Agronomy and Crop Sciences Commons^™

Aquaporins Contribute To Aba-Triggered Stomatal Closure Through Ost1-Mediated Phosphorylation, Alexandre Grondin, Olivier Rodrigues, Lionel Verdoucq, Sylvain Merlot, Nathalie Leonhardt, Christophe Maurel

Department of Agronomy and Horticulture: Faculty Publications

Stomatal movements in response to environmental stimuli critically control the plant water status. Although these movements are governed by osmotically driven changes in guard cell volume, the role of membrane water channels (aquaporins) has remained hypothetical. Assays in epidermal peels showed that knockout Arabidopsis thaliana plants lacking the Plasma membrane Intrinsic Protein 2;1 (PIP2;1) aquaporin have a defect in stomatal closure, specifically in response to abscisic acid (ABA). ABA induced a 2-fold increase in osmotic water permeability (P_f) of guard cell protoplasts and an accumulation of reactive oxygen species in guard cells, which were both abrogated in …

A Dedicated Type Ii Nadph Dehydrogenase Performs The Penultimate Step In The Biosynthesis Of Vitamin K1 In Synechocystis And Arabidopsis, Abdelhak Fatihi, Scott Latimer, Stefan Schmollinger, Anna Block, Patrick Dussault, Wim F.J. Vermaas, Sabeeha S. Merchant, Gilles J. Basset

Department of Agronomy and Horticulture: Faculty Publications

Mutation of Arabidopsis thaliana NAD(P)H DEHYDROGENASE C1 (NDC1; At5g08740) results in the accumulation of demethylphylloquinone, a late biosynthetic intermediate of vitamin K₁. Gene coexpression and phylogenomics analyses showed that conserved functional associations occur between vitamin K biosynthesis and NDC1 homologs throughout the prokaryotic and eukaryotic lineages. Deletion of Synechocystis ndbB, which encodes for one such homolog, resulted in the same defects as those observed in the cyanobacterial demethylnaphthoquinone methyltransferase knockout. Chemical modeling and assay of purified demethylnaphthoquinone methyltransferase demonstrated that, by virtue of the strong electrophilic nature of S-adenosyl-Lmethionine, the transmethylation of the demethylated precursor …

Proteomic Profiling Of Maize Opaque Endosperm Mutants Reveals Selective Accumulation Of Lysine-Enriched Proteins, Kyla J. Morton, Shangang Jia, Chi Zhang, David R. Holding

Department of Agronomy and Horticulture: Faculty Publications

Reduced prolamin (zein) accumulation and defective endoplasmic reticulum (ER) body formation occurs in maize opaque endosperm mutants opaque2 (o2), floury2 (fl2), defective endosperm*B30 (DeB30), and Mucronate (Mc), whereas other opaque mutants such as opaque1 (o1) and floury1 (fl1) are normal in these regards. This suggests that other factors contribute to kernel texture. A liquid chromatography approach coupled with tandem mass spectrometry (LC-MS/MS) proteomics was used to compare non-zein proteins of nearly isogenic opaque endosperm mutants. In total, 2762 proteins were identified that were enriched for biological processes such as protein transport and folding, amino acid biosynthesis, …

Tonoplast Sugar Transporters (Sbtsts) Putatively Control Sucrose Accumulation In Sweet Sorghum Stems, Saadia Bihmidine, Benjamin T. Julius, Ismail M. Dweikat, David M. Braun

Department of Agronomy and Horticulture: Faculty Publications

Carbohydrates are differentially partitioned in sweet versus grain sorghums. While the latter preferentially accumulate starch in the grain, the former primarily store large amounts of sucrose in the stem. Previous work determined that neither sucrose metabolizing enzymes nor changes in Sucrose transporter (SUT) gene expression accounted for the carbohydrate partitioning differences. Recently, 2 additional classes of sucrose transport proteins, Tonoplast Sugar Transporters (TSTs) and SWEETs, were identified; thus, we examined whether their expression tracked sucrose accumulation in sweet sorghum stems. We determined 2 TSTs were differentially expressed in sweet vs. grain sorghum stems, likely underlying the massive difference in sucrose …

Selection For Silage Yield And Composition Did Not Affect Genomic Diversity Within The Wisconsin Quality Synthetic Maize Population, Aaron Lorenz, Timothy M. Beissinger, Renato Rodrigues Silva, Natalia De Leon

