Tolerance of finger millet to propanil. 3 Relationship between propanil binding by chloroplast and inhibition of photosynthetic electron transport.

Abstract

Difference in propanil binding to chloroplast and its inhibition of photosynthetic electron transport system among the three gramineous plant species were studied.Chloroplasts were isolated from rice, barnyardgrass and finger millet grown to the 3rd or 4th leaf stage. No significant difference was obtained among the species in either inhibition constant (Ki) of photosynthetic electron transport by propanil or its binding constant (K) to chloroplast. Specific binding of propanil was almost identical to its inhibition of electron transport. But the herbicide bound to rice chloroplast slightly more than to barnyardgrass or finger millet at high inhibitor concentration.It was concluded that there was no difference in either inhibition of photosynthesis by propanil or the herbicide binding to chloroplast among three species of plants.