为探讨酸化处理及钙对酸化处理下平邑甜茶根系抗氧化酶活性及线粒体功能的影响,将平邑甜茶幼苗分2组分别置于pH 3,4,5,6(对照)的1/2 Hoagland营养液中及3个钙离子浓度梯度(10,20,30 mmol·L-1)的pH值为3的1/2 Hoagiand营养液中,于第0,2,3,4天分别测定抗氧化酶活性及线粒体指标.结果表明:与对照相比,各处理的SOD,CAT酶活性在处理的第2天达到最大值,POD酶活性变化不一,pH 3与pH 4处理在第2天达到最大值,pH5处理在第3天达到最大值；根系线粒体膜通透性、膜电位及细胞色素c/a随着酸度增加和时间的延长逐渐降低；H2O2含量先降低后升高.低浓度外源钙(10,20 mmol·L-1)处理能提高SOD,CAT,POD酶活性并维持一定时间,缓解线粒体各项功能的伤害,抑制H2O2的积累,主要表现在与单独酸处理相比H2O2含量降低了6.78％,13.43％,且20 mmol·L-1钙离子缓解效果最好；30 mmol· L-1钙离子处理却加剧了酸化伤害,H2O2含量上升了8.96％.酸化处理会对平邑甜茶根系造成伤害而营养液适量加钙可以缓解其伤害.%The purpose of this paper is to explore the effects of acid treatment and exogenous application of calcium to nutrient solution on the functions of antioxidant systems and mitochondria in Malus hupehensis var. pingyiensis roots. The M. hupehensis var. pingyiensis rootstock seedlings were cultured in 1/2 Hoagland nutrient solutions of different pH (3,4, 5 and 6) and different Ca2+ concentrations (10, 20 and 30 mmol·L-1) with pH3 , respectively. The antioxidant enzyme activities and the characteristics of mitochondria were measured in day 0,2,3 and 4. Compared with the control (pH6) , the maximum activity of SOD, CAT in the treatments occurred in day 2, and the change of POD activity was different, the maximum activity of POD occurred in day 2 in pH 3 and pH 4, and in day 3 pH 5. Meanwhile, the mitochondrial membrane permeability, potential ( △ψm ) and cytochrome c/a decreased with the increasing of the acidity and the treatment time and the content of H2O2 was decreased at first and then increased. The exogenous application of calcium (10 and 20 mmol·L-1) in the nutrient solution under acid treatment ( pH 3) increased the activities of SOD, POD and CAT, relieved the damage of the mitochondrial functions by the acidity and inhibited the accumulation of H2O2 (the decline, with 10 and 20 mmol·L-1, was 6.78% and 13.43% of the accumulation caused by the single acid treatment, respectively). The 20 mmol·L-1 Ca2+ had better effect whereas the 30 mmol·L-1Ca2+ increased the damage and increased the content of H2O2 by 8. 96% . The above results suggested that the acid treatments would damage the roots of M. hupehensis var. pingyiensis and the exogenous application of dilute calcium in the nutrient solution could relieve the damage of acid treatment to the roots.
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