Loss and re-establishment of desiccation tolerance in the germinated seeds of Sesbania virgata (Cav.) (Pers.)

Resumo

This research aimed to investigate the cellular alterations during the loss and re-establishment of desiccation tolerance (DT) in germinated Sesbania virgata seeds. The loss of DT was characterized in germinated seeds with increasing radicle lengths (1, 2, 3, 4 and 5 mm) when subjected to dehydration in silica gel, followed by rehydration. To re-establish DT, the germinated seeds were incubated for 72h in polyethylene glycol (PEG, -2.04 MPa) with or without ABA (100 μM) before dehydration in silica gel. Cell viability was assessed by seedling survival, and DNA integrity was evaluated by gel electrophoresis. Seeds with 1 mm radicle length survived dehydration to the original moisture content (MC) of the dry seed (approximately 10%). PEG treatment was able to re-establish DT, at least partially, with 2, 3 and 4 mm but not in 5 mm radicle lengths. Germinated seeds treated with PEG+ABA performed better than those treated only with PEG, and DT was re-established even in germinated seeds with a 5 mm radicle length. Among the PEG-treated germinated seeds dehydrated to 10% MC, DNA integrity was maintained only in those with a 1 mm radicle length.