NaCl胁迫对阿月浑子实生苗活性氧代谢与细胞膜稳定性的影响

EFFECTS OF NACL STRESS ON ACTIVE OXYGEN METABOLISM AND MEMBRANE STABILITY IN PISTACIA VERA SEEDLINGS

为研究阿月浑子(Pistaciavera)的耐盐性,对新疆两个主栽品种‘长果’和‘Kerman’的1年生实生苗进行了控制条件下的NaCl胁迫实验,实验浓度为50、150、250和500mmol·L-1,NaCl胁迫5、10和20d后取叶片测定其细胞膜透性、丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的变化。实验结果显示,在NaCl胁迫下,‘长果’和‘Kerman’的膜透性和MDA含量均随NaCl浓度的升高而增加,表明NaCl胁迫致使阿月浑子膜脂过氧化程度加强,细胞膜稳定性受到破坏,其中‘长果’品种的膜透性和MDA含量增加幅度较大,受到的盐害较大。而SOD、CAT和POD活性则随NaCl浓度的升高先增加后下降,抗氧化酶活性(SOD、POD和CAT)之间协调变化有利于清除活性氧,维持活性氧代谢平衡,保护膜结构。实验结果也显示,随着NaCl胁迫时间的延长,两个品种的细胞膜结构和功能受损害程度有所缓解。这些指标中,‘长果’和‘Kerman’品种的膜透性和MDA含量与SOD活性呈显著相关,表明植物细胞的质膜透性与脂质过氧化产物(MDA)含量有关,也与组织中自由基含量和保护酶活性密切相关。综合各项生理指标,‘Kerman’品种相对‘长果’品种显示了较强的抗氧化能力,具有较强的耐盐能力。

Pistachio （ Pistacia vera ） is one of the most important dried fruit trees in the world and is mainly cultivated in Xinjiang, China. However, soil salinization is one of the main limiting factors for its promising potential of development. In this experiment, the effects of NaCl stress on physiological and biochemical characteristics were investigated in seedlings of two cultivars of Pistacia vera, ‘Changguo＇ and ‘Kerman＇. Seedlings were grown in pots and treated with four NaCl concentrations： 50, 150, 250 and 500 mmol·L^-1 The membrane permeability, malondialdehyde content （MDA）, superoxide dismutase （SOD） activity, catalase （CAT） activity and peroxidase （POD） activity in the leaves of these two cultivars were measured and compared after 5, 10 and 20 days of NaCl treatments. The experimental results showed that the membrane permeability and MDA content in both cultivars increased considerably with the increasing NaCl stress, which aggravated the degree of membrane lipid peroxidation and injured the membrane stability. The membrane permeability and MDA content in the ‘Changguo＇ cultivar increased more quickly than the ‘Kerman＇ cultivar and thus experienced greater damage at higher NaCl concentrations. The activities of SOD, CAT and POD had similar trends for both cultivars, first increasing with NaCl concentrations up to 250 mmol·L^- 1 and then decreasing at the highest NaCl stress of 500 mmol·L^- 1 The coordinated changes of activities among the antioxidant enzymes of SOD, POD and CAT could scavenge active oxygen and maintain a balance of active oxygen accumulation in cells to protect membrane structure. The results also showed that the damage by NaCI stress to the membrane structure and function for both cultivars were mitigated considerably 20 days after the treatments were initiated. There were significant correlations among the membrane permeability, MDA content and the activity of SOD in both cultivars, which implied that the membrane permeability in the plant cells had a close relation with MDA content and oxygen free radical content, as well as the activity of antioxidant enzymes. Together, these results indicated that the ‘Kerman＇ cuhivar has higher antioxidant levels and greater salt-tolerance than the ‘Changguo＇ cultivar of Pistachio.