BRANKA SALOPEK and NIKOLA LJUBESlC

The fine structure of plastids and carotenoid content of the pepper fruit (Capsicum annuum) were studied during the various stages of ripening. Red ripe fruits contained spindle-shaped chromoplasts which originated from leuco-chloroplasts. The bleaching herbicides amitrole and SAN 9789 inhibited the biosynthesis of total carotenoids and the development of typical spindle-shaped chromoplasts. Both herbicides prevented the forma­ tion of tubules and increased the accumulation of plastoglobules. In SAN 9789 treated fruits, plastids contained few single dilated thylakoids, while amitrole caused dilatations of the retuculum which was filled with tiny grainy material. The results are discussed with regard to the already known action of these herbicides.