Fig. 3. Changes in antioxidant concentrations in apple leaves and the transcript levels of genes implicated in the AsA–GSH cycle under heat stress.

Concentrations of a ascorbic acid (AsA), b dehydroascorbate (DHA) and c AsA + DHA and d AsA / DHA. Concentrations of e glutathione (GSH), f oxidized glutathione (GSSG) and g GSH + GSSG and h GSH/GSSG. These data were measured 4 h after heat treatment. Changes in the expression of i APX, j GR, k MDHAR, and l DHAR1 under heat stress. Total RNA was isolated from leaf samples collected after 2 h of heat stress. Data are shown as the means of three replicates with SEs. Different letters indicate significant differences between treatments, according to one-way ANOVA and Tukey’s multiple range test (P < 0.05).