Change in plasma membrane ATPase activity during dormancy release of vegetative peach-tree buds

Plant dormancy and dormancy breaking depend, at least partially, on peculia r short distance relationships between buds and tissues underlying buds (bu d stands), In peach-tree, it was previously observed that dormancy was rela ted to a high nutrient absorption capacity in tissues underlying buds, This situation could be linked to higher plasma membrane ATPase activity (EC 3. 6.1.3), inducing a higher nutrient absorption, in bud stands, This work con sists of characterization of the plasma membrane ATPase activity in vegetat ive buds and bud stands during the rest period and dormancy release. During the dormant period (October and November), plasma membrane ATPase activity was found to be higher in bud stands than in buds, This was correlated wit h a lower amount of plasma membrane ATPase in buds compared to bud stands d uring this period, Moreover, plasma membrane ATPase activation by trypsin t reatment was not the same in both tissues and different levels of ATPase ac tivation could be noted within the same tissue during the different stages of dormancy release, According to these results, it can be postulated that dormancy release in peach-tree, is related to modifications of plasma membr ane ATPase properties in buds and bud stands during winter time,