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Polyamine Metabolism In Arabidopsis: Transgenic Manipulation And Gene Expression, Rajtilak Majumdar

Doctoral Dissertations

The metabolism of polyamines (Putrescine, Spermidine and Spermine) in wild type and transgenic Arabidopsis thaliana (Col 0 ecotype) plants was studied using the techniques of transgenic manipulation and gene expression. Two specific objectives were: (1) To study the effects of inducible and constitutive transgenic manipulation of polyamines via a mouse ornithine decarboxylase (mODC) gene on plant metabolism. (2) To analyze the spatial and temporal expression patterns of Arabidopsis thaliana S-adenosylmethionine decarboxylase genes (AtSAMDC3, AtSAMDC4 and AtSAMDC5) during its life cycle.

The major findings are: (i) Orn becomes a limiting substrate for Put biosynthesis in transgenic Arabidopsis expressing mODC gene, (ii) …

Seasonal, Biogeochemical, And Microbial Response Of Soils To Simultaneous Warming And Nitrogen Additions, Alexandra R. Contosta

Doctoral Dissertations

Climate warming and nitrogen deposition are global environmental threats that could alter soil microbial communities and the biogeochemical processes they perform. Few studies have examined interactive effects of elevated temperatures and nitrogen inputs. Many studies have also not considered the role that season plays in mediating the response of soils to warming and nitrogen. Finally, most research has not linked changes in the soil microbial community with ecosystem-scale dynamics. One objective of this dissertation was to examine season-specific microbial and biogeochemical responses to simultaneous warming and nitrogen additions. Another aim was to investigate whether warming and nitrogen can restructure microbial …

Assessing Relationships Of Moose Populations, Winter Ticks, And Forest Regeneration In Northern New Hampshire, Daniel Henry Bergeron

Master's Theses and Capstones

This study examined relationships among winter ticks, weather, and the nutritional and reproductive status of moose, and the impact of moose on regeneration of commercial forests in northern New Hampshire. Three methods were evaluated to assess their usefulness as indices of relative winter tick abundance, and predictors of tick epizootics: tick counts on harvested moose and roadside, spring hair-loss surveys were considered time and cost effective to index winter tick abundance. Physical characteristics of harvested moose (1988--2009) indicated ovulation rates (∼20%), and mean body weight (<200 kg) of yearlings declined since 1988; because adult body weight and ovulation rates remained stable, habitat quality was unlikely related. Winter tick epizootics are likely influenced by abnormal large scale weather events, as evident in the widespread die-off in 2002 associated with warm snowless conditions into mid-December 2001 that extended tick transmission to moose. Spring and fall weather should be monitored for unusual conditions causing high tick abundance and tick loads, particularly warm and snowless conditions in April and December. Mean stocking rate of all age classes of commercial tree species was above the threshold in all regions (49--87%); forest regeneration was not considered a regional problem at any moose density.

Saprotrophic Fungi As A Mechanism For Vertical Nitrogen Transport In A Chronically Fertilized Northern Hardwood Forest, Katharine M. Burnham

Master's Theses and Capstones

Decay studies often observe that plant litter increases in the amount of nitrogen within the first year of decomposition, yet sources are uncertain. The Harvard Forest Chronic Nitrogen Amendment Experiment, Petersham, MA, was utilized to quantify vertical N translocation from soil up into decomposing litter and determine if long-term, chronic N application has affected this process. Litter bags were designed to facilitate or restrict fungal hyphal connectivity between the soil-litter interface and placed in control, low N+S and high N plots. After five or 12 months, a 15N-(NH 4)2SO4 solution was horizontally injected into organic soil beneath bags. 15N enrichment …

Effects Of Habitat Fragmentation And Water Quality On Wood Frog Population Genetic Structure In Vernal Pools, Charlotte Gabrielsen

