Retranslocation of Accumulated 14C-assimilates as Affected by Dormancy Breakers in “KYOHO” grapevines
Two-year-old potted “Kyoho” grapevines were supplied with 14CO2 in autumn, and treated with mixed solution of cynamide and Merit, ethylene-chlorohydrins with nickling and non-treatment, respectively, after pruning (February the following year). The accumulation and retranslocation of 14C-assimilates, the percentage and efficiency of budbreak were investigated from leaf-fall stage to 12-leaf stage of newly developed shoot in following spring. At the leaf-fall stage, 67% of 14C-photosynthates were distributed to the roots, trunk and cane, and especially higher ratio in the roots. The percentage and efficiency of budbreak were evidently higher for the treatment of mixed solution of cynamide and Merid after pruning, and reached a maximum percentage retranslocation of 14C as much as 21 at 6-leaf stage, but only 10 and 14 for the treatment with ethylene-chlorohydrins with nickling and non-treatment, respectively. At 6-leaf stage, the respiration consumption of 14C was lower for the treatment of mixed solution of cynamide and Merid which promotes the total quantity and velocity of retranslocation of stored carbohydrates and the newly shoot growth. Such a results was recognized also by auto-radiography.