. The durability of Bs2 is due to the widespread conservation of the avrBs2 locus in diverse pathogen isolates of Xanthomonas campestris pv. vesicatoria. Mutation of avrBs2 prevents wild type levels of bacterial growth on susceptible pepper cultivars lacking Bs2 . Another example is found in rice where a functional avrXa7 avirulence locus is required for full virulence of Xoo . Isolates carrying an avrXa7 mutation can cause disease in the presence of the Xa7 R gene although greenhouse tests demonstrated that the severity of disease was reduced . Tests have further demonstrated that spontaneous mutants of avrXa7 could be recovered from Xa7 plants in the field; however these virulent isolates did not persist. Field tests over six years demonstrated that the presence of Xa7 was sufficient to prevent any Xoo epidemics even when avrXa7 mutants had appeared . In contrast, these field tests demonstrated that epidemics were common in fields planted with rice carrying the Xa10 R gene. Xoo with mutations in avrXa10 displayed no loss of fitness in controlled studies and disease in the field was common on Xa10 plants over the same 6-year analysis . These results indicate that some R genes can confer durable resistance if loss of their cognate avirulence locus confers some fitness penalty for the pathogen. Using such R/avr combinations may be a rational strategy for generating durable resistance.An alternate strategy to breeding is to directly introduce a cloned resistance gene into a plant via transgenic technology. Introduction of a gene by transgenic means can overcome the limitations of traditional breeding, namely interspecies sterility. Additionally, transgenic technologies allows multiple genes to be inserted simultaneously. However, validation of the function of the transgene and its stability and heritability after transformation requires a significant investment of time and resources. Further, the transgenic lines must also undergo subsequent analysis for agronomic traits before release.

This is particularly restrictive for horticultural crops, in which many varieties are required to meet different seasonal production requirements and diverse consumer preferences, and any single variety has a relatively small market share. For example, dozens of different types and varieties of lettuce are grown throughout the year as production shifts between summer and winter locations in California, Arizona and Florida. Some agronomic seed companies budget $50 million for the full commercialization of a new biotech crop, in addition to the standard costs for developing and marketing a traditional variety. Given the small acreage of horticultural crops and their much lower overall value, it is difficult to justify the investment in transgenic horticultural crops. For example, the total U.S. market for iceberg lettuce seed is about $27 million. A typical single variety is worth about $150,000 to $250,000 during its 5-year market lifetime, which suggests that garnering a large market share of lettuce varieties with significant added value would be necessary in order to pay for the additional costs imposed on biotech varieties.Despite this gloomy picture, regulatory strategies may be possible that would protect public and environmental safety while decreasing the cost of introducing biotech specialty crops . Plant breeding companies employing biotechnology can manage and reduce regulatory costs by carefully and deliberately determining the necessary testing requirements. Costs can be reduced by focusing development on biotech genes that have already been commercialized in agronomic crops, since expensive toxicity studies done on a new protein produced in a biotech agronomic crop can be used for the same protein produced in a biotech horticultural crop.

The USDA IR-4 program conducts and pays for the collection of efficacy and safety data on pest-control chemicals for “minor” or “specialty” crops, which include most horticultural crops . A new,vertical farm expanded “biotech IR-4” program focused on full crop registration, including EPA, USDA and FDA requirements, could benefit horticultural crops being developed in universities, government laboratories and small companies. This is particularly critical for the next generation of transgenic products, which will be more consumer-oriented and specific to horticultural crops. Because horticultural products in the pipeline are likely to have altered nutritional or quality traits, specific safety tests will be required that cannot rely on data generated for agronomic crops. Without a program like IR-4, testing requirements could preclude such products from ever being developed and reaching the market. As demonstrated by Calgene and Zeneca with their early tomato products, consumers are receptive to labeled products that have clear quality or price benefits. However, focusing entirely on consumer-oriented traits would forgo valuable benefits for crop production, such as virus resistance, which could have enormous advantages for producers that would not be readily recognized by consumers. As further experience is gained with biotech methods, regulatory requirements should be relaxed for categories of products posing little health or environmental risk. In addition, generic crop and gene approvals , rather than the current “event-specific” approach , would do much to encourage further development of such products. Around the world, farmers desire and in some cases demand the benefits that can come from the improved varieties. In India, for example, extensive precommercialization field trials of insect-resistant cotton found average yield increases of 80% along with a 68% reduction in insecticide use . Farmers saw the value of the varieties and grew 25,000 acres of insect-resistant cotton in 2001, prior to government approval .

Similarly, a significant percentage of soybeans in Brazil was grown from herbicide-resistant seeds smuggled into the country from Argentina and propagated by farmers, as Brazilian courts held up their release despite governmental approval. While planting of insect-resistant corn has not been approved in Mexico, Mexican workers returning from the United States have brought back seed corn for planting, and biotech food grain sold in Mexico has also been planted. At the 2002 Institute of Food Technologists’ annual meeting, E.C.D. Todd of Michigan State University reported that Thai farmers are smuggling and planting biotech seeds from China. While the distribution of biotech varieties outside of legal channels cannot be condoned, these examples illustrate that farmers are aware of the advantages these varieties can deliver. As research continues at many companies, universities and government laboratories, biotech horticultural products having similar attractions for growers and consumers may overcome the current financial and logistical hurdles facing their commercial development.Despite vocal opposition, agricultural biotechnology continues to advance. China has made significant strides in commercializing GE horticultural crops over the past 10 years and may well become the world’s leader during the next 10 years . China was the first country to commercialize biotech plants, beginning with field production of thousands of acres of virus-resistant tobacco in 1988, followed by virus-resistant tomatoes and sweet pepper in 1994 . In the mid-1990s, China was criticized by an American delegation for having only a provincial and not a national product-approval system. For several years afterward, it was difficult to determine whether further commercial plantings of biotech crops occurred in China . Interestingly, China established 1997 as the “official” commercialization date for biotech cotton, tomato, sweet pepper and petunia, which is when the crops were authorized by the agricultural-biotechnology safety office of the Chinese Ministry of Agriculture .

China currently claims to be second only to the United States in agricultural biotech research, development and cultivation, and China is taking full advantage of uncertainty caused by the European Union’s stance on biotech approvals. Beijing University vice president Chen stated, “I expect that in 10 years between 30% and 80% of the rice, wheat, maize, soya, cotton and oil seed crops in China will be transgenic crops. We can take advantage of this 4-year halt [E.U. moratorium] to turn China into a world power in genetically modified organisms.” China is in an excellent position to develop and create internal markets for biotech horticultural crops and clearly has the opportunity to surpass the United States in biotech crop development. Recently, China erected barriers to the importation of biotech grains, creating confusion for U.S. and world exporters, while backing away from some of its earliest commercial biotech products . It is not known whether this is due to internal concern over biotech products or fear of jeopardizing its own export markets to Europe, or is a trade barrier to allow for additional internal development of biotech products. Greater clarity will occur should this issue come before the World Trade Organization . Regulatory issues and costs are reducing commercial opportunities for new biotech crops in the United States. Of course, China will need to meet the requirements of any country receiving their exports,nft vertical farming but currently it is unclear whether any of China’s biotech products are being exported. Korea and Japan are not likely to press this as a trade issue. Other internal political issues are currently complicating commercialization efforts within China, but these are likely to be only short-term barriers . While the United States falters over biotech fruits and vegetables, China is positioning itself to be the world leader in coming years. For the American horticultural industry, the results could be devastating if the United States loses its current competitive edge and more agricultural production moves overseas.Most plants obtain the majority of their nitrogen through root absorption of NH4 + and NO3 – ions from the soil solution. Roots are thought to assimilate most of the NH4 + near the site of absorption to avoid accumulating the high amounts of free NH4 + that would dissipate the transmembrane proton gradients required for respiratory electron transport and for sequestering metabolites in the vacuole . In contrast, plants can store high concentrations of NO3 – in their tissues without toxic effect and may translocate a large portion of this NO3 – to the shoots . The chemical form of the nitrogen source, NH4 + or NO3 – , influences a myriad of plant processes including responses to CO2 enrichment , and each source elicits distinct patterns of gene expression . Nonetheless, characteristics of the root apex under exposure to physiological levels of NH4 + or NO3 – have received relatively little attention. A previously published study profiled net fluxes of NH4 + , NO3 – , and H+ along the axis of the seminal root in a maize seedling . Local influx was measured by depletion of nitrogen from the bathing solution surrounding the root. When nitrogen was supplied as NH4NO3, net influx of NH4 + was rather uniform through the root cap and root growth zone, When nitrogen was supplied as Ca2, the pattern of nitrogen influx was significantly different: net NO3 – influx increased from 1.5 nmol mm 1 h 1 in the root cap to much higher values, 5.4 and 7.6 nmol mm 1 h 1 at 3.5 and 11 mm, respectively, from the root apex.

The presence of NH4 + inhibited net NO3 – influx. This inhibition together with the observed pattern of H+ fluxes indicated that the entire maizeroot apex absorbed more exogenous NH4 + than NO3 – when both forms were present in the medium. The approach in this study is to compare endogenous ‘deposition rates’ of NH4 + and NO3 – with the values for net influx of the exogenously supplied nitrogen forms reported in the earlier study. This leads to an understanding of the source and sink relationships for nitrogen in the growing root. Deposition rates are defined to be the net rate at which a nutrient is added to or removed from the local tissue element. These rates can be calculated from data on tissue concentration and growth velocity . This kinematic approach has illuminated physiology in a number of studies of plant–environment interactions . Here, the spatial profiles of the nitrogen concentrations provide information about metabolic function. Moreover, comparison of net deposition to exogenous influx shows whether the net import or export is occurring at a particular location. Finally, this study extends the approach to show the total uptake of nitrogen into a tissue element during its expansion and displacement. In the following experiments, maize roots were exposed to a nutrient solution that contained NH4 + or NO3 – as sole N sources, both forms together, or no N source. The concentration of NH4 + or NO3 – in the solutions containing them was 0.1 eq m 3 N, a level consistent with those found in soil solutions . Net deposition rates of NH4 + and NO3 – were calculated and root contents of NH4 + and NO3 – and other solutes were measured along the root axis from the apex to 60 mm and in the xylem sap to assess the relative contributions of NH4 + and NO3 – both to the N budget and to the osmolarity in the apical 60 mm, including the 10 mm that comprised the elongation zone.Individual seedling roots were gently blotted dry before they were rapidly frozen on a thermoelectric cold-plate mounted under a dissecting microscope. Axial sections of 1-mm length were made with a fine razor at 1-mm increments from 1 to 10 mm and at 20, 40, and 60 mm from the apex along each of 10 roots. Root sections from each location were pooled. Root sections pooled from 10 roots were weighed to estimate fresh mass and then oven dried at 50  C and weighed to estimate dry mass. Root sections from another 10 roots were placed directly into the sample chamber of a Wescor 5100 Thermocouple Psychrometer to assess osmolarity. Potassium was extracted from sections from a different 10 roots with a solution of 2% acetic acid and analysed using atomic emission spectrometry . Soluble carbohydrates were extracted with boiling water and analysed via HPLC with mass selective detection . Organic acids were extracted with 80% ethanol solution, evaporated under nitrogen at 50  C, redissolved in 0.1 M H2SO4 plus 0.05% EDTA, and analysed via HPLC with UV detection at 195 and 245 nm . Lastly, sections from 10 other roots were collected in Eppendorf tubes containing 1.5 ml of 1 mol m 3 CaSO4, which was adjusted to pH 3 with H2SO4, sonicated for 30 min, and centrifuged.For each N-treatment, there were three or four replicates of sections pooled from 10 roots each for osmolarity, two replicates for potassium, two for soluble carbohydrates, one for organic acids, and at least three for NH4 + and NO3 – .

