Phosphoenolpyruvate carboxylase activity of the flag leaf and the ear organs and its relationship with grain weight and protein content 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,P0.05),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,P0.01).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.