5-bisphosphate carboxylase activities in wheat ears Effects of sucrose and ammonium nitrate on phosphoenolpyruvate carboxylase and ribulose-1

The effects of sucrose and ammonium nitrate (NH4NO3) levels on the activities of phosphoenolpyruvate carboxylase (PEPC) and ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) in ear organs (glume and grain), and on grain mass and nitrogen concentration were investigated using a culture of detached ears of wheat (Triticum aestivum L.). Results showed that PEPC and Rubisco activities in the glume and grain, as well as grain mass and grain nitrogen accumulation differentially increased as sucrose and NH 4 NO 3 levels increased. Grain N concentration progressively increased as the NH 4 NO 3 level increased, but decreased as sucrose level increased. Correlation analysis showed that PEPC activity in the glume and grain was positively correlated with grain N concentration. These results suggest that PEPC and Rubisco can be manipulated by external C and N supplies, and PEPC may play an important role in grain protein accumulation.

Zhang, Y. H., Zhou, S. L., Huang, Q., Leng, G. H., Xue, Q. W., Stewart, B. A., & Wang, Z. M.

Effects of sucrose and ammonium nitrate on phosphoenolpyruvate carboxylase and ribulose-1,5-bisphosphate carboxylase activities in wheat ears Academic Article