The market penetration rates used for the “worlds” and run years to be modeled will be based on the results from the expert interviews and workshops . Although these results will be used as a basis, some variation will be allowed to conduct a sensitivity analysis during the modeling effort.ATSC is the dynamic optimization of signal cycle times and phases to synchronize signals along selected arterial routes. If all the signal controllers along a route are assigned a common cycle time, users can experience a progressive green wave along the route. An ATSC system can also incorporate dynamic actuation of traffic signals to respond to changes in traffic demand. All traffic signals in the SMART Corridor study area are linked to the Los Angeles Department of Transportation ATSAC System. ATSAC is an interconnected and coordinated signal system which monitors and manages surface street traffic. Traffic is monitored by detectors and traffic surveillance cameras and various timing programs are automatically implemented in response to fluctuating traffic demands.A set of signal input files will be created to represent the alternative scenarios being modeled, as discussed in the section “Proposed Model Runs.” The UC Berkeley team did not intend to simulate ramp metering; consequently, they did not code any of the ramp meters in the Santa Monica Freeway Corridor into the link file. In addition, the INTEGRATION model has not been previously tested with regard to its ability to model ramp metering. As a result,ebb and flow ramp metering is not likely to be directly included in the scope of the modeling effort for the current research project.The ETC technology makes use of a pocket-sized tag containing a radio transponder that is placed inside a vehicle’s windshield.

The transponder transmits radio frequencies to an electronic antenna as the vehicle passes through the toll collection lane, and the appropriate fare is deducted automatically. Such systems have the capacity to move five times as many vehicles as conventional toll lanes, reducing congestion, fuel consumption, and air pollution at toll plazas. As well as saving travel time for motorists, ETC systems are viewed as very convenient . No ETC facilities currently exist along the SMART Corridor. Since the Corridor is only 11 miles long, it would only be feasible to deploy one ETC facility. Recent discussion regarding the implementation of ETC and the modeling of this technology for this project have centered around the issue of HOT lanes . It has been argued that this is the most reasonable application of ETC within the Santa Monica Freeway Corridor. It is not yet clear whether the INTEGRATION model is capable of simulating the deployment of HOT lanes. This will be determined shortly through continuing discussions with the model developers. An ETC facility can be modeled within INTEGRATION by changing the characteristics of a link or links on the network at the location of the ETC facility. Prohibitions can also be assigned to certain vehicle types for use of certain links or lanes .En-route driver information consists of real-time information about traffic conditions, incidents, construction, transit schedules, and weather conditions, which are provided to drivers once travel begins. Real-time traffic conditions can be obtained from surveillance stations or from probe vehicles that drive through the network and transmit data back to the control center. The primary travel behavior impact of such a system would be caused by drivers choosing better routes to their destination or changing their destination or both. Mode choice and trip chaining formation may also be influenced. Information can be provided via in-vehicle displays or voice messages or both, via Highway Advisory Radio , or externally via CMS. This study will attempt to model the impact of in-vehicle information and also CMS. HAR may also be contrasted to CMS.

The INTEGRATION model allows the user to define five different vehicle types in terms of the frequency of information that they receive and a measure of the error likely to be inherent in the information received. The parameters for these vehicle types are defined in the master control file, as described in an earlier section. Nodes within the network will be coded to act as information nodes that transmit traveler information to vehicle types that are coded to receive it.Route guidance systems provide simple instructions to a user to follow a suggested route in order to reach a specified destination. Such information can be provided at the start of a trip or throughout the trip or both with regular updates to an in-vehicle device. Real-time route guidance systems update directions based on real-time traffic conditions, status of transit systems, and road construction/closures. The directions consist of simple instructions for turns or other upcoming maneuvers. The effectiveness of a route guidance system is a function of the market penetration levels of in-vehicle or hand-held route guidance devices, the quality of the information provided, and the response of users to the information provided . This study will model en-route route guidance systems within the context of the scenarios that have been developed.According to Professor Hempel, approaches to environmental policy are becoming more “integrated.” This increased integration takes the form of mandating “ecosystem management” and “sustainable communities:” i.e., air, water, and land use issues are considered together rather than separately. In addition, as environmental policy is increasingly subsumed under “sustainable development,” policies protecting the “environment” may make greater efforts to balance economic, social, and environmental concerns. Balancing multiple goals is extremely complex, according to Professor Hempel, and policies must be informed by large amounts of technical information and data. New technologies, such as Geographic Information Systems and ITS, can help generate this information and data to assist policymakers in taking such an integrated approach to environmental protection.

In addition to more integrated approaches, another trend in environmental policy is the increasing use of market-based approaches, with the latest example in California being the energy deregulation scheme. Professor Hempel believes that excessive reliance on market approaches raises environmental concerns. If price is the final arbiter of what is deemed “environmentally acceptable,” policymakers must be sure that those prices reflect full social and environmental costs. Fully reflecting these costs is not always possible,however. For example, when asking “what is the price of a tree” , this price will not reflect the full value of the tree because the real value is in its “ecological inter-connection” . Nature, according to Professor Hempel, is not just a resource component and cannot always be reduced to a separable level.The Sacramento Metropolitan region is expected to grow in population and employment opportunities over the next ten years. This region is expected to absorb another 700,000 people,greenhouse benches and employment is projected to increase between 40 and 50 percent . A majority of this growth will be in Sacramento County. In fact, downtown Sacramento can expect a 38 percent increase in employment and a 37 percent growth in population . Job growth is projected to be strong in the: 1) I-80 corridor between Roseville and Rocklin, 2) I-5 corridor around North Natomas, 3) Rancho Cordova, and 4) West Sacramento. Strong residential growth is expected in Franklin/Laguna, the Vineyard Area I-5/Route 99 corridor, Roseville/Rocklin corridor, and the North Natomas . Many transportation issues arise with an increase in demographics. One issue that will affect many people is congestion. With the growth in population and employment, vehicle trips will increase by approximately one third . Daily VMT will increase from 36,212,000 miles in 1996 to 22,202,000 miles in 2005 . With the increased demand on the freeway network, it is predicted that congestion will increase four fold . Along with the increased travel due to residents living in the metropolitan area, many long distance travelers, passing through the area, will also contribute to congestion in the region . In addition, suburb to suburb travel is rising quickly. In fact, suburb to suburb trips are increasing at a faster rate than suburb to downtown trips . Many of these trips were not anticipated by transportation planners as the area’s transportation system is not designed to carry the large volume of suburb to suburb trips . As a result, many of the corridors are congested. At present, other travel mode choices are very limited, and public transit most often requires that individuals make transfers . Currently, this region supports a light rail and bus system. Many critics have Stated that there is a lack of public transit in this region. Many citizens would like to expand the light rail system and provide more express buses . The goal of increased transit is to reduce congestion and increase the mobility of those who cannot drive by making public transportation more convenient. In a survey distributed in Sacramento and Yolo counties, the respondents preferred improvements to public transit over street widening . Air pollution is directly related to vehicle emissions. Currently, the Sacramento Metropolitan Area is classified as severe non-attainment area for ozone under the federal standards . Other measurements of air quality include PM-10 and CO. In Sacramento, both of these pollutant also are classified as non-attainment .

The baseline figures for the pollutants are given in Table B-6 below. Most of the pollutants decrease over time, with the exception of NOx and PM-10. Specifically, PM- 10 increases slightly, and NOx remains constant .The experience of Bacon et al. highlighted the difficulties associated with coding and calibrating the various aspects of a transportation network. Since the focus of this current research project is on evaluating the energy and environmental impacts of various ITS deployment scenarios, and not on calibrating a network or testing simulation models, it is highly desirable to make use of an existing calibrated network. As the selected simulation model is INTEGRATION, it is also desirable to have a network already coded for this model. In this light, the choices include: 1) the Urbansville and Thruville networks ; 2) the Smart Corridor ); and 3) the TravTek Orlando network .As mentioned earlier, we have selected the I-10 smart corridor for our simulation modeling exercise in this project. The main advantages of the Smart Corridor network are that it is partly calibrated, and it is the only California-based network of these options. There are advantages to using the Urbansville and Thruville networks, not the least of which is that they are already available to the project team. However, the work by Mitretek has been somewhat conceptual in nature and has not consisted of the calibration of an actual traffic network. The Urbansville network is a representation of Detroit, Michigan and its suburbs, consequently, it cannot be correctly calibrated with real-world measured traffic flows. Is it essential to have an accurately calibrated network to simulate the relative impacts of various ITS strategies involving a range of technologies/user services? It can be argued that if the same network is used for each scenario, the degree of calibration may not be critical, but the use of a calibrated network is likely to make the results of the study more credible. In addition to the requirement for a carefully coded network for simulation efforts, there is a need for information about the specific operational characteristics of the technologies to be modeled. The literature reviews and collection of FOT data that has occurred over the last year has provided the project team with much of this necessary information. One of the useful products of this research may be the specification of data needs from FOTs in order to be able to conduct detailed assessments of environmental benefits. This was addressed as an important issue by the ‘Expert Panel’ meeting held by Apogee in Washington, DC. .Presently, streambed restorations in California are actively pursued by a number of agencies, government jurisdictions, water districts, public and private land trusts, and research scientists. In general, most of these programs are governed by legal requirements related to the Clean Water Act and are implemented under the dual jurisdiction of both state and federal agencies. Nearly all programs implemented under this regulatory framework are properly classified as horticultural restoration programs.

The effort required to simulate a network is directly proportional to the size and complexity of the network.” One of the limitations encountered with the INTEGRATION model was the inability to establish a run with the network loaded entirely with unguided vehicles. Hence, the base run for the ATIS investigations was carried out with a network loaded entirely with guided vehicles. The research by Bacon et al. also highlighted the difficulty that detailed simulation models have in determining origin-destination demand patterns. Hence, it was recommended that a travel demand model be applied to generate origin-destination matrices for future simulation exercises. These investigations revealed that for a minor incident, a 100 percent IVIS system could offset the adverse traffic effects. However the effect of the major incident was only partially offset by all vehicles in the system being guided vehicles. Bacon et al. did not comment on how the results might change if not all vehicles were guided. There is a generally accepted theory that a threshold exists for increasing benefits from the penetration of IVIS technologies. Glassco et al. State that “the value of information to the ITS user decreases as the proportion of the population receiving that information increases. The value of information to the overall system, however, generally increases as the proportion of the population receiving that information increases.” The exception to this is when a very large proportion of the population reacts to the information, in which case the system performance may decrease. Gardes and May found that more than half of the system benefits resulting from the presence of guided vehicles on a portion of the Santa Monica Freeway corridor was possible with the first five percent of guided vehicles.

An average travel time savings of 3.8 percent resulted from the presence of five percent guided vehicles,blueberry grow pot compared to 5.6 percent for 25 percent guided vehicles, and 6.2 percent for 100 percent guided vehicles. Additionally, Gardes and May found that the travel time benefits of route guidance were similar under incident and non-incident scenarios. Another interesting finding of the study by Bacon et al. study was the conclusion that the effect of “distorted” information on total trip time was almost as adverse as a major incident upon which motorists receive perfect information. Despite the difficulties encountered with applying the INTEGRATION model, Bacon et al. still considered it to be the most suitable model for such studies. Unfortunately, this same study made no attempt to assess the environmental impacts. Nevertheless, this project team intends to consider extending their work to evaluate energy and environmental impacts.Glassco et al. found that adaptive signal control strategies and traveler information services have positive impacts on user and system efficiency for both recurrent congestion and non-recurrent congestion scenarios. However, the modeling studies revealed greater benefits resulting from these ITS user services, under non-recurrent congestion conditions . One specific finding was that vehicles that bypass incidents in an inter-city corridor network due to a route guidance system can reduce travel delays by 50 percent or more. The potential benefits of the ITS user services modeled were found to be greater when the network experiences a greater deviation from expected conditions. Hence, these ITS technologies may be most beneficial for a highly variable transportation system. In a highly predictable system, traffic control systems and travelers tend to adapt their plans according to the anticipated congestion. This process can take place without the influence of ITS technologies such as traveler information services. One of the interesting key findings of the study by Glassco et al. is that “the value of traveler information is proportional to the value of the alternative opportunities available. When the time required to follow an alternate route or to shift mode is high, then the timeliness and accuracy of travel time prediction is more critical.”