Department of Agronomy and Horticulture: Faculty Publications

Maize silage is forage of high quality and yield, and represents the second most important use of maize in the United States. The Wisconsin Quality Synthetic (WQS) maize population has undergone five cycles of recurrent selection for silage yield and composition, resulting in a genetically improved population. The application of high-density molecular markers allows breeders and geneticists to identify important loci through association analysis and selection mapping, as well as to monitor changes in the distribution of genetic diversity across the genome. The objectives of this study were to identify loci controlling variation for maize silage traits through association analysis …

A Roadmap For Functional Structural Variants In The Soybean Genome, Justin E. Anderson, Michael B. Kantar, Thomas Y. Kono, Fengli Fu, Adrian O. Stec, Qijian Song, Perry B. Cregan, James E. Specht, Brian W. Diers, Steven B. Cannon, Leah K. Mchale, Robert M. Stupar

Department of Agronomy and Horticulture: Faculty Publications

Gene structural variation (SV) has recently emerged as a key genetic mechanism underlying several important phenotypic traits in crop species. We screened a panel of 41 soybean (Glycine max) accessions serving as parents in a soybean nested association mapping population for deletions and duplications in more than 53,000 gene models. Array hybridization and whole genome resequencing methods were used as complementary technologies to identify SV in 1528 genes, or approximately 2.8%, of the soybean gene models. Although SV occurs throughout the genome, SV enrichment was noted in families of biotic defense response genes. Among accessions, SV was nearly eightfold less …

Overexpression Of The Transporters Atzip1 And Atmtp1 In Cassava Changes Zinc Accumulation And Partitioning, Eliana Gaitán-Solis, Nigel J. Taylor, Dimuth Siritunga, William Stevens, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Zinc deficiency in humans is a serious problem worldwide with an estimated one third of populations at risk for insufficient zinc in diet, which leads to impairment of cognitive abilities and immune system function. The goal of this research was to increase the bioavailable zinc in the edible portion of cassava roots to improve the overall zinc nutrition of populations that rely on cassava as a dietary staple. To increase zinc concentrations, two Arabidopsis thaliana genes coding for ZIP1 and MTP1 were overexpressed with a tuber-specific or constitutive promoter. Eighteen transgenic events from four constructs, out of a total of …

Cover Crops And Ecosystem Services: Insights From Studies In Temperate Soils, Humberto Blanco-Canqui, Tim M. Shaver, John L. Lindquist, Charles A. Shapiro, Roger Wesley Elmore, Charles A. Francis, Gary W. Hergert

Department of Agronomy and Horticulture: Faculty Publications

Cover crops (CCs) can provide multiple soil, agricultural production, and environmental benefits. However, a better understanding of such potential ecosystem services is needed. We summarized the current state of knowledge of CC effects on soil C stocks, soil erosion, physical properties, soil water, nutrients, microbial properties, weed control, crop yields, expanded uses, and economics and highlighted research needs. Our review indicates that CCs are multifunctional. Cover crops increase soil organic C stocks (0.1–1 Mg ha^–1 yr^–1) with the magnitude depending on biomass amount, years in CCs, and initial soil C level. Runoff loss can decrease by up …

Genetic Control Of Morphometric Diversity In The Maize Shoot Apical Meristem, Samuel Leiboff, Xianran Li, Heng-Cheng Hu, Natalie Todt, Jinliang Yang, Xiao Li, Xiaoqing Yu, Gary J. Muehlbauer, Marja C.P. Timmermans, Jianming Yu, Patrick S. Schnable, Michael J. Scanlon

Department of Agronomy and Horticulture: Faculty Publications

The maize shoot apical meristem (SAM) comprises a small pool of stem cells that generate all above-ground organs. Although mutational studies have identified genetic networks regulating SAM function, little is known about SAM morphological variation in natural populations. Here we report the use of high-throughput image processing to capture rich SAM size variation within a diverse maize inbred panel. We demonstrate correlations between seedling SAM size and agronomically important adult traits such as flowering time, stem size and leaf node number. Combining SAM phenotypes with 1.2 million single nucleotide polymorphisms (SNPs) via genome-wide association study reveals unexpected SAM morphology candidate …

Differential Expression Analysis In Rna-Seq By A Naive Bayes Classifier With Local Normalization, Yongchao Dou, Xiaomei Guo, Lingling Yuan, David R. Holding, Chi Zhang

