The role of wheat ears as a source of nitrogen （N） and carbon （C） in the grain filling process has barely been studied. To resolve this question, five wheat genotypes were labeled with 15N-enriched nutrient soluti...The role of wheat ears as a source of nitrogen （N） and carbon （C） in the grain filling process has barely been studied. To resolve this question, five wheat genotypes were labeled with 15N-enriched nutrient solution. N remobilization and absorption were estimated via the nitrogen isotope composition of total organic matter and Rubisco. Gas exchange analyses showed that ear photosynthesis contributed substantially to grain filling in spite of the great loss of C due to respiration. Of the total kernel N, 64.7% was derived from the N acquired between sowing and anthesis, while the remaining 35.3% was derived from the N acquired between anthesis and maturity. In addition, 1.87 times more N was remobilized to the developing kernel from the ear than from the flag leaf. The higher yielding genotypes showed an increased N remobflization to the kernel compared to the lower yielding genotypes. In addition, the higher yielding genotypes remobilized more N from the ears to the kernel than the lower yielding genotypes, while the lower yielding genotypes remobilized more N from the flag leaf to the kernel. Therefore, the ears contribute significantly toward fulfilling C and N demands during grain filling.展开更多
基金supported by Breeding to Optimise Chinese Agriculture (OPTICHINA) (Coordination and support action: FP7-KBBE-2010-4, 266045)the projects AGL 2011-30386C02-02 and AGL 2013-44147-R funded by the Spanish Ministry of Economy and Competitiveness+1 种基金a Ramon y Cajal research grant funded by the Spanish Ministry of Economy and Competitivenessa Basque Country Postdoctoral Fellowship funded by the Department of Culture and Linguistic Politics of the Basque Country Government
文摘The role of wheat ears as a source of nitrogen （N） and carbon （C） in the grain filling process has barely been studied. To resolve this question, five wheat genotypes were labeled with 15N-enriched nutrient solution. N remobilization and absorption were estimated via the nitrogen isotope composition of total organic matter and Rubisco. Gas exchange analyses showed that ear photosynthesis contributed substantially to grain filling in spite of the great loss of C due to respiration. Of the total kernel N, 64.7% was derived from the N acquired between sowing and anthesis, while the remaining 35.3% was derived from the N acquired between anthesis and maturity. In addition, 1.87 times more N was remobilized to the developing kernel from the ear than from the flag leaf. The higher yielding genotypes showed an increased N remobflization to the kernel compared to the lower yielding genotypes. In addition, the higher yielding genotypes remobilized more N from the ears to the kernel than the lower yielding genotypes, while the lower yielding genotypes remobilized more N from the flag leaf to the kernel. Therefore, the ears contribute significantly toward fulfilling C and N demands during grain filling.