This would implies that pre-trip information has greater potential for providing benefits than en-route information, as once a traveler has started a trip he is not likely to have the opportunity to change mode, and by definition the number of route choices decreases for any trip as the traveler gets closer to the destination. In addition, once the trip has begun, the choice has already been made to make the trip at that time. If information was provided prior to the trip, warning of high levels of congestion, travelers have the option of postponing or even canceling the trip. Glassco et al. concluded that perhaps one of the most positive results of their studies of ATIS user services was that a relatively small number of probe vehicles are needed to support adequate network surveillance. They found that an unguided probe population as low as one percent can provide over 50 percent of the benefit of full surveillance, and that the value of route guidance with low probe percentages can be increased by updating travel times more frequently than every ten minutes. It is more effective to use unguided vehicles as probes than guided vehicles, since if all guided vehicles are being routed around an incident, the route guidance system does not learn that congestion has dissipated when the incident is cleared. Van Aerde and Rakha present the methodology and results of a modeling study of the Orlando TravTek operational field test. This test involved the deployment of 100 vehicles equipped with in-vehicle information systems for a one-year period. The modeling study attempted to extrapolate from the available field data the expected performance of a TravTek type system for levels of market penetration ranging from one percent to 100 percent, in terms of measures of effectiveness such as vehicle stops, fuel consumption, vehicle emissions, and accident risk. The Orlando TravTek network consisted of 2,700 links and 90 origin-destination zones, with a traffic loading of approximately 65,000 vehicles. The INTEGRATION model was used to simulate recurring congestion scenarios and freeway incidents for the afternoon peak period, with a small number of simulations of increased and reduced traffic demand to represent future and off-peak conditions, respectively. Consistent with findings by Glassco et al. , travel time benefits were found to be greater for the higher levels of congestion. An interesting finding relating to the much debated issue of latent demand, was that the LMP can be increased to provide travel time savings that have the potential to offset much of the induced demand that may be generated.

Travel time reductions were found for all levels of market penetration analyzed; however, the most significant marginal benefits were achieved at lower market penetration levels. The maximum reduction in travel time was found to occur for a LMP of 100 percent, where the network travel time saving was 15 percent. In addition to travel time savings, the study considered travel distance savings and found that a 7 percent reduction was possible at an LMP of 100 percent. En-route traveler information can have two conflicting effects on travel distance: distance traveled can be reduced by route guidance information which minimizes navigational errors, and distance traveled may be increased when users receive real-time traffic information and subsequently divert around an incident. The fuel consumption benefits of the TravTek system were predicted to be proportional to the travel time savings, with respect to the various LMPs. The magnitude of potential fuel consumption benefits is related to the topology of the network. That is, if when an incident occurs there are alternative routes available with little or no increase in travel distance, the potential for energy savings is greater. This is similar for emission benefits; however, the relationship between vehicle emissions,square plastic pot and traffic conditions and distance traveled is much more complex than for fuel consumption. HC emissions were found to decrease for all LMPs, with a maximum of 16 percent being achieved at a LMP of 100 percent. CO emission increased up to three percent for LMP’s less than 10 percent, and then decreased up to seven percent for LMP’s up to 100 percent. Van Aerde and Rakha claimed that ATIS may tend to always cause an increase in NOx emissions—they predicted increases in NOx of up to five percent, with the only reduction being one percent at an LMP of 100 percent.FOTs have provided little direct evidence of emission impacts of ITS in general, but they do provide some insights to ETC and ATSC. The US DOT’s comprehensive review of data available from FOTs does not even classify emissions or other environmental impacts in their summary table. Other FOT reviews do extract some limited results specific to ETC and ATSC and other traffic flow control systems, but echo the DOT’s general conclusion that FOTs have provided limited insight into environmental impacts. Little and Wooster reported that the focus of most of the FOTs had been on “technical feasibility and, to a lesser extent, user response.” Further, they note that most of these tests address more conventional traffic management user services, such as dynamic signal coordination. ETC facilities are one of the types of ITS technologies for which FOTs have produced emission assessments. Large emission reductions can be achieved at individual electronic toll facilities; however, the overall benefit is dependent on the frequency of toll plazas. The reductions, although large, are highly localized and may be insignificant at the network level. ATSC has shown significant potential for providing energy and environmental benefits in more than one FOT. Modeling results support the FOT conclusions regarding ETC and ATSC and provide additional insight for traveler information and vehicle guidance. Results reported in US DOT show that the application of the ATMS user services provided a general increase in speed and a reduction in total delay, although they do not analyze emissions specifically. Maximum benefits were achieved with the simultaneous implementation of signal coordination on arterial streets and ramp metering on freeway facilities.

Glassco et al. found that ATSC strategies and traveler information services have positive impacts on user and system efficiency for both recurrent congestion and non-recurrent congestion scenarios. However, the modeling studies showed greater benefits resulting from these ITS user services under non-recurrent congestion conditions . Modeling results reveal mixed results for navigation and traveler information systems. Analysis of Orlando’s TravTek network indicated varying levels of travel time, travel distance, and emissions effects depending on levels of market penetration. HC emissions were found to decrease for all LMPs, with a maximum of 16 percent being achieved at a LMP of 100 percent. CO emission increased up to three percent for LMPs less than 10 percent, and then decreased up to seven percent for LMPs up to 100 percent. Van Aerde and Rakha claimed that ATIS may always tend to cause an increase in NOx emissions. They predicted increases in NOx of up to five percent, with the only reduction being one percent at an LMP of 100 percent.Many researchers are trying to estimate the market for various ITS technologies. Three methods that are popular for estimating the market for ITS technologies include: focus groups with potential market segment members, interviews, focus groups and surveys of ITS experts, and evaluations of the traveler response to ITS demonstration programs . Without actual data and experience, it becomes virtual impossible to accurately predict the market for single and multiple ITS products and services. In market and traveler behavior research, the more innovative the solution or the farther into the future an innovation will be introduced, the more researchers must rely upon survey research methods and participant responses to experimental situations to understand the types of impacts that are probable or even possible. Turrentine and Kurani conclude that an experimental situation will often elicit and engage the decision processes of its participants and reveal participant lifestyle goals.Based on their new technology experience, Turrentine and Kurani conclude that current Stated preference survey methods often produce inaccurate estimates of the demand for unknown and new technologies. Other methods such as interactive Stated response when presented in the context of a household’s actual activity space and modal split data can produce more accurate demand estimates. In market evaluations of electric vehicles , many Stated preference studies often estimate huge price penalties for limited-range vehicles . In general, these studies rely on data from hypothetical-choice experiments in which participants are presented with choice sets of the vehicle. Then, participants are asked to identify the one vehicle, from each of the choice sets, they would be willing to purchase.

Petiole NO3 – , an indicator of recent N status in conventionally-produced vegetables, was measured in the most recently-matured leaves. Petiole NO3 – changes rapidly with growth stage, so the data are graphed by post-transplanting growing degree day to account for phenological differences among fields as a result of slightly different sampling times relative to transplanting.Root RNA was extracted using Trizol reagent according to the manufacturer’s guidelines followed by DNase digestion using RQ1 RNase-free DNase . Total RNA was purified using the RNeasy Plant Mini Kit . RNA concentrations and quality were assessed using the Agilent Nanodrop and the RNA 6000 Nano Assay . Only RNA samples with RNA integrity numbers of at least 7.0 were used for subsequent analyses. These RNA were used for cDNA synthesis for qRT-PCR analysis. cDNA was synthesized from 0.5 μg DNase-treated total RNA using the Superscript III kit . Quantitative real-time RT-PCR was performed as described in previous work , using the primer pairs tested and reported therein and using a Step OnePlus Real-Time PCR system . Seven key genes involved in root N uptake and assimilation that had previously been shown to be responsive to an N pulse in an organic soil were assessed: high-affinity NH4 + transporters AMT1.1 and AMT1.2 ; high-affinity NO3 – transporter NRT2.1 ; nitrite reductase Nii ; cytosolic and plastidic glutamine synthetases GS1 and GS2 ; and NADH-dependent glutamate synthase NADHGOGAT . The tomato actin and ubiquitin genes were used as reference control genes as they did not exhibit differential expression among N treatments in previous field experiments. Relative expression was analyzed according to the ΔΔCT method with multiple reference control genes and using inter-run calibration.Means for variables in all tables, figures,strawberry gutter system and the text are expressed with 95% confidence intervals .

CIs can assist with means comparisons based on the “inference by eye” method. Roughly, 95% CIs that overlap with another mean are not different but when the overlap of intervals is no more than half of one interval arm, then the means are different at p  0.05. Intervals that barely touch are significant at p  0.01 and intervals that are separated by at least half of one interval arm are different at p  0.001. Soil NH4 + and NO3 – showed positive skewing and thus were log transformed prior to calculation of means and CIs. Back-transformed means and 95% CIs are shown for these variables. Fields were clustered based on 28 plant, soil, and microbial variables using the k-means method implemented in R. The optimal number of groups chosen was based on the Calinski-Harabasz criterion and by examining sums of squared error scree plots. F-statistics were calculated for each variable based on their cluster grouping to assess the relative magnitude of the “cluster effect”, i.e. higher F-statistics indicate more differentiation among clusters for a given variable.The 13 organically-managed Roma-type tomato fields spanned a three-fold range of soil C and N and had similar soil texture, soil types, and soil pH . Field numbers are in order of increasing total soil C. Variation in nutrient inputs, including highly-labile secondary inputs indicated diverse and intensive organic management strategies across these farms . The 13 fields encompassed the majority of the variation in the focal landscape , i.e. all but one of the five clusters, or landscape types, identified by GIS and multivariate analysis were represented . Thus, a range of soil characteristics representative of this region was accounted for by the fields sampled. Other characteristics, such as the low number of crop rotation types differed little across the clusters and reflect the intensity of agricultural management in this region.Measures of tomato N sufficiency varied widely across the 13 organic fields, ranging from deficient to luxury N levels.

Total above ground N concentration at mid-season overlapped or fell slightly below the critical N concentration for processing tomatoes in most fields , with N concentrations between 2.5 and 3.5% . Exceptions were fields 1 and 2 which were markedly lower and field 4, which was higher . The same general pattern occurred for the harvest sampling. Petiole NO3 – concentration in four fields overlapped the sufficient concentration, based on published guidelines , while five fell below it, and four rose above it . Petiole NO3 – was especially high in field 4. Petiole NO3 – -N showed a broadly similar pattern to total above ground N concentration, as reflected in the strong linear relationship between them . At the mid-season sampling, shoot δ15N ranged from 4.22 ± 0.65‰ in field 10 to 13.29 ± 1.18‰ in field 6. Fields 3, 4, 6, and 9 had the highest shoot δ15N, all above 12‰, and all but field 3 used seabird guano. Fields 8, 10, 11, and 13 had the lowest shoot δ15N, close to 4‰, and all but field 8 used Chilean nitrate. Mean harvestable fruit yield across all 13 fields was 86.7 ± 7.2 Mg ha-1 and was similar to the overall Yolo County mean 2011 tomato yield , which included both conventional and organic fields . Field 4 had the highest yield overall followed closely by field 9 , and field 1 had the lowest . Nine of 13 fields had means higher than the county average, and six of these fields were significantly higher. There was also substantial variability in tomato above ground biomass and N content at harvest across fields , which largely reflected the pattern of fresh weight yields. For instance, total above ground N ranged from 64 kg N ha-1 in field 1 to 243 kg N ha-1 in field 4 with a mean across all fields of 154 kg ha-1.Expression of cytosolic glutamine synthetase GS1 in roots was more strongly related to indicators of plant-soil N cycling than were the other six key genes involved in root N metabolism . Of the soil variables, GS1 was more strongly related to soil bio-assays for N availability than to inorganic N pools .

