Brassica vegetables play a unique nutritional and sensory role in human diets around the world. Their characteristic flavors come from the break down products of glucosinolate (GS) compounds, a large group of nitrogen (N) and sulfur (S) containing glucosides. Glucosinolates are hydrolyzed by myrosinase to isothiocyanates (ITCs) which are biologically active. Mounting evidence of this process is of scientific interest due to the potential for high consumption of Brassica vegetables containing several GSs and their respective hydrolysis products that are associated with cancer chemoprevention. Glucosinolates are sulfur-rich hydrophilic, nonvolatile plant secondary metabolites; and. over the past few decades, their importance has increased following discoveries of their hydrolysis products, ITCs, as potential anticarcinogens. The importance of selenium (Se) to human health has increased in recent years due its antioxidant potential and cancer suppression properties. Recent studies have demonstrated that certain Se containing compounds like Se-methyl-Se-Cysteine and Se-methionine are effective chemoprotective agents, reducing the incidence of breast, liver, prostate, and colorectal cancers in model systems. Brassicaa species are able to hyperaccumulate selenium at concentrations of up to 10-15 mg Se·g-1 dry weight in their shoots while growing on naturally-occurring soils containing only 0.2-10 mg Se·kg-1. The non-specific integration of Se into the S assimilation pathway enables the plant to metabolize selenoamino acids, selenocysteine and selenomethionine, into proteins. The process is believed to be the major contributor of Se toxicity in plants. The ability of hyperaccumulators to accrue and tolerate high concentrations of Se is thought to be associated with a distinct metabolic capacity that enables the plants to convert these selenoamino acids into non-protein amino acids.

Flue Gas Desulfurization (FGD) gypsum is a potential soil amendment for agricultural use in the state of Tennessee. FGD gypsum is a potential source of calcium and sulfur that may improve the soil both chemically and physically. FGD gypsum has the potential to raise pH, improve soil structure, increase infiltration rates, ameliorate subsoil acidity and improve crop yields. However, the addition of gypsum can also lower pH in some circumstances and cause magnesium and potassium losses in soil. In this study FGD gypsum was applied at a single rate to fields on thirteen farms located on the northern and southern Highland Rim and in the southern Outer Central Basin region of the state. These fields were then managed in conjunction with the farms’ conventional practices. Soil samples were collected and analyzed for pH, K, Ca, Mg and Al. Results showed that the application of FGD gypsum can either increase or decrease pH with the dependent factor seeming to be the initial pH level of the soil. Decreases were seen in K and Mg content of the soil. On the sites with the most acid subsoils, exchangeable aluminum was reduced in the upper subsoil. Increases in Ca were observed deep into the profile after the second year of the study. Soil physical properties were largely unchanged, as indicated by penetrometer, soil water and bulk density measurements. It is believed that the traffic associated with the application of the FGD gypsum negated most of the beneficial structural effects that are often seen with mined gypsum. Also since most of the locations were managed as no-till systems the effects of gypsum on water infiltration were negated by the residue left on top of the soil surface. This resulted in the absence of effect in the soil water measurements that were collected over the two years of the study. Corn yields were seen to improve after the application of FGD gypsum indicating the material is potentially a viable option for some farming operations in the state.