Master's Theses and Capstones

Habitat fragmentation associated with suburbanization can have negative consequences on population persistence through the reduction of dispersal and concomitant gene flow. Using nine polymorphic microsatellite loci, I assessed the effects of forest fragmentation and water quality on the genetic structure of a vernal pool-breeding amphibian, the wood frog ( Lithobates sylvaticus), across 20 ponds in an unfragmented, forested landscape and 45 ponds in a fragmented landscape. Analyses were performed at the broad-scale of the study area and at a fine-scale, with spatially independent clusters of ponds selected within each landscape. Bayesian clustering approaches and AMOVA identified little population structure at …

Addition Of Sodium Bicarbonate To Colostrum: Effects On Igg Absorption And Hematocrit In Neonatal Calves, Colleen E. Chapman

Master's Theses and Capstones

Twenty-six Holstein bull calves born from primiparous and multiparous cows without dystocia were assigned to a randomized complete block design to one of two treatments within each block: colostrum with no supplemental sodium bicarbonate or colostrum with 30 g of supplemental sodium bicarbonate. Calves were fed colostrum from nine different batches with an immunoglobulin G (IgG) concentration of 82.05 +/- 8.45 g/L and the total amount of IgG fed of 329.89 +/- 34.56 g at 0 h and 6 h postpartum. Calves were fed 2 L of milk replacer (MR) at 24, 36, and 48 h postpartum. The addition of …

Interrelations Among Leaf And Canopy Nitrogen, Optical And Structural Traits, Franklin Brown Sullivan

Master's Theses and Capstones

A correlation between canopy nitrogen and albedo has been observed across a wide range of forest types. Determining the nature and mechanisms behind the relationship would help to understand the role of nitrogen in the climate system and better understand forest-climate interactions. The purpose of this study was to examine sources of variation in leaf and canopy optical traits with respect to variation in nitrogen concentrations at both scales.

We found that %N was significantly correlated with leaf and canopy albedo and that both %N and albedo were strongly correlated with forest composition. Many canopy structural traits were found to …

An In Vitro Technique To Estimate Digestibility Of Amino Acids In Dairy Cattle Feeds, Scott Joseph Talbot

Master's Theses and Capstones

Three soybean meal (SBM), 3 SoyPlusRTM (SP), 5 dried distillers' grains with solubles (DDGS), and 5 fishmeal (FM) were obtained from FeedAC, Inc. (Homer, NY) and along with 5 cornsilage hybrid samples (CS), were used in an experiment to calculate total tract digestibility of crude protein (CP) and amino acids (AA). An in vitro procedure was used that incorporated the modified three step procedure (mTSP) developed by Calsamiglia and Stern (1994) and then modified by Gargallo et al. (2006) and the protease incubation procedure developed by McNiven et al. (2001) which replaces the in situ rumen incubation step in the …

Herbage Mass Accumulation In An Intensive Rotational Grazing System At Unh's Organic Dairy Research Facility, Ashley Green

Master's Theses and Capstones

Pasture-based animal management in the Northeast U.S. relies on the ability to efficiently estimate pasture production and animal intake. Accuracy and precision of a rising plate meter, NDVI meter, and height measurements for estimating pasture biomass were compared relative to hand-clipped samples. Pasture measurements were used to describe biomass accumulation, lactating dairy herd intakes, and re-growth patterns for intensively rotated pastures. Pastures were measured from May-September, 2009 at the UNH Organic Dairy Research Facility in Lee, NH. The rising plate meter provided the most robust estimates of biomass (R²=0.58, SEE=2.73). Forty-seven paddocks were measured for 82 total grazing events; grazing …

Nonlinear Evaluation Of Stock Assessment And Marine Ecosystem Models, Laura Storch

Master's Theses and Capstones

In fisheries management, single-species stock assessment models use fisheries-dependent catch and landings data along with fishery-independent estimates of relative or absolute abundance to make estimates of species biomass for a given area. This output is used by the Atlantis marine ecosystem model as input. Atlantis uses an array of physical, biological, and anthropogenic factors to predict biomass for individual species or functional groups of species. Nonlinear analysis was used to assess the output for both the stock assessment, and Atlantis models for the marine ecosystem off the California coast. The number of time series displaying nonlinear characteristics decreases from raw …