Polyamine Titre in Relation to Chill-Sensitivity inPhaseolus sp.

Abstract

Guye, M. G., Vigh, L. and Wilson, J. M. 1986. Polyamine titre in relation to chill-sensitivity in Phaseolus sp.—J. exp. Bot. 37: 1036-1043. Endogenous levels of the polyamines putrescine, spermidine and spermine were quantified in the primary leaves of five cultivars of bean (Phaseolus sp.) differing in their 'wilting response' to a chilling exposure of 5 °C for 24 h. Levels of polyamines prior to chilling treatment did not appear to be correlated with chill-tolerance as levels in the non-chilled controls were highest in cultivars of medium chill-sensitivity. Plants grown under a vapour saturation deficit (PSD) of 8-4 g m ~ 3 day/6-1 g m ~ 3 night exhibited a mild hardening as compared to plants grown under a VSD of 5-7 g m3 day/4-1 g m ~3 night, as the former showed less wilting on chilling. Hardening at high VSD had the effect of slightly lowering the putrescine content of non-chilled tissue but total polyamine content remained unchanged. However, on chilling, the largest relative increase in polyamine levels, in particular that of putrescine, occurred in hardened plants. There was also a significant relative increase in putrescine titre in response to chilling in non-hardened genotypes of high chill-tolerance, whereas more chill-sensitive genotypes remained unchanged or slightly declined in putrescine content on chilling. Relative changes in putrescine content rather than absolute levels appears to be correlated with chill-tolerance. These results are discussed in view of present knowledge on the adaptive significance of stress-induced changes in polyamines, especially with regard to membrane stability.