The demand for optimum putting conditions requires golf course superintendents to manage cool season creeping bentgrass (Agrostis stolonifera L.) in the transition zone and upper south. Summer heat stress combined with low mowing heights and constant traffic are challenges that superintendents must face in order to successfully manage creeping bentgrass from early May to late September. A field experiment was conducted on a Crenshaw putting green under golf course conditions during the 2006 summer and twice during the 2007 summer in Knoxville, TN. 2006 enriched air treatments of ~692 ppm CO2 and ~891 ppm CO2 were compared to a control of ambient air (~363 ppm CO2). 2007 enriched air treatments of ~716 ppm CO2 and ~1076 ppm CO2 were compared to a control of ambient air (~451 ppm CO2). Indirect heat stress was characterized by measuring the accumulation of total nonstructural carbohydrates (TNC) which is the sum of soluble carbohydrates and insoluble starch. The effects of CO2 enriched air on TNC during the ante meridiem (between 12 midnight and 12 noon) photoperiod were determined using near infrared reflectance spectroscopy (NIRS). The effects of CO2 enriched air on turfgrass quality during the ante meridiem photoperiod were determined using normalized difference vegetative index (NDVI) chlorophyll measurements. Disease and visual quality differences amongst treatments or locations were measured on an incidental basis. No significance occurred within the 2006 and 2007 TNC or NDVI analysis for differences amongst treatments. 2006 average TNC for shoots were 24.8, 20.1, and 28.5 mg g-1 of tissue for the 363, 692, and 891 ppm CO2 levels, respectively. 2006 average NDVI for shoots were 7.2, 7.3, and 7.3 for the 363, 692, and 891 ppm CO2 levels, respectively. 2007average TNC for shoots were 25.6, 18.9, and 23.1 mg g-1 of tissue for the 451, 716, and 1076 ppm CO2 levels, respectively. 2007 average NDVI for shoots were 7.9, 8.0, and 8.0 for the 451, 716, and 1076 ppm CO2 levels, respectively. All results were analyzed at 0.05 probability level within SAS 9.1. No incidence of disease or visual quality differences among treatments or locations occurred.

Populus is one of the most important tree species for pulp, paper, wood products, and more recently for biomass energy. The increasing need for wood and decreasing land area for forest trees demand the development of fast-growing trees with desirable quality. This experiment was conducted to alter poplar growth and development by manipulating endogenous auxin and ethylene levels through genetic transformation. Since auxin stimulates vascular differentiation and wood formation, indole-3-acetic acid (IAA) biosynthetic gene,iaaM, driven by a vascular specific promoter, glycine-rich protein promoter (GRP), was inserted into a hybrid aspen (P. canescens x P. grandidentata) to increase the endogenous auxin level. However, because elevated auxin can trigger overproduction of ethylene, which can inhibit plant growth, an ethylene inhibition gene,1-acetocyclopropane-1-carboxylic acid deaminase (ACC deaminase) under the control of cauliflower mosaic virus 35S (CaMV35S) promoter conjugated with GRP-iaaMgene was also inserted into the aspen via the Agrobacterium tumefaciensTi plasmid vectors. Fourteen transgenic plants having GRP-iaaM and thirteen transgenic plants having GRP-iaaM-35S-ACC deaminasegenes were confirmed by polymerase chain reaction (PCR) and Southern blot. Transgenic plants were propagated by cuttings and their heights and diameters were measured to determine the effect of the inserted genes on aspen. The amounts of IAA and ethylene were also measured to investigate the expression of the inserted genes. Two lines in 2003 and four lines in 2004 of the GRP-iaaM-35S-ACC deaminase transgenic plants were significantly taller than non-transgenic plants while the GRP-iaaM transgenic plants were shorter or similar height with non-transgenic plants. No significant differences in the growth of height and diameter of the GRP-iaaM transgenic plants may be due to the use of a weak promoter because the levels of IAA showed slightly higher than non-transgenic plants, but the differences were not statistically significant. The GRP-iaaM-35S-ACC deaminase transgenic plants showed no significant differences in IAA levels, but had less or similar levels of ethylene compared to nontransgenic control while the GRP-iaaM transgenic plants had elevated ethylene amount. This indicates that the iaaM gene expressed at a low level increased the level of ethylene, but the ACC deaminase gene appeared to reduce the elevated ethylene in the GRP-iaaM-35S-ACC deaminase transgenic plants. The GRP-iaaM-35S-ACC deaminase transgenic plants having modified IAA and ethylene levels showed more growth in height and volume than the GRP-iaaM transgenic in the linear contrast, and a negative correlation between ethylene amounts and heights was shown. This result indicates that an increased auxin level might have a negative effect in the growth of trees resulted from elevated ethylene level triggered by elevated auxin, but a decreased ethylene level in addition to an increased auxin level might have a positive effect on the growth of trees. Although further detailed analyses are needed, this research suggests that it is possible to manipulate plant hormones, especially ethylene, to change plant growth.