Department of Agronomy and Horticulture: Faculty Publications

To improve the applicability of RNA-seq technology, a large number of RNA-seq data analysis methods and correction algorithms have been developed. Although these new methods and algorithms have steadily improved transcriptome analysis, greater prediction accuracy is needed to better guide experimental designs with computational results. In this study, a new tool for the identification of differentially expressed genes with RNA-seq data, named GExposer, was developed. This tool introduces a local normalization algorithm to reduce the bias of nonrandomly positioned read depth. The naive Bayes classifier is employed to integrate fold change, transcript length, and GC content to identify differentially expressed …

Soil And Crop Response To Stover Removal From Rainfed And Irrigated Corn, Ian Kenney, Humberto Blanco-Canqui, Deann R. Presley, Charles W. Rice, Keith Janssen, Brian Olson

Department of Agronomy and Horticulture: Faculty Publications

Excessive corn (Zea mays L.) stover removal for biofuel and other uses may adversely impact soil and crop production. We assessed the effects of stover removal at 0, 25, 50, 75, and 100% from continuous corn on water erosion, corn yield, and related soil properties during a 3-year study under irrigated and no-tillage management practice on a Ulysses silt loam at Colby, irrigated and strip till management practice on a Hugoton loam at Hugoton, and rainfed and no-tillage management practice on a Woodson silt loam at Ottawa in Kansas, USA. The slope of each soil was <1%. One year after removal, complete (100%) stover removal resulted in increased losses of sediment by 0.36–0.47 Mg ha-1 at the irrigated sites, but, at the rainfed site, removal at rates as low as 50% resulted in increased sediment loss by 0.30 Mg ha-1 and sediment-associated carbon (C) by 0.29 kg ha-1. Complete stover removal reduced wet aggregate stability of the soil at the irrigated sites in the first year after removal, but, at the rainfed site, wet aggregate stability was reduced in all years. Stover removal at rates ≥ 50%resulted in reduced soil water content, increased soil temperature in summer by 3.5–6.8 °C, and reduced tem-perature in winter by about 0.5 °C. Soil C pool tended to decrease and crop yields tended to increase with an increase in stover removal, but 3 years after removal, differences were not significant. Overall, stover removal at rates ≥50% may enhance grain yield but may increase risks of water erosion and negatively affect soil water and temperature regimes in this region.

High Tunnel Design, Site Development, And Construction, Stacy A. Adams, Kim Todd

Department of Agronomy and Horticulture: Faculty Publications

High tunnels are low technology plant growing structures that provide opportunity for season extension, severe weather protection, and modified environments to increase productivity and visual quality of harvested plant products. This publication describes high tunnel components, site selection, development, covering materials, installation, and operation.

Experienced specialty plant growers can increase the quality of their products and the duration of their marketing of high- value crops through the use of high tunnels. High tunnels give growers the opportunity to plant earlier and include more sequential planting dates. This can result in early- season, high- dollar returns and the ability to offer …

Generation Of An Attenuated, Cross-Protective Pepino Mosaic Virus Variant Through Alignment-Guided Mutagenesis Of The Viral Capsid Protein, Godwill M. Chewachong, Sally A. Miller, Joshua J. Blakeslee, David M. Francis, Thomas Jack Morris, Feng Qu

School of Biological Sciences: Faculty Publications

Mild variants of many viruses are able to protect infected plants from subsequent invasion by more severe variants of the same viruses through a process known as cross-protection. In the past, the cross-protective viral variants were commonly derived from mild field isolates that were sometimes genetically heterogeneous, providing variable levels of crossprotection. Here, we report a novel approach to rapidly generate crossprotective variants of the tomato-infecting Pepino mosaic virus (PepMV) independently of the availability of mild field isolates. Our approach sought to attenuate PepMV by mutating less conserved amino acid residues of the abundantly produced capsid protein (CP). These less-conserved …

The Influence Of Production Practices, Tillage, And Endophytic Bacteria On Bell Pepper Productivity And Physiology Under Different Irrigation Regimes, Zheng Wang

Theses and Dissertations--Plant and Soil Sciences

To evaluate the strip tillage in organic bell pepper (Capsicum annuum L.) production as an integrated system for sustainable vegetable cropping two-years of field trials were conducted in 2011 and 2012. The field trials were conducted to determine the viability of strip tillage in conventional and organic bell pepper production systems by comparing plant growth, water status, and fruit yield to plastic mulch grown plants application under different irrigation regimes. The two-year field data demonstrated that organic pepper with strip tillage application was a viable combination that produced comparable yield to conventional plastic mulch system and utilized water more …

