Light and Nitrogen Affect Storage Protein Mobilization in Germinating Cottonseed1
- C. D. Elmore and
- R. N. Paul2
Laboratory germination studies to evaluate seed performance and seed quality attributes are routinely conducted in the dark with distilled water used to moisten the seed blotter paper. This study was conducted to determine the effect of light and N on storage protein mobilization during the first 5 days of germination of cottonseed (Gossypium hirsutum L.). Dry weight, hydrolysate amino acid composition, and free amino acid composition of cotyledons and axis were determined. Ultrastructure of cotyledons was examined. In the absence of N, light enhanced the protein body breakdown and coalescence of protein bodies into the central vacuole of cotyledonary cells. The presence of N in the nutrient solution had little effect on the protein body breakdown in the light (as revealed by electron microscopy) but slowed the mobilization process in the dark. Total free amino acid content and individual amino acid composition support this conclusion. Light increases the total free amino acid content of cotyledons at 3 and 5 days in the absence of N and at 5 days in the presence of N. Similar results are seen for the prominently affected amino acids, asparagine, arginine, γ-aminobutyric acid, and histidine. These results indicate that seed germination is sensitive to environmental factors such as light and mineral nutrients.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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