Microbial biomass N and PMN were most strongly associated with expression of GS1 in roots, followed by soil NO3 – . Permanganate oxidizable C and MBC, both indicators of labile soil C pools, also had significant associations with GS1 expression in roots, but soil NH4 + did not. Expression of GS1 also was positively associated with shoot N and petiole NO3 – , as was glutamate synthase NADH-GOGAT. Inclusion of GWC as a covariate in multiple linear regression models improved the proportion of explained variation in GS1 expression .PCA of 28 indicators of yield and plant nutrient status, root N metabolism, and soil C and N cycling showed strong relationships among suites of variables, which clearly differentiated fields along the first two principal components . The first principal component explained 28.3% of the variation; on the left side of the biplot are higher values of most variables, including yield, soil bio-assays, expression of root GS1 and NADH-GOGAT, and labile and total soil C and N pools . Soil NH4 + and NO3 – concentrations from all three sampling times as well as AMT1.2 were associated with one another and with positive values along principal component 2, which explained 19.4% of the variation. Total soil C and N were strongly associated with EOC and EON,hydroponic fodder system the soil C:N ratio, and POXC. These variables had negative values along axis 2 and thus contrasted with the pattern of soil inorganic N. Weak loading of AMT1.1, NRT2.1, Nii, and GS2 on the first two principal components reflects the lack of association of expression levels of these genes with bio-geochemical and plant variables. Non-overlapping confidence ellipses for seven out of 13 fields on the PCA biplot indicated distinct N cycling patterns . Fields 1 and 2, with the highest values along axis 1, had low values of all variables included in the analysis. Field 4 had the highest values along axis 2 corresponding with higher soil NH4 + and NO3 – . Fields 10, 11, 12, and 13 were associated with high values of labile and total soil C and N. Overlapping confidence ellipses of fields 3, 5, 6, 7, 8, and 9 close to the origin indicate similar, moderate values of this suite of variables for these fields. Three groups of fields were identified by k-means cluster analysis of the same 28 variables included in the PCA . Group 1 included fields 1 and 2, which had low mean values for yield , the lowest mean soil C and N and soil inorganic N pools , and the lowest mean value of GS1 relative expression in roots. Groups 2 and 3 had similarly higher mean yield , shoot N, and petiole NO3 – than group 1, but these two groups differed substantially in their soil C and N pools. Group 2 had higher soil NH4 + and NO3 – pools as well as root expression of AMT1.2 while group 3 had higher total and labile soil C pools. Expression of GS1 was similar in both groups. Based on the relative magnitude of F-statistics calculated for each variable, soil C and N, EOC, EON, shoot N, and soil NO3 – at transplant and anthesis were most strongly differentiated across the three groups. The high F-statistics of AMT1.2 and GS1 relative to other N metabolism genes indicate that root expression of these genes are most responsive to soil N cycling.This study confirms that working organic farms can produce high yields with tightly-coupled N cycling that minimizes the potential for N losses.

Such farms had the highest soil C and N and used high C:N organic matter inputs coupled with labile N inputs that resulted in high soil biological activity, low soil inorganic N pools, high expression for a root N assimilation gene, adequate plant N, and high yields. Organic systems trials have previously shown crop N deficiencies that lead to less-than-ideal crop productivity; losses of N when Navailability is poorly synchronized with crop N demand; or alternatively, that organic production can reduce N losses. But how working organic farms achieve yields competitive with high-input conventional production with low potential for N losses has not been demonstrated. Elevated expression of a key gene involved in root N assimilation, cytosolic glutamine synthetase GS1, in fields with tightly coupled N cycling confirmed that plant N assimilation was high when plant-soil-microbe N cycling was rapid and inorganic N pools were low, thus showing potential as a novel indicator of N availability to plants. Improving biologically-based farming systems will benefit from research that uses novel tools to uncover innovations happening on farms, especially if the research process helps facilitate knowledge exchange among farmers and researchers.To characterize the substantial variation in crop yield, plant-soil N cycling, and root gene expression across 13 fields growing the same crop on similar soil types, we propose three N cycling scenarios: “tightly-coupled N cycling”, “N surplus”, and “N deficient”. Values of indicator variables suggest differing levels of provisioning, regulating, and supporting ecosystem services in each scenario . Fields in group 3 show evidence of tightly-coupled plant-soil N cycling, a desirable scenario in which crop productivity is supported by adequate N availability but low potential for N loss. Despite consistently low soil NO3 – pools in these fields, well below the critical mid-season level for conventional processing tomatoes in California, total above ground N concentrations were very close to or only slightly below the critical N concentration for processing tomatoes. Tomato yields were also above the county average . This discrepancy between low soil inorganic N pool sizes and adequate tomato N status is due to N pools that were turning over rapidly as a result of efficient N management, high soil microbial activity, and rapid plant N uptake. Composted yard waste inputs with relatively high C:N ratios in concert with limited use of labile organic fertilizers applied during peak plant N demand provided organic matter inputs with a range of N availability. A companion study showed how high potential activities of N-cycling soil enzymes but lower activities of C-cycling enzymes in this set of fields reflect an abundant supply of C but N limitation for the microbial community, thus stimulating production of microbial enzymes to mineralize N. Plant roots can effectively compete with microbes for this mineralized N, especially over time and when plant N demand is high.

The majority of this use is in horticultural crops with California and Florida together accounting for 80% of the 35 million pounds applied each year for preplant fumigation . Many genes are available that potentially could be used to enable alternative weed-control strategies. Horticultural crops are also limited in the numbers of herbicides registered for use. Loss of registration for a few key chemicals could markedly limit grower options, making crop resistance to broad-spectrum herbicides more critical. Resistance to fungal and bacterial diseases would also be desirable, as in some areas extensive use of pesticides is currently undertaken for their control. As for herbicides, it is also difficult to maintain registrations for minor crops grown on smaller acreages, which are primarily horticultural. Biotech strategies are being developed that could provide broader spectrum disease control and reduced dependence upon chemical pesticides . Resistance to viral diseases would be valuable in many horticultural crops, as there are few other options for control, and methods for engineering virus resistance are well established. Tree fruit, nuts and grapes. Research is well under-way to build a robust platform of technologies to utilize genomics in the discovery of useful traits for trees . Transformation technology has been developed and trait evaluation is under way on apple, almond, peach, citrus, walnut, pear, plum, grapevine and persimmon. Good progress has been made in developing resistance to codling moth and fire blight in apple, plum pox virus in plum/Prunus, crown gall and codling moth in walnut, citrus tristeza virus in citrus and Pierce’s disease in grapevine. Engineering of resistance to codling moth in apple to reduce the use of chemical pesticides has advanced to the point of commercial interest in product development. Work is also under way to develop productivity and quality traits such as modified sugar metabolism and ripening in apple and he pivotal year in the history of Hawaii’s papaya industry was 1992.

In May 1992, papaya ring spot virus was discovered in Puna on Hawaii Island, where 95% of Hawaii’s papaya was being grown. Just one month earlier,nft hydroponic system a small field trial to test the resistance of a transgenic papaya line had been started on Oahu Island, where papaya production had previously been devastated by PRSV. The timely commercialization of PRSV resistant transgenic papaya trees has revived Hawaii’s papaya industry and provides an example of the challenges and opportunities for horticultural biotechnology. In 1945, D.D. Jensen made the first report in Hawaii of PRSV, a potyvirus that is transmitted non-persistently by aphids . PRSV was first discovered on Oahu and caused such severe damage that the papaya industry was relocated to Puna in the late 1950s and early 1960s. The papaya industry expanded and prospered inPuna, primarily because PRSV was absent. However, by the 1970s PRSV was found only about 19 miles away in Hilo, and the Hawaii Department of Agriculture took rouging and quarantine actions to prevent its spread to Puna. In 1986, efforts were initiated to develop a virus-resistant transgenic papaya by transforming commercial lines of Hawaiian papaya with the coat protein gene of PRSV from Hawaii. By 1991, the team of Maureen Fitch, Jerry Slightom, Richard Manshardt and Dennis Gonsalves identified a transgenic line that showed resistance under greenhouse inoculations. These plants were micropagated and established in a field trial in Waimanalo on Oahu in April 1992. By December 1992, it was evident that line 55-1 was resistant under field conditions. From the 1992 field trial, two cultivars were developed and designated ‘SunUp’ and ‘Rainbow’. ‘SunUp’ is homozygous for the coat protein gene while ‘Rainbow’ is an Fl hybrid of ‘SunUp’ and the non-transgenic ‘Kapoho’. Unfortunately, by October 1994, PRSV had spread throughout much of Puna, causing HDOA to abandon rouging efforts to slow the spread of PRSV. The race was on to move the transgenic papaya line to commercialization. A 1995 field trial in Puna conclusively showed that ‘SunUp’ and ‘Rainbow’ were resistant under prolonged and heavy disease pressure.

The U.S. Department of Agriculture’s Animal Plant Health Inspection Service deregulated transgenic line 55-1 in November 1996, and the U.S. Environmental Protection Agency deregulated it in August 1997. The consultation process with the U.S. Food and Drug Administration was completed in September 1997. Licenses to commercialize the transgenic papaya were obtained by the Papaya Administrative Committee in Hawaii by April 1998. A celebration was held to mark the debut of the transgenic papaya on May 1, 6 years after PRSV was discovered in Puna and after the first field trial of line 55-1 was initiated. The transgenic fruit is currently sold throughout the United States. In 1992, Puna produced 53 million pounds of papaya, but by 1998 production had dropped to only 26 million pounds as PRSV spread throughout the region. Since then, the transgenic varieties have enabled farmers to reclaim infected areas and in 2001, Puna produced 40 million pounds of papaya. The resistance has held up remarkably well and remains stable after 5 years of extensive plantings. Hawaii also exports papaya to Canada and Japan. The transgenic papaya was recently deregulated in Canada, which is a relatively small market for Hawaii. The main challenge is deregulation of transgenic papaya in Japan, where Hawaii sells about 30% of its papaya. Presently, non-transgenic papaya must also be produced in Hawaii to satisfy the Japanese market, but this is increasingly difficult due to the disease pressure. Exporters face added expenses to guard against the accidental shipment of transgenic papaya to Japan. In December 2000, Japan’s Ministry of Agriculture, Forestry and Fisheries approved line 55-1, and the Ministry of Health, Labor and Welfare is reviewing a recently submitted petition for deregulation. Anticipated approval of transgenic papaya in regulation of self-incompatibility in almond and other Prunus species. Some deployment strategies for transgenic trees are also being developed, such as the use of transgenic trees as “trap crops” to control insects in conventional orchards and the use of transgenic root stocks to control diseases and pests in non-transgenic scion varieties . The latter approach avoids the task of transforming many varieties of a particular tree crop and in the future may be used to regulate quality and productivity traits.Although more difficult technically and therefore not close to market, there are many potential opportunities for enhancing the nutritional value or consumer appeal of horticultural products through biotechnology. In addition to modification of ripening, projects to increase the content of vitamins, minerals or nutraceuticals in horticultural products are in progress .

