Anatomical observation on release of tuber dormancy in water yam (Dioscorea alata L.)

Abstract

The effects of gibberellin (GA) and a gibberellin inhibitor were investigated on bud growth of two water\ryam (Dioscorea alata L.) varities. The tubers were harvested after plants senescenced and were\rsubsequently treated with GA and the gibberellin inhibitor uniconazole-P (UP). Tuber dormancy was\rradically prolonged by GA, but not influenced by UP. The bud germination was observed 90 days after\rharvesting in both varieties. However, the differentiated shoot meristem was found under microscope\robservation on top of tuber (corm) at harvesting. It was thought that the shoot meristem development\rstarted before harvesting. The observed dormancy period of 90 days was not actual dormancy period,\rand the true plant dormancy released before or with plant senescence. GA treatment after plant\rsenescence inhibited the shoot meristem development