Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Allahabad 211002, India.
Ecotoxicol Environ Saf. 2018 Oct;161:318-331. doi: 10.1016/j.ecoenv.2018.05.060. Epub 2018 Jun 8.
The current study was carried out to investigate the role of exogenous sulphur (KSO: S; 60 mg S kg sand) and calcium (CaCl: Ca; 250 mg Ca kg sand) individually as well as in combination (S + Ca) in ameliorating the inhibitory effect of As (NaHAsO·7HO: As; 15 mg As kg sand and As; 30 mg As kg sand) by analyzing biomass accumulation, mineral nutrients uptake, photosynthetic pigments content, redox status of the cell, enzymatic and non-enzymatic defense system in Brassica juncea L. seedlings. Biomass accumulation, uptake of mineral nutrients, photosynthetic pigments (chlorophyll a, b and carotenoids) content and the activity of proline dehydrogenase (ProDH) declined with increasing accumulation of As in root as well as leaves in As dose dependent manner. Contrary to this, exogenous application of S, Ca and S + Ca, markedly reduced the negative impact of As on above captioned traits except ProDH activity. On the other hand, ROS and their biomarkers (superoxide radical; O₂˙-, hydrogen peroxide; HO malondialdehyde; MDA equivalents content and membrane damage; electrolyte leakage), activities of enzymatic (superoxide dismutase; SOD, peroxidase; POD, catalase; CAT and glutathione-S-transferase; GST) and non-enzymatic antioxidant i.e. proline (Pro) content and its enzyme pyrroline-5-carboxylate synthetase; P5CS activity were increased in root and leaves under As stress. While, exogenous application of S, Ca and S + Ca, further enhanced the activities of above mentioned enzymes and Pro content thereby causing considerable reduction in O₂˙-, HO, MDA equivalents content and electrolyte leakage. This study suggests that exogenous application of S and/or Ca efficiently (particularly S + Ca) lowered the negative impact of As on biomass accumulation in Brassica seedlings by improving the uptake of essential mineral nutrients', content of photosynthetic pigments, activities of enzymatic and content of non-enzymatic antioxidants.
本研究旨在通过分析生物量积累、矿质养分吸收、光合色素含量、细胞氧化还原状态、酶和非酶防御系统，研究外源硫（KSO：S；60mg S kg 砂）和钙（CaCl：Ca；250mg Ca kg 砂）单独以及联合（S + Ca）对砷（NaHAsO·7HO：As；15mg As kg 砂和 As；30mg As kg 砂）抑制作用的缓解作用。在 Brassica juncea L. 幼苗中。生物量积累、矿质养分吸收、光合色素（叶绿素 a、b 和类胡萝卜素）含量和脯氨酸脱氢酶（ProDH）活性随根和叶中 As 积累量的增加而呈剂量依赖性下降。与此相反，外源 S、Ca 和 S + Ca 的应用显著降低了 As 对上述特征的负面影响，除 ProDH 活性外。另一方面，ROS 及其生物标志物（超氧自由基；O₂˙-，过氧化氢；HO 丙二醛；MDA 当量含量和膜损伤；电解质泄漏）、酶活性（超氧化物歧化酶；SOD、过氧化物酶；POD、过氧化氢酶；CAT 和谷胱甘肽-S-转移酶；GST）和非酶抗氧化剂即脯氨酸（Pro）含量及其酶吡咯啉-5-羧酸合成酶；P5CS 活性在根和叶中均随着 As 胁迫的增加而增加。然而，外源 S、Ca 和 S + Ca 的应用进一步增强了上述酶的活性和 Pro 含量，从而导致 O₂˙-、HO、MDA 当量含量和电解质泄漏的显著减少。本研究表明，外源 S 和/或 Ca 的应用有效地（特别是 S + Ca）通过提高必需矿质养分的吸收、光合色素的含量、酶的活性和非酶抗氧化剂的含量，降低了 As 对 Brassica 幼苗生物量积累的负面影响。
