不同水分条件下冬小麦旗叶和穗器官的PEPC活性及其与粒重和蛋白质含量的关系

为了明确小麦叶与非叶器官磷酸烯醇式丙酮酸羧化酶 (PEPC) 活性对水分胁迫的反应,在春不浇水和春浇2水两种水分条件下,对11个冬小麦品种旗叶、穗、颖片及籽粒的PEPC活性进行了测定,并分析了该酶活性与粒重和蛋白质含量的关系.结果表明,小麦不同品种和不同器官间PEPC活性存在明显差异,且受水分条件的影响.与正常供水处理(春浇2水)相比,水分胁迫处理(春不浇水)灌浆期旗叶PEPC活性下降,而颖片PEPC活性相对稳定,籽粒PEPC活性上升.水分胁迫使最终粒重降低、蛋白质含量增加.相关分析表明,灌浆期旗叶PEPC活性与粒重呈显著正相关(r＝0.504~*),颖片PEPC活性与籽粒蛋白质含量呈弱的正相关,籽粒PEPC活性与籽粒蛋白质含量呈极显著正相关(r＝0.692~(**)).

Phosphoenolpyruvate Carboxylase Activity of Flag Leaf and Ear Organs and Its Relationship with Grain Weight and Protein Concent in Winter Wheat under Different Water Treatments

Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme involving in carbon and nitrogen metabolism. PEPC activity can be manipulated by Environment. In this study, 11 winter wheat cultivars were selected to study the effects of no irrigation and 2 times irrigation in spring on PEPC activities of flag leaf, glume and grain, grain weight and protein concentration and the correlations between them. The results showed that there were significant differences in PEPC activity among cultivars and among organs, and PEPC activity can be regulated by water supply. Compared to normal water supply (2 times irrigation in spring), PEPC activity of flag leaf blade in no irrigation treatment reduced, PEPC activity of glume was relatively constant, PEPC activity of grain increased during grain filling, while the final grain weight decreased and grain protein concentration increased. Correlation analysis showed that PEPC activity of flag leaf was significantly and positively correlated with grain weight (r＝0.504, P<0.05), that of glume was positively correlated with grain protein concentration weakly, and that of grain was significantly and positively correlated with grain protein concentration (r＝0.692, P<0.01). According to relative studies, we proposed that PEPC can regulate carbon and nitrogen metabolism in plant, and the increase of PEPC activity in leaf and non-leaf organs may be benefit to improve grain yield and protein concentration simultaneously.