Conservation Agriculture In Kentucky: Investigating Nitrogen Loss And Dynamics In Corn Systems Following Wheat And Hairy Vetch Cover Crops, Rebecca Erin Shelton

Theses and Dissertations--Plant and Soil Sciences

Unintentional nitrogen (N) loss from agroecosystems produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, adoption of conservation agricultural management practices, such as no-till and cover cropping, has increased. This study assessed N loss via leaching, NH₃ volatilization, N₂O emissions, and N retention in plant and soil pools of corn conservation agroecosystems across a year. Three systems were evaluated: 1) an unfertilized organic system with cover crops Vicia villosa, Triticum aestivum, or a mix of the two; 2) an organic system with a Vicia cover crop employing three fertilization schemes (0 N, organic N, …

Inducing Stress Early And Reducing Stress Late To Increase Soybean (Glycine Max) Yield, Gary L. Gregg

Theses and Dissertations--Plant and Soil Sciences

Relatively little change in national soybean (Glycine max) yield over the previous years have led many farmers to creating management regimes focused on plant stress. Field experiments consisting of two different relative maturity (2.8RM and 4.5 RM) soybean cultivars were established at three locations across Kentucky in 2013 and 2014. Each maturity group received a single application, sequential applications, or a combination of the following treatments: N’N-diformyl urea, lactofen, lambda-cyhalothrin with thiamethoxam, and azoxystrobin with propiconazole. Relative maturity and yield environment*treatment interactions were observed to be significant (p 0≤.05). 4.5 RM soybean cultivars yielded significantly greater (800 kg …

Soil Management And Nitrogen Dynamics In Burley Tobacco Rotations, Congming Zou

Theses and Dissertations--Plant and Soil Sciences

Agronomic practices, including tillage, crop rotation and N fertilization, have been developed to efficiently manage soil N dynamics and crop N nutrition. These practices can affect soil organic carbon (SOC) and soil total nitrogen (STN) sequestration, and consequently influence soil nitrogen mineralization (SNM) and crop N nutrition. However, little research has been systematically and simultaneously conducted to examine the effect of agronomic management on (1) SOC and STN stocks; (2) SNM; and (3) crop N nutrition. Burley tobacco (Nicotiana tobacum L.) is a N demanding crop and subject to inefficiency in N fertilization. Moreover, conservation tillage and rotation have been …

Functional Analysis Of Drought-Resistant Genes In Barley Using Vigs, Natalie Catherine Martin

Honors Program Theses

The following study analyzed the role of the gamma-aminobutyric acid transaminase (GABAT) gene in the response of barley plants to drought stress. Expression of GABAT in barley was suppressed using virus-induced gene silencing (VIGS). In VIGS, an RNA virus is used to replicate a small portion of the target RNA. In this study, barley stripe mosaic virus (BSMV), that carries a piece of the GABAT gene to infect barley, was used. As the virus replicates inside infected barley plants, it also makes RNA that is complementary to GABAT messenger RNA (mRNA) that is normally made by the host. The presence …

Focus Paddocks Trial Report - Benchmarked Result Summary 2010 - 14, Martin Harries, Geoff Anderson

Grain and other field crops published reports

This report was co-funded by GRDC through project no. DAW00213 - Putting the Focus on Profitable Crop and Pasture Sequences in WA.

Crop and pasture sequences in south-western Australia have changed in the past decade. These survey results from the Focus Paddock project provide data to help growers employ profitable and sustainable crop and pasture sequences. The project compiled information on the nature, suitability and productivity of crop and pasture sequences from 184 paddocks over five years. The results of the analyses of chemical and physical attributes of the soil, weed counts and disease management are presented here.

