Glycine betaine-induced lead toxicity tolerance related to elevated photosynthesis, antioxidant enzymes suppressed lead uptake and oxidative stress in cotton
Glycine betaine-induced lead toxicity tolerance related to elevated photosynthesis, antioxidant enzymes suppressed lead uptake and oxidative stress in cotton
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DOI：
10.3906/bot-1304-65
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发表时间：
2014-01-01
影响因子：
1.8
通讯作者：
Ahmad, Muhammad Sajid Aqeel
中科院分区：
文献类型：
--
作者：
Bharwana, Saima Aslam;Ali, Shafaqat;Ahmad, Muhammad Sajid Aqeel
人类活动污染土壤的重金属浓度包括铅（Pb），镉（Cd），铜（Cu）和铬（Cr）。铅比其他重金属更容易在土壤中积累、沉淀和中毒。本研究通过外源甜菜碱（GB）的施用，利用3个水平的铅（0，50和100 μ m）和2 GB水平（0和1 mM）诱导溶液培养生长的棉花耐铅性。结果表明，铅胁迫降低了叶片的气体交换特性（净光合速率、气孔导度、蒸腾速率、水分利用效率、叶绿素、类胡萝卜素和SPAD值）和抗氧化酶的活性。GB的应用减轻了铅胁迫的毒性效应，这反过来又增加了植物的生长和气体交换特性，通过降低性能的丙二醛（MDA），过氧化氢（H2O2），电解质泄漏。抗氧化酶活性的增加有助于介导的铅胁迫的不利影响相比，单独与铅处理的植物。结果表明，外源GB可通过改善棉花的生长、生物量和光合参数来缓解铅毒害。植物GB通过提高叶绿素合成、光合活性和抗氧化酶活性，降低电解质渗漏、MDA和H2O2水平，提高了铅胁迫下的耐铅性。
Anthropogenic activities contaminate soils with heavy metal concentrations including lead (Pb), cadmium (Cd), copper (Cu), and chromium (Cr). Pb has higher potential for ready accumulation, sedimentation, and poisoning of the soil than other heavy metals. The present study was conducted to induce Pb tolerance, in solution culture-grown cotton, by exogenous glycinebetaine (GB) application using 3 levels of Pb (0, 50, and 100 mu m) and 2 GB levels (0 and 1 mM). The results revealed that Pb stress decreased gas exchange characteristics (net photosynthetic rate, stomatal conductance, transpiration rate, water use efficiency, chlorophyll, carotenoids, and SPAD value) and the performance of antioxidant enzymes. Toxic effects of Pb stress were mitigated by GB application, which in turn increased the plant growth and gas exchange characteristics by reducing the performance of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolytic leakage. An increase in the activity of antioxidant enzymes helped in mediating the adverse effect of the Pb stress as compared to plants treated with Pb alone. The results revealed that exogenous application of GB significantly alleviated the Pb toxicity by improving the growth, biomass, and photosynthetic parameters in cotton (Gossypium L.) plants. GB increased Pb tolerance by enhancing the chlorophyll synthesis, photosynthetic activities, and antioxidant enzyme activities and by lowering the electrolytic leakage, MDA, and H2O2 levels.