通讯机构：
[Zhu, Jian] C;[Liu, Zhiming] E;Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410004, Peoples R China.;Eastern New Mexico Univ, Dept Biol, Portales, NM 88130 USA.
关键词：
Accumulation and translocation;Cadmium;Mineral silicon;Rice (Oryza sativa L.);Soil health
摘要：
Exogenous silicon has been shown to enhance plant growth and alleviate heavy metals toxicity, but the regulation mechanismof silicon on cadmiummigration and transformation in the soil-rice systemis still unclear, which isworth further study. In this study, a pot experiment was carried out to explore the influence of different doses (0, 1 and 5%) of mineral silicon on soil properties, nutrient availability, rice growth, soil enzyme activities, Cd bioavailability, and uptake and accumulation of Cd in high-accumulating (H) and low-accumulating (L) rice cultivars grown in contaminated soils. Results showed that mineral-Si treatment could increase the total biomass and grain yield, with an increased rate of 17.7-27.3% and 14.7-19.1% for H; while 26.2-33.4% and 21.3-30.3% for L. Compared with non-mineral-Si treatment, the soil EX-Cd decreased by 3.9-13.3% (H) and 2.3-10.7% (L). Additionally, the Cd content in rice grain was significantly declined by 29.5-31.3% (H) and 34.9-35.2% (L). MineralSi enhanced urease, sucrase, and neutral phosphatase activities in both cultivars, but suppressed catalase activity in H. A selective change in bacterial community structure was observed under mineral-Si treatment, however, the bacterial community remained stable, suggesting that the mineral-Si had no adverse effect on the microbial community. The positive response of soil enzymes activities, rice growth and the overall stabilization of microbial environment for mineral-Si addition to the Cd contaminated soils indicated that mineral-Si could mitigate the risk of Cd and well maintain the soil health, proving it to be eco-friendly and low-cost amendment for soils remediation. (C) 2020 Published by Elsevier B.V.
摘要：
The frequent occurrence of thallium (Tl) in surface water has led to the imposition of strict environmental regulations. The need for an overview of effective and feasible technology to remove Tl from water/wastewater has therefore become urgently. This review introduced the current available methods for Tl removal, including adsorption, oxidation-reduction precipitation, solvent extraction and ion exchange processes, and summarized their advantages and disadvantages. The results showed that a single treatment technology was difficult to remove Tl to a trace level of "mug L(-1)", which required combined multi-technology to enhance the removal efficiency. In addition, the potential emergency and feasible technologies for Tl removal were recommended. However, several fundamental issues, such as the comparative toxicity of Tl(I) and Tl(III), the confliction of hydrolysis constants, the interference of complexant ligands as well as the influence of redox potential, were still needed to be addressed, since they would profoundly affect the selection of adopted treatment methods and the behavior of Tl removal. Future research efforts concerning the improvement of existing Tl removal technologies should be devoted to (a) developing multi-functional chemicals and adsorbents, non-toxic extractants, easy-recovery ion exchange resin and high-efficient coupling technology for advanced treatment, (b) carrying out large-scale experiments and economic assessment for real wastewater, and (c) providing safe-disposal treatment for the exhausted adsorption materials or sludge.
关键词：
Antioxidant enzymes;Cadmium;Chemical forms;Gene expression;Salix;Subcellular distribution
摘要：
Cadmium (Cd) is a highly toxic element for plant. In order to reveal the effects of NaHS on Cd uptake, physiological and molecular responses of salix to Cd toxicity, NaHS-mediated hydroponics of salix under Cd stress was performed. The addition of NaHS reduces the salix biomass reduction caused by Cd poisoning. NaHS did not obviously reduce the total Cd level absorbed by salix, but significantly reduced the soluble Cd fractions and increased the insoluble Cd fractions in salix leaves and roots. NaHS reduced the distribution of Cd in organelles and vacuoles and increased the distribution of Cd in the cell wall of salix leaves and roots. NaHS promotes the level of antioxidant enzyme activities and gene expression of salix, and reduces the accumulation of MDA and H2O2 caused by Cd. NaHS increases the content of GSH and endogenous H2S in salix leaves and roots. The addition of NaHS can reduce the toxicity of Cd to salix without obviously reducing the Cd uptake by salix, thus improving the application of salix in phytoremediation to Cd.
作者机构：
[杨雨中; 朱健; 肖媛媛; 谭蓉; 王平; 陈润华; 徐海音; 杨雄] College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha;410004, China;Hunan Engineering Laboratory for Control of Rice Quality and Safety, Changsha;[杨雨中; 朱健; 肖媛媛; 谭蓉; 王平; 陈润华; 徐海音; 杨雄] 410004, China;[朱健; 王平] 410004, China<&wdkj&>Hunan Engineering Laboratory for Control of Rice Quality and Safety, Changsha
摘要：
Koelreuteria paniculata were cultivated in nutrient solution with different concentrations of Cd (0, 50, 150, 250 and 500microM) and sampled after 90 days. The resistance, translocation, accumulation and stress responses in Koelreuteria paniculata were investigated by hydroponic experiments. The results showed that Koelreuteria paniculata is an efficient Cd excluder that can tolerate high concentrations of Cd (up to 150-250microM of Cd). The concentration of Cd never exceeds 5ppm in leaves and 10ppm in roots. The high concentration of Cd (>/= 250microM) had a toxic effect on K. paniculata and significantly restricted the plant growth. The accumulation ability of Cd by different plant tissues followed the sequence of roots > leaves > stems. The bioconcentration factors and translocation factors both were less than 1. Cd has the highest content in the cell wall and is migrated to soluble fractions and organelles at high concentrations. Undissolved Cd phosphate, pectates and protein-bound Cd were the predominant forms. The low concentration of Cd (</=150microM) promoted the synthesis of soluble proteins, AsA and GSH, while high concentration of Cd clearly inhibited the physiological and biochemical process, caused membrane lipid peroxidation and severe membrane damages, and increased MDA and H2O2 contents. POD, CAT and SOD exhibited positive and effective responses to low concentration Cd stress, but could not remove the toxicity caused by high concentration Cd stress. The content of IAA, GA and ZT decreased and ABA content was significantly increased under high-concentration Cd stress.
作者机构：
[朱健; 王平; 雷明婧; 张伟丽; 陈仰] College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
College of Environmental Science and Engineering, Central South University of Forestry and Technology, Changsha, China
