The effect of photoperiod on chlorophyll loss and lipid peroxidation in excised senescing rice leaves

Summary The Retarding Effect Of Light On Leaf Senescence Has Been Widely Reported And In Most Of The Cases The Experimental Leaves Were Exposed To Continuous White Light. In The Present Study The Effect Of Different Photoperiods On The Senescence Of Excised Rice Leaves Was Examined. The Pattern Of Chlorophyll Loss In Senescing Leaves Is Different In Short (≤8-H) And Long (≥ 12-h) photoperiods, the pattern in the former more closely resembling natural conditions. Variations in leaves senescing under different photoperiods or under continuous light with respect to protein and «-amino nitrogen levels are not marked, but differences in chlorophyll degradation and lipid peroxidation are clearly demonstrated. It is proposed that to understand the mechanism of leaf senescence studies should be undertaken in the appropriate photoperiod simulating the natural environment of the plant rather than in continuous dark or in continuous light.