The effects of kinetin and contaminating bacteria on the incorporation of (32)P-orthophosphate into various fractions of nucleic acid extracted from radish leaves.

By comparing (32)P-orthophosphate incorporation into nucleic acid extracts of sterile and non-sterile radish leaf discs, it was shown that contaminating bacteria cause a 2-4 fold increase in the rate of precursor incorporation and alter the pattern of label distribution after fractionation of the extracts by sedimentation through sucrose gradients or chromatography on MAK(1) columns. Using sterile senescing radish leaf discs, a stimulation of (32)P-orthophosphate incorporation into various fractions of nucleic acid was observed as a result of kinetin treatment.