Mesotrione, a carotenoid biosynthesis inhibiting herbicide, was evaluated for its use in turfgrass systems. Experiments were conducted to evaluate smooth crabgrass (Digitaria ischaemum) control with preemergence applications of mesotrione plus prodiamine. Experiments evaluated the influence of application timing on the efficacy of mesotrione plus prodiamine combinations and compared mesotrione plus prodiamine to current preemergence and early-postemergence herbicide treatments used for control of crabgrass. Greenhouse studies were conducted to compare the effects of foliar, soil, and soil plus foliar application of mesotrione on yellow nutsedge (Cyperus esculentus) and large crabgrass (Digitaria sanguinalis). Research was conducted in environmental growth rooms to investigate the effects of light intensity and temperature on perennial ryegrass (Lolium perenne) and large crabgrass carotenoid composition following mesotrione application.

The former Van Deventer garden (1924) in Knoxville, Tennessee is one of the rare masterpieces designed by the landscape artist Jens Jensen (1860-1951), who was a distinctive pioneer in the history of American landscape architecture. Very few of his major works survive in the Midwest which was the center of his career, and his residential designs are especially threatened by urban sprawl and land development in modern society. This historic Knoxville garden has been quietly surviving over 80 years through a few private ownerships, and Jensen’s landscape is slowly diminishing as invasive species are fast to colonize in the native woodland where Jensen saw an abundance of native plants in the early 1920s. The purpose of this research was to document the existing condition of the garden and to assess its historical significance, which can be used for a future nomination to the National Register for Historic Places. There are ten signature design elements that Jensen used in the majority of his work, defined by the Jensen scholar, Robert Grese in his book Jens Jensen: Maker of Natural Parks and Gardens (1992): (1) Use of Native Plants, (2) Spaces, (3) Light and Shadow, (4) Movement, (5) Water, (6) Stonework, (7) Council Ring, (8) Players’ Greens, (9) Formal Gardens, and (10) Time and Change. Data collected from historical research and site survey revealed that seven of his signature design elements are evident in the garden today. From a comparison of an existing plant survey and the original plantings indicated on Jensen’s 1924 design, approximately 90 percent of the plants sited by Jensen on the original 1924 planting design have disappeared. This change in plant palette was expected to happen in Jensen’s intention for the landscape. However, the basic landscape vii features, which have strong historic significance, remain intact with minor deteriorations. Preservation recommendations for this Jensen garden are (1) the preservation treatment option as outlined by the U.S. Secretary of the Interior, (2) eradication of the dominate invasive species, (3) plant pest control, (4) removal of fallen trees and plant debris from the significant landscape features, and (5) an easement option for future land protection.

Athletic field managers often make decisions regarding what turfgrass species and varieties to use from past experiences, or from non-sports turf related research such as the National Turfgrass Evaluation Program results. The wear tolerance of turfgrass varieties varies among species and varieties, which can greatly affect the performance of an athletic field. Mowing can also influence athletic field turf. Therefore advancements in mowing technology were tested to determine the impact of mowing, and mowing plus grooming on wear tolerance. A two-year study was conducted at the University of Tennessee East Tennessee Research and Education Center in Alcoa to test four popular bermudagrass varieties (Cynodon dactylon [L.] Pers. x Cynodon transvaalensis Burt-Davy) commonly used as athletic field turfs in the transition zone. The performance of ‘Tifway’, ‘Patriot’, ‘Mississippi Choice’, and ‘Riviera’ bermudagrass were compared after being subjected to either mowing or mowing plus grooming three times a week, as well as fall overseeding with perennial ryegrass (Lolium perenne L.) .Simulated athletic traffic was applied twice a week to mimic high school football schedules using a Cady traffic simulator. Digital image analysis for each traffic event was used to measure changes in percent green cover, color, and turfgrass quality. Surface hardness values were determined using a Clegg Impact Hammer and total turf cover was measured visually once bermudagrass dormancy occurred. Variety performance differed for each year of the study due to weather conditions. Overseeded and non-overseeded ‘Tifway’ and ‘Riviera’ bermudagrass consistently provided the highest percent green cover, color and quality ratings. However, overseeding bermudagrass improved wear tolerance of all varieties tested. Mowing plus grooming three times a week reduced percent turf cover in 2006 but not 2007, and had no effect on color or quality. Mowing plus grooming increased perennial ryegrass stand density following overseeding by providing better seed to soil contact. ‘Tifway’ and ‘Riviera’ bermudagrass provided the best color.

