Abstract: Changes in desiccation tolerance of pea ( Pisum sativum) seeds during imbibition were studied in this paper. Water uptook by seeds was initially rapid , and then slowly increased until a plateau was reached . Rate of electrolyte leakage increased initially until 11 h , and then declined with imbibition . During imbibition , germination percentage of seeds gradually increased , and water content at which 10% and 50% of seeds and axes were killed by subsequent dehydration significantly increased while desiccation tolerance of seeds and axes was progressively lost . Gibberellin and abscisic acid altered seed germination characteristics and improved desiccation tolerance of axes . These results showed that the loss of desiccation tolerance of imbibed pea seeds was a quantitative feature, and the changes in desiccation tolerance of imbibing orthodox seeds could serve as a model system for the study of seed recalcitrance .

Key words: Abscisic acid, Recalcitrant