The development of Golden Rice with enhanced betacarotene in the grain demonstrated the potential for biotechnology to increase nutritional value. Whether such products will have sufficient consumer appeal in fully developed markets to drive their commercialization remains to be seen.Since floricultural and ornamental plants are grown for aesthetic or other nonedible purposes, there may be less potential for public concern about GE varieties than there has been with biotech food crops. Flower color. Several ornamental plants, including carnation, rose and gerbera, have been engineered for modified flower color. Research has focused on the manipulation of either anthocyanins or carotenoids,hydroponic nft system with the intent of creating a wider range of flower colors than occurs naturally, as well as to produce natural dyes for industrial purposes . Florigene is selling Transgenic Moon series carnations engineered for dark violet-purple color around the world. The varieties are developed in Australia and flowers are produced primarily in South America for marketing in the United States and Japan. Floral scent. Putting the scent back into flowers that have “lost” this trait over years of traditional hybridization and selection, or creating new fragrances in plants, has considerable potential and appeal. Research on genes controlling the different biochemical pathways for various floral fragrances is being conducted on wild plants and on crops such as snapdragon, petunia and rose . Plant size. Currently, growth regulating chemicals are applied to ornamental plants to inhibit gibberellic acid synthesis and reduce plant height during crop production. Many newly introduced ornamental species are receiving particular attention via conventional breeding for dwarf plants because their natural habits do not fit into marketing systems requiring compact plants. The manipulation of GA metabolism via biotechnology has the potential to produce ornamental and flowering plants with reduced-height phenotypes . The development of lawn grasses that require significantly less frequent mowing is another obvious application.Leaf life. Engineering of plants to delay leaf senescence is also being pursued in ornamental crops. For years, ornamental breeders have selected new cultivars of plants with more attractive “stay green” phenotypes. Cytokinins are plant hormones well known to delay the loss of chlorophyll in leaves; using biotechnology, targeted expression of genes involved in cytokinin synthesis is now possible. When a gene promoting cytokinin biosynthesis is inserted into plants in conjunction with a regulator that turns the gene on only Fruit and vegetable crops are under constant pressure from pests such as weeds, viruses, fungi, bacteria, insects and nematodes. If not controlled, many of these pests substantially lower yields. Successful agricultural production has depended on the use of pesticides for 100 years, and, yet, losses still occur due to certain pests that are poorly controlled. Some crops incur high costs for hiring laborers to hoe weeds because there are no effective herbicides. In addition, new pests routinely arrive for which effective controls have not yet been developed. Agricultural researchers continuously seek out new methods to control pests, including biological agents, new chemicals and plant resistance through classical breeding. Biotechnology also offers a solution in some situations where traditional methods are ineffective or costly. Numerous researchers around the world are investigating biotechnological solutions to pest problems of horticultural crops.

In 2002, the National Center for Food and Agricultural Policy released a study of current and potential biotechnological approaches to pest management in a wide array of crops . Current plantings. The study identified three varieties of transgenic fruits and vegetables that are currently planted on small acreages in the United States: virus-resistant squash is grown on 5,000 acres in the Southeast, to prevent late-season losses to mosaic viruses; virus-resistant papaya is widely planted in Hawaii ; and insect-resistant sweet corn is planted on a small number of acres and has reduced use of insecticide sprays.Withdrawn varieties. Two transgenic horticultural varieties were available for a short time in the United States but were withdrawn due to marketing concerns. Insect- and virus resistant New Leaf potatoes were planted on 4% of the nation’s acreage in 1999 and were credited with reducing insecticide use. If the transgenic varieties had not been withdrawn due to processor resistance they could have been planted extensively in the Northwest, reducing insecticide use by 1.4 million pounds. In 1999, the U.S. Environmental Protection Agency granted Wisconsin sweet-corn growers emergency permission to spray herbicide-tolerant varieties . The transgenic varieties were not widely planted due to marketing concerns and growers have not reapplied for the use despite continued production losses. Crops currently being tested. Numerous fruits and vegetables have been transformed through genetic engineering and are being tested for their potential role in improving pest management. For example, University of Florida researchers are testing virus resistant tomatoes as a substitute for the extensive insecticide spraying currently utilized to control insects vectoring geminiviruses. In California, herbicide-tolerant processing tomatoes have been tested and have the potential to reduce grower costs by $30 million and replace the use of 4.2 million pounds of fumigants. UC researchers have tested herbicide tolerant lettuce that could reduce herbicide use by 140,000 pounds a year. Herbicide-tolerant strawberries could save Eastern growers several hundred dollars per acre in weed-control costs. Nematode-resistant pineapple is being developed at the University of Hawaii to replace 1.4 million pounds of fumigants. Insect-resistant broccoli developed at Cornell University could improve yields in years of heavy insect pressure. Virus resistant raspberries developed by U.S. Department of Agriculture researchers in the Northwest could help combat bushy dwarf virus, which is present in 80% of Northwest plantings. And transgenic apples resistant to fire blight bacteria have been developed and tested at Cornell University; the transgenic varieties would replace the use of antibiotics, which are used to kill the bacteria on 25% of U.S. apple acreage. Emerging pests. Several research programs are focused on biotechnological approaches to control emerging pest problems.

These studies do not automatically provide information about which, if any, environmental variables are responsible for the pattern. One can test whether patterns of differentiation match an environmental gradient, but this is necessarily a post-hoc interpretation . Association studies use a regression approach to identify loci in which genetic variation is associated with variation in trait values or home environment. Such analyses can be carried out at the individual or population level. Genotype-to-environment association studies identify loci that vary along environmental gradients . An association between an SNP and aridity, for example, suggests that the gene or its regulatory region affects performance in wet vs dry environments. This does not reveal how the locus affects phenotype, and careful interpretation is needed as a result of correlation between climatic variables. Genotype-to-phenotype association studies identify loci correlated with a particular phenotype , but the phenotype may or may not be relevant for fitness in the field. Most association studies in conifers to date have used SNPs in a limited number of candidate genes . This ensures that genes suspected of involvement are surveyed, but limits the ability to identify additional loci. However, with the decreasing cost of sequencing, approaches that generate large numbers of SNPs are increasingly being used for genome-wide association studies . One set of approaches, including RAD-seq and geno typing-by-sequencing, flood and drain tray involves the use of restriction enzymes to cut and sequence a small subset of the genome . This can produce tens of thousands of SNPs with high coverage .

Many of these SNPs will be in noncoding regions, which is good for the potential discovery of regulatory regions, but can limit the number of gene associations detected. Another approach involves the creation of a transcriptome or full genome sequence for a species, and the development of probes for all or most of the putative genes to identify SNPs . This approach can also yield useful gene expression data if multiple tissue types or treatments are included in the development of the transcriptome .Most drought gene expression studies in conifers have focused on pine seedlings, with a few investigating other Pinaceae genera . The direction of expression responses to the environment, including dry conditions, is highly conserved between Pinus contorta and Picea glauca 9 engelmannii, even though average expression levels often differ . It is unclear whether this is true across conifer families. No expression studies have focused on adult drought responses. The methods used to induce drought stress vary. Studies have withheld water for a specified period , until soil moisture reached a threshold or needles wilted , or needle water content declined to a certain level . Some have used chemically induced water stress . Caution must therefore be used in interpreting differences across studies, as these could be methodological artifacts . Genes related to signaling and gene transcription are frequently upregulated in drought-stressed seedlings. Changes in signal cascades must precede changes in their targets, and such expression shifts often occur within the first week of drought stress. Those in the ABA pathway are well represented . In addition to being involved instomatal closure, ABA signaling can affect shoot growth and water uptake . However, there are also ABA-independent pathways in most taxa, which may use leaf water potential as a signal .

Upreg ulation of genes in the ethylene pathway could be related to reduced shoot growth or leaf area . Genes related to protective molecules are also frequently upregulated . Late-embryogenesis-abundant proteins, named for their role in seeds, appear to stabilize proteins and membranes and prevent protein aggregation . Dehydrins, a subgroup of LEAs, often protect against drought stress, although some are induced by other abiotic stresses . Heat shock proteins, detoxification enzymes and genes in the synthesis and transport pathways of osmoprotective carbohydrates and proline may also be upregulated. Genes involved in pathogen or biotic stress defenses are often upregulated during drought stress, but those involved in growth, including cell division and wall construction, are often downregulated . Up or down changes in carbohydrate and lipid metabolism and protein handling pathways are also evident, although these are more difficult to interpret. Aquaporins, which affect membrane water permeability, were found to be upregulated in two studies . When drought-stressed seedlings are re-watered, most gene expression quickly returns to normal. In Pinus taeda, only 76 of the 2445 genes with altered expression during drought were still different after 48 h of recovery . Lorenz et al. found 11 genes upregulated in ‘recovered’ P. taeda seedlings relative to either drought-stressed or well-watered seedlings, including probable cell wall proteins, an aquaporin and a gene involved in vacuole function. These may reflect recovery or repair processes that occur once drought stress is removed.Gene families illustrate the complexity of expression responses to drought. Pinus pinaster has at least eight dehydrin genes, based on expressed sequence tag analyses . Three of five were downregulated during drought, whereas the other two were upregulated . Most dehydrin induction occurred after 20 d of drought , which may be why a similar but shorter study did not reveal the upregulation of dehydrins. Expression can also vary by tissue.

Of seven dehydrins examined in P. abies, drought stress upregulated four in needles, but only two in bark, with one being down regulated in bark . To investigate the link between drought and defense gene expression, Fossdal et al. exposed P. abies seedlings to a pathogen , drought stress or both, and examined the transcription of 14 candidate defense genes. Genes were upregulated more slowly in drought-stressed seedlings than in pathogen inoculated seedlings. The combined treatment led to more rapid and/or higher expression of many defense genes than either alone, which may be related to the synergistic mortality risks posed by biotic and abiotic stressors. Pleiotropic effects for some drought/ defense-related genes are also possible, but none have been identified to date.Multiple provenance studies have identified patterns consistent with local adaptation to drought. Trees from drier climates often exhibit conservative growth strategies , such as slower height or needle growth , less above ground biomass or a shorter growing season . Seedlings from dry environments often also exhibit more root growth and higher drought survival . Provenance trials of Pinus halepensis have shown mixed responses, with low growth and high water use efficiency in dry-sourced populations , but high growth in populations from intermediate-aridity areas , which may be related to growth plasticity. Because of the importance of carbon resources for plants, WUE – the ratio of carbon fixed to water lost – has long been considered to be closely tied to drought tolerance . Measures that integrate over longer time periods, such as the carbon isotope ratio d13C ,nft hydroponics are most frequently used to represent changes in WUE in trees. However, although different measures of WUE are often correlated , they are not interchangeable. For example, carbon discrimination is sensitive to chloroplast carbon concentrations and mesophyll conductance, whereas WUE itself is heavily influenced by evaporative demand, which does not directly affect D . In addition, nitrogen fertilization can increase WUE and decrease D, but does not affect gs or transpiration . Thus, WUE and D do not always co-vary, and caution is needed in the interpretation of d13C as a measure of WUE. Additional caution is warranted when using WUE as an indication of drought tolerance. High WUE may not be adaptive in some dry environments if the use of less water per unit carbon fixed does not result in slower depletion of soil water , or if plants with higher WUE grow faster and thus use more total water. Although a few studies have shown higher d13C for populations from dry sites , others have shown the opposite . There was no difference between three populations of Pinus ponderosa seedlings from varying climates in d13C or instantaneous WUE; the drought adapted populations exhibited greater plasticity in water use . In P. halepensis, however, individuals from more mesic sources showed higher plasticity of WUE than those from drier sources , but dry sources may show higher average WUE . Highly plastic growth and water usage reduce apparent WUE over the whole season compared with consistently moderate to low water usage . Instantaneous measures of WUE can change over a day, whereas integrated measures can differ significantly for a source population grown under different conditions or for the same tree across years . Changes in WUE may thus be a useful indication of drought stress, but, in conifers, radial growth and WUE are often weakly or negatively correlated . In pines, higher WUE usually results from reduced gs and/or reduced leaf area , which can limit photosynthesis and growth . Low gs can also result in higher tissue temperatures, which can be damaging, particularly in seedlings . Drought length and severity can influence measures of relative drought tolerance between populations. In P. ponderosa seedlings,the relative growth rate under moist conditions was positively correlated with previously measured tolerance to severe drought, whereas, under 4-wk drought, the intermediate-drought-tolerant population grew faster .

