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Heat shock proteins (HSPs) are expressed in response to environmental stresses. Compared to other kingdoms, plant HSP families are larger, presumably the result of adaptation to a wide range of stresses. Following on an analysis of drought stress characteristics in loblolly pine (Watkinson et al., 2003), expression patterns of HSP gene expression during photosynthetic acclimation were examined. One cycle of mild (-1Mpa) followed by two cycles of severe stress (-1.7Mpa) were probed for conditioning effects. Photosynthetic acclimation occurred after the first cycle. No acclimation occurred without the first mild cycle. Microarray/RT-PCR analyses showed that a pine homolog to GRP94 (ER-resident HSP90) was up-regulated after rehydration coincident with acclimation. This GRP94 is closely related to GRP94 from the desiccation tolerant plant X. viscosa, supporting the importance of this gene during acclimation to water deficit. HSP genes whose products localized to the mitochondrion showed gradual up-regulation after consecutive cycles of severe drought. The Arabidopsis pine GRP94 homolog, (AtHSP90-7) was then analyzed, using bioinformatics (Pati et al., 2006) and laboratory tools. Genes encoding putative candidate co-chaperones for GRP94 and other HSP90s were discovered, which contained water stress-related cis-elements. Arabidopsis (Col-0) wild type and two T-DNA insertion mutants in HSP90-7 were used to study the importance of this gene for photosynthetic acclimation. Only the mutants were able to acclimate to drought stress, with the level of AtHSP90-7 expression in the mutants being reduced compared to the wild type. AtHSP90-7 may have a different role in Arabidopsis, and its reduced expression activated other protective genes (Klein et al., 2006). Responses to extreme drought in resistant (Sullu) and susceptible (Negra Ojosa) lines of Andean potatoes were also compared in order to identify relationships between HSPs gene expression, and tolerance, defined as the ability to maintain photosynthesis at 50% after 25 days of drought and to recover from the stress. Tolerance was correlated with up-regulation of HSPs (mostly chaperonins) and antioxidant genes all of whose gene products are located in the chloroplast. / Ph. D.

Mature field-grown apple trees were used to gain a better understanding of the influences of light and fruit on leaf physiology. Light effects on net photosynthesis (Pn), specific leaf weight (SLW), leaf N content (Weight/area) (Nw), and leaf N concentration (% dry weight) (Np) of spur leaves from two canopy locations were evaluated on four dates in 1987. Interior leaves had lower Pn, SLW, Nw, and Np than exterior leaves. In 1988 the influence of %available photosynthetic photon flux (PPF) on the same parameters was examined throughout the season. On most measurement dates both Pn and SLW increased quadratically while Nw increased linearly with increasing PPF. In both years positive linear relationships existed between Pn and Nw, SLW and Nw, and Pn and SLW. / Ph. D.

