Abstract: Malus sieversii and Malus hupehensis were treated with 20% polyethylene glycol(PEG6000) . The results are followed: The contents of DNA and RNA in leaves of sieversii were decreased slower than hupehensis treated with 20%PEG6000. The ratio of dry weight to fresh weight and the relative conductivity in leaves of sieversii were increased slower than hupehensis. In the experiment of dyed reaction with 0.1%NBT, the time of dyed in leaves sieversii was later than hupehensis. Physiology and biochemistry indexes could not only to identify fruit plants’ programmed cell death but also to measure sensitivity to water stress and to reflect drought resistance and senescence of Malus as parameters.

Key words: Malus, drought stress, programmed cell death, physiology and biochemistry parameters