Phytochrome control of chlorophyll synthesis in potato tubers

Abstract

The previously unreported involvement of a phytochrome control in chlorophyll (Chl) synthesis by potato tubers was demonstrated. Significant differences between this system and the greening of etiolated seedlings were observed. The lag phase of Chl synthesis by potato tubers was approx. 23 h, and the duration of the lag phase was found to be under the control of phytochrome. A daily illumination of 10 min of far-red light (FR) was found to inhibit synthesis of both chlorophyll a (Chl a) and chlorophyll b (Chl b) by 80-90%. Inhibition of Chl accumulation due to FR light resulted whether red light (R) or white light was used to stimulate Chl formation. Phytochrome appeared to affect Chl synthesis by potato tubers through control of the lag phase, rather than by control of the steady-state rate of synthesis. © 1979.