Farooq Muhammad A, Li Lan, Ali Basharat, Gill Rafaqat A, Wang Jian, Ali Shafaqat, Gill Muhammad B, Zhou Weijun
Institute of Crop Science and Zhejiang Key Laboratory of Crop Germplasm, Zhejiang University, Hangzhou, 310058, China.
Environ Sci Pollut Res Int. 2015 Jul;22(14):10699-712. doi: 10.1007/s11356-015-4269-1. Epub 2015 Mar 11.
Environmental contamination due to arsenic (As) has become a major risk throughout the world; this affects plant growth and productivity. Its accumulation in food chain may pose a severe threat to organisms. The present study was carried out to observe the toxic effects of As (0, 50, 100, and 200 μM) on physiological and biochemical changes in four Brassica napus cultivars (ZS 758, Zheda 619, ZY 50, and Zheda 622). Results showed that As toxicity provoked a significant inhibition in growth parameters of B. napus cultivars and this reduction was more obvious in cultivar Zheda 622. The highest concentration of MDA, H2O2, and O2 (-) contents in both leaf and root tissues were observed at 200 μM As level, and a gradual decrease was observed at lower concentrations. Increasing As concentration gradually decreased chlorophyll and carotenoids contents. Activity of antioxidant enzymes such as SOD, CAT, APX, GR, and GSH was positively correlated with As treatments in all cultivars. The microscopic study of leaves and roots at 200 μM As level showed the disorganization in cell organelles. Disturbance in the morphology of chloroplast, broken cell wall, increase in size, and number of starch grains and immature nucleus were found in leaf ultrastructures under higher concentration of As. Moreover, damaged nucleus, diffused cell wall, enlarged vacuoles, and a number of mitochondria were observed in root tip cells at 200 μM As level. These results suggest that B. napus cultivars have efficient mechanism to tolerate As toxicity, as evidenced by an increased level of antioxidant enzymes.
砷（As）造成的环境污染已成为全球的一个主要风险；这会影响植物生长和生产力。其在食物链中的积累可能对生物体构成严重威胁。本研究旨在观察砷（0、50、100和200 μM）对四个甘蓝型油菜品种（浙油758、浙达619、ZY 50和浙达622）生理和生化变化的毒性作用。结果表明，砷毒性对甘蓝型油菜品种的生长参数产生了显著抑制，这种抑制在浙达622品种中更为明显。在200 μM砷水平下，叶片和根组织中丙二醛（MDA）、过氧化氢（H2O2）和超氧阴离子（O2 (-)）含量最高，在较低浓度下则逐渐降低。随着砷浓度的增加，叶绿素和类胡萝卜素含量逐渐降低。所有品种中，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）和谷胱甘肽（GSH）等抗氧化酶的活性与砷处理呈正相关。在200 μM砷水平下对叶片和根进行的微观研究显示细胞器紊乱。在高浓度砷处理下，叶片超微结构中发现叶绿体形态紊乱、细胞壁破裂、淀粉粒大小和数量增加以及细胞核不成熟。此外，在200 μM砷水平下，根尖细胞中观察到细胞核受损、细胞壁扩散、液泡增大和大量线粒体。这些结果表明，甘蓝型油菜品种具有耐受砷毒性的有效机制，抗氧化酶水平的提高证明了这一点。
