Fig. 1

Overview of the work flow. The 27-day-old tomato plants were subjected to the four treatments for 20 h. They included (1) ‘a [CO₂], 400 ppm [CO₂] + 25/20 °C + irrigation; (2) a [CO₂] + combined stress, 400 ppm [CO₂] + 35/30 °C + no irrigation;(3) e [CO₂], 800 ppm [CO₂] + 25/20 °C + irrigation and (4) e [CO₂] + combined stress, 800 ppm [CO₂] + 35/30 °C + no irrigation. Then, the plants at combined stress regardless of [CO₂] were irrigated by water, which was defined as the recovery from DS (drought stress) for 16 h. Finally, the temperature was changed to 25/20 °C, which defined as the recovery from HS (heat stress) lasting 6 h