Department of Bioscience and Biotechnology, Banasthali University, Rajasthan-304022, India.
Plant Physiol Biochem. 2012 May;54:17-26. doi: 10.1016/j.plaphy.2012.02.003. Epub 2012 Feb 8.
To investigate the ability of sensitive and tolerant variety of Brassica juncea to adapt to a saline environment in a field, we examined the activities of antioxidant enzymes in relation to photosystem II, chlorophyll a fluorescence, photosynthetic pigment concentration, protein (D1) and proline in plants exposed to salt stress. We observed a greater decline in the photosynthetic rate (∆F/Fm') and electron transport rate (ETRsat) and saturating photosynthetically active photo flux density (PPFDsat) under salt stress in var. Urvashi (sensitive variety) than in var. Bio902 (tolerant variety). Var. Urvashi was found to be more sensitive to high salinity. In var. Bio902, chlorophyll a, chlorophyll b and total chlorophyll concentrations were higher than in the sensitive variety. Proline and protein contents were also higher in var. Bio902 as compared to their lower accumulation in var. Urvashi. The improved performance of the var. Bio902 under high salinity was accompanied by an increase in ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6), though no salt-dependent increase in the activity of superoxide dismutase (SOD, EC 1.15.1.1) was observed. However, no such increase in APX and CAT was observed in var. Urvashi, though there was significant increase in SOD activity. These results suggest that var. Bio902 is potentially more tolerant to salt damage and is associated with better adaptive responses found in var. Bio902 than var. Urvashi. Increased photoinhibition in var. Urvashi as observed by its reduced thylakoid membrane protein, D1 probably results from the greater photosynthetic damage caused by salt stress than var. Bio902.
为了研究芥菜敏感和耐盐品种在田间适应盐环境的能力，我们研究了抗氧化酶与光系统 II、叶绿素 a 荧光、光合色素浓度、蛋白质（D1）和脯氨酸的关系，以研究植物在盐胁迫下的反应。我们观察到，在盐胁迫下，Urvashi 品种（敏感品种）的光合速率（∆F/Fm'）和电子传递速率（ETRsat）以及饱和光化学活性光通量密度（PPFDsat）下降幅度大于 Bio902 品种（耐盐品种）。发现 Urvashi 品种对高盐度更敏感。在 Bio902 品种中，叶绿素 a、叶绿素 b 和总叶绿素浓度高于敏感品种。脯氨酸和蛋白质含量也高于敏感品种 Urvashi。与 Urvashi 品种相比，Bio902 品种在高盐胁迫下的表现有所改善，这与抗坏血酸过氧化物酶（APX，EC 1.11.1.11）和过氧化氢酶（CAT，EC 1.11.1.6）活性的增加有关，尽管没有观察到超氧化物歧化酶（SOD，EC 1.15.1.1）活性的盐依赖性增加。然而，在 Urvashi 品种中没有观察到 APX 和 CAT 的增加，尽管 SOD 活性显著增加。这些结果表明，Bio902 品种可能对盐害更具耐受性，并且与 Bio902 品种比 Urvashi 品种更好的适应性反应有关。在 Urvashi 品种中观察到的光抑制增加，其类囊体膜蛋白 D1 减少，可能是由于盐胁迫对光合作用的破坏大于 Bio902 品种。
