Thesis (Ph. D.)--Ohio state university, 1922. / Cover-title. Autobiography. "Papers from the Department of botany, the Ohio state university, no. 171." "Literature cited": p. 265-266.

No description available.

Selenium (Se) is an essential element for human and livestock with antioxidant and anticancer characteristics. Although Se is not an essential element for plants, it has been reported that it can improve plant growth. This experiment was conducted at the Isfahan University of Technology in winter 2010. The experiment was factorial based on a completely randomized design (CRD) with 4 replications. Se was added to nutrient solution in 4 concentrations 2, 4, and 6 mg/l sodium selenite (Na2SeO3). Root volume, fresh and dry weights of shoots and roots, number and weight of fruits, chlorophyll content and photosynthesis traits (photosynthesis rate, stomata internal carbon dioxide (CO2) concentration, stomata conductance) were measured. Results showed that Se increased root dry weight. Fresh and dry weights of shoot increased in the 2 mg/l Se treatment and decreased at the higher level of Se. Chlorophyll content and photosynthesis rate were not affected by Se. Stomata internal CO2 concentration and stomata conductance decreased by Se addition. Overall, Se at 2 mg/l application rate was effective in some physiological characteristics of cucumber.

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

From Introduction: In 1934 the Government started an active campaign on the eradiction of Jointed Cactus. This plant was causing considerable damage to the farms and commonages of the Eastern Province, and was spreading at an alarming rate. The Officer in Charge of eradication, Mr E. du Toit, was stationed at Grahamstown which is fairly centrally situated in the infested area. In 1935 Dr A. Leemann of the Division of Plant Industry made his headquarters at Rhodes University College.

Stomata act as small valves that help in the regulation of gas exchange in plants. These valves arise from epidermal stem cells that asymmetrically divide to become meristemoids, which are precursor cells that eventually give rise to guard cells. Our lab used microarray-based gene expression profiling to identify genes that might play a role in maintaining or controlling meristemoid behavior. One gene, At5g60880, encodes a small protein that plays a role in stomata patterning. The sequence of this protein provides little information about its putative function. In order to gain insight into the function of this protein, we obtained mutant plants (SALK_86936) and characterized their phenotype. These plants exhibited abnormal asymmetric divisions resulting in clustered stomata. Since nothing is known about this protein, we determined the At5g60880 gene expression pattern by making transgenic plants carrying a fusion between the native At5g60880 promoter and green fluorescent protein (GFP). Confocal laser scanning microscopy was used to visualize the expression pattern of GFP in developing leaves. At5g60880 appears to be expressed in most epidermal cells. To better understand the possible activity of this protein, we also created transgenic plants used to deduce the protein subcellular localization. These plants constitutively express a translational fusion between the At5g60880 protein and GFP driven by the CaMV 35S promoter. Preliminary results reveal cortical and cytoplasmic localization of this fusion protein. Understanding the function of this novel protein will ultimately contribute to our knowledge of stomata patterning mechanisms, and more generally stern cell differentiation in plants.

Most plants produce leaves with stomata on either both surfaces (amphistomatous) or on the lower surface only (hypostomatous). The importance of stomata to plant survival suggests that these two stomatal distribution patterns may be adaptive, and this problem is explored. It is concluded that amphistomaty is an adaptation to produce a high conductance to CO₂ diffusion into the leaf. As such it is advantageous to plants with high photosynthetic capacity leaves in high light environments, experiencing rapidly fluctuating or continuously available soil water. Plants meeting these criteria are found to be almost exclusively amphistomatous; those not meeting the criteria are mostly hypostomatous. Also investigated is the adaptive significance of differences in stomatal conductances and conductance responses to environmental factors between the two surfaces of amphistomatous leaves. Although differences in stomatal conductance are found between the two surfaces in sunflower, differences in conductance response to light intensity and water vapor pressure difference across the stomatal pore were neglible. Water stress relieved one day prior to experiments caused upper stomatal conductance to be reduced more than lower, but responses to light and water vapor pressure difference remained essentially parallel for the two surfaces. For these differences in conductance to be adaptive differences in photosynthetic characteristics between the two surfaces. In addition, estimation of the resistance to diffusion of CO₂ across the mesophyll yields values low enough to preclude steep gradients in CO₂ partial pressure in the mesophyll. In the absence of CO₂ gradients within the leaf, differences in photosynthetic characteristics between the two surfaces cannot exist. It is concluded that differences in stomatal conductance between the two surfaces of amphistomatous leaves are not adaptations to differences in CO₂ uptake characteristics.

No description available.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. William H. Outlaw Jr., Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed June 18, 2004). Includes bibliographical references.