Wheat plants (T. aestivum cv. Chinese Spring) were grown in a greenhouse and watered daily to avoid drought stress. The main stem ears were labelled when flowering. At 12 days after anthesis, the plants were transferred to growth chambers with a temperature regime of 24/17◦C (14 h/10 h) day/night cycle. At 15 days after anthesis, half of the plants were applied a temperature regime of 37/17◦C for 3 days and were harvested on the 4th day after 4 h under heat with light; the remaining plants were kept at 24/17◦C as a control and were harvested at the same sampling time.