Chang Yuxiao, Lin Lihong, Shen Jianlin, Lin Zheng, Deng Xingying, Sun Weimin, Wu Xinyue, Wang Yifan, Li Yongquan, Xu Zhimin
Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.
College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
J Hazard Mater. 2025 Jan 5;481:136588. doi: 10.1016/j.jhazmat.2024.136588. Epub 2024 Nov 19.
This study developed a biochar-loaded Ac material and clarified its chemical and microbial mechanisms for cadmium (Cd) immobilization and plant growth promotion. Results showed that biochar-loaded nitrogen-fixing bacteria (Azotobacter chroococcum; BAc) enhanced Cd adsorption by forming stable complexes with bacterial secretions and activating biochar functional groups. Compared with BC and Ac, after BAc application, Ac successfully colonized the lettuce rhizosphere, tagged with green fluorescent protein. It improved plant nitrogen by 47.39-72.47 % and increased root and shoot biomass by 50.35-107.32 % through nitrogen fixation and amino acid release. BAc reduced soil Cd bioavailability by 16.67-46.42 % and Cd accumulation in root and shoot by 14.28-69.74 %. This occurred through increasing soil pH and converting exchangeable Cd to carbonate-bound and Fe/Mn oxide-bound fractions. Importantly, BAc improved the rhizosphere nutrient environment and promoted the deterministic assembly of the rhizosphere microbial community. It also increased microbial diversity and attracted taxa like Actinomycetales (7.59 %), Solirubrobacteriales (5.17 %), Rhizobiales (5.17 %), and Sphingomonadales (5.17 %), all associated with nitrogen fixation, plant growth promotion, and Cd immobilization. Structural equation modeling (SEM) confirmed that BAc increased nitrogen utilization efficiency in lettuce and facilitated biotic immobilization of soil Cd by optimizing the microbial structure. This study provides insights into how biochar-loaded Ac improve plant growth and control soil Cd pollution.
本研究开发了一种负载生物炭的醋酸杆菌材料，并阐明了其固定镉（Cd）和促进植物生长的化学及微生物机制。结果表明，负载生物炭的固氮菌（褐球固氮菌；BAc）通过与细菌分泌物形成稳定络合物并激活生物炭官能团来增强Cd吸附。与生物炭（BC）和醋酸杆菌（Ac）相比，施用BAc后，Ac成功定殖于生菜根际，并带有绿色荧光蛋白标记。它通过固氮和释放氨基酸使植物氮含量提高了47.39 - 72.47%，根和地上部生物量增加了50.35 - 107.32%。BAc使土壤Cd生物有效性降低了16.67 - 46.42%，根和地上部Cd积累量降低了14.28 - 69.74%。这是通过提高土壤pH值并将可交换态Cd转化为碳酸盐结合态和铁/锰氧化物结合态实现的。重要的是，BAc改善了根际养分环境，促进了根际微生物群落的确定性组装。它还增加了微生物多样性，并吸引了放线菌目（7.59%）、太阳红红螺菌目（5.17%）、根瘤菌目（5.17%）和鞘脂单胞菌目（5.17%）等分类群，这些都与固氮、植物生长促进和Cd固定有关。结构方程模型（SEM）证实，BAc通过优化微生物结构提高了生菜的氮利用效率，并促进了土壤Cd的生物固定。本研究为负载生物炭的醋酸杆菌如何改善植物生长和控制土壤Cd污染提供了见解。