Contamination of soils with toxic metals such as arsenic and cadmium has become a major environmental and human health risk. Phytoremediation provides a method to remove contaminants from soils that is not only economically viable but also environmentally sound. Metallohistins are proteins that have the capability to bind divalent metal ions such as Ni2+, Zn2+, Co2+, Cu2+ and Cd2+. In this study, a concatemer sequence was designed to try to increase the presence of metal-binding proteins in transgenic plants. Two methods to increase translational efficiency of the metallohistin protein were used: 1) characterization of the full-length metallohistin AgNt84 gene, and 2) construction of three vectors containing different fragments of the AgNt84 cDNA which were transformed into Nicotiana tabacum. The concatemer sequence proved toxic to Escherichia coli cells and could not be cloned into vectors for plant transformation. Explants genetically transformed with vectors containing either the entire AgNt84 cDNA or the 5’ untranslated and coding region of the cDNA recovered from tissue culture. Explants genetically transformed with a vector containing only the coding region of the cDNA produced shoots but not roots in tissue culture, and then became necrotic. Characterization of the transformants is underway. The first exon and portion of the intron of the gene has been sequenced. Phytosensors that can recognize and report the presence of arsenic would provide remediators with a management tool for phytoremediation. A transmission and scanning electron microscopy study of Pteris vittata tissue culture revealed callus formation on epidermal cells of gametophytes, presence of an extracellular matrix on calli, and the formation of croziers during differentiation. Calli induced on semi-solid medium consisted of distinct meristematic nodules. These nodules differentiated randomly, and are unfit for genetic transformation. A new differentiation medium is also described. A preliminary genetic transformation study was successful in creating protoplasts from both Pteris vittata gametophytes and sporophytes, but unsuccessful with biolistic bombardment of calli. Low yields, cellular debris, and autofluorescence exhibited by the protoplasts hampered polyethylene glycol-mediated genetic transformation and detection of transgene expression.

In the 1970s, a push for research on the effects of ultraviolet (UV) radiation on food crops began. Since that time, multiple agricultural and horticultural crops have been studied with results showing that the morphological and physical reactions are species dependent. The purpose of these studies to determine how increasing UV radiation affects Allium fistulosum L. (scallion onions) and Allium tuberosum Rottl. (garlic chives), and how UV radiation affects 16 cultigens of A. fistulosum. The effects of UV radiation were determined by shoot height, fresh weight, carotenoid and chlorophyll pigment concentrations, and photochemical efficiency (Fv/Fm). The scallions showed decreases in shoot height and fresh weight in both studies, while the chives showed increases in both shoot height and fresh weight. High performance liquid chromatography showed changes in concentrations of nutritionally important carotenoids like lutein and the xanthophyll carotenoids were noted, while â-carotene concentrations did not change. Changes in chlorophyll a and b concentrations and ratios were also found. Changes in the xanthophyll cycle were found in the scallion cultigens, indicating irradiation stress. The scallion cultigens were found not to differ much between UV radiation treatments, but there were significant differences among the cultigens. To our knowledge, this is the first study to date that has examined the effects of UV radiation on Allium carotenoids.