When Silim et al. examined Picea sitchensis, P. glauca and their hybrids, they found that P. sitchensis and the hybrids had the highest WUE and growth in well-watered conditions, but P. glauca and the hybrids had higher WUE and growth in drought conditions. Similarly, the relative transpiration and photosynthetic rates, WUE and growth of P. halepensis tree provenances differed between near-desert and Mediterranean planting sites . Such shifts in ranking are often a result of plasticity differences between populations. Provenances of P. pinaster from across the species’ range did not vary in cavitation resistance, suggesting uniform selection or lack of genetic variation . In P. halepensis, however, the percentage loss of conductivity differed significantly between provenances, but not between environments . Although plasticity has been observed in xylem wall thickening, time to thickening and number of cells in Picea mariana in drought experiments , cell anatomy studies often focus on only one population, so that the extent of local adaptation is unknown.Genome scans have identified loci in conifers that may be under differential selection across environments . Of 13 candidate genes for drought response in P. pinaster, two showed signs of divergent selection, although only one exhibited a pattern correlated with a climatic gradient; three, including two dehydrins, showed evidence of balancing selection . Prunier et al. examined SNPs from 313 candidate genes in P. mariana and found 16 that exhibited differentiation correlated with precipitation, including a LEA protein and genes in the ubiquitin protein handling pathway. However, differentiation between populations can be driven by processes unrelated to climatic gradients. Conifer populations are likely to violate the assumptions of such tests because they rarely form discrete isolated populations and are often far from demographic equilibrium; mis-specification of population hierarchical structure can lead to high false positive rates . However, newer methods are being developed that avoid frequently violated assumptions and reduce false positives . The approach preferred by recent studies is to directly assess the association of loci with environmental gradients , whilst controlling for population structure . Jaramillo Correa et al. examined the correlation of P. pinaster candidate gene SNP allele frequencies with climate principal component axes, using transcriptome-wide SNPs to control for population structure and demographic history. They identified 18 environmentally associated SNPs, many of which were in genes relating to carbohydrate transport, cell wall construction and photosynthesis. Two surveys of P. taeda examined associations between candidate gene SNPs and environmental gradients. One examined the association of these loci with five climatic PC axes , whereas the other used an aridity index for each county . There was some overlap in function between the loci identified . However, the studies disagreed on whether SNPs associated with climate also tended to be Fst outliers. G2E associations have been detected even over short geograph ical distances, suggesting that selection can drive local adaptation in the presence of high gene flow. Eckert et al. examined Pinus lambertiana populations around Lake Tahoe, an area of c. 35 9 65 km2 , and found 11 genes associated with environmental PCs reflecting differences in water availability. These included genes involved in carbohydrate metabolism and transport and response to biotic stress .

Despite high AR exposure levels , both studies reported very low numbers of animals dying primarily from AR exposure. Nevertheless, AR poisoning may significant impact mortality rates in Californian fisher populations , with increasing prevalence from 2007 to 2014. AR contamination is not limited to mammals. It was also documented in northern spotted owl and barred owl populations, likely through secondary poisoning from predation on contaminated rodents . Despite some limitations due to small sample sizes , these studies draw attention to a potential ecological threat posed by illicit cultivation methods. Far less is known about application of chemicals in legal growing operations, which vary greatly by region and country. While some ARs are illegal or heavily restricted in the United States, various other pest-control methods have been reported for cannabis . In the US, due to the crop’s federally illegal status, no commercially available pesticides have been approved for use on cannabis . In Canada, 25 pesticide and fungicide compounds have been approved for legal use on cannabis.Wang, et al. measured biogenic volatile organic compounds emitted by cannabis plants grown under conditions mimicking greenhouse cultivation. Results suggested BVOC emissions from indoor cultivated cannabis in Colorado could contribute to ozone formation and particulate matter pollution. The authors acknowledged limitations due to small sample sizes,4x8ft rolling benches sub-optimal growing conditions, and a focus on only 4 out of 620 reported cannabis strains.

In a follow-up study, Wang, et al. estimated terpene emissions and regional ozone impacts from indoor cannabis cultivation facilities in Colorado using the Comprehensive Air Quality Model. Results predicted increases in hourly ozone concentrations which may have consequences for regional air quality. This approach was limited by reliance on estimates and assumptions in the absence of data regarding emission capacity of most cannabis strains, number of plants and plant biomass. Nevertheless, preliminary findings indicated that concentrated indoor cannabis cultivation could influence ozone pollution through BVOC emissions from terpenes, particularly in areas where nitrogen oxides are not the limiting factors in ozone formation . Surface- and ground-water pollution from the cannabis industry, including from soil erosion, pesticide and fertilizer in run-off, chemical processing or waste disposal operations, is a likely risk . Nevertheless, we found no peer-reviewed study quantifying the impacts of cannabis cultivation on water quality, although current pilot projects in California are underway. We did find an academic book series and five peer-reviewed publications documenting the effects of pollution from cannabis consumption on water quality. These studies used THC-COOH concentrations in sewage systems, presumably originating from human consumption, as a proxy. Evidence of THC-COOH presence was found in both raw and biologically treated wastewater across major European cities as well as in raw wastewater in the US . Concentrations of chemical compounds derived from cannabis were lower in treated than in raw wastewater. Nevertheless, accumulation of these compounds may contribute to waterway contamination downstream from wastewater effluent discharges in urban areas, although likely to a lesser extent than other illicit drugs . While these studies primarily aim to document urban cannabis consumption, they also point towards potential contamination issues impacting downstream freshwater ecosystems.

Our current understanding of the consequences of wildlife exposure to cannabis-related chemicals remains limited. Parolini, et al. sought to bridge this gap through experimental exposure of zebra mussels to concentrations of cannabis active compounds Δ-9-THC and THC COOH. Results showed that prolonged exposure could contribute to oxidative and genetic damage in the mussels. Still, given the lack of knowledge regarding actual Δ-9-THC and THC COOH concentrations in aquatic ecosystems, and the lack of documentation of the compounds’ effects on mussels or other organisms in the wild, it is difficult to draw broader conclusions about potential environmental risks posed by exposure to active compounds in cannabis for aquatic organisms.Because there are environmental trade-offs across production methods, it is important for policy makers to consider the potential unintended consequences of policy decisions. For example, in California, stringent water-use regulations for outdoor production may incentivize cultivators to turn to alternative indoor production methods. While this shift may alleviate water-stress in sensitive ecosystems, it may also increase the carbon footprint of cannabis by encouraging energy-intensive indoor production. Identifying and understanding trade-offs within and across systems is thus important, and cannabis regulation should be comprehensive in order to prevent impacts from being displaced from one pathway to another. The emerging literature on cannabis and the environment already provides useful insights to guide policy. Still, the majority of studies reviewed here were individual case studies, mostly geographically centered in Northern California. There is a tremendous need for similar studies to be carried out across different biophysical, socioeconomic, historical and cultural contexts, both to confirm the generalizability of these results and to avoid exporting environmental problems from the developed to the developing world. We expect that continued liberalization worldwide will provide expanded geographic scope for this work for years to come, and researchers should be ready to act on this expansion.

Most of the literature reviewed here relies on observational or model-based methodologies . While these approaches provide insights, experimentation is fundamentally needed to understand basic agroecological functions and processes governing cannabis cultivation. Trials quantifying the energy footprints, water use, and nutrient requirements of different cultivation and management methods are also needed to improve the efficiency of production systems. Given increased liberalization trends, we expect to see a normalization of cannabis-related research. Scientists should be encouraged to carry out a range of experiments to bolster scientific capacity to assess the environmental impacts of an expanding cannabis sector. Additionally, as regulations around cannabis cultivation are implemented, long-term studies are needed to understand how these regulations affect cannabis cultivation practices. Cannabis cultivation may lead to additional environmental impacts, which remain scientifically undocumented to our knowledge. For instance, solid waste management of materials originating from cultivation, packaging, or other production processes, will need to be addressed. Life-cycle assessments of the cannabis sector could provide information on how to minimize such waste and more generally increase the efficiency and sustainability of cannabis production processes. Other potential areas for future research include odor pollution risks in communities where increased cannabis production has led to farms being sited near residential areas, cross pollination issues between cannabis and hemp , alternative cannabis farming or transportation efficiency. These topics, and many others, should make the study of cannabis’ environmental impacts a rich field for discovery for many years to come. Traditionally, cannabis has been cultivated remotely and at small scales. Legalization is altering this through cultivation expansion, shifts toward urban areas, and increased size of production facilities , which may in turn affect the environmental impacts of the industry. The intensification of cultivation activities at large-scale facilities may magnify negative impacts. Conversely,flood and drain table economies of scale may increase the efficiency of larger facilities which may have broader capacities to invest in sustainable production processes. Larger facilities are also less likely to be located in remote sensitive areas than historical smaller farms, but may lead to land use trade-offs with other forms of agriculture. Continued diligence by policy makers and consumers is needed to ensure that the move towards industrialization is not a move away from sustainability – and researchers must continue to document shifts in the industry and their environmental impacts. In conjunction with legalization, social and ecological certification schemes could increase environmental performance of the industry. Emerging programs such as Sun and Earth Certification or planned appellation designations in California constitute first steps in this direction. By contributing to consumer awareness and providing incentives for growers to produce in sustainable ways, these programs may pave the way for the development of a more sustainable cannabis sector. In many ways, the question of how to best produce and consume cannabis while protecting the environment echoes larger debates about the environmental impacts of agricultural production in general. Current discourse on the optimal ways to address shifts in the cannabis sector touches upon fundamental sustainability framings such as land sparing vs. land sharing, intensification vs. expansion, technology-driven agriculture vs. agroecology, the role of smallholder farmers vs. industrial-scale facilities. Policy makers working with cannabis have strong interests in developing effective regulations following legalization and are also dealing with regulatory “blank slates”. This may equip them with a novel combination of increased freedom and institutional capacity to test and evaluate the effectiveness of multiple policy approaches. Ultimately, failures and successes of environmental regulations for cannabis may lead to important lessons-learned for agriculture more broadly. This study represents original research on the manufacture of plant-made biologics and plant-made industrial products through application of analytical modeling tools in silico. The main goal of this study was to evaluate unit operations in two plant-made bio-manufacturing processes and estimate the cost of goods of the active ingredient and the impact of those costs on the cost of the final product.

