The Physiology and Biochemistry Analyzing of Programmed Cell Death under Drought Stress in Malus hupehensis and M. sieversii The Physiology and Biochemistry Analyzing of Programmed Cell Death under Drought Stress in Malus hupehensis and M. sieversii Research of Programmed Cell Dea th Under Wa ter Stress in Malus robustaRehd. and Malus hupehensis ( Pamp. ) Rehd. Cytotoxin-induced Apoptosis in Meristematic Cells of Maize Roots Damage to DNA Primary Structure and Antioxidant Enzymes in Lemna minor Induced By Hg2+(in English) Ethylene Induction of Apoptosis in Carrot Protoplasts Research of Programmed Cell Dea th Under Wa ter Stress in Malus robustaRehd. and Malus hupehensis ( Pamp. ) Rehd.