College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Marine Environment and Ecology, Ministry of Education of China, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China.
J Environ Manage. 2022 Aug 15;316:115200. doi: 10.1016/j.jenvman.2022.115200. Epub 2022 May 6.
Biochar and plant cooperation in remediation of heavy metal contaminated soil is effective and important, but there still have knowledge gaps of synergistic effect between the two and the synergistic pathway has not been clarified. We prepared the Enteromorpha prolifera biochar at 400 °C and 600 °C (denoted as BC400 and BC600). The Pb fractions changes in soil and Pb toxicity in Brassica juncea were investigated by adding 30 g kg biochar to soil containing 1200 mg kg Pb in a pot experiment. There was a significant synergistic effect between biochar and plants on Pb immobilization in soil, according to the "E > 0" of Pb fractions in the interaction equation. Pb immobilization rates of biochar-plant treatments (BJBC4 and BJBC6) were 12.47% and 11.38% higher than biochar treatment (BC4, BC6), and 17.66% and 16.28% plant treatment (BJ). BJBC4 had a better immobilization effect than BJBC6. Biochar alleviated the phytotoxicity of Pb by increasing the antioxidant enzymes activities of plants. These results indicated two synergistic pathways: (1) The high pH and oxygen-containing functional groups of biochar could immobilize Pb through ion exchange, precipitation, or complexation. (2) Biochar enhanced the activity of the antioxidant enzyme system in plants thus improving the Pb tolerance of plants. Statistical analysis methods such as the partial least squares path modeling (PLS-PM) also confirmed the pathways. In a word, clear synergistic effects and pathways could guide the application of biochar and plants in Pb-contaminated soil.
生物炭与植物在修复重金属污染土壤方面的协同作用是有效的且重要的，但两者之间协同效应的知识空白仍然存在，协同途径也尚未阐明。我们在 400°C 和 600°C 下制备了浒苔生物炭（分别记为 BC400 和 BC600）。通过在含有 1200mg/kg Pb 的土壤中添加 30g/kg 生物炭进行盆栽实验，研究了土壤中 Pb 形态变化和油菜（Brassica juncea）中 Pb 毒性。根据交互方程中 Pb 形态的“E>0”，生物炭和植物之间对土壤中 Pb 固定具有显著的协同作用。生物炭-植物处理（BJBC4 和 BJBC6）的 Pb 固定率分别比生物炭处理（BC4、BC6）高 12.47%和 11.38%，比植物处理（BJ）高 17.66%和 16.28%。BJBC4 的固定效果优于 BJBC6。生物炭通过增加植物的抗氧化酶活性来缓解 Pb 的植物毒性。这些结果表明存在两种协同途径：（1）生物炭的高 pH 值和含氧官能团可以通过离子交换、沉淀或络合作用固定 Pb。（2）生物炭增强了植物抗氧化酶系统的活性，从而提高了植物对 Pb 的耐受性。偏最小二乘路径模型（PLS-PM）等统计分析方法也证实了这些途径。总之，明确的协同作用和途径可以指导生物炭和植物在 Pb 污染土壤中的应用。
