Abstract

A hydroponic experiment in NaCl tolerant mangrove, Bruguiera cylindrica plantlets was done to investigate the interactive effects of CdCl₂+NaCl as well as the individual effects of CdCl₂. CdCl₂ alone results in enhanced level of cell membrane lipid peroxidation, damaging normal structure, and function of the membrane and there by leading to reduction of membrane stability index and thus severely promoting the electrolyte leakage than the combined treatment of CdCl₂+NaCl. Antioxidants greatly contribute to cope with the stress by scavenging ROS and were more prominent in individual stress than combined stress. B. cylindrica can be categorized as a highly tolerant mangrove species with a Tolerance Index (TI) of above 60% toward CdCl₂+NaCl (TI is 70 and 75% in leaf and root). But TI was only 63 and 67% in leaf and root, respectively, on exposure to CdCl₂ alone indicating that this plant is less tolerant to Cd alone. The existence of B. cylindrica depends on the heavy metals being introduced into the mangrove ecosystem and imparts a combination stress along with NaCl. In this regard, B. cylindrica survives up to 0.20 mM CdCl₂ along with NaCl. Thus, the high NaCl tolerance mechanisms in this mangrove species could be equally efficient in imparting tolerance toward high concentration of Cd along with NaCl and exhibits phytostabilization in polluted coastal wetlands.

摘要

在耐 NaCl 的红树林Bruguiera cylindrica幼苗中进行了水培试验，以研究 CdCl _{2 +NaCl 的相互作用以及 CdCl 2}的个体效应。_{与CdCl 2} +NaCl联合处理相比，单独使用CdCl ₂会导致细胞膜脂质过氧化水平升高，破坏膜的正常结构和功能，从而导致膜稳定性指数降低，从而严重促进电解液泄漏。抗氧化剂通过清除 ROS 极大地有助于应对压力，并且在个体压力中比在联合压力中更为突出。B. 圆柱形可以归类为对 CdCl ₂ +NaCl 的耐受指数 (TI) 高于 60% 的高耐受性红树树种（叶和根的耐受指数为 70% 和 75%）。_{但仅暴露于 CdCl 2}时，叶和根中的 TI 分别仅为 63% 和 67% ，这表明该植物对单独的 Cd 的耐受性较低。B. cylindrica的存在取决于重金属被引入红树林生态系统，并与 NaCl 一起产生复合胁迫。在这方面，B. cylindrica可在高达 0.20 mM CdCl _{2的环境中存活}与氯化钠一起。因此，这种红树林物种的高 NaCl 耐受机制在赋予对高浓度 Cd 和 NaCl 的耐受性方面同样有效，并在受污染的沿海湿地中表现出植物稳定性。