Abstract
This paper reports the results of the studies on the effects of nicotinamide on the activities of nitrate reduction and photosynthesis. 1. Nitrate reductase activity was stimulated by nicotinamide in cucumbcr cotyledons which were grown in the growth cabinet with nitrate. 2. Nitrate reductase activity was induced by nicotinamide in the detached cucumber cotyledons which were grown in the dark and in the absence of nitrate. 3. Synergistic induction of nitrate reductase activity occurred by nicotinamide plus KNO3 and nicotinamide plus benzylaminopurine in cucumber cotyledons. 4. The growth and chlorophyll formation in cucumber cotyledons were markedly stimulated by nicotinamide plus KNO3. 5. The effect of nicotinamide on nitrate reductase activity was prevented by cycloheximide and markedly stimulated by chloramphenicol. 6. Chlorophyll formation was stimulated by nicotinamide in etiolated rice seedlings. 7. Nicotinamide stimulated RuDP carboxylase activity and increased soluble protein in rice seedlings. 8. Apparent photosynthesis was stimulated by nicotinamide in rice seedlings.
