EFFECT OF SHORT-TERM AND LONG-TERM LOW-TEMPERATURE STRESS ON POLYAMINE BIOSYNTHESIS IN WHEAT GENOTYPES WITH VARYING DEGREES OF FROST TOLERANCE

Two series of experiments were carried out to examine the short- and l ong-term effects of low temperature on polyamine biosynthesis in wheat . In the first series, studies were made on the polyamine accumulation in the leaves, crowns and roots of winter wheat varieties with varyin g degrees of frost: tolerance subjected to short-term low temperature stress (6 h, -2 degrees C). A marked accumulation of Put was observed. Agm accumulation was also examined and found comparable to that of Pu t. This suggests that Agm, which is an intermediate product of Put syn thesis only in higher plants, may play an important role during short- term cold treatment. The second series of experiments was aimed at dis covering the effect of wheat chromosomes 5A and 7A, which contain majo r genes responsible for frost resistance, on the polyamine synthesis t aking place in various parts of the seedlings during long periods of c old treatment, and especially on the alternative metabolic pathway pre sent only in higher plants.