The cuticles of tomato and soybean leaves are much thinner, and therefore foliar absorption will be more rapid. Here, our findings indicate that a relatively high percentage of total Zn in the leaves from foliar applications would be bound to the cell wall rather than be present in a soluble, intercellular form. Zn mainly exists in a bound form in the cytoplasm, as well as in other cellular compartments, to avoid uncontrolled Zn2+ binding to nontarget sites. Various studies have also shown that the abundance of negatively charged sites in the cell wall limits the translocation of positively charged Zn2+ . For example, the major component of pectin in cell walls is polygalacturonic acid, which has a high binding capacity for Zn2+.Our previous research also shown that most of the Zn was deposited in the cell walls of apple leaves in coordination with different stages of development, with the nature of Zn binding being dependent on tissue age, as old and mature leaves exhibited higher proportions of Zn in the cell wall than young leaves. In general, there is low potential for remobilization of foliar-absorbed nutrients until the potential binding sites for that element within the leaf are saturated. Therefore, we hypothesized that there would be very limited utilization of Zn applied to the adaxial leaf surface because of the highly hydrophobic cuticular wax layer that would limit Zn penetration,dutch bucket wholesale as well as having a higher capability for cationic Zn fixation.

Previous studies have suggested that there is high diversity among trichome structure and function, which can hinder or promote water penetration. In the present study, we found that a relatively high trichome density resulted in a high degree of hydrophobicity , which was not consistent with the results of several studies that reported that trichomes may participate actively in the absorption of water and foliar-applied nutrient solutions. These differences may be related to the surface roughness provided by the high density, chemical composition, and structure of trichomes on apple leaves. The high density of nonglandular trichomes creates the hydrophobic characteristic of apple abaxial leaf surfaces to a certain degree, and repulsion of fertilizer drops by abaxial leaf trichomes could hinder the penetration of liquid Zn solutions. Our findings were similar to the results of Fernandez et al., who used Holm oak as a model to assess the capability of abaxial surfaces versus adaxial surfaces to absorb surface-deposited water drops. Another study by Li et al. also demonstrated that trichomes are not part of the primary pathway through which foliar-applied Zn moves across the leaf surface, even though Zn was found to accumulate around the base of trichomes. On the other hand, the possible contribution of stomata to the penetration of leaf-applied chemicals has been a matter of controversy for many decades, and it is still not fully understood whether stomata allow the penetration of foliar-applied solutes. Nonetheless, several studies show a clear effect of stomata in promoting foliar solute penetration, even in the absence of surfactants. However, the underlying mechanism is not understood, although it is hypothesized that penetration of solutes through stomata is restricted by their morphological and physical properties. Our study provides further evidence that supports the relevance of stomatal nutrient absorption, as indicated by the increased penetration rates from plant surfaces whose stomata were present and open.

Information about nutrient interactions will guide fertilization practices and optimize the efficiencies of fertilization strategies. The levels of two different elements for each pixel in an XRF data set can often provide important chemical information.Here, we analyzed the ionic changes that occurred in leaves in response to foliar Zn application to reveal the interactions between and homeostasis of Zn and other metals. Induction of element accumulation was observed after foliar Zn penetration for all the tested nutrients . One of the possible reasons for this promotional effect may be the important role of Zn in the constituents of enzymes involved in photosynthesis. The concentration of water-soluble Zn in leaves was found to be closely correlated with the levels of chlorophyll. The positive influence of foliar Zn fertilizer on photosynthesis and chlorophyll synthesis may help increase mineral nutrient absorption and accumulation in functional mature leaves. A reduction in this accumulation was observed for Mn and Fe along with a further increase in Zn. This might be due to the possible Zn toxic reaction in the treated leaves because locally toxic levels of Zn may occur at the point of fertilizer application. Excess Zn may cause uncontrolled displacement of essential cofactor metal cations such as Mn2+ and Fe2+. For example, it was reported that exposure to high Zn can subsequently inhibit PSII activity by replacing Mn in thylakoid membranes. The underlying mechanisms of the above effects remain uncertain, and further research is needed to uncover the complex interaction between foliar Zn status and plant nutrient responses. The increased spatial correlation of Zn versus P along with the penetration of foliar Zn fertilizer , together with the presence of Zn-phytic acid in the treated leaves , suggested that P may play an important role in the complexation of Zn, potentially in response to toxic concentrations of Zn.

