Senescence: Action of Auxin and Kinetin in Control of RNA and Protein Synthesis in Subcellular Fractions of Bean Endocarpl

Sionnnary. A comiparative study was made of the efffects of auxin (a-naphthalene acetic acid), kinetin (6-furfurylaminopurine) and a mixture of auxin and kinetin applied in vivo on synthesis okf RNA and protein and the distribution of such synthesis am'ongst the subcellular fractions of sections of endocarp from Kentucky Wonder pole beans (Phascolus vulgaris, L.). Auxin caused considerable enhancement of incorporation of labeledl precursors into RNA and protein of all suibcellular fractions, and induced net synthesis of RNA and protein. That auxin-induced net synthesis of protein is repressed by actinomycin D indicates that auxin acts primarily to stimulate synthesis of RNA. as a result of which synthesis of protein tis enhanced. The effect of kinetin alone on synthesis of RNA, or of kinetin on auxin-induced synthesis of RNA was variable, with either stimulation or inhibition observed in different experiments. Kinetin-enhancement of synthesis of both RNA and protein in subcellular fractions also varied, with enhancement of synthesis in 1 or all subcellular fractions amnong different experimenits. The variable effect of kinetin did not seem to be related to the amount of endogenous or added auxin. The mlode of action of kine-tin is discussed.