花后短暂高温对小麦籽粒蛋白质含量的影响及其生理机制

采用人工气候室控温， 研究花后短暂高温对弱筋小麦扬麦9号和中筋小麦扬麦12籽粒蛋白质含量的影响及其生理机制。结果表明，开花至花后33 d，35℃以上高温处理使籽粒蛋白质含量显著高于对照， 温度越高上升越显著；花后33 d以后遇高温胁迫对蛋白质含量影响相对较轻。籽粒灌浆前期，花后6~8 d 35℃以上高温胁迫对蛋白质含量的影响最大，花后1~3 d处理影响次之；在灌浆中后期，花后19~21 d高温胁迫对蛋白质含量影响较大，花后36~38 d处理的影响较小，且灌浆前期籽粒蛋白质含量受高温胁迫的影响较灌浆中后期大。剑叶硝酸还原酶（NR）和谷氨酰胺合成酶（GS）活性以25℃处理较高，随温度的升高而降低, 与籽粒蛋白质含量呈极显著负相关。高温胁迫导致粒重下降，籽粒蛋白质含量相对上升。花后短暂高温胁迫导致弱、中筋小麦籽粒蛋白质品质变劣。

Effects of Transient High Temperature after Anthesis on Grain Protein Content and Physiological Mechanism in Wheat (Triticum aestivum L.)

Wheat grain yield and quality are affected by environmental factors. Temperature is a major component in environmental variations with a marked effect on grain filling in wheat. Short period of heat shock, above 30℃ for a few days, happens frequently during grain filling period in many wheat-growing areas in the world, and becomes an important factor limiting wheat yield and quality. The present study investigated the effects of transient high temperature after anthesis on grain protein content and activities of nitrate reductase(NR) and glutamine synthetase(GS) in wheat(Triticum aestivum L.) to understand the mechanism of heat damage. We arranged daily average temperature 25, 30, 35, and 40℃, respectively in a phytotron, and treated wheat plants during different grain filling periods. The tested wheat cultivars were Yangmai 9 with weak gluten and Yangmai 12 with medium gluten. The results showed that grain protein content under the temperature above 35℃ from anthesis to the 33rd days after anthesis (DAA) was significantly higher than that under normal temperature, and significantly increased with the raise of temperature. There was a little effect of heat stress on protein content after the 33rd DAA. High temperature at different filling stages had different effects on protein content in grains. When heat shock temperature was above 35℃ at the early filling stage, the effect of heat shock from the 6th to 8th DAA was the greatest, followed by that from the 1st to 3rd DAA. Under the same temperature at the middle and late stages, the effect of heat shock from the 19th to 21st DAA was greater, while that from the 36th to 38th DAA was lower. Effects of heat shock at the early filling stage on grain protein content were greater than those at the middle and late stages. At the same stage, the higher the temperature, the lower the NR and GS activities in flag leaves. High temperature stress during grain filling decreased the duration of grain filling and grain weight, which increased grain protein content relatively. Heat damage led to lower quality of grain protein in wheat.