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Effects Of Excitation Pressure On Variegation And Global Gene Expression In Arabidopsis Thaliana, Rainer Bode

Electronic Thesis and Dissertation Repository

I assessed the effects of photosystem II excitation pressure on chloroplast biogenesis and leaf sectoring in the Arabidopsis thaliana variegated mutants im, spotty, var1, var2, chs5 and atd2. The plants were grown under varying degrees of excitation pressure induced by growth at increasing irradiance at different temperatures and the extent of variegation was quantified throughout the plant’s development. I found that the degree of variegation was positively correlated with excitation pressure, regardless of whether high light or low temperature was used to induce increased excitation pressure in all the mutants tested. This was irrespective of …

Myb10 And Myb72 Are Required For Growth Under Iron-Limiting Conditions, Christine M. Palmer, Maria N. Hindt, Holger Schmidt, Stephan Clemens, Mary Lou Guerinot

Dartmouth Scholarship

Iron is essential for photosynthesis and is often a limiting nutrient for plant productivity. Plants respond to conditions of iron deficiency by increasing transcript abundance of key genes involved in iron homeostasis, but only a few regulators of these genes have been identified. Using genome-wide expression analysis, we searched for transcription factors that are induced within 24 hours after transferring plants to iron-deficient growth conditions. Out of nearly 100 transcription factors shown to be up-regulated, we identified MYB10 and MYB72 as the most highly induced transcription factors. Here, we show that MYB10 and MYB72 are functionally redundant and are required …

Modelling C3 Photosynthesis From The Choroplast To The Ecosystem, Andy Vanloocke, Carl J. Bernacchi, Justin E. Bagley, Shawn P. Serbin, Ursula M. Ruiz-Vera, David M. Rosenthal

Andy VanLoocke

Subset Of Heat-Shock Transcription Factors Required For The Early Response Of Arabidopsis To Excess Light, Hou-Sung Jung, Peter A. Crisp, Gonzalo M. Estavillo, Benjamin Cole

Dartmouth Scholarship

Sunlight provides energy for photosynthesis and is essential for nearly all life on earth. However, too much or too little light or rapidly fluctuating light conditions cause stress to plants. Rapid changes in the amount of light are perceived as a change in the reduced/oxidized (redox) state of photosynthetic electron transport components in chloroplasts. However, how this generates a signal that is relayed to changes in nuclear gene expression is not well understood. We modified redox state in the reference plant, Arabidopsis thaliana, using either excess light or low light plus the herbicide DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), a well-known inhibitor of photosynthetic …

Use Of Capacitance Sensors For Development Of Conservative Irrigation Regimes, Ethan Daniel Hagen

Masters Theses

Several experiments were conducted to further develop capacitance sensor-based automated irrigation systems. The first experiment tested whether the photosynthetic response to decreasing volumetric water content (VWC) differed among four species tested. A sigmoidal curve best described the relationship for all species (r² [r-squared]>0.86). The VWC that maintained maximum photosynthesis at 90% was selected as a potential conservative irrigation set point and values were not different between species, nor were 100% container capacity values. This indicates that a single set point is adequate to initiate irrigation and that a common upper threshold for VWC can be used for this …

Photosynthetic Characteristics Of Veratrum Californicum In Varied Greenhouse Environments, Youping Sun, Sarah A. White, David Mann, Jeffery Adelberg

Plants, Soils, and Climate Faculty Publications

Corn lily or California false hellebore (Veratrum californicum Durand), a perennial species native to the western United States, produces several alkaloid compounds. A derivative of these alkaloid compounds, primarily veratramine and cyclopamine, shows promise as a therapeutic agent for treatment of a variety of tumor types. Here we report the first study of corn lily cultivated in greenhouse. Growth response of corn lily was examined under two light levels (ambient and supplemental), two fertilization types (20 N-4.4 P-16.6 K Peat-lite special and 15N-2.2P-12.5K CalMag special) at 100-mg·L-1 total nitrogen, and three irrigation cycles [sub-irrigation every day (wet), every third day …

Physiological Effects Of Low Mowing Heights, Rolling, And Foot Traffic On Creeping Bentgrass Putting Greens, Joseph Ronald Young

