Temporal Pattern of Changes in Desiccation Tolerance during Imbibition of Pisum sativum Seeds

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.