The formation of Zn-phytic acid in vegetative tissues was reported to occur under two circumstances: within some hyperaccumulator species or under conditions in which plants are exposed to high exogenous Zn concentrations, the binding of Zn to phytic acid helps plants limit Zn mobility and reduces toxicity. Our results were consistent with the previous findings showing an increased proportion of Zn-phytate in wheat leaves after Zn-EDTA and ZnSO4 applications. Agronomic strategies aim to deliver phyto available Zn via the application of Zn fertilizers to leaves. Knowledge of the ability and mechanism of Zn to penetrate the leaf surface from the site of application and the factors that are associated with penetration efficiency is critical for the development of strategies for Zn bio-fortification of crops. In the present study, the high spatial resolution and direct imaging capability of XRF was valuable for distinguishing differences in Zn penetration of epidermal cells,blueberry grow pot and these techniques provided a powerful strategy for investigating foliar microelement applications to plants with a high level of sensitivity. By the use of micro- and nano-XRF techniques, our results provide direct visual evidence for Zn penetration of the leaf surface. Furthermore, we provide new insights that can help in the development of Zn bio-fortification approaches in fruit crops. To further increase the Zn content in food crops, future studies need to focus on elucidating the pathway by which Zn penetrates plant leaves, the subcellular compart mentation of Zn, and the specific formulation of Zn foliar fertilizers.Educational theorists have recently begun to call for more immersion of trainee scientists and medical practitioners in the humanities, particular through the study of history as part of their educational program. In a widely circulated analysis that first appeared in an August 2014 Inside Higher Education supplement, Elizabeth H. Simmons suggests that “to fully prepare for careers in science, it is essential that students grasp how the impetus for scientific work arises from the world in which the scientist lives, often responds to problems the scientist has personally encountered, and ultimately impacts that society and those problems in its turn.” Every nascent scientist, according to Simmons, “should read, think, and write about how science and society have impacted one another across cultural and temporal context” because “ethical concepts absorbed” in such study will help them “hew more closely to the scientific ideal of seeking the truth.”Since C.P. Snow’s famous 1959 Rede Lecture lamented the gap between the “Two Cultures” of the sciences and humanities, academic initiatives such as Stanford University’s Science, Society, and Technology program have been founded to assert the wider societal impact of the natural sciences.Yet far fewer programs and courses have been designed to show how scientific endeavors might benefit from the study of the humanities, particularly history.

The newest version of the Medical School Admissions Test now encompasses questions on the psychological, social, and biological determinants of behavior to ensure that admitted medical students are “prepared to study the sociocultural and behavioral aspects of health.” But as Simmons notes, while “pre-medical and engineering students are being required to learn about issues linking science and culture, most students in science fields are still not pushed to learn about the human context of their major disciplines.”As Dean of the College of Liberal Arts at Michigan State University, Simmons may well know that her state’s own educational system incorporates a project with important implications for the nexus between the humanities and the sciences. The Decolonizing the Diet project at Northern Michigan University has begun to show how the study of early American history – particularly Native American history – can inform public policy and healthcare paradigms, while also impacting the agenda of cutting edge research in the biological, nutritional, and ecological sciences. In the project, students and local community members have learned how the move away from their ancestral nutritional principles has been detrimental to the health of Native Americans and the wider ecology of the Great Lakes region of North America. Aware of disproportionate instances of diabetes, heart-disease, depression, fertility problems, and chronic inflammatory conditions, project members have studied and then simulated pre-European contact Native American diets, using historical and anthropological methods. They have even begun to produce medically-relevant data on improvements in health and well-being after their nutritional intervention. A similar project, the American Indian Health and Diet Project , has been inspired by the work of Devon Abbott Mihesuah, a Choctaw historian and writer. Through her teaching and writing, Mihesuah has used the study of history, anthropology, and literature to inform contemporary health and nutritional practices – coming a little closer to the diets that many Native American communities consumed prior to European contact.The Decolonizing the Diet project is currently restricted to the Great Lakes region, where the authors of this article reside and work. As a professor of history and a researcher in biological science, we aim to show how a model course in the University of Minnesota system might offer a new pedagogical paradigm for the study of ancestral health principles. The course builds on the aims of the existing projects detailed above. But it also synthesizes their methods and objectives with the latest peer-reviewed research in evolutionary health and nutrition, bringing about new insights and research paradigms relating to the link between nutrition, metabolic health, and immunity to infectious disease. Some recently founded nutritional programs have aimed to educate public-sector workers in order to prevent a mismatch between their optimal nutrition, as understood from within an evolutionary health framework, and their current eating habits.This article demonstrates how the same public health agenda might be explored from within a large public research university system, led by a joint effort between professors in the humanities and teachers and researchers in the biological sciences. The 1862 Morrill Land-Grant Acts defined the American public research university’s ongoing mission “to promote the liberal and practical education of the industrial classes in the several pursuits and professions in life.”From the 1950s scientists used the land-grant system to ally their scientific and nutritional research with new policies that came to be promoted by the federal government. Within the University of Minnesota system, for example, Ancel Keys famously sought a new research agenda in order to question the health benefits of fats from animals, fish, and dairy. Contrary to those who highlighted the problematic medical implications of foods that were readily converted into glucose, as well as the potential inflammatory effects of polyunsaturated fats, Keys and others used their land-grant mandate to promote research that supported the government of the day in its stated desire to increase agricultural output in soy, wheat, corn, and seed oils.Scholars, scientists, public policy analysts, and journalists have begun to suggest that the resulting federally recommended food-pyramid has worsened certain aspects of American public health, particularly through the associated growth of metabolic disorders such as diabetes, and even in the prevalence of certain forms of heart disease .This article examines the present state of historical research in early American studies in order to assess whether similarly problematic associations and health markers appeared among Native American communities many decades – and even centuries – before the development of the problematic modern American food pyramid.