INFLUENCE OF POLYAMINES ON THE LONG-DISTANCE TRANSPORT OF K (RB-86) IN POTATO CUTTINGS (SOLANUM-TUBEROSUM CV SIRTEMA) - COMPARATIVE-STUDY WITH SOME PHYTOHORMONES

Plantlets of Solanum tuberosum L. cv. Sirtema were used to study the regulation of the long-distance transport of potassium. The effects of polyamines and two plant hormones, abscisic acid (ABA) and benzyladenine (BA), on this process were investigated. Foliar sprays of putrescine or BA increased the transport of (K) Rb-86 to the upper part of the plant. In contrast, spermidine treatment enhanced the translocation into the growing tuber, as did ABA. These specific effects were partially correlated to the distribution of endogenous polyamines within the plant. Spermidine was the predominant polyamine in the tuber while putrescine was as abundant as spermidine in the leaves. The total amount of putrescine. spermidine and spermine decreased with the physiological age of the leaves and tubers. Moreover, from heat-girdling experiments, it was shown that the polyamine, C-14-putrescine, supplied to a leaf, was transported via the phloem. It is suggested that polyamines like phytohormones have a regulatory role in long-distance transport.