冬小麦籽粒淀粉合成相关酶活性的日变化

蔗糖向淀粉的转化是决定小麦籽粒产量的重要因素.田间条件下研究了两个小麦(Triticum aestivum L.)品种"鲁麦22"和"鲁麦14"籽粒淀粉合成相关酶:蔗糖合酶(sucrose synthase,SS)、腺苷二磷酸葡萄糖焦磷酸化酶(ADP-glucose pyrophosphorylase,ADPGPPase)、可溶性淀粉合酶(soluble starch synthase,SSS)、束缚态淀粉合酶(starch granule-bound synthase,GBSS)的活性以及籽粒ATP含量的日变化.结果表明,上述酶活性呈现明显的昼夜变化特征,酶活性一般在白天较低,而在夜间呈现较高活性,而籽粒ATP含量趋势相反.相关分析表明,白天较低的酶活性可能与气温超过其适宜温度有关.对籽粒淀粉合成相关酶活性日变化的可能因子进行了讨论.

Diurnal Changes in Activities of Related Enzymes to Starch Synthesis in Grains of Winter Wheat

The conversion from sucrose to starch in grains is a key process during yield formation of wheat. In a field study, diurnal changes in ATP content and activities of enzymes catalyzing starch synthesis in grains of two winter wheat (Triticum aestivum L.) cv. Lumai 22 and Lumai 14 were investigated. The enzymes included sucrose synthase (SS; EC 2.4.1.13), ADP-glucose pyrophosphorylase (ADPGPPase; EC 2.7.7.27), soluble starch synthase (SSS), and starch granule-bound synthase (GBSS; EC 2.4.1.21). Activities of these enzymes and ATP content showed obvious diurnal patterns. The enzyme activities were generally higher during the nighttime than the daytime, but ATP content showed an opposite pattern. It was found that the super-optimum air temperature could be partly responsible for the low enzyme activities during the daytime. The possible factors influenced the diurnal changes in activities of the enzymes for starch synthesis in wheat grain were discussed.