Transcript levels of (a) SlGR1, (b) SclAPX, (c) SlSOD, (d) SlCAT1, (e) SlSPS, (f) SlP5CS, and (g) SlT6PS genes, in leaves of SlHK2 RNAi and WT tomato plants. Control, normal (hydrated) conditions (C); drought stress, 5 days no watering (D); heat stress, 5 days 32/26 °C day/night (H); combined drought and heat stress, 5 days no watering + 32/26 °C day/night for 5 days (D + HS). The relative expression level is determined by quantitative real-time PCR (using the SlActin gene as reference). Values represent mean ± SE (n = 6). Different letters show significant differences among treatments at p < 0.05.