Effects of rootstock and interstock on 15N-labeled nitrogen absorption and distribution in 'Kawanakajima Hakuto' peach trees

The absorption and distribution of applied nitrogen were determined in 4-year-old 'Kawanakajima Hakuto' peach trees grafted on Prunus persica (L.) Batsch (PP) and P. tomentosa Thunb. (PT) rootstocks and compatible interstock ('Chikuma') / P. tomentosa (IS) by using a N-15 tracer in the pot experiments. At fruit harvest, 55.7 to 61.3% of the absorbed nitrogen was partitioned to the leaves. The N-15 atom% excess in every scion part and the total amount of absorbed N-15 were significantly higher in PP and IS than in PT. These results suggest that the use of a compatible interstock, 'Chikuma', improves absorption and upward movement of applied nitrogen, thus it overcomes incompatibility between 'Kawanakajima Hakuto' and P. tomentosa.