Effect of Diphenyl Carbazide on the Metribuzin Induced Inhibition of Photosystem-ll Photochemistry

Biochemical parameters with respect to inhibition of PS II photochemistry by metribuzin like Ki, Hill coefficient and quantum requirement have been determined. The effect of metribuzin in isolated chloroplasts was found to be independent of cation induced structural and functional changes in thylakoid membranes. DPC - an electron donor on the oxidizing side of PS II, was found to relieve the metribuzin induced inhibition of PS II photochemistry. The results suggest that DPC may alter the binding of metribuzin presumably because of overlapping binding domain in the Q_B, pocket as reported earlier for some other herbicides also.