Chlorophyll, carotene and xanthophyll levels of leaves of intact rice (Oryza sativa L.) seedlings were higher in penicillin treatments than in controls. Higher rates of incorporation of 14C thymine, 14C uracil and 14C Chlorella protein hydrolyzate by isolated chloroplasts in the presence of penicillin indicate the probable involvement of this antibiotic in the synthesis of nucleic acids and proteins necessary for chloroplast structure and pigment formation. Penicillin-induced enhancement of activities of enzymes of chlorophyll biogenesis both in rice and mungbean (Vigna radiata L. Wilczek) suggests the same possibility. Hill activity was also largely promoted by penicillin.