The survey …

Evaluating A Satellite-Based Seasonal Evapotranspiration Product And Identifying Its Relationship With Other Satellite-Derived Products And Crop Yield: A Case Study For Ethiopia, Tsegaye Tadesse, Gabriel B. Senay, Getachew Berhan, Teshome Regassa, Shimelis Beyene

Department of Agronomy and Horticulture: Faculty Publications

Satellite-derived evapotranspiration anomalies and normalized difference vegetation index (NDVI) products from Moderate Resolution Imaging Spectroradiometer (MODIS) data are currently used for African agricultural drought monitoring and food security status assessment. In this study, a process to evaluate satellite-derived evapotranspiration (ETa) products with a geospatial statistical exploratory technique that uses NDVI, satellite-derived rainfall estimate (RFE), and crop yield data has been developed. The main goal of this study was to evaluate the ETa using the NDVI and RFE, and identify a relationship between the ETa and Ethiopia’s cereal crop (i.e., teff, sorghum, corn/maize, barley, and wheat) yields during the main rainy …

Germplasm Enhancement For Resistance To Pyrenophora Tritici-Repentis In Wheat, Manisha Shankar, Diane E. Mather, Dorthe Jorgensen, Hossein Golzar, Ken J. Chalmers, Grant J. Hollaway, Mark S. Mclean, Stephen M. Neate, Rob Loughman

Conference papers and presentations

Yellow spot (syn. tan spot), caused by Pyrenophora tritici-repentis, is an important foliar disease of wheat in Australia that causes losses exceeding 50 % when conditions are favourable for disease development. Although good progress has been made internationally to understand yellow spot resistance, relatively few resistance genes have been identified and mapped in Australian germplasm and only one (tsn1 on chromosome 5BL) is in general and known use in Australian breeding programs. Although tsn1 is an important yellow spot resistance gene, it doesn’t explain the full spectrum of resistance and there is a significant opportunity to enhance expression …

A Real-Time Plant Discrimination System Utilising Discrete Reflectance Spectroscopy, Paul Symonds, Arie Paap, Kamal Alameh, J Rowe, C Miller

Research outputs 2014 to 2021

An advanced, proof-of-concept real-time plant discrimination system is presented that employs two visible (red) laser diodes (635. nm, 685. nm) and one near-infrared (NIR) laser diode (785. nm). The lasers sequentially illuminate the target ground area and a linear sensor array measures the intensities of the reflected laser beams. The spectral reflectance measurements are then processed by an embedded microcontroller running a discrimination algorithm based on dual Normalised Difference Vegetation Indices (NDVI). Pre-determined plant spectral signatures are used to define unique regions-of-classification for use by the discrimination algorithm. Measured aggregated NDVI values that fall within a region-of-classification (RoC) representing an …

Interplanting Annual Ryegrass, Wheat, Oat, And Corn To Mitigate Iron Deficiency In Dry Beans, Emmanuel Chiwo Omondi, Andrew R. Kniss

Agricultural and Environmental Sciences Faculty Research

This study evaluated whether grass intercropping can be used to alleviate Fe deficiency chlorosis in dry beans (Phaseolus vulgaris L.) grown in high pH, calcareous soils with low organic matter. Field studies were conducted at the University of Wyoming Sustainable Agriculture Research and Extension Center in 2009 and 2010. Black- and navy beans were grown alone or intercropped with annual ryegrass (Lolium multiflorum Lam.), oat (Avena sativa L.), corn (Zea mays L.), or spring wheat (Triticum aestivum L.) in a two-factor factorial strip-plot randomized complete block design. All four grass species increased chlorophyll intensity in dry beans. However, grass species …

Soil Carbon And Nitrogen Mineralization And Crop Parameters In Typical Maize-Bean Intercropping In Western Kenya, Judith A. Odhiambo, Urszula Norton, Emmanuel C. Omondi, Dennis Ashilenje, Jay B. Norton

Agricultural and Environmental Sciences Faculty Research

Smallholder farmers in western Kenya who plant maize (Zea mays L.) intercropped with beans (Phaseolus vulgaris L.) face many challenges associated with nutrient-poor soils and weather-related crop failures. In regions where temperatures are favorable, crops are grown twice per year during long and short rainy seasons and in other regions, once per year during one long growing season. Growing crops two times per year necessitates frequent land preparation using inversion-type tillage. Little is known about the impact of current tillage-intensive crop management on annual soil organic matter (SOM) recovery. The aim of this study was to assess changes to soil …

Metabolic Engineering Of Oilseed Crops To Produce High Levels Of Novel Acetyl Glyceride Oils With Reduced Viscosity, Freezing Point And Calorific Value, Jinjie Liu, Adam Rice, Kathleen Mcglew, Vincent Shaw, Hyunwoo Park, Thomas E. Clemente, Mike Pollard, John Ohlrogge, Timothy P. Durrett

