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    盐胁迫和洗盐处理对贴梗海棠生理特性的影响

    Effects of salt stress and salt leaching on the physiological characteristics of Chaenomeles speciosa

    • 摘要: 以贴梗海棠3年生盆栽苗为材料,经50、100和150 mmol/L NaCl处理14 d,随后进行洗盐处理,测定其间盐害指数、叶绿素含量、相对电导率、MDA含量、抗氧化酶活性和可溶性蛋白质含量的变化,探讨了贴梗海棠的耐盐性。结果表明:随土壤中NaCl浓度的增加及处理时间的延长,盐害指数、相对电导率和MDA含量呈上升趋势,而叶绿素含量和可溶性蛋白质含量则不断降低,表明贴梗海棠在盐胁迫下受害严重。即使在50 mmol/L NaCl处理中仍表现出明显的盐害症状,证明贴梗海棠属于盐敏感植物。在盐胁迫初期,贴梗海棠中SOD酶的活性随NaCl浓度升高显著升高,各盐处理在第7天时达到最大;而在第14天急剧下降。50 mmol/L NaCl处理的CAT活性高于对照,并随胁迫时间延长而升高,到第14天时达到最大值。而在100和150 mmol/L NaCl处理中CAT活性至第7天时达到最大值,在第14天时迅速下降。APX和POD与CAT有类似的变化趋势。说明抗氧化酶系统在贴梗海棠抵御盐胁迫过程中具有重要作用。洗盐处理37 d后,50 mmol/L NaCl处理的贴梗海棠的各项生理指标可恢复到对照处理的水平。而100和150 mmol/L NaCl处理的贴梗海棠也有显著的恢复,但是恢复速度和程度低于50 mmol/L NaCl处理,说明植物在盐胁迫中的恢复能力与其所受到的盐害程度明显相关,也可作为评价植物耐盐性的指标。

       

      Abstract: To evaluate salt tolerance of Chaenomeles speciosa, salt injury index, chlorophyll content, relative conductivity, MDA content, antioxidant enzyme activities and soluble protein content were measured during the potcultured 3\|yearold seedlings exposed to 50, 100 and 150 mmol/L NaCl for 14 days and following salt leaching for 37 days. The results showed that, the salt injury index, relative conductivity and MDA content increased with the increase of NaCl concentration and exposure periods, while chlorophyll content and soluble protein content decreased, indicating that C. speciosa suffered serious salt injury during salt exposure, even in 50 mmol/L NaCl treatment. So C. speciosa was one of saltsensitive shrubs. During the early stage of salt stress, the superoxide dismutase (SOD) activity was enhanced in a salt concentration and exposure duration dependent manner, and reached the maximum on the 7th day, then turned to sharply decrease on the 14th day. In 50 mmol/L treatment, the catalase (CAT) activity was higher than that of control, and rose with salt exposure extension, and maximized on the 14th day. While in 100 and 150 mmol/L NaCl treatment, the maximum of CAT activity shifted to the 7th day, and the activity decreased rapidly on the 14th day. The ascorbic acid peroxidase (APX) and peroxidase (POD) had the similar variation trend with the CAT activity. The results demonstrated that the antioxidant enzymes played important role in C. speciosa resisting to salt stress. After salt leaching for 37 days, the physiological indexes of 50 mmol/L NaCl treatment recovered to the control level. C. speciosa in 100 and 150 mmol/L NaCl treatments also apparently recovered from salt injury during salt leaching, but with lower speeds and less degrees compared with that of 50 mmol/L treatment. The results indicate that the recovering ability from salt injury has a close relation with salt injury degree, which might be used as a physiological index to evaluate plant salt tolerance.

       

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