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|Title:||Chlorophyll Retention in Near-Isogenic Lines of Soybeans|
|Author(s):||Caro, Roque Fernando|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Backcross-derived near-isogenic lines of soybeans (Glycine max L. Merrill) having nuclear genes (genetic greens) and cytoplasm (cytoplasmic greens) controlling chlorophyll retention in Clark and Harosoy backgrounds were compared from one to three years to their normal counterparts in order to evaluate the physiological, genetic, and agronomic effects associated with chlorophyll retention.
Several agronomic traits were measured for two years, and changes in Rubisco activities, specific leaf weights (SLW's), and chlorophyll content and ratios were investigated during leaf senescence of the different genotypes. Chlorophyll-proteins were isolated by SDS-PAGE from chloroplast thylakoids of normal and chlorophyll-retention cotyledons, and their relative changes were analyzed during cotyledon senescence.
Differences in seed yield, oil percentage, protein percentage, and weight showed no definite pattern to suggest a direct connection between these traits and chlorophyll retention genes or cytoplasm. Seed germination, however, and an apparent delay in flowering and maturity, indicated either pleiotropic or epistatic effects associated with chlorophyll retention genes (or the short chromosome segment carrying them). Leaves of genetic green types, as compared to the normal lines, remained green until maturity, had higher Rubisco activity and SLW's, and retained both chlorophylls a and b. Leaves of cytoplasmic green lines also remained green at maturity, and retained preferentially chlorophyll b. Cotyledon chloroplasts of genetic green genotypes retained both the P-700 chlorophyll a-protein complex (CP I) and the light-harvesting chlorophyll a/b-protein complex (LHCP). Cotyledon chloroplasts of cytoplasmic green types retained preferentially the LHCP complex. This, coupled with changes in grana and stroma thylakoids would indicate that retention of chlorophyll in soybeans is associated with stability of thylakoid proteins.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
|Date Available in IDEALS:||2014-12-16|