Figure 6.

Changes in photosynthesis. (A) Carbon assimilation rate; (B) Maximum quantum yield of photosystem II (PSII; Fv/Fm); (C) activity of Calvin–Benson cycle enzyme SBPase as affected by TDC silencing and exogenous melatonin in tomato leaves under chilling stress. Tomato plants at the 6-leaf stage were exposed to chilling stress (4 °C) for 12 h and leaf photosynthesis was measured using a portable photosynthesis system. Leaf samples were collected for the determination of SBPase activity. The values presented are means ± SDs (n = 3). Different letters (a–d) above bars indicate significant difference at p < 0.05 among treatments.