Changes in antioxidant activity in sub-cellular fractions of tolerant and susceptible wheat genotypes in response to long term salt stress
Changes in antioxidant activity in sub-cellular fractions of tolerant and susceptible wheat genotypes in response to long term salt stress
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DOI：
10.1016/s0168-9452(02)00037-7
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发表时间：
2002-06
期刊：
影响因子：
5.2
通讯作者：
R. Sairam;G. Srivastava
中科院分区：
文献类型：
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作者：
R. Sairam;G. Srivastava
研究了长期、中等水平（浸膏电导率(ECe)=6.85 dS m−1）氯化钠（NaCl）盐度对耐（Kharchia 65）和敏感（HD 2687）小麦基因型的影响。NaCl盐度降低了小麦相对含水量（RWC）、叶绿素（CHL）、膜稳定性指数（MSI）和抗坏血酸（AA）含量，增加了过氧化氢（H2O2）、硫代巴比妥酸活性物质（TBARS）（脂质过氧化的衡量指标）和超氧化物歧化酶（SOD）及其各种同型酶、抗坏血酸过氧化物酶（APOX）和谷胱甘肽还原酶（GR）的活性。耐盐小麦cv。与盐敏感的HD 2687相比，Kharchia 65全组织RWC、CHL和MSI的下降幅度较小。与盐敏感的HD 2687相比，Kharchia 65各亚细胞组分中AA含量的下降幅度较小，H2O2、TBARS含量的增加幅度较小，SOD及其同工酶、APOX和GR的增加幅度较大。叶绿体部分H2O2、TBARS含量和AA含量较高。叶绿体部位总SOD、APOX和GR活性较高，线粒体部位总SOD和GR活性次之，细胞质部位APOX活性次之。线粒体部分Mn-SOD活性最高，细胞质部分Mn-SOD活性也有残留。Cu/ Zn-SOD和Fe-SOD在所有亚细胞组分中均存在，但在叶绿体组分中活性均较高。总Cu/ Zn-SOD活性（各组分活性之和）高于其他SOD亚型。HD 2687对长期盐胁迫的敏感性可能是由于在盐胁迫下SOD同工酶的诱导相对较少，叶绿体和线粒体APOX和细胞质GR没有诱导，叶绿体GR降低，导致h2o2和TBARS含量升高，MSI和CHL降低。
Effects of long term, medium level (electrical conductivity of extract (ECe)=6.85 dS m−1) sodium chloride (NaCl) salinity were studied in tolerant (Kharchia 65) and susceptible (HD 2687) wheat genotypes. NaCl salinity caused decrease in relative water content (RWC), chlorophyll (CHL), membrane stability index (MSI) and ascorbic acid (AA) content, and increased the contents of hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS) (measure of lipid peroxidation) and activities of superoxide dismutase (SOD), its various isozymes, ascorbate peroxidase (APOX) and glutathione reductase (GR) in wheat genotypes Kharchia 65 (tolerant) and HD 2687 (susceptible). Salinity tolerant wheat cv. Kharchia 65 showed less decline in RWC, CHL, MSI estimated in whole tissue than salt sensitive HD 2687. Kharchia 65 also exhibited less decrease in AA content, less increase in H2O2, TBARS contents and higher increase in SOD and its isozymes, APOX and GR in all sub-cellular fractions than salt sensitive HD 2687. H2O2, TBARS contents and AA contents were higher in chloroplastic fraction. Chloroplastic fraction showed higher total SOD, APOX and GR activity, followed by mitochondrial fraction in case of total SOD and GR, while cytosolic fraction was in second place in case of APOX activity. Though Mn–SOD activity was highest in mitochondrial fraction, but residual activity was also observed in cytosolic fraction. Cu/Zn–SOD and Fe–SOD were observed in all the sub-cellular fractions, however, the activities were higher in chloroplastic fraction for both the isoforms. Total Cu/Zn–SOD activity, sum of activity observed in all the fractions, was higher than other SOD isoforms. Susceptibility of HD 2687 to long-term salinity stress seems to be due to relatively less induction of SOD isozymes, no induction in chloroplastic and mitochondrial APOX and cytosolic GR and decrease in chloroplastic GR under salt stress resulting in higher oxidative stress in the form of H2O2and TBARS contents and decrease in MSI and CHL.