Institute of Crop Science and Zhejiang Key Laboratory of Crop Germplasm, Zhejiang University, Hangzhou 310058, China.
Institute of Crop Science and Zhejiang Key Laboratory of Crop Germplasm, Zhejiang University, Hangzhou 310058, China; Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
Ecotoxicol Environ Saf. 2018 Oct;161:634-647. doi: 10.1016/j.ecoenv.2018.06.014. Epub 2018 Jun 19.
Selenium (Se) is an essential micro-element for human and animals. In higher plants, Se essentiality or phyto-toxicity is less explored. Therefore, we aimed to examine the effects of Se (0, 25, 50, and 100 µM) as sodium selenite on the physio-chemical, cell ultra-structural and genomic alterations in hydroponically grown seedlings of four cultivars of B. napus (cvs. Zheda 619, Zheda 622, ZS 758, and ZY 50). Results showed that excessive (100 µM) Se (IV) exhibited significant reduction in plant growth parameters, declined pigment contents, lower water-soluble protein levels, and overproduction of HO and MDA contents. A significant increase in antioxidant enzyme activities and transcript levels of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR), except catalase (CAT) were noticed in the leaves and roots. Non-enzymatic antioxidants including glutathione (GSH) and oxidized glutathione (GSSG), except GSSG in roots were enhanced under higher Se (IV) levels. Transmission electron microscopy analysis revealed the ultrastructural damages in leaf mesophyll and root tip cells induced by excessive Se (IV). Less-significant phytotoxic effects were observed in above-mentioned parameters at 50 µM Se (IV). Overall, Se (IV) supplementation at 25 µM displayed marginal beneficial effect by enhancing plant growth, pigment contents, protein levels and restrict HO and MDA overproduction. A marginal increase/decrease in ROS-detoxifying enzymes (except CAT activity) and elevated GSH and GSSG levels were noticed. The accumulation of Se (IV) was much higher in roots as compared to leaves. This accumulation was maximum in Zheda 622 and minimum in ZS 758, followed by Zheda 619 and ZY 50. Overall findings showed that Zheda 622 was the most sensitive and ZS 758 as most tolerant to Se (IV) phyto-toxicity. In addition, Se (IV) was found beneficial until 25 µM Se (IV) but phytotoxic at higher Se levels especially at 100 µM Se (IV).
硒（Se）是人和动物必需的微量元素。在高等植物中，硒的必需性或植物毒性研究较少。因此，我们旨在研究硒（0、25、50 和 100µM 作为亚硒酸钠）对水培生长的四个油菜品种（浙 619、浙 622、ZS 758 和 ZY 50）幼苗的生理化学、细胞超微结构和基因组变化的影响。结果表明，过量（100µM）Se（IV）显著降低了植物生长参数，降低了色素含量、水溶性蛋白质水平，并产生了更多的 HO 和 MDA 含量。在叶片和根系中，抗氧化酶活性和超氧化物歧化酶（SOD）、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）的转录水平显著增加，除过氧化氢酶（CAT）外。在较高的 Se（IV）水平下，非酶抗氧化剂包括谷胱甘肽（GSH）和氧化谷胱甘肽（GSSG），除了根中的 GSSG 外，都有所增强。透射电子显微镜分析显示，过量 Se（IV）诱导叶片叶肉和根尖细胞的超微结构损伤。在 50µM Se（IV）下，上述参数的植物毒性作用不明显。总的来说，25µM 的 Se（IV）补充通过促进植物生长、色素含量、蛋白质水平和限制 HO 和 MDA 的过度产生表现出轻微的有益效果。ROS 解毒酶（除 CAT 活性外）略有增加/减少，GSH 和 GSSG 水平升高。与叶片相比，根中 Se（IV）的积累量更高。在浙 622 中积累最多，在 ZS 758 中积累最少，其次是浙 619 和 ZY 50。总的来说，研究结果表明，浙 622 对 Se（IV）毒性最敏感，而 ZS 758 最耐受 Se（IV）。此外，在 25µM Se（IV）之前，Se（IV）是有益的，但在较高的 Se 水平下，尤其是在 100µM Se（IV）时，Se（IV）是有毒的。
