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Seasonal Patterns Of Photosynthesis And Respiration In Atriplex Confertifolia And Ceratoides Lanata, Richard S. White

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Net photosynthesis and dark respiration studies were conducted on Atriplex confertifolia (Torr. and Frem.) S. Wats and Ceratoides lanata (Pursh) J.T. Howell under field and laboratory conditions. These woody species are commonly found in salt desert shrub communities of the Intermountain West. During these investigations, the effects of air temperature, plant moisture stress, soil water potential, irradiation, and plant phenological status were examined with respect to their influence on carbon dioxide (CO₂) exchange.

Intensive field studies were carried out between April and October. This interval corresponded to the major period of physiological activity in both species. The factors …

Photosynthesis, Dark Respiration, And Growth Of Rumex Patientia L. Exposed To Uv-B (280-315 Nm) Irradiance Corresponding To Reduced Atmospheric Ozone Concentrations, William B. Sisson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Net photosynthesis, dark respiration, chlorophyll concentrations and growth were determined for Rumex patientia L. exposed to UV-B radiation corresponding to reduced atmospheric ozone concentrations. The hypothesis of whether reciprocity is maintained in the response of R. patientia to polychromatic UV-B radiation was tested. On the basis of the relationships derived from these studies, a simulation model was developed for the prediction of photosynthesis and growth of R. patientia exposed to UV-B radiation corresponding to any atmospheric ozone reduction.

Photosynthetic rates were found to be depressed after two hours exposure to UV-B irradiance simulating a 0.18 atm·cm ozone column when the …

Relationship Between Physiological And Morphological Characteristics And Yield Of Nondormant Alfalfa Clones, A. L. Foutz, Wallace Wilhelm, A. K. Dobrenz

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Alfalfa (Medicago sativa L.) breeders are constantly striving to improve the productivity of alfalfa. Yields have been increased primarily through the selection of plant materials resistant to insects and diseases. The objective of this study was to evaluate physiological characteristics which might be used as selection criteria in alfalfa improvement. Alfalfa clones were grown under field conditions on a Mojave clay loam soil. Carbon dioxide flux was evaluated in a closed system using an infrared gas analyzer. The physiological variables measured in these studies did not account for the varialion in yield among the clones. Apparent photosynthetic rates, dark …