The allocation percentages of N absorbed by roots in leaves and branches were 7%-10% and 7%-12% respectively,and the nitrogen demand for leave and branches growth was mainly met by internal N stocks.

• 根系吸收氮在叶片和枝的分配率分别为7%25~10%25和7%25~12%25,叶片和枝生长需要的氮素主要由其内源N库提供。