Kinetics of photoaccumulation of β-carotene inPhycomyces blakesleeanus

摘要

Upon carbon starvation the β-carotene content ofPhycomycesmycelium grown on minimal agar medium disappears with a time lag of about 90 min and a T1/2of 68–75 min. If continuous light is given 2 h after starvation, there is an increase in β-carotene content with respect to the dark control. This increase has a time lag of 20–25 min. The fluence rate-response curve ofwtis biphasic and two mutants in the genemadA (madA7,madA35) and in the genemadB (madB101,madB104) have higher thresholds thanwt; madB mutants are blinder thanmadA mutants. Only blue light is effective and we suggest that it has an effect solely on the catabolism of β-ca