INHIBITORY EFFECTS OF SOME POLYSUBSTITUTED PHENOXYACETIC ACID-DERIVATIVES ON PHOTOSYNTHETIC ACTIVITY OF CHLOROPLASTS AND ON CHLOROPHYLL PRODUCTION IN WHEAT AND CHLORELLA-VULGARIS

The inhibition of oxygen evolution rate in spinach chloroplasts and ch lorophyll production in algae Chlorella vulgaris as well as in wheat p lants caused by some polysubstituted phenoxyacetic acid derivatives wa s investigated. 2,4,5-Trichlorophenoxyacetic acid and its derivatives exhibited substantially higher activity with respect to the inhibition of photosynthetic processes in spinach chloroplasts than the correspo nding 2,4-dichloro and 2-methyl-4-chloro analogues. From the changes o f EPR spectra of spinach chloroplasts in the presence of the studied c ompounds it can be supposed that these interact with both photosynthet ic centres 1 and 2. The antialgal effect of the majority of studied co mpounds at the concentration 10(-4) mol dm(-3) is not pronounced.