College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, People's Republic of China.
Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, 321004, People's Republic of China.
Environ Sci Pollut Res Int. 2023 Sep;30(41):94988-95001. doi: 10.1007/s11356-023-29040-4. Epub 2023 Aug 5.
Cadmium (Cd) contamination has led to various harmful impacts on soil microbial ecosystem, agricultural crops, and thus human health. Nanomaterials are promising candidates for reducing the accumulation of heavy metals in plants. In this study, graphitic carbon nitride (g-CN), a two-dimensional polymeric nanomaterial, was applied for ameliorating Cd phytotoxicity to soybean (Glycine max (L.) Merr.). Its impacts on rhizosphere variables, microorganisms, and metabolism were examined. It was found that g-CN increased carbon/nitrogen/phosphorus (C/N/P) content, especially when N contents were averagely 4.2 times higher in the g-CN-treated groups. g-CN significantly induced alterations in microbial community structures (P < 0.05). The abundance of the probiotics class Nitrososphaeria was enriched (on average 70% higher in the g-CN-treated groups) as was Actinobacteria (226% higher in the g-CN group than in the CK group). At the genus level, g-CN recruited more Bradyrhizobium (122% higher) in the Cd + g-CN group than in the Cd group and more Sphingomonas (on average 24% higher) in the g-CN-treated groups. The changes of microbial clusters demonstrated the potential of g-CN to shape microbial functions, promote plant growth, and enhance Cd resistance, despite observing less pronounced modifications in microbial communities in Cd-contaminated soil compared to Cd-free soil. Moreover, abundance of functional genes related to C/N/P transformation was more significantly promoted by g-CN in Cd-contaminated soil (increased by 146%) than in Cd-free one (increased by 32.8%). Therefore, g-CN facilitated enhanced microbial survival and adaptation through the amplification of functional genes. These results validated the alleviation of g-CN on the microbial communities in the soybean rhizosphere and shed a new light on the application of environmental-friendly nanomaterials for secure production of the crop under soil Cd exposure.
镉（Cd）污染对土壤微生物生态系统、农作物以及人类健康造成了各种有害影响。纳米材料是减少植物重金属积累的有前途的候选材料。在这项研究中，二维聚合纳米材料石墨相氮化碳（g-CN）被用于改善大豆（Glycine max（L.）Merr.）对镉的植物毒性。研究了其对根际变量、微生物和代谢的影响。结果发现，g-CN 增加了碳/氮/磷（C/N/P）的含量，特别是 g-CN 处理组的 N 含量平均高出 4.2 倍。g-CN 显著诱导了微生物群落结构的变化（P < 0.05）。有益菌类硝化螺旋菌的丰度增加（g-CN 处理组平均高出 70%），放线菌的丰度增加（g-CN 组比 CK 组高出 226%）。在属水平上，g-CN 在 Cd+g-CN 组中比在 Cd 组中招募了更多的慢生根瘤菌（高出 122%），在 g-CN 处理组中比在 CK 组中招募了更多的鞘氨醇单胞菌（平均高出 24%）。微生物群的变化表明，g-CN 具有塑造微生物功能、促进植物生长和增强 Cd 抗性的潜力，尽管与无 Cd 土壤相比，g-CN 对受 Cd 污染土壤中微生物群落的修饰作用不那么明显。此外，g-CN 更显著地促进了受 Cd 污染土壤中与 C/N/P 转化相关的功能基因的丰度（增加了 146%），而不是在无 Cd 土壤中（增加了 32.8%）。因此，g-CN 通过放大功能基因促进了微生物的生存和适应。这些结果验证了 g-CN 对大豆根际微生物群落的缓解作用，并为在土壤 Cd 暴露下安全生产作物的环保型纳米材料的应用提供了新的思路。
