Remobilization of Storage Nitrogen in Young Pear Trees Grafted onto Vigorous Rootstocks (Pyrus betulifolia)

The remobilization of storage nitrogen (N) is affected by growth characteristics young pear trees. Aboveground parts trees grafted on P. betulifolia grew more vigorously than that dwarfing rootstocks. Therefore, the N within vigorous rootstocks may be different from A 15N tracing experiment, including six groups one-year-old in 2016, was conducted to investigate mobilization 2016 2018. Results indicated about 44%, 31.4% and 24.6% remobilized new derived trunk, shoots roots, respectively. Most organs were supplied trunks shoots. About 82.2% withdrawn senescent leaves recovered trunk during autumn. aboveground played a important role roots cycling process However, as compared with rootstocks, due nutrient requirement parts.