As energy prices continue to rise, concern grows about the economy and about petroleum supplies. On January 1, 2009 The Energy Independence and Security Act of 2009 was enacted. It states that 500 million gallons of biomass-based biodiesel must be produced in 2009 and 1 billion gallons by 2012. In the United States 90 % of the biodiesel is produced from soybean oil, despite its shortcomings. The biggest problem facing the soy diesel industry is the American Society of Testing and Materials (ASTM) specifications for Biodiesel and Biodiesel Blends. The two categories that are in need of immediate improvement to enhance test results and produce a better burning fuel are cloud point and oxidation stability. Monounsaturated fatty acid methyl ester (FAME) are reported to strike the best balance between cold flow properties and oxidative stability to enhance biodiesel test results and produce a better burning fuel. In addition, treating fuels derived from fatty acid alkyl esters with oxidation inhibitors (antioxidants) has been reported to increase resistance to oxidation. Fuel properties: acid value, cloud point, iodine value, pour point, peroxide value, induction period, onset temperature, and kinematic viscosity were used to evaluate a newly developed Roundup Ready® soybean recombinant inbred line with a novel oil profile, exhibiting an elevated level of monounsaturated FAME and the possibility of using selenium as a natural antioxidant for use in the biodiesel industry. We were able to demonstrate higher polyunsaturated content lead to lower IP values, lower PV values were indicative of increased monounsaturated FAME content and elevated levels of saturated FAME content resulted in higher CP and PP values.

The objectives of this study are three-fold: to determine the within row plant spacing and time of planting that will produce optimal yields and seed isoflavone content, to explore the feasibility of incorporating edamame soybeans [Glycine max (L.) Merrill] in a double-cropping system with strawberries [Fragaria X ananassa], and to study the potential as an edamame soybean of newly identified line TN03-349. Line TN03-349 was planted into raised, plasticulture, irrigated strawberry beds at the University of Tennessee’s East Tennessee Research and Education Center. Five within-row spacings were used (0.08m, 0.15m, 0.30m, 0.60m, and 1.20m) in 2004 and 2005. A second raised bed, irrigated plasticulture experiment was conducted at the Plateau Research and Education Center in Crossville, TN, using four soybean lines (Gardensoy-43, TN00-60, USG 5601T, and TN03-349) and two planting dates (May 24 and June 14, 2005). A final field experiment at the same location used the same four soybean lines, four within-row spacings (0.04m, 0.08m, 0.15m, and 0.30m), and three planting dates (May 24, June 14, and July 6) in 2005 and 2006. All experimental plantings were harvested at both the R6 (green) and the R8 (dry) stages. Analysis of R6 and R8 data, averaged over two years (2004 and 2005), from the East Tennessee location showed that total pod yield was highest up to plant spacing 0.30m (at a mean of 10,450 kg ha-1) and dropped off at the 0.60m (8370 kg ha-1) and 1.20m (5985 kg ha-1) spacings. Similarly, shelled seed yield responded to spacing treatments with 3419 kg ha-1 at 0.30m and decreased to 1880 kg ha-1 at the 1.20m spacing. While seed numbers (per 100 pods) from R6 harvest did not change, seed size did, increasing as space between plants increased with means of 371mg seed-1 for 0.08m and 916mg seed-1 for 1.20m. Seed isoflavone content was not significantly affected by spacing treatment. Analysis of R6 data from the Plateau strawberry bed experiment showed that genotype significantly affected total plot yield (p<0.01) and seed size (p<0.05). While line Gardensoy-43 had the lowest shelled seed yield, it had the largest seeds (1070mg seed-1). The other lines did not differ in shelled seed yield, but TN00-60 and TN03-349 differed from USG 5601T (smallest at 260mg seed-1) in seed size. Planting date did not significantly affect yield or seed size. Analysis of R8 data at Crossville, TN showed line TN03-349 to have significantly higher total yield than all others at 876 kg ha-1 and Gardensoy-43 (lowest yield at 274 kg ha-1) differed from TN00- 60 (549 kg ha-1) and USG 5601T (497 kg ha-1) where p<0.0001. Three isoflavones were significant for genotype: daidzin (p<0.05), malonyl daidzin (p<0.001), and malonyl glycitin (p<0.0001). Total seed isoflavone and oil content were not significantly affected by genotype. Seventeen of eighteen measured amino acids were affected by genotype (p-values varied). Results from the field experiment revealed that genotypic effects were significant (p<0.01) to all measurements across all three planting dates for the R6 development stage. The edamame lines Gardensoy-43 and TN03-349 consistently produced larger seeds and heavier pod weights than the others. Planting date also had a significant effect on seed size (p<0.05) with June giving the largest (mean seed size, 360mg seed-1) and May the smallest (mean seed size, 350mg seed-1) size. Spacing treatment significantly affected seed size (p<0.05), total pod yield (p<0.01), and shelled seed yield (p<0.01). The widest spacing treatment, 0.30m, gave the largest seed size (0.36g) while the closest spacing treatment, 0.04m, yielded the lowest seed size (0.35g). Total pod and shelled seed yields only differed at the widest spacing (0.30m) and were significantly lower than all the other treatments, which did not differ from each other. Analysis of R8 harvested soybeans for 2005 and 2006 revealed that the 2005 experimental plantings produced higher yields than those in 2006 (p<0.0001), which were reduced by deer damage. Genotype played a significant part in R8 seed yield (p<0.0001). Line TN00-60 produced the highest weight (4374 kg ha-1) and differed significantly from the other three lines, which were not different from each other (Gardensoy-43, 2941 kg ha-1; TN03-349, 3373 kg ha-1; USG 5601T, 2970 kg ha-1). Spacing had no significant effect.

