Thermoinhibition alters the polyamine levels in cotyledons and embryonic axes during germination of stratified chick-pea seeds

Abstract

The aim of the present work is to know how much the levels of both free and bound polyamines are altered in the cotyledons of Cicer arietinum by the presence or absence of embryonic axes during the first 24 h of germination under thermoinhibitory conditions (30°C). As an approach, embryonic axes and cotyledons were separated from dry seeds and also from germinated whole seeds. All classes of polyamines decreased both in cotyledons and embryonic axes from dry seeds during the stratification (0–4°C) period (12 month). At 25°C (control) all the polyamine types studied decreased in the cotyledons from germinated whole seeds, and accumulated in the isolated ones (embryonectomized). In cotyledons from germinated whole seeds, a supraoptimal temperature of 30°C provoked a rise in free spermine, free and bound spermidine, and putrescine bound to macromolecules, as compared to the control. However, all polyamines, except putrescine and spermine bound to small substances which remained unaffected, rose at 30°C in the embryonectomized cotyledons. In the embryonic axes separated from whole seeds, the free polyamine content was higher than in isolated ones, and vice versa for polyamines bound to low and high molecular compounds; this last effect being decreased by supraoptimal temperatures.