<I>Rhododendron maximum</I> L. (Ericaceae) is an evergreen shrub that grows in dense thickets and currently covers large areas of the understory in the deciduous forests of the southeastern United States. Thickets of R. maximum are inhibitory to recruitment and regeneration of many understory plants including canopy tree seedlings. By effectively lowering the survivorship of woody species trying to establish within thickets, <I>R. maximum</I> could influence stand level regeneration patterns and ultimately the community structure of these deciduous forests. This dissertation outlines research conducted to determine if: 1) below and above ground resources are lower within thickets of <I>R. maximum</I> when compared to forest sites where <I>R. maximum</I> is absent; 2) <I>Quercus rubra</I> and <I>Prunus serotina</I> seedlings growing in thickets have lower mid-day photosynthetic rates; 3) <I>Quercus rubra</I> and <I>Prunus serotina</I> seedlings growing within thickets are low light acclimated when compared to seedlings growing in forest without <I>R. maximum</I>; 4) the presence of <I>R. maximum</I> constrains CO₂ assimilation of <I>Quercus rubra</I> seedlings exposed to light flecks of different durations and intensities; 5) the presence of <I>R. maximum</I> constrains the light fleck responses of <I>Quercus rubra</I> seedlings exposed to eight light flecks in rapid succession; and 6) canopy openness regulates the capacity of <I>Quercus rubra</I> seedlings to assimilate carbon when exposed to eight consecutive light flecks. <I>Rhododendron maximum</I> thickets altered resource availability for seedlings when compared to areas of forest without <I>R. maximum</I>. Diffused photosynthetically active radiation (PAR) averaged less than 5 μmol m⁻² s⁻¹ throughout the growing season in sites with <I>R. maximum</I> in comparison to 10-30 μmol m⁻² s⁻¹ in sites without <I>R. maximum</I>. Soil moisture content, measured using Time Domain Reflectometry was approximately 6% lower in forest sites with <I>R. maximum</I> compared to sites without <I>R. maximum</I> throughout the growing season. Most nutrient concentrations (e.g.,, C, N and most cations) and nitrogen mineralization rates were significantly lower in sites with <I>R. maximum</I>. Temperature and atmospheric relative humidity are slightly lower under thickets of <I>R. maximum</I>. In general, sites with <I>R. maximum</I> are associated with lower resource availability above and below ground in comparison with sites without <I>R. maximum</I>. Attenuation of below canopy PAR by thickets of <I>R. maximum</I> negatively influences the photosynthetic capacity of <I>Quercus rubra</I> and <I>Prunus serotina</I> seedlings as indicated by measurements of mid-day photosynthesis. In 1996, the seasonal mean mid-day photosynthetic rate of first year <I>Q. rubra</I> seedlings growing in <I>R. maximum</I> thickets (1.3 μmol m⁻² s⁻¹) was 62% lower than the seasonal mean mid-day photosynthetic rate (2.1 μmol m⁻² s⁻¹) of seedlings growing in forest sites without <I>R. maximum</I>. For second year seedlings in 1997, seasonal mean mid-day photosynthesis was 183% higher for plants growing outside of thickets (1.7 μmol m⁻² s⁻¹) compared to the mean rate (0.6 μmol m⁻² s⁻¹) for plants located within thicket sites. The mean mid-day PAR available to seedlings located in forest sites without <I>R. maximum</I> during measurements of photosynthesis was 354% higher in 1996 and 257% higher in 1997. First year <I>Prunus serotina</I> seedlings growing in forest without <I>R. maximum</I> also had greater seasonal mean mid-day photosynthesis (0.7 μmol m⁻² s⁻¹) when compared to the mean rate (-0.1 μmol m⁻² s⁻¹) for plants growing within thickets. <I>Prunus serotina</I> seedlings located in the presence of <I>R. maximum</I> received on average 67% less PAR. Photosynthetic acclimation to low light was assessed for <I>Q. rubra</I> and <I>P. serotina</I> seedlings growing under both forest conditions by measuring photosynthetic responses to light <I>in situ</I> using even aged one-year old seedlings. <I>Quercus rubra</I> seedlings growing in forest sites without <I>R. maximum</I> had significantly higher light saturated rates of photosynthesis. For both species, photosynthetic responses to light were otherwise similar irrespective of the presence or absence of <I>R. maximum</I>. The impact of the <I>R. maximum</I> subcanopy on understory PAR and subsequent influence on canopy tree seedling photosynthetic capacity implies that sunflecks are critical for seedling net carbon gain in these forest understory environments. To determine the effect of <I>R. maximum</I> on the photosynthetic response to sunflecks of oak seedlings, light flecks were simulated on 288 randomly chosen, even aged, two-year old seedlings <I>in situ</I>. Half of the seedlings were located within <I>R. maximum</I> thickets. Seedlings were randomly assigned one of four light fleck durations (30, 60, 120, and 300s) and one of three intensities (100, 500, 1000 μmol m⁻² s⁻¹). Half of all seedlings were dark pre-acclimated prior to light fleck simulations by covering with aluminum foil for at least 12 hours, while the remaining seedlings were pre-acclimated under ambient conditions. Analysis of covariance showed that a significant, positive, linear relationship exists between the length of a light fleck and total carbon gain during a light fleck for seedlings in forest sites with and without <I>R. maximum</I> regardless of pre-acclimation status, or light fleck intensity. Furthermore, there was a significant effect of <I>R. maximum</I> on the slope of the relationship such that following ambient pre-acclimation, seedlings located within thickets assimilated significantly less carbon with increasing light fleck length than seedlings located in forest sites without <I>R. maximum</I>. When seedlings were dark pre-acclimated there was no difference in carbon gain with increasing fleck length between seedlings in forest with and without <I>R. maximum</I> except for flecks of 1000 μmol m⁻² s⁻¹. The data lead to the conclusion that under natural conditions the presence of <I>R. maximum</I> likely prohibits <I>Q. rubra</I> seedlings from utilizing sunflecks as effectively as seedlings growing in forest sites where <I>R. maximum</I> is absent. Because sunflecks often occur clustered together during a short period of time during the day, another field study was conducted to further characterize the effect of <I>R. maximum</I> on the photosynthetic response of oak seedlings to eight consecutive light flecks. Within 10 paired sites, (i.e., with and without <I>R. maximum</I>) 3 even aged three-year old <I>Q. rubra</I> seedlings were selected. Over each seedling, a hemispherical canopy photograph was taken and analyzed for percent canopy openness. Each seedling was dark pre-acclimated for 12 hours and then exposed to eight light flecks in rapid succession during which time photosynthesis was logged every two seconds. Each light fleck was 500 μmol m⁻² s⁻¹ in intensity and lasted for 120s. Following each light fleck, leaves were exposed to 10 μmol m⁻² s⁻¹ PAR for 60s before the next light fleck. Mean carbon gain and maximum photosynthesis achieved during each light fleck was significantly lower for seedlings located in the presence of <I>R. maximum</I> for all flecks in an eight-fleck simulation. In addition, seedlings located within thickets generally had significantly lower pre-illumination photosynthesis following the first of eight light flecks. The mean photosynthetic light use efficiency of seedlings located in forest with <I>R. maximum</I> was significantly lower for the first six of eight light flecks in succession. Using regression analysis and analysis of covariance, percent canopy openness was used to explain the variation in carbon gained from all eight light flecks in succession for seedlings under both forest conditions. However, significant relationships failed to exist between under either forest condition and precluded using analysis of covariance. The results from these studies lead to the conclusion that light limitation is a major mechanism responsible for the extirpation of canopy tree seedlings from within thickets of <I>R. maximum</I>. Tree seedlings growing in forest sites with <I>R. maximum</I> receive less solar irradiance, have lower mid-day photosynthesis, fail to acclimate to the lower light conditions within thickets, and utilize sunflecks less effectively as well as less efficiently when compared to plants growing in forest sites without <I>R. maximum</I>. / Ph. D.

Loblolly pine (Pinus taeda L.) occupies 13 million hectares in the United States and represents a critical component of the global carbon (C) cycle. Forest management alters C dynamics, affecting the C sequestration capacity of a site. Identifying drivers that influence C cycling, quantifying C fluxes, and determining how management alters processes involved in C cycling will allow for an understanding of C sequestration capacity in managed forests. Objectives of the first study included (1) investigating environmental, soil C, root, and stand influences on soil CO2 efflux on the South Carolina coastal plain and (2) quantifying soil CO2 efflux over a rotation in loblolly pine stands located on the South Carolina coastal plain and the Virginia piedmont. In relation to the first objective, temporal variation in soil CO2 efflux was most highly related to soil temperature. Spatial and temporal variability in soil CO2 efflux was weakly related to soil C and root biomass, and not related to coarse woody debris, stand age, stand volume, or site index [Chapter 2]. Soil CO2 efflux was not related to stand age on the South Carolina sites while efflux was positively related to age on the Virginia sites. Cumulative soil C efflux on the South Carolina sites over 20 years is an estimated 278.6 Mg C/ha compared with an estimated 210.9 Mg C/ha on the Virginia sites [Chapter 3]. Objectives of the second study were (1) to investigate short-term effects of fertilization on processes permitting enhanced growth in loblolly pine and (2) to determine the short-term effects of fertilization on autotrophic, heterotrophic, and soil respiration. Major results from the study include the finding that fertilization caused a transient rise in photosynthetic capacity, which paralleled changes in foliar nitrogen. Leaf area accumulation and enhanced growth following fertilization was partly due to enhanced C fixation capacity [Chapter 4]. Fertilization altered the contribution of autotrophic and heterotrophic respiration to total soil CO2 efflux. Enhanced specific root respiration was short-lived while suppressed microbial respiration following fertilization was maintained over the course of the nearly 200-day study. Respiring root biomass growth increased total soil respiration over time [Chapter 5]. / Ph. D.

