Date of Award:
Master of Science (MS)
Department name when degree awarded
Martyn M. Caldwell
Previous studies indicate that the degree of UV-Binduced photosynthetic inhibition may be highly dependent upon the photosynthetic photon flux density (PPFD, total quantum flux in the waveband 400-700 nm) incident on a plant. This study illustrates that Essex soybean leaves (Glycine max) preconditioned under high PPFD suffered less UV-B-induced photoinhibition than when preconditioned under low PPFD. However, sensitivity to UV-B increased when soybean leaves received high-PPFD as a concomitant treatment.
The relative msgnitude of UV-B-induced damage was similar for both light-limited and light-saturated photosynthesis. This probably indicates that UV-B is inhibiting fundamentally different photosynthetic processes.
Soybean leaves preconditioned under high PPFD had greater specific-leaf-weight, chlorophyll a/b ratio, and crude flavonoid content. The total chlorophyll concentration of soybean leaves preconditioned under high PPFD increased slightly over a UV-B irradiation period of five hours. Total chlorophyll concentration of leaves preconditioned under low PPFD decreased slightly in response to the same irradiation period.
Warner, Charles W., "Influence of Photosynthetic Photon Flux Density on UV-BInduced Photoinhibition in Soybean Leaves: Comparison of Preconditioning and Concomitant Light Treatments" (1982). All Graduate Theses and Dissertations. 6345.
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