Four bioassays were conducted to evaluate an ecotype of Poa annua L. from Chattanooga for resistance to prodiamine, pendimethalin, and dithiopyr herbicides. MSmedia, filter-paper, and soil-based bioassays all evaluated root growth response in mature seed from the Chattanooga ecotype and a sensitive control. The hydroponics bioassay evaluated mature tiller response. All the bioassays were able to diagnose the Chattanooga population as resistant to prodiamine and pendimethalin. The soil-based bioassay was able to detect minimal resistance to dithiopyr. Additionally, the Chattanooga population exhibited variability of resistance to dinitroanalines.

The purpose of this thesis project was to, firstly, establish and optimize protocols for high-throughput callus induction and plant regeneration for the new, higher yielding switchgrass (Panicum virgatum L.) cultivars NSL and SL93. Secondly, to subclone the complementary DNA (cDNA) of the anthocyanin transcription factor, C1, from pBECKS.red into pUC18 and pBSL15 for downstream use. For the first part of this project the cultivars, NF/GA992, NF/GA993, NSL, and SL93, were tested for callus induction by plating whole dehusked caryopses on callus induction media (CIM) containing 8.5uM of the auxin dicamba. NF/GA992 responded best to the treatment with 44% of plated seeds producing callus. For the second experiment seeds of the cultivars NSL, SL93, and Alamo were plated on CIM containing various molar concentrations of dicamba (0uM, 8.5uM, 17uM, and 34uM) and 6-benzylamino purine (BAP) (0uM, 5uM, 15uM, and 45uM). This research revealed that the presence of BAP in CIM plates did not promote callus induction in Alamo, SL93, and NSL, but elevated concentrations (34uM) of dicamba significantly increased callus formation in all three cultivars. It was also found that the SL93 callus derived from CIM plates containing 34uM dicamba and 15uM BAP regenerated the most shoots, 27 shoots were regenerated from 3 calluses. Seed pretreatments were evaluated to determine their impact on callus induction and subsequent plant regeneration. For this experiment, seeds of NSL, SL93, and Alamo were plated on CIM containing 34uM of dicamba. Seeds were subjected to one of three treatments before plating: a) dehusked with H2SO4 , b) chilled for two weeks at 4°C then plated, and c) sterilized with sodium hypochlorite and ethanol. This research revealed that seed pretreatment significantly increased callus induction amongst the three tested cultivars. The second part of this experiment compared the shoot regeneration efficiencies of seed-derived calluses to inflorescence-derived calluses. Analysis showed that SL93 calluses induced from inflorescences produced significantly more shoots than any of the other explants. The final arm of this thesis project focused on sub-cloning the C1 anthocyanin regulatory cDNA. The C1 cDNA isolated from pBECKS.red was sub-cloned into pUC18 and pBSL15 using a sticky-end ligation.