[Effects of pyridazinones and cerulenin on the biosynthesis and functional state of photosystem 2 in barley leaves].

The effects of pyridazinones and cerulenin on the formation of photosystem 2 in etiolated barley leaves and its functional state in green leaves were studied. It was shown that the reaction centers of photosystem 2 in greening leaves are formed after 2.5--3.

[Effect of pyridazinone herbicides on the photosynthetic electron transport chain of chloroplasts and Chlorella].

In order to establish the site of pyridazinone herbicides action on the photosynthetic electron transport chain, their effect on the photochemical activity of chloroplasts and Chlorella was studied. It was shown that these compounds similar to diuron inhibit the delta F of chloroplasts but enhance the delta F and cause the disappearance of slow transient processes in Chlorella and change the light-off time course of delta F both in Chlorella and in the chloroplasts. The inhibiting effect is observed at herbicide concentration of 5 x 10(-6) M and is maximal at 10(-4) M.

[Increase in the phosphorescence and delayed fluorescence of chlorophyll in barley leaves after selective suppression of carotene biosynthesis].

The action of inhibitors of carotenoid biosynthesis--herbicides SAN 9789 and SAN 6706 on the pigment composition and chlorophyll low temperature (-196 degrees) delayed luminescence (delayed fluorescence and phosphorescence) has been studied in the barley leaves. The herbicides were introduced into etiolated leaves before greening. It is shown that in the mature leaves which were developed in the presence of herbicides biosynthesis of alpha, beta and gamma carotenes is selectively blocked while the concentration of xanthophylls and chlorophylls is not essentially changed.