CHANGES IN POLYAMINE METABOLISM IN SEEDLINGS OF 3 WHEAT (TRITICUM-AESTIVUM L) CULTIVARS DIFFERING IN SALT SENSITIVITY

Germination is a developmental stage extremely sensitive to salinity. We studied the effects of three regimes of salinity (50, 100 and 150 mM NaCl) on polyamine (PA) metabolism during the germination of seeds of three wheat (Triticum aestivum L.) cultivars. These three genotypes exhibited inhibition of germination by salt, in the following order: Ardenica > Agimi > Dajti. The presence of salt decreased the putrescine (Put) level, especially in roots. On the contrary, the levels of spermidine (Spd) and spermine (Spm) were increased by salt with a greater effect in shoot. A positive correlation with the growth inhibition of the three cultivars was observed for the level of Spd and Spm and, even better, for the PA/diamine ratio. Feeding experiments with [C-14]Put showed that, in the presence of 150 mM NaCl, Ardenica tissues synthesize more PAs than Dajti tissues. The effect of salinity on PA metabolism and the use of PAs as a markers of salt sensitivity in wheat seedlings are discussed.