Effect of Photoperiod on Key Enzyme Activities of Respiration in Nectarine Buds During Dormancy Induction

Shuguang (Prunus persica var. nectariana cv. Shuguang) nectarine was used to study effects of photoperiod on key-enzyme activities of respiration during dormancy induction. The dormancy status was determined with sprouting ability. Spectrophotometry was used to investigate activities of phosphohexose isomerase (PGI), malic dehydrogenase (MDH), and glucose-6-phosphate dehydrogenase (G6PDH). The results revealed that short day (SD) treatment promoted dormancy induction while long day (LD) treatment postponed the process. During dormancy induction, PGI activities declined, MDH activities changed little, and G6PDH activities increased both in flower buds and leaf buds. PGI activities and MDH activities in SD treatment were lower than control, and G6PDH activities were higher, which was opposite with LD treatment. The changes of respiratory key-enzyme activities were adjusted by photoperiod and correlated with the development of dormancy induction.