Key Lab of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, PR China.
College of Biological Science & Engineering, Shaanxi University of Technology, Hanzhong, 723001, PR China.
Chemosphere. 2021 Sep;278:130446. doi: 10.1016/j.chemosphere.2021.130446. Epub 2021 Mar 31.
Organic acids-assisted phytoremediation is a promising strategy to remove metal pollutants from the soil. However, few reports have focused on the mechanisms of organic acids promoting the uptake of heavy metals by hyperaccumulators. In this study, 5 types of organic acids, namely polybasic carboxylic acids, acidic amino acids, acidic plant growth regulators, phosphoric and gluconic acids, were comprehensively investigated the effects on the solubility of Cd and Pb in the soil along with their uptake by Cd hyperaccumulator Solanum nigrum L. The results indicated that the addition of Hydroxyethylidene-1,1-diphosphonic acid (HEDP) and d-Gluconic acid (D-GA) effectively extracted the most of acid-extractable and some of reducible and oxidizable fractions of Cd and Pb in the soil, with the extraction rates of 64.8% and 34.4% for total Cd and 53.6% and 30.0% for total Pb, respectively. HEDP and D-GA significantly increased the accumulations of Cd (57.1% and 35.0%) and Pb (43.4% and 31.9%) by S. nigrum without the inhibition of its biomass, making the great removal efficiencies of Cd (1.35% and 1.16%) and Pb (0.039% and 0.036%) from the soil. The enhanced phytoremediation efficiency of S. nigrum was due to the increase of the extractable Cd and Pb in the rhizosphere but little changes of soil pH and enzyme activities (catalase and urease). Among all of organic acids, HEDP may be an alternative to EDTA because of its characteristics of environmental friendliness and high efficiency.
有机酸辅助植物修复是一种从土壤中去除金属污染物的有前途的策略。然而，很少有报道关注有机酸促进超积累植物吸收重金属的机制。在这项研究中，综合研究了 5 种有机酸，即多羧酸、酸性氨基酸、酸性植物生长调节剂、磷酸和葡萄糖酸，它们对 Cd 和 Pb 在土壤中的溶解度及其在 Cd 超积累植物龙葵中的吸收的影响。结果表明，羟基亚乙基二膦酸（HEDP）和 D-葡萄糖酸（D-GA）的添加有效地提取了土壤中酸可提取的和部分可还原和可氧化的 Cd 和 Pb ，其总 Cd 的提取率分别为 64.8%和 34.4%，总 Pb 的提取率分别为 53.6%和 30.0%。HEDP 和 D-GA 显著增加了龙葵对 Cd（57.1%和 35.0%）和 Pb（43.4%和 31.9%）的积累，而没有抑制其生物量，使 Cd（1.35%和 1.16%）和 Pb（0.039%和 0.036%）从土壤中的去除效率很高。龙葵的植物修复效率提高是由于根际可提取的 Cd 和 Pb 增加，而土壤 pH 值和酶活性（过氧化氢酶和脲酶）变化不大。在所有的有机酸中，HEDP 可能是 EDTA 的替代品，因为它具有环保和高效的特点。
