POLYAMINES IN RELATION TO DORMANCY BREAKING IN GRAPE BUDS (Vitis vinifera L.) cv ‘PERLETTE’

Abstract

In this research changes of polyamine content during budbreaking in grapes (Vitis vinifera L.), as well as the changes in bud weight, were evaluated. Four levels of chilling units (0,150,300 and 450 CU) and two rates of thidiazuron (0 and 300 mg L^-1 of TDZ) were applied to three node cuttings. Chilling was attained at 4ª C in chamber and TDZ was sprayed after such treatments. Afterwards, the cuttings were transferred to chambers at 22±2 ºC. The experimental design was a 4x2 factorial in a randomized block design with three replications. The experimental unit contained five cuttings. Budbreak (%), increments in fresh weight (IPFY), and concentration of putrescine (Put), Spermidine (Spd) and Spermine (Spm) were recorded. The treatment with the highest Put content (670 nmol g^-1FW) was 300 CU+ 300 mg L^-1 TDZ. The treatments 150 CU + 300 mg L^-1 TDZ, 450 CU + 300 mg L^-1 TDZ and the control contained 577.5, 542.7 and 143.6 nmol g^-1 FW, of Put respectively. CU and TDZ increased the Put content by 95 and 55 % respectively, increases that were related to IPFY and budbreak after 12 days. In contrast Spd and Spm were not related to IPFY and budbreak; CU did not estimulate the polyamine content but TDZ did.