Fig. 2.

Quantities of endogenous GA₁ in grapevine buds throughout the dormancy cycle. Buds were sampled weekly from the vineyard and were frozen immediately as described in Fig. 1. Buds were homogenized, and GA₁ was quantified by LC–MS/MS (Acheampong et al., 2015). ²H-labeled GA₁ was spiked as internal standard. The levels of GA₁ were calculated from the peak area ratios of the endogenous GA₁ to its ²H-labeled internal standard. Three biological replications (10 buds per replicate) were analyzed for each time point, and means from three time points during endodormancy induction, maintenance, and release (1–13 November, 20 November–18 December, and 25 December–8 January, respectively) served to calculate GA₁ levels. Data points with different letters indicate significantly different values (P<0.05) according to Tukey’s HSD test.