Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, 400715, China.
Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration of North-western China, Key Lab for Restoration and Reconstruction of Degraded Ecosystem in North-western China (Ministry of Education), Ningxia University, Yinchuan, 750000, China.
Ecotoxicol Environ Saf. 2020 Mar 15;191:110230. doi: 10.1016/j.ecoenv.2020.110230. Epub 2020 Jan 23.
The potential for the phytoremediation of halophytes has been widely recognized. However, the effects of salt on Cd accumulation characteristics in different halophytic species, which may also be related to their salt tolerance, are still unclear. This study investigated the effects of salinity on Cd accumulation and distribution in two distinct halophytes, Suaeda glauca (euhalophyte) and Limonium aureum (recretohalophyte). Seedlings of the two species were treated with 0, 3, and 6 mg kg soil Cd in combination with or without 0.3% NaCl in a pot experiment. The amount of Cd within the rhizosphere and plant tissues, plant biomass, and the subcellular distribution and chemical forms of Cd were examined. Results showed that the addition of NaCl significantly increased Cd bioavailability at high Cd levels due to the rhizosphere acidification effect. Meanwhile, salinity differently impacted plant biomass allocation, and enhanced Cd uptake and translocation in both studied halophytes. Excess Cd was excreted from the leaf surface, possibly by salt glands of L. aureum, with the salinity facilitating this process. Majority of the Cd was found within the cell walls and vacuolar compartments of two species. However, S. glauca plants had higher proportions of inactive Cd (extracted by 2% HAc and 0.6 M HCl) and lower proportions of active Cd (extracted by 80% ethanol and water), as opposed to L. aureum, which would better inform S. glauca's higher Cd accumulation. Based on these results, S. glauca seems more applicable for phytomanagement of Cd-contaminated saline soils due to its higher capacity for Cd enrichment and tolerance amplified by NaCl.
盐生植物的植物修复潜力已得到广泛认可。然而，盐度对不同盐生植物中 Cd 积累特性的影响，这可能也与它们的耐盐性有关，目前仍不清楚。本研究调查了盐度对两种不同盐生植物（盐地碱蓬（真盐生植物）和黄花补血草（泌盐盐生植物））中 Cd 积累和分布的影响。在盆栽试验中，用 0、3 和 6 mg·kg-1 土壤 Cd 处理两种植物的幼苗，同时分别添加或不添加 0.3% NaCl。研究了根际和植物组织中 Cd 的含量、植物生物量以及 Cd 的亚细胞分布和化学形态。结果表明，由于根际酸化效应，高 Cd 水平下添加 NaCl 显著增加了 Cd 的生物有效性。同时，盐度对植物生物量分配有不同的影响，并增强了两种盐生植物对 Cd 的吸收和转运。过量的 Cd 通过黄花补血草的盐腺从叶片表面排出，盐度促进了这一过程。大部分 Cd 存在于两种植物的细胞壁和液泡区室中。然而，与黄花补血草相比，盐地碱蓬植物具有更高比例的非活性 Cd（用 2% HAc 和 0.6 M HCl 提取）和更低比例的活性 Cd（用 80%乙醇和水提取），这表明盐地碱蓬植物具有更高的 Cd 积累能力。基于这些结果，由于盐地碱蓬植物对 Cd 的富集能力更高，并且 NaCl 增强了其耐盐性，因此它似乎更适用于 Cd 污染的盐碱土壤的植物修复管理。
