Sheng Ziwei, Luo Tao, Wang Linjie, Chen Min, Ma Bingbing, Liu Lijun, Wang Bo, Kuai Jie, Wang Jing, Zhao Jie, Xu Zhenghua, Zhou Guangsheng
Ministry of Agriculture (MOA) Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
Front Plant Sci. 2024 Oct 17;15:1481732. doi: 10.3389/fpls.2024.1481732. eCollection 2024.
Soil contamination with copper (Cu) threatens ecological security and human health. Rapeseed demonstrates potential in remediating copper-contaminated soil, and biochar-assisted phytoremediation is increasingly being employed to improve remediation efficiency. However, the combined application of them has not been thoroughly studied in terms of the synergistic effects and the mechanisms of their interaction.
In this regard, this study conducted a pot experiment to evaluate biochar-assisted remediation under Cu-contaminated soil with varying biochar application rates; Furthermore, the plant physiological mechanism and soil physicochemical properties involved in the biocharrapeseed system was explored.
Our results showed that the exchangeable pool of copper in soil decreased by 10.0% and 12.3% with adding 5% biochar (BC1) and 10% biochar (BC2) relative to control (BC0), respectively, prior to rapeseed cultivation. The rapeseed cultivation for one season further reclaimed 4.9%, 9.0%, and 13.6% of the available copper in this soil by root extraction under the BC0, BC1, and BC2 treatments, respectively. The overall copper concentration in plants decreased by 23.7% under BC2 and 13.3% under BC1 compared to BC0. However, the plant's dry biomass at BC1 and BC2 treatments increased by 1.7-fold and 2.7-fold relative to BC0, which offset the negative impact of the decreased copper concentration on phytoremediation. Physiological analysis showed adding 10% biochar decreased the MDA content by 36% in the leaf and 49% in the root, compared to BC0. The transmission electron microscopy for cell wall ultrastructure in root tips showed that biochar addition in Cu-contaminated soil increased the mechanical strength of the celL wall, explicitly increasing the thickness of the secondary cell wall. Further cell wall components analysis revealed a remarkable increment of the pectin content in BC2 relative to BC0, increased by 56% in the leaf and 99% in the root, respectively. Additionally, 10% biochar application led to a roughly 2-fold increase in seed yield via ameliorating the soil physicochemical properties and increasing the rapeseed growth.
These findings offer insights into synergistic rapeseed-biochar use for Cu-contaminated soil remediation.
土壤铜（Cu）污染威胁生态安全和人类健康。油菜在修复铜污染土壤方面具有潜力，生物炭辅助植物修复正越来越多地用于提高修复效率。然而，它们的联合应用在协同效应及其相互作用机制方面尚未得到充分研究。
在这方面，本研究进行了盆栽试验，以评估不同生物炭施用量下生物炭辅助修复铜污染土壤的效果；此外，还探讨了生物炭 - 油菜系统中涉及的植物生理机制和土壤理化性质。
我们的结果表明，在种植油菜之前，相对于对照（BC0），添加5%生物炭（BC1）和10%生物炭（BC2）分别使土壤中铜的交换态含量降低了10.0%和12.3%。在BC0、BC1和BC2处理下，一季油菜种植通过根系提取分别进一步回收了该土壤中4.9%、9.0%和13.6%的有效铜。与BC0相比，BC2处理下植物中的总铜浓度降低了23.7%，BC1处理下降低了13.3%。然而，BC1和BC2处理下植物的干生物量相对于BC0分别增加了1.7倍和2.7倍，这抵消了铜浓度降低对植物修复的负面影响。生理分析表明，与BC0相比，添加10%生物炭使叶片中丙二醛（MDA）含量降低了36%，根系中降低了49%。对根尖细胞壁超微结构进行的透射电子显微镜观察表明，在铜污染土壤中添加生物炭增加了细胞壁的机械强度，特别是增加了次生细胞壁的厚度。进一步的细胞壁成分分析显示，BC2中果胶含量相对于BC0显著增加，叶片中增加了56%，根系中增加了99%。此外，施用10%生物炭通过改善土壤理化性质和促进油菜生长使种子产量提高了约2倍。
这些发现为油菜 - 生物炭协同用于铜污染土壤修复提供了见解。
