Abstract
Formation of protochlorophyllide and ribulose-l, 5-diphosphate carboxylase, both of which were constituents proper to chloroplast, was inhibited in the radish cotyledons grown with 4-thiouridine (0.5 mM), though the growth of the seedlings, activities of a cytoplasmic enzyme glucose-6-phosphate dehydrogenase and of a mitochondrial enzyme glutamate dehydrogenase in the cotyledones were not affected. Photo-induced formation of chlorophyll pigments and of chloroplastic ribosomal RNAs in the 4-thiouridine treated cotyledones were depressed as compared with controls. Interestingly, the effect of 4-thiouridine, however, disappeared with continuous illumination. Based upon these results, specific development of the chloroplast is discussed.
