Nucleases and Nucleic Acids During Maturation and Following Dormancy of Potato Tubers

Summary Potato tubers at three physiological stages (Young, mature and sprouting) were analyzed respective of their nuclease activity and of their contents of sRNA, high molecular weight RNA and DNA. Calculated on the basis of fresh or dry weight, nucleic acid contents were highest in young tubers, lower upon maturation and still further reduced upon sprouting. The activity of RNase on a fresh weight basis was high in young tubers; it decreased upon maturity, after which it increased up to the time of sprouting to the same level as it had displayed in young tubers. The activity per mg protein in the sprouting tuber was 50 Ofo higher than that in the young tuber. One interesting observation was the appearance of a high DNase activity at the time of sprouting, whereas DNase activity had been significantly lower in maturing tubers. The significance of the findings is discussed.