Liner production is a key segment in the nursery industry. Due to a lack of specific of quality standards by governing industry organizations as well as a lack of general consensus among growers of perceived liner quality, a conjoint analysis study was developed to determine buyer and grower preferences for nursery liner product features during point-of-purchase decisions. The study used a visual survey using six variables (first order lateral roots (FOLR), price, region of production, and height, canopy density and caliper uniformity) with varying levels yielding a 3 x 3 x 3 x 2 x 2 x 2 factorial design. Surveys were administered at tradeshows and events around the southeastern United States. Results indicated that a high FOLR, a uniform canopy density and height were most important to purchasing decisions of nursery liner buyers, while liner price and region of production were found not to be important. From the experimental model, utility values for each product feature were derived and can be inserted into an equation to determine a hypothetical quality rating. Growers can use this formula to determine hypothetical quality ratings for their products and serve as a marketing tool for growers. To determine if the production of premium quality liners is economically feasible and help aid growers to take advantage of niche opportunities we investigated production costs of growing ornamental nursery liners in a USDA Plant Hardiness Zone 6b to 7a nursery. We used three contemporary nursery liner production systems: a fieldgroundbed system, a polyhouse-covered groundbed, and a polyhouse covered container system. We estimated capital requirements, fixed costs and variable costs for each system. We also compared production costs of a deciduous plant, a broadleaf evergreen, and a needle leaf evergreen to allow inferences about the widest variety of nursery liner crops.

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.

Imidacloprid, a neonicotinoid insecticide, is commonly applied on eastern hemlock to reduce populations of Hemlock woolly adelgid (HWA). A large number of other herbivorous and transient insects also are associated with eastern hemlock. These herbivorous insects may acquire imidacloprid through feeding on treated plants. Predatory insects may acquire imidacloprid when they feed on insecticide-contaminated prey. To investigate this phenomenon, a study was conducted at Indian Boundary Campground, Cherokee National Forest, 2005-2007. This study was conducted to: 1) ascertain the effect of imidacloprid used against HWA on the predatory guild associated with eastern hemlock, 2) determine seasonal abundance of the predatory guild on eastern hemlock, and 3) assess influence of vertical stratification on spiders and other predators. During this study, 4,917 predators representing 75 families and 10 orders were collected. Spiders were the most dominant predator group, and the most abundant spider families were Mimetidae (1,038), Salticidae (736), Araneidae (733), Gnaphosidae (517), Philodromidae (330), Theridiidae (168), Tetragnathidae (161) and Thomisidae (142). The most abundant insect predator families were Vespidae (132), Ichneumonidae (50), Braconidae (31), Pentatomidae (25), Reduviidae (24), Coccinellidae (15), and Elateridae (15). Predator densities were not significantly different between pesticide application times (Fall and Spring). In both years, predator densities in control treatments and horticultural oil treatments were significantly (p<0.05) greater than those in imidacloprid treatments. However, predator densities were not significantly (p<0.05) different among soil drench, soil injection, and tree injection treatments or between control and horticultural oil treatments. Predator densities were at least 1.5-3X greater in the imidacloprid-treated plots in 2007 than in 2006, possibly suggesting a rebound in predator densities 1-1½ years after treatment. Predator densities were significantly (p<0.05) greater in the top and middle canopy than in the lower canopy. Imidacloprid concentration level declined progressively from the bottom stratum to the top stratum of the tree canopy. Highest levels were observed in the bottom stratum which shows that higher concentrations of imidacloprid lead to lower numbers of predators and lower concentrations of imidacloprid lead to higher numbers of predators.

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.