Graduate Theses and Dissertations

Golf course superintendents are managing creeping bentgrass (Agrostis stolonifera L.) putting greens throughout the transition zone where temperatures can exceed optimum levels for consecutive days in the summer. The stress of creeping bentgrass associated with these supraoptimal temperatures has been well documented, but the management practices implemented on putting greens to increase green speeds may exacerbate these environmental stresses. To date, the physiological effects of these management practices in combination have not been evaluated for putting green turf. The objective of this dissertation project was to determine the effect of mowing heights, light-weight rolling, and foot traffic on performance and …

Top And Bottom Photosynthetic Activity In Nerium Oleander And Pandanus Baptistii, Ryan Arima, Jacob Gonzalez

Featured Research

Photosynthesis can be performed on any part of a leaf, yet many plants orient their leaves in different ways and are composed of different leaf anatomies. In this experiment we attempted to discover if there is a significant difference between photosynthesis on the top and bottom of Nerium oleander, a dicot that orients its dorsal face towards the sun, and Pandanus baptistii, a monocot that does not orient its leaves specifically to the sun. To perform this experiment, we used both the LI-6400 and the LiCor Integrating Sphere. With the LI-6400, we measured the photosynthetic rate of the top and …

Leaf Traits Within Communities: Context May Affect The Mapping Of Traits To Function, Jennifer L. Funk, William K. Cornwell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The leaf economics spectrum (LES) has revolutionized the way many ecologists think about quantifying plant ecological trade-offs. In particular, the LES has connected a clear functional trade-off (long-lived leaves with slow carbon capture vs. short-lived leaves with fast carbon capture) to a handful of easily measured leaf traits. Building on this work, community ecologists are now able to quickly assess species carbon-capture strategies, which may have implications for community-level patterns such as competition or succession. However, there are a number of steps in this logic that require careful examination, and a potential danger arises when interpreting leaf-trait variation among species …

Functions And Toxicity Of Cadmium In Plants: Recent Advances And Future Prospects, Tuan Anh Tran, Losanka Petrova Popova

Turkish Journal of Botany

Heavy metals are important environmental pollutants and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional, and environmental reasons. Of all non-essential heavy metals, cadmium (Cd) is perhaps the metal that has attracted the most attention in soil science and plant nutrition due to its potential toxicity to humans, and also its relative mobility in the soil-plant system. This review emphasises Cd toxicity on plants with regards to ecological, physiological, and biochemical aspects. It summarises the toxic symptoms of Cd in plants (i.e. growth and plant development, alterations in photosynthesis, stomatal regulation, enzymatic activities, water relation, mineral …

Role Of Exogenous Glycinebetaine And Humic Acid In Mitigating Drought Stress-Induced Adverse Effects In Malus Robusta Seedlings, Lixin Zhang, Mei Gao, Linsen Zhang, Binzhi Li, Mingyu Han, Ashok Kumar Alva, Muhammad Ashraf

Turkish Journal of Botany

Glycinebetaine (GB) and humic acid (HA) are 2 commercial growth regulators that are being used worldwide to enhance the tolerance of most crops, including fruit trees, to various stresses, including drought stress (DS). Malus robusta Rehder is considered as one of the most important rootstocks for apple in China, but its growth and productivity is believed to be adversely affected by DS. The effects of different concentrations and combinations of GB (0, 100, and 200 mg L^{–1}) and HA (0, 500, 1000, and 1500 mg L^{–1}) on M. robusta seedling growth, photosynthesis characteristics, osmolyte accumulation, and antioxidant responses were evaluated …

Chlorophyll Fluorescence And Thermal Stress In Archaias Angulatus (Class Foraminifera), Heidi M. Toomey

USF Tampa Graduate Theses and Dissertations

ABSTRACT

Benthic foraminifers that host algal symbionts are similar to corals in that they rely on their algal endosymbionts for their energy needs, calcify prolifically, and are sensitive to changes in environmental conditions. They are abundant in the benthos of coastal coral-reef areas and are found throughout the tropical and subtropical regions. Pulse Amplitude Modulated (PAM) chlorophyll fluorometry and chlorophyll a extraction techniques were used to quantify and compare the photosynthetic responses of the benthic foraminiferal, Archaias angulatus and their isolated endosymbionts, Chlamydomonas hedleyi, to short-term changes in temperature. Maximum quantum efficiency (F_v/F_m) and rapid …