Turnover of Phytochrome in Pumpkin Cotyledons

摘要: By using density labeling, it was found that the protein moiety of phytochrome is synthesized de novo in red-absorbing form cotyledons dark-grown pumpkin (Cucurbita pepo L.) seedlings, as well those irradiated with red light and returned to dark. The rate synthesis appears be unaffected by treatment. Turnover also detected dark grown seedlings while turnover far already implied from known "destruction" observed seedlings. In both cases, true degradation involved, but constant may up two orders magnitude greater than form. data indicate that, cotyledons, levels are regulated against a background continuous through divergent constants forms relative proportions present.