Effects of NaCl Stress and Iso-osmotic PEG Treatment on Growth of Malus

Salt-sensitive species of Malus baccata (L.) Borkh, medium salt-tolerant species of Malus xiaojinensis Cheng et Jiang and salt-tolerant species of Malus zumi Mats were used as experimental materials. Malus seedlings were treated with NaCl stress and iso-osmotic PEG (polyethylene glycol), and roots length, shoot height and fresh weight were determined after 10 days treatment. 50 mmol/L NaCl stress on salt-tolerant species of Malus zumi Mats had a role in promoting growth, indicating the effect of low concentrations of Na+ ions played a role. High concentrations (100 and 150 mmol/L) of NaCI stress inhibited the growth of salt-sensitive species more than that of salt-tolerant one. High concentrations of iso-osmotic PEG treatment significantly inhibited the growth of Malus, and NaCl stress under corresponding osmotic potential inhibited the growth of Malus more, especially salt-sensitive species of Malus baccata (L.) Borkh. behaved more obviously, possible toxic effect of Na+ ions affected the growth.