Department of Agronomy and Horticulture: Faculty Publications

Seed oils have proved recalcitrant to modification for the production of industrially useful lipids. Here, we demonstrate the successful metabolic engineering and subsequent field production of an oilseed crop with the highest accumulation of unusual oil achieved so far in transgenic plants. Previously, expression of the Euonymus alatus diacylglycerol acetyltransferase (EaDAcT) gene in wild-type Arabidopsis seeds resulted in the accumulation of 45 mol% of unusual 3-acetyl-1,2- diacyl-sn-glycerols (acetyl-TAGs) in the seed oil (Durrett et al., 2010 PNAS 107:9464). Expression of EaDAcT in dgat1 mutants compromised in their ability to synthesize regular triacylglycerols increased acetyl-TAGs to 65 mol%. Camelina and soybean …

Dissection Of Gray Leaf Spot Of Maize Through Functional Genomics, Robert Louis Hirsch

Graduate Theses and Dissertations

Gray leaf spot, caused by Cercospora zeae-maydis, is a devastating disease of maize that reduces yields and increases management costs. C. zeae-maydis penetrates maize leaves through stomata, but the biological and molecular bases of this process are poorly understood. The goal of this research was to elucidate the biological parameters of stomatal infection in C. zeae-maydis, and to identify and characterize novel genetic pathways involved in stomatal sensing and pathogenesis. Histopathological observations of a GFP-expressing strain of C. zeae-maydis during infection of maize indicated that the fungus responded to host-derived stomatal cues during the infection process. C. zeae-maydis was observed …

The Phenotypic Effects And Transcript Response Of Salt Stress, The Impact Of Viral Infection On Salt Stress Symptoms, And The Effect Of Salt Stress On Soybean Virus Vector Activity In Soybean Varieties That Vary In Chloride Uptake, Alma Glenn Laney

Graduate Theses and Dissertations

With the increase in saline soils worldwide, understanding the mechanisms for salt tolerance in plants is important to reduce yield loss due to salt stress. Soybean, Glycine max (L.) Merr., genotypes differ in chloride uptake with genotypes that take up chloride into foliar tissues tending to be salt-sensitive whereas those that partially exclude chloride from the leaves are more salt-tolerant. Transcriptional and physiological responses were measured in two soybean cultivars, Clark and Manokin, which differ in chloride uptake in response to salt stress and in combination with Soybean mosaic virus (SMV) and its aphid vector, Aphis glycines . The interaction …

The Effects Of Poultry Litter Biochar And Water Source On Radish Growth And Nutrition, Julia Marie Allen

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Many row-crop fields today have declined in soil fertility due to poor management practices and overuse of pesticides. Under these conditions, plant nutrient uptake can be sub-optimal. There are several soil amendments that can be used to improve soil quality and plant growth such as traditional fertilizers and manure applications. This study focused on the addition of biochar to the soil and the use of structured water to enhance plant growth. Biochar is a nutrient rich product that is produced by pyrolysis of organic feedstocks and contains high rates of carbon. Previous studies which focused on biochar have shown an …

Winter Field Pea As A Leguminous Cover Crop In Corn Production, Matthew Carroll Marsh

Graduate Theses and Dissertations

Leguminous cover crops, which fix nitrogen (N) from the atmosphere and add to the N content of the soil, have the potential to replace or partially replace commercial nitrogen fertilizers. In this experiment, field pea (Pisum arvense) was used as the leguminous cover crop in a conventional tilled corn (Zea mays) production system. In a 2-yr experiment (2008 and 2009), conducted at two locations in Arkansas, field pea was planted on half the field in the fall and allowed to grow until late April to early May. Field pea biomass was recorded, N content of biomass determined and then the …

Studies To Characterize Heavy Metal Content And Migration From Recycled Polyethyleneterephthalate, Michael John-Ross Whitt

Master's Theses

Packaging Materials account for 31% of the world’s municipal solid waste. Agencies like the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) are pushing for the increased use of recycled thermoplastic materials. Polyethylene terephthalate (PET) is a commonly recycled thermoplastic which is used to package ready-to-eat fruits and vegetables. Most recycled polyethylene terephthalate (RPET) packaging materials contain heavy metal catalysts, the most common being antimony. The recent increased use of recycled plastic materials has been suspected as the source of increased human heavy metal exposure. In this study, cadmium, chromium, nickel, lead and antimony …