A secondary but equally important goal was to compare the manufacturing cost of plant-produced AI to the cost of the same AI manufactured by predecessor technologies. Much progress has been made towards the development of manufacturing infrastructure for plant-made pharmaceuticals , which typically consist of recombinant proteins applied as vaccine antigens, therapeutic enzymes, or monoclonal antibodies. Progress has also been made in the manufacture of plant-based biologics, biochemicals, and bio-materials for industry, food, and other applications. Significant and industrially relevant advances in gene expression and bio-processing methods have been achieved during the past two decades, as reviewed in several prior studies. Yet, to date, only three PMP products have been approved by regulatory agencies for commercial sale, including an anti-caries antibody , an animal health vaccine , and a therapeutic enzyme to manage a metabolic disorder]. This relative scarcity of PMP products reflects the magnitude of the challenges in creating a new manufacturing industry. The development of the plant-based platform has slowly progressed through a multinational “labor of love” in the absence of the levels of investment originally made by the bio-pharmaceutical industry , which resulted in elevation of fermentation-based systems to their current level of dominance.Interestingly, beginning in 2009, the US Defense Advanced Research Projects Agency’s Blue Angel program made several multi-million dollar investments at various sites with the goals of accelerating the scale up of the PMP infrastructure and assessing production of relevant volumes of pandemic influenza candidate antigens as a model product to test the plant-based platform . This was a shared investment initiative, and as a result of federal and state government and private investments, the expanded PMB manufacturing capacity should now support production of at least several of the many plant-made vaccines, bio-therapeutics, bio-materials, and bio-catalysts that are under development by companies and institutions worldwide . Although capacity expansion helped companies that would manufacture their own or partnered products , these investments also helped expand capacity at PMP contract development and manufacturing organizations such as Kentucky Bio-Processing . This was important to our modeling because the decision to construct a new dedicated manufacturing facility versus contracting services from a CDMO could yield very different cost-of-goods projections. Fundamental to the commercial introduction of PMB products is the availability of an efficient plant-based manufacturing infrastructure that is at a minimum competitive with and ideally superior to traditional animal cell and microbial fermentation systems as well as to extraction from raw materials from natural sources. The cost to manufacture any product is of paramount importance to its market acceptability, availability to those who need it most, and to the profitability of the product for its manufacturer. While plant based technologies are often assumed to offer significant cost advantages relative to cell-based fermentation, such assumptions are based on the lower upstream capital investments required for plant growth, lower cost of media, no adventitious agent removal, and other factors. However, few of these studies have listed engineering process assumptions or analyzed unit operations adequately; reports such as those of Evangelista et al. and Nandi et al. are exceptions. Therefore, results of recent technoeconomic evaluations for PMP/PMB/PMIP have not been widely available in the public literature. To analyze and quantify the cost efficiency of plant based manufacturing, we chose two enzymes representing active ingredients for diverse product classes and derived for each AI the bulk product and per dose or per-unit costs.

DIM BOA-Glc levels on the other hand may not be significantly altered as previously shown for ABA treated plants which is consistent with our results. Fv is highly resistant to MBOA and has the ability to detoxify the compound by actively metabolizing it into N- malonamic acid which is nontoxic. Consistent with Fv detoxification of MBOA, the concentration of MBOA tended to inversely track pathogen bio mass. However, this did not hold true at 2x[CO2] between +H2O and -H2O plants which would suggest additional interactive effects of 2x[CO2] and -H2O on benzoxazinoids metabolism. Further research investigating the effects of multiple climate change factors on maize benzoxazinoids and their derivatives in interaction with a pathogen more sensitive to these defense metabolites will be necessary to fully understand the potential implications of the abiotic stress induced changes in maize benzoxazinoid dominated defenses. Although the fumonisin contamination was significantly higher in infected stems under simultaneous conditions of 2x[CO2] and -H2O, the amount of fumonisin per unit Fv biomass was reduced compared to +Fv maize at 1x[CO2]. These data are consistent with previous results indicating that elevated [CO2] compromises the transcriptional response of many of the 9- and 13-lipoxygenase and their signaling products, which have the potential to stimulate mycotoxin production. Even though the transcript levels of LOX genes were not measured in this study, the metabolite analysis supports this notion. The addition of drought did not ameliorate the effects of elevated [CO2] on the influx of fatty acid substrate needed for oxylipin biosynthesis, nor did it negate the dampened accumulation of the 13-LOX oxylipin JA following Fv infection . Nevertheless, even though host-derived mycotoxin stimu lants are potentially still reduced,stackable planters the even larger amount of Fv biomass on maize at 2x[CO2]- H2O was ample to lead to greater fumonisin levels and could therefore be an agriculturally relevant food safety concern.

Considering that the drought treatment imposed in these experiments was specifically designed to account for the physiological changes in water utilization at 2x[CO2], it is possible that, in comparison to a more moderate drought stress treatment at 1x[CO2], the amount of fumonisin contamination would be higher instead of lower. Numerous reports indicate that drought enhances maize susceptibility to Fv and fumonisin; however, in these experiments at 1x[CO2]-H2O plants displayed both less Fv biomass and fumonisin compared to irrigated plants. Since maize utilizes more water at 1x[CO2] and the degree of drought stress was higher , the percentage of water in the stem tissues was significantly less . Therefore, it is likely that this lower water activity was not conducive to fungal growth and reduced Fv biomass and fumonisin production. While normalizing for soil moisture content would provide additional insight into the effects of [CO2] at variable levels of drought, this is beyond the scope of the current manuscript. The difference in soil water content was a consequence of the plant’s physiological response to elevated [CO2] which was a factor being studied and was thus intentionally not controlled in these experiments. Elevated [CO2] has the potential to ameliorate the severity of drought; therefore, it is essential to understand how these abiotic factors will interact and influence Fv infection in comparison to conditions which will not receive this same benefit of water conservation. Timing of infection will likely also play an important role in fumonisin contamination levels as during episodes of drought maize at 2x [CO2] may also provide a more favorable environment for pathogen growth, allowing for a prolonged period of mycotoxin accumulation. Furthermore, while the chamber based studies provide valuable data in understanding the defense response under controlled conditions of biotic stress, there are multiple limitations including light intensity, breadth of spectral wave length, and hindered root establishment. These factors likely contribute to the abiotic stress imposed and influence resource availability and distribution.

Additional laboratory studies coupled with field based free air gas concentration enrichment experiments are needed to determine the trade offs between the photosynthetic advantage of water conservation and increased susceptibility on maize grain productivity during simultaneous conditions of elevated [CO2] and drought. Nonetheless, given the heightened climate change concerns and the potential consequences of our uncertainties for future agricultural maize production, our findings have provided a foundation for additional research necessary for the development of climate resilient mycotoxin control strategies.Horticultural crops provide 60 percent of total farm revenue in California agriculture, and Cali fornia provides 37 percent of the horticultural crop value in the United States. Clearly, these industries comprise an important part of the agricultural economy. This study provides a detailed statistical profile of California’s horticultural crop industries at the farm level, based on a survey of specialty crop growers that was conducted during the spring of 2002. The Risk Management Agency of the United States Department of Agriculture supported the re search, and the California Office of the National Agricultural Statistics Service helped conduct the survey. Specialty crops, also referred to as horticultural crops, include tree and vine crops, vegetables, and ornamental crops. The statistical profile of California’s horticultural farm industries presented here is the most comprehensive ever undertaken for these industries, drawing on survey data collected from approximately one-third of all horticultural crop producers in the state. Specialty crops are diverse. They differ in their product characteristics, production processes, and market environments. Such heterogeneity extends to risk characteristics of the crops and to the ways farmers cope with various risks. As a preliminary step to development of effective risk management tools, it is important to better understand factors that affect these risks. This report is intended to provide such information to help us understand specialty crop industries, the sources of risk, and behavioral risk responses in these industries.

The following summary of results is organized by topic.About 86 percent of the farms surveyed produced primarily orchard and vine crops, 5 percent produced vegetable crops, and 9 percent produced ornamental crops. About 25 percent of the farms were located in coastal areas, 13 percent in the Sacramento Valley, and 47 percent in the San Joaquin Valley. The remaining 15 percent were in the northern mountain areas, the Sierra Nevada, the Southern coast, and the deserts. Average farm size was 203 acres,stacking pots but the median farm comprised only 34 acres. There were relatively few very large farms and many very small farms. The average number of acres per farm varied substantially among the three crop categories: fruits/nuts, vegetables, and ornamental crops. The average land holding by vegetable growers, 1,106 acres, far exceeded the average of 157 acres for fruits/nuts and 200 acres for ornamental crops. These land figures include land planted to secondary crops . When we examined land planted only in primary crops, our data showed that fruit/nut and vegetable farmers held, on average, about 50 percent of their land in primary crops . However, land for ornamental crops, on average, accounted for only 10 percent of the average 200 acres per farm.Crop diversification has long been recognized as an important risk management tool. Our data showed that crop diversification was much less common for orchard farms than for vegetable farms. About 70 percent of fruit/nut farmers were single-crop growers as opposed to 26 per cent for vegetable farms. The scope of diversification also differed. Fruit/nut farmers predominantly diversified their crops with other varieties of fruits and nuts; only 20 per cent of them used crops other than fruits and nuts for diversification. Vegetable farmers, on the other hand, frequently used other crops for diversification; only one-third of the vegetable farms were diversified among only vegetable crops. Our survey also indicated that primary crop acreage increases with crop diversification for both fruit/ nut and vegetable crops. Farms growing five or more vegetables were, on average, four times larger in vegetable acreage than farms growing a single vegetable crop. In California, 6 percent of specialty crop farmers had some organic or transitional-organic land. In terms of crop category, these farms represented 6 percent of orchard farms, 14 percent of vegetable farms, and 4 percent of ornamental crop farms. Our data showed that these farms also engaged in conventional farming and that they devoted, on average, about one-third of their primary crop lands to organic farming. Judging from acreage assigned to primary crops, the farms were about average in acreage for fruit/nut farms but much smaller than average conventional vegetable farms.Marketing is an important component of risk management. Marketing channels vary by product use . Processing crops are delivered in bulk directly to processing plants, whereas fresh-use crops are sent to operations to be sorted, packaged, cooled , and distributed through marketing channels. California producers were highly specialized in terms of use. Most fruit/nut farms produced mainly for processing use and most vegetable farms produced mainly for fresh use . Only 7 per cent of specialty crop farmers supplied both processing and fresh market outlets.

In processed-use markets, contracts played a major role with contracts with a predetermined price being the most prevalent form. In fresh-use markets, grower/shippers, which combine the packing/shipping business with field production under one ownership, provide a form of vertically integrated business. Our survey showed that grower/shippers accounted for 13 percent of vegetable farmers and 3 percent of orchard farmers and that they mainly supply mass merchandisers . The other fresh-market growers tended to use diverse marketing channels, including selling directly to consumers, marketing through cooperatives and independent shippers, and selling directly to commercial buyers. For fresh vegetable markets, “directly to consumers” was the most commonly used outlet , not by volume of production but by number of farms using this marketing channel.We investigated year-to-year yield variations using yield information for the preceding five years. Taking the average of the five annual yields as an individual’s normal yield, we calculated the percent deviation from the normal yield and then arrived at sample mean deviations for sample categories. Our data indicated that annual yield deviated, on average, 15 percent for fruits/nuts and 8 percent for vegetables over the previous five years. For price and profit fluctuations, we elicited information on the range of the highest fluctuation experienced over the same five year period . For both price and profit, the median of the accumulated distribution fell in the 25–49 percent range for fruits/nuts and the 10–24 percent range for vegetables, indicating that prices as well as profits tend to fluctuate less for vegetables than for fruits/nuts. In response to a list of options as the main cause for the lowest profit, “poor yield,” “low market price due to high domestic production,” and “low market price due to imports” were the three most often cited causes for all crops except ornamentals. They accounted for 70 per cent of the responses for fruit/nut and vegetable farmers. For fruit/nut crops, poor yield was the most cited reason for the lowest profit , but for vegetables, low market price due to high production was cited most , followed by low market price due to imports . This underscores the relative importance of production risks for orchard crops and of market risks for vegetable crops.Two sources of risk, adverse temperature and output price fluctuation, were listed as most important; input price fluctuation, pests, and disease were considered to be moderately important. Crop insurance was a preferred risk management tool for orchard and vineyard farmers, and crop diversification was preferred by vegetable and ornamental crop growers. Diversified marketing was reported to be the second most preferred tool for all three crop categories.As expected, their preferences were closely linked to availability. The most available tools were crop insurance for orchard crops and crop diversification for vegetables and ornamental crops . Orchard and vineyard farmers reported relatively limited availability of other risk management tools.About 53 percent of fruit/nut farmers, 31 percent of vegetable farmers, and 13 percent of ornamental crop farmers said they had purchased crop insurance in the preceding five years and most of those farmers had purchased it for all five years Single-peril insurance is mostly offered by private firms, most commonly for damage from frost, rain, and hail. This insurance was purchased by about 20 percent of fruit/nut farmers and about 10 percent of vegetable farmers.

