Effects of 2-alkylthio-6-aminobenzothiazoles and their 6-N-substituted derivatives on photosynthesis inhibition in Chlorella vulgaris and spinach chloroplasts.

2-Alkylthio-6-aminobenzothiazoles and their 6-N-substituted derivatives 3-(2-alkylthio-6-benzothiazolylaminomethyl)-2-benzothiazolineth iones and 3-(2-alkylthio-6-benzothiazolylaminomethyl)-6-bromo-2-benzothia zolinones inhibit photosynthetic processes in spinach chloroplasts and the chlorophyll production in Chlorella vulgaris. The inhibitory activity depends on the alkyl chain length of the thioalkyl substituent. The site of action of the effectors studied is on the donor side of photosystem 2 before the site of action of diphenylcarbazide. The highest antialgal effects were exhibited by compounds containing bromine.