Influence of temperature on the dynamics of ATP, ADP and non-adenylic triphosphate nucleotides in vegetative and floral peach buds during dormancy

The nucleotides test of endodormancy, which is based on the capacity of tis sues to synthesize ATP and non-adenylic triphosphate nucleotides (NTP), can not be used for floral buds, and it is of questionable use for vegetative b uds. In an attempt to find an alternative test, we examined whether the dor mancy state of vegetative and floral buds of trees exposed to different tem perature conditions during the rest period is directly related to their ATP , ADP and NTP concentrations and ATP/ADP ratio. Once the buds had entered e ndo- or paradormancy, the nucleotide concentrations and the ATP/ADP ratio w ere low in the vegetative primordia and very low in the floral primordia. O nly after the action of chilling, when the buds were considered to have com pleted the endodormancy and paradormancy phases, did the nucleotide concent rations increase, accompanied by a steep rise in ATP/ADP ratio. We conclude that the ATP/ADP ratio could be used to characterize the bud dormancy stat e by comparison with critical values of 1.5 for vegetative primordia and 1. 0 for floral primordia.