A constellation of bird cages suspended like lanterns house paper canaries, possibly metaphoric bellwethers for the fortunes of a site, that was after all, was once a mine.Situated 1 km away as the crow flies, but considerably further around the lake shore on foot, the University Gardens comprised projects by nine design schools.Whereas the garden plots allotted to each Master’s Garden were relatively level and orthogonal with a thick bamboo buffer, the University Garden sites exhibited a quite different set of conditions. Set on the banks of one of the Expo’s artificial lakes, half of the garden sites occupy direct water frontage, while those further up-slope benefit from the enhanced overview that comes with elevation. With a greater divergence of lot sizes ranging between 7 500 and 13 000 sq ft, the typically elongated and irregular form of the sites increased the perimeter-to-area ratio of each garden when compared to the more symmetrical Masters’ Garden plots. Furthermore, unlike the Masters’ Gardens, no bamboo buffer was predetermined, so that the individual garden plots were by default directly adjacent and entirely open to neighboring allotments and the surrounding landscape, further amplifying the effect of interface rather than the introversion associated with the Masters’ sites . In the descriptions that follow, I roughly corral the nine University Gardens into four categories; sensory, labyrinthine, representation,blueberry planter and process. As per the masters gardens, I use this draft rubric to explore two University Gardens in detail, two at a more cursory level, and the remaining five in passing.

Three gardens effectively elevate the non-visual senses, so famously repressed as unreliable and deviant under the rationalist hegemony of the all conquering eye of modernity. Employing a multifaceted indulgence of the olfactory senses, the Scent Garden by the University of Toronto is the most legible example . A grove of conifers provides the base-scent, amongst which a survey grid of perforated poles use wind-generated turbines to dispense accent aromas. Finally, a crystal pavilion displays bottled fragrances in the round, acting as a kind of scent-bank for posterity. The Sky Garden by the University of Southern California aims to amplify the sense of touch; not in terms of the haptics of rough and smooth texture, but as a membrane through which the interoceptive senses ascertain temperature . The garden generates extreme microclimates with two mechanical contraptions; at one end a half sphere of adjustable reflective plates creates a solarium effect, while at the other, a complex three-dimensional matrix of overhead wires houses an array of mist emitters forming an artificial cloud. By destabilizing the very ground that we move on, The Net garden by Peking University amplifies the internal feedback mechanism which tracks the relative position of parts of the body to the top of the sensory hierarchy . A field of multi-canted planes clad in flexible expanded mesh of various gauges destabilizes movement, forcing the visitor to recalibrate the habits of bodily calibration and orientation. Despite massively over-engineered safety balustrades that were installed against the designer’s wishes, the garden invokes Shusaku Arakawa and Madeline Gins’ early fractalized Perceptual Landing Sites, where ‘forcing the body off balance forces it to show itself for whom or what it is’.To experience moving over this alien scape requires an investment of effort; as Phillip Ball notes, ‘journeys in fractal land are arduous’, they are ‘noisy and unpredictable’.For Arakawa and Gins, through the act of negotiating the many inclines and declines of the fractalized surface, the perceiver ‘…switches off automatic and onto alert; she realizes that she must, from now on, anticipate the consequences of her every move’.

Over this ‘difficult ground’,visitors become so preoccupied with the immediacies of proprioceptive action that they neglect to maintain sight of the larger picture, leaving themselves vulnerable to disorientation. When moving in such a tactical manner, the distant goal-oriented nature of vision is used less for direction-finding, although the eyes still have a role to play, albeit in a revised capacity.Close vision is body-based in the sense that when it judges distances and textures, it does so not to control or indulge a scene, but to guide the immediacies of movement. Evaluating bodily potential to move between or make contact with a succession of objects, vision effectively becomes a haptic sense; much in the way that bats use their ears to see, the eyes are no longer a device for seeing, but for feeling. In this mode of operation, distant landmarks and sightlines go unnoticed, leaving navigational duties to the habitual nature of proprioception, which is only able to keep the body oriented in the short term. Like the gyroscopes used to track dead-reckoning vectors in ships and airplanes, the error compounded from registering many body-referenced direction changes provides an unreliable account of one’s passage. Indeed, when the visitor steps off The Net and back onto dry land, there is a moment of re-acclimatizing sea legs where we discover that we cannot readily reconcile our point of entry with our exit. Soon—as we look up from our feet and recalibrate distant vision—we re-establish orientation, but while the disjunction lasts, we are, in the words of Arakawa and Gins, ‘more body and less person’. As the only labyrinthine exhibit amongst the University Gardens, the Garden of the Forking Paths by U.C. Berkeley plays on the notion of choice without lucid outcomes . Framed on two sides by a bamboo frame, the garden is entered through a single aperture at the highest corner of the site. Having crossed this threshold,nft channel a critical scene confronts the visitor: the path bifurcates repeatedly, so that one way becomes many, fanning out over the convex landform that runs down to the lake. At eye height, small trees partially obfuscate the view ahead, making the relative value of each fork unclear.

Either side of the path, two flush steel channels are fed with water upwelling from a single source; each time the path bifurcates, the water runnels are also split in concert. At each fork, the visitor must make a choice and then again and again. Further, as the way becomes clearer, paths begin to topographically separate on the vertical axis. Some runnels also separate from pathways, holding level as the path falls away with the lie of the land. One path becomes thirty—some resolving seamlessly at the lake level, others requiring steps to make the transition. At the far corner of the garden, a bonsai tree balances on an elevated but unreachable plane that meets eye level as one descends the adjacent steps. In the collective Chinese imagination, rivers flow from west to east, but the Chan-Ba River, upon whose floodplain the garden is situated, flows in reverse—from east to west . Referencing this site-specific hydrological myth, the garden concept reverses the automated tendency of water to converge, establishing in its place a system of divergent flows of both people and hydrology. Read metaphorically, the bifurcating flows question a worldview in which history converges to form a meta-narrative. Within this familiar order, the tributaries of history, like water, progress downstream converging inextricably towards a single cogent outcome; ‘we say that time flows’, notes Bernard Cache, ‘but we also place ourselves in landscape where … we are already funneling it into a gullet’.Inverting this pattern creates multiplicity rather than resolution; the notion of parallel worlds or stories rather than singular histories. It implies a type of labyrinth with a single entrance and many exits, where each egress is slightly different, invoking perhaps the Borgesian short story in which the Garden of Forking Paths becomes to be understood as ‘an enormous riddle, or parable, …a growing, dizzying net of divergent and parallel times’.But unlike the matrix labyrinth and the single-path labyrinth , the forking labyrinth is never clearly resolved with a critical revelation or a return to the beginning. In the case of the Garden of the Forking Paths, being delivered down to the lake edge is evasive but is reward enough.Unlike the Masters’ Gardens, which focused on the representation of mythical landscapes and nation-states, the two representationally oriented University Gardens attempted the translation of the designers’ home ‘range’ into hilltop garden plots. In the most extreme example, the Pampa Traces garden by Universidad Torcuato de Tella seeks to literally translate an iconic Argentinean landscape to the other side of the world . The Wind Poem garden by University of Hong Kong takes a contrasting approach, viewing the garden as an opposite foil to the restless 24hr lifecycle of their city; the world’s densest.By seeking to embody and amplify dynamic ecological processes, this category included the most polemic garden proposals of the university collection. With waterfront locations, two of the gardens make use of the potentially dynamic interstitial edge of the lake. Seeking scaffoldings for secessional ecologies, the Eco-Plane garden by Columbia University uses a sliding deck while the Thickened Waterfront garden by the Architectural Association employs an enfolded landform of miniature ecotones and peninsulas. Eco-Time garden by Feng Chia University takes a more cybernetic approach wiring up green columns that are designed to dematerialize under the future cloak of verdancy.

To be sure, while processualconcepts are integral to landscape design theory and praxis, it is difficult terrain in a garden expo, given the short window for ‘ecological emergence’ and the singular nature of most visitations; just as geological time is invisible to us in the landscape, so too emergent time is invisible to the Expo visitor.When explicitly interpreted by a designer or commentator, individual garden references become explained. But without such guidance, what do the general public make of these cryptic projects that are so different from the other transparent thematics on offer at the Expo? In this context, is it, as Jane Gillette postulates, ‘very difficult for the garden designer to express complex ideas using only the garden’, and even more ‘difficult for an audience to ‘read’ them’?In this regard, I observe two meta-approaches within the gardens under discussion. Regarding the first, many of the gardens in focus can be defined as theme gardens under Marc Treib’s definition of a theme as ‘perceptually apparent idea’ that has been applied ‘to fashion the garden’s form’. Treib concedes that an ‘obvious concept’ does not necessarily imply significance, but does nevertheless carry a certain ‘underlying assertion of validity’.For example, the labyrinthine-type gardens traded in the stability of a universally accepted theme with which to ground this semiotic transferal between designer and audience. Once the visitor accepts the terms-of-reference that typically come attached to a labyrinth, they appear more open to accepting the garden as a ‘game-board’ and indulging in its idiosyncrasies. Meaning is constructed in a closed/open exchange; while the designer establishes a scaffolding of meaning, the audience seeks to unwittingly deconstruct this edifice by flooding the garden like water or like ants, investigating every interstitial nook for holes and gaps and in the process evolving the dynamic significance of the garden. Here, in answer to Gillette, complex ideas are expressed through the garden, but most importantly they are also received. The great risk associated with themes is their potential for wearing out through overuse, and indeed the labyrinth—although handled with inventive dexterity by those designers who employed it at the Expo—treads this fine line between novelty and cliché. The second meta-approach encompasses garden designs that do not fall so readily under an obviously identifiable concept. To appropriate Treib’s usage of the term, I identify these approaches under the rubric of ‘zeitgeist; they seek to substitute stable but potentially exhausted garden themes with inventions that attempt to capture the essence of a contemporary cultural preoccupation. The ‘processual’ type gardens that I identified as characterizing a number of University Gardens—and to a lesser extent some of the ‘representational’ gardens—fall under this umbrella. Each attempted to build significance around fluid concepts of ecology and process, ideas which are by no means new, but are yet to establish agreed safety lines of communication between author and audience. The result was that zeitgeist gardens had no fallback position and tended to rely on their own self-referential narrative. In these instances semiotic transferal—whether intended or fabricated—was demonstrably absent on the ground, and the limitations of the garden as a conveyor of complex syntax was exposed.