花后土壤水分状况对小麦籽粒淀粉和蛋白质积累关键调控酶活性的影响

在温室盆栽条件下，以2个不同蛋白质含量的冬小麦(Triticum aestivum L．)品种皖麦38和扬麦9为材料，研究了花后第4天开始的土壤干旱(SRWC=45％～50％)和渍水对籽粒蛋白质和淀粉积累关键调控酶活性的影响。小麦叶片和籽粒的测定结果均表明，小麦源库器官中籽粒蛋白质和淀粉积累的关键调控酶活性变化趋势在2个品种间基本一致。与对照(SRWC=75％～80％)相比，干旱和渍水均明显降低了花后旗叶中蔗糖含量和磷酸蔗糖合成酶(SPS)活性，而氨基酸含量和谷氨酰胺合成酶(GS)活性略有下降。干旱和渍水均降低了籽粒库蔗糖合成酶(SS)和结合态淀粉合成酶(GBSS)活性，可溶性淀粉合成酶(SSS)活性降低尤甚。其中干旱处理下SS的下降比渍水更为明显。与对照相比，渍水明显降低了籽粒谷丙转氨酶(GPT)和GS活性，而干旱的影响较小。相关性分析结果表明籽粒淀粉产量和含量与SPS，SSS和GBSS活性的关系比与SS活性的关系更为密切，籽粒蛋白质产量和含量与叶中GS和籽粒中GPT活性的关系比与籽粒中GS关系活性更为密切。这些结果表明小麦源库器官中调控籽粒蛋白质和淀粉积累的关键酶活性变化是花后不同水分状况影响籽粒淀粉和蛋白质特性的重要因素。

Effects of Post-Anthesis Soil Water Status on the Activities of Key Regulatory Enzymes of Starch and Protein Accumulation in Wheat Grains

Two winter wheat ( Triticum aestivum L.)varieties differing in grain protein content, Wanmai 38 and Yangmai 9 potted in a greenhouse, were used to investigate the effects of soil drought (SRWC=45%-50%) and waterlogging beginning from 4 days after anthesis (DPA) on the activities of key regulatory enzymes of grain starch and protein accumulation. The results in both leaves and grains showed that the patterns of changes in the activities of enzymes were similar in the two varieties. Compared with CK (SRWC= 75%-80%) , sucrose content and sucrose phosphate synthase (SPS) activity declined more markedly than amino acid content and glutamine synthetase (GS) activity under drought and waterlogging. Both drought and waterlogging resulted in decreases in the activities of sucrose synthase (SS) and granule-bound starch synthase (GBSS), and especially in that of soluble starch synthase (SSS). And more marked decreases in the activity of SS occurred under drought than under waterlogging. Compared with CK, GS and glutamate pyruvic aminotransferase (GPT) activities in grain decreased markedly under waterlogging, but decreased a little under drought. By correlation analyses, it was found that the SPS, SSS and GBSS activities were more closely correlated than SS to the yield and grain starch, and GS activity in grain was correlated to a lower degree to the yield and content of grain protein than GS in leaf and GPT in grain. Further analysis revealed that the changes in activity of key regulatory enzymes of grain starch and protein accumulation in source and sink organs of wheat were the main factors through which different post-anthesis soil water status affected grain starch and protein characters.