Abstract: 【Objective】The aim of this paper is to analyze the difference between root and shoot of apple rootstocks function with different fertility levels.【Method】One-year seedlings of Malus hupehensis ‘Pingyitiancha’, M. robusta, M. micromalus ‘Laiwunanyan’, were used as materials in the experiment. Root and leaf function difference of different apple rootstock seedlings among different fertilizer levels were studied.【Result】In the proportion of the above-ground part and underground part, with the enhancement of the soil fertility, the shoot/root ratio decreased. But the ratio’s decrease in different species was different. In high soil fertility, the content of chlorophyll was rich. The result indicated that pigments degradation was affected by soil fertility. Diurnal changes of Pn were double peak curve; the average of Pn was proportional to soil fertility. There were many differences between different apple stocks. The Pn of ‘Laiwunayan’ was higher than the other two apple stocks. A significant correlation between R/T and WUE was observed. The chlorophyll fluorescence was determined. The result indicated that the thermal dissipation ability of same apple stock was distinct under different soil fertilities, which might be the reason that the components of photosynthetic pigment were changed by the supply of soil fertilizer. 【Conclusion】According to different apple stocks, the roots growth can be controlled moderately by adjusting soil fertility. As root/shoot ratio being changed, it will be of benefit to reduce growth tediousness. This is an important step for effective method for figuring tree structure.

Key words: apple , stock , fertilize , root/shoot ratio , growth tediousness