With two apple rootstock seedlings,Malus hupehensis Rehd.and Malus toringoides Rehd.,the effects of hypoxia stress on growth and physiological characteristics were studied with the nutrient solution culture.The results showed that hypoxia stress decreased the number of new leaves,length of root and maximum length of new root of apple rootstock,and decreased the contents of chlorophyll a (Chl a),total chlorophyll (Chl) and carotenoid (Car) ,which leaded to the changes of ratio between different pigments.Hypo...