Reducing equivalents were extracted from in vitro photosynthesis and used to drive cell-free and enzyme-free biochemical reduction reactions in this research. To investigate photosynthetic electron flow, an algal extract dense in chloroplasts was made from the microalga Scenedesmus sp. A6. The algal extract was subjugated to a variety of environmental parameters and exogenous quinones in order to optimize electron extraction. To monitor electron extraction and donation to metabolites, a novel assay was created that monitored the chemiluminescence (CL) produced by superoxide radicals formed during the process. In particular, these formed when a reduced exogenous quinone oxidized spontaneously. Our studies found that calcium chloride improved the reduction of low redox potential mediators along with prolonged exposure to red light. Other salts and environmental conditions examined had diverse effects on the quinones based on structure, redox potential, and site of electron extraction. We next applied our assay for monitoring the reduction of different metabolites. The CL recorded for different metabolites was compared to the Gibbs free energy of reduction and a highly correlated relationship was found. The assay was then applied to the reduction of metabolites via the oxidation of glucose in an alkaline environment. To exhibit the diverse application of the CL assay, urine of healthy individuals, patients with chronic kidney disease (CKD), and patients with bladder cancer (BCa) were characterized through their interactions with different quinones. The CL output was compared to that of SurineTM and urea followed by ANOVA analysis. Statistically significant differences were found for all quinones with 1,2-napthoquinone-4-sulfonate (NQS) producing significant differences between all groups examined. Monitoring algal phenotypes for biofuels or photosynthetic output requires arduous protocols and advanced instrumentation. Both of these energy producing options were explored along with rapid, high-throughput protocols for measuring reduction reactions. To monitor the phenotypes and health of our microalgae, Raman microscopy was applied to algal cultures of Scenedesmus sp. A6 grown under stress. Statistically unique phenotypes were found based on environmental factors during cell growth. ANOVA analysis determined the effect of stressors that caused significant change to algal phenotypes related to photosynthesis and lipids. / Doctor of Philosophy / Photosynthesis is the process by which plants and algae harness sunlight to convert CO2 to plant mass. Photosynthesis is performed in the chloroplast which can excite electrons and use them to generate energy. Detecting how much energy a chloroplast can produce and what chemicals effect the chloroplast requires complex procedures with complicated instruments. In this thesis the chloroplast from the microalgae Scenedesmus sp. A6 were isolated to evaluate how they are affected by different chemicals in the environment using a new, rapid and robust assay. Then, a group of chemicals called quinones were used to steal electrons (plant energy), and this process was optimized in this research. The purpose of stealing this plant energy from photosynthesis was so it could be re-directed into synthesizing valuable chemicals that are normally produced from fossil fuels. A new sensor was also developed in this research that would "light-up" the environment whenever this plant energy (electron) stealing process was successful allowing us to measure the efficiency of this energy transfer. Once a quinone stole an electron, it would spontaneously give up the electron to oxygen, creating an unstable molecule that could then react with the chemical luminol, forming a strong luminescence (light) signal. We found that calcium chloride greatly enhanced a quinone's ability to harvest electrons from the chloroplast. We also reported unique effects caused by salt, magnesium, phosphate, a mild detergent, and changing the amount of light the chloroplast would receive. This information was then used to transfer electrons from the chloroplast to make new valuable chemicals. We found that electrons could be donated to multiple chemicals using a quinone, chloroplasts, and light. We were also able to take electrons from glucose with our quinones when glucose was in an environment with a high pH. Electrons from glucose could also be donated to chemicals of interest using quinones. In addition, Quinones were used