Poster: Seed biology
Abs #
727: Effects of elevated temperature and CO2 on timing and morphological attributes of single seed growth of soybean
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Presenter: |
Thomas, Jean M.G., jmth@grove.ufl.edu |
Authors | Thomas, Jean M.G. (A) Boote, Kenneth J. (A) Pan, Deyun (A) Allen, L. Hartwell (B) | | Affiliations: |
(A): University of Florida
(B): USDA - Agricultural Research Service
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Soybean reproductive phenology and single seed growth will likely be affected by rising CO2 and associated projected changes in temperature. To determine the impact of twice the current carbon dioxide concentration ([CO2]) combined with elevated temperature on development of soybean [Glycine max (L.) Merr.], 'Bragg' plants were grown in two experiments in sunlit, controlled-environment chambers. Diel, sinusoidal temperature treatments ranged from 28/18 to 44/34ºC daytime maximum/nighttime minimum values. There was no effect of [CO2] on seed cell development, growth rate, or timing of maturation. Microscopic examination of cotyledon cells implied that high temperature affects nuclear and/or plastid duplication during the cell division phase of seed development. Few nuclei were visible in one-week old cotyledon cells from plants grown at 40/30ºC compared to numerous nuclei visible in cotyledon cells from plants grown at 28/18ºC. Cells of seed grown at 40/30ºC appeared highly vacuolated with few plastids or organelles. The number of cells per cotyledon was highest at 32/22ºC and decreased at higher temperatures. With increasing temperature treatments from 28/18ºC to 44/34ºC, onset of seed growth (R5 stage) was earliest at 28/18ºC and was progressively delayed, up to two weeks, as temperature increased to 40/30ºC. Seed growth was even more delayed at 44/34ºC. Single seed growth rate was most rapid at 28/18ºC (6.1 mg sd-1 d-1) and decreased to 2.9 mg sd-1 d-1 as temperature increased to 40/30ºC. Moreover, only a few seed were produced at 44/34ºC. Final seed size decreased as temperature increased, and almost all mature seed from plants grown at 40/30ºC were shriveled, while no shriveled seed were observed at 28/18ºC.
