Protochlorophyllide resynthesis in dark-grown bean leaves.

The protochlorophyllide content of dark-grown bean leaves was determined at various ages. It was detectable the second day after germination and reached a maximum on about the tenth day.The resynthesis of protochlorophyllide following a single irradiation and the rate of the 685 to 673 mmu shift of the newly formed chlorophyll was examined. Leaves up to 5-days old show no lag phase in protochlorophyllide resynthesis. By the sixth day, a lag phase is evident which increases with age. The rate of the 685 to 673 mmu shift is similarly age dependent.