once more to find differences in the urine composition of healthy individuals and those with chronic kidney disease or bladder cancer. The urine from healthy individuals produced a unique luminescence signal when interacting with the quinones. Thus, quinones could be used for rapidly detecting changes in a patient's kidney and bladder function. We also developed a new method for detecting changes in the health of an algal culture. Algal cultures are used for producing biofuel, food, and pharmaceuticals, therefore it is imperative to track the growth of a culture to avoid contamination and algal death. Scenedesmus sp. A6 was exposed to chemicals harmful to algal health to see how these chemicals caused the algae to grow differently. Raman spectroscopy was used to collect data on algae grown under different conditions. The Raman spectra obtained then underwent statistical analysis to determine the chemicals that had the greatest impact on algal function. Methyl viologen, nickel sulfate, salt, and light exposure had the greatest impact on the algae.

Every architecure is being with life-force such as a plant who lives on the photosynthesis that need carbon dioxide + water + light energy, and provide oxygen in day time. On the contrary, Plants need oxygen and release carbon dioxide while they can not carry out the photosunthesis in night time. But both chemical reactions occurring on the same plant in different time in a day. People normally spend one-third of their for working in an office or studying in school, and their home is empty during the day time. People use the rest of their time on a dinner in restaurant outside, other activities or events; back to home to rest and nobody occupies commercial area in night time. Why can we not do all of life's events in the same building or place whenever we wish? / Master of Architecture

Rhododendron maximum L. is a dominant subcanopy species in the southern Appalachian Mountains. R. maximum undergo distinct thermonastic leaf movements (TLM). The purpose of these movements has not yet been determined. Previous studies have suggested TLM are a photoprotective mechanism for the dynamic light environment of the subcanopy in a deciduous forest during winter. The present study aimed to determine the effects of restricting TLM on photoinhibition, net photosynthesis, and other gas exchange parameters, particularly during the early spring. After restricting TLM on certain leaves, we observed the above parameters from autumn 2005 to late spring 2006. Our results indicated that photoinhibition increased (lower Fv/Fm) in treatment leaves over reference leaves throughout the winter. The difference became greater during the early spring, when reference leaves began to return to normal levels of photochemical efficiency and treatment leaves sustained low Fv/Fm. Net photosynthesis was lower for treatment leaves than reference leaves. This became most significant during the early spring, when maximum carbon gain is possible. Finally, gas exchange parameters as measured by light and CO2 response curves did not indicate any significant difference between treatment and reference leaves post canopy closure. Out results suggest that TLM are an important mechanism for photoprotection, allowing leaves of R. maximum to recover quickly during the early spring and maximize their early spring carbon gain. / Master of Science

Mother nature has laid out a beautiful blueprint to capture sunlight and convert to usable form of energy. Inspired by nature, donor-acceptor systems are predominantly studied for their light harvesting applications. This dissertation explores new donor-acceptor systems by studying their photochemical properties useful in building artificial photosynthetic systems. The systems studied are divided into phthalocyanine-porphyrin-fullerene-based, perylenediimide-based, and aluminum porphyrin-based donor-acceptor systems. Further effect of solvents in determining the energy or electron transfer was studied in chapter 6. Such complex photosynthetic analogues are designed and characterized using UV-vis, fluorescence spectroscopy, differential pulse voltammetry and cyclic voltammetry. Using ultrafast transient absorption spectroscopy, the excited state properties are explored. The information obtained from the current study is critical in getting one step closer to building affordable and sustainable solar energy harvesting devices which could easily unravel the current energy demands.