Abstract
The effect of kinetin (10 mg/ liter) on changes in the amount of chlorophyll, RNA, DNA, the rate of incorporation of P32 into RNA and DNA, and the activity of ribonuclease and deoxyribonuclease in excised barley (var. Wolfe) leaves was examined. Kinetin retarded the decline in the amount of chlorophyll, RNA, and DNA; maintained the synthesis of RNA and DNA at almost the same rate as in fresh leaves; and suppressed the activity of ribonuclease and deoxyribonuclease. It is suggested that kinetin, by maintaining synthesis and by suppressing destruction of nucleic acids, may preserve the integrity of the nucleic acid apparatus, especially of polyribosomes, and thus maintain protein synthesis which is essential for the survival of the detached leaves.