College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, PR China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, 321004, PR China.
College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua, Zhejiang, 321004, PR China; Key Laboratory of Watershed Earth Surface Processes and Ecological Security, Zhejiang Normal University, Jinhua, Zhejiang, 321004, PR China.
Plant Physiol Biochem. 2024 Jun;211:108701. doi: 10.1016/j.plaphy.2024.108701. Epub 2024 May 7.
Graphitic carbon nitride (g-CN) is a promising candidate for heavy metal remediation, primarily composed of carbon (C) and nitrogen (N). It has been demonstrated that g-CN adjusts rhizosphere physicochemical conditions, especially N conditions, alleviating the absorption and accumulation of Cadmium (Cd) by soybeans. However, the mechanisms by which g-CN induces N alterations to mitigates plant uptake of Cd remain unclear. This study investigated the impact of g-CN-mediated changes in N conditions on the accumulation of Cd by soybeans using pot experiments. It also explored the microbiological mechanisms underlying alterations in soybean rhizospheric N cycling induced by g-CN. It was found that g-CN significantly increased N content in the soybean rhizosphere (p < 0.05), particularly in terms of available nitrogen (AN) of nitrate and ammonium. Plants absorbed more ammonium nitrogen (NH₄⁺-N), the content of which in the roots showed a significant negative correlation with Cd concentration in plant (p < 0.05). Additionally, g-CN significantly affected rhizospheric functional genes associated with N cycling (p < 0.05) by increasing the ratio of the N-fixation functional gene nifH and decreasing the ratios of functional genes amoA and nxrA involved in nitrification. This enhances soybean's N-fixing potential and suppresses denitrification potential in the rhizosphere, preserving NH₄⁺-N. Niastella, Flavisolibacter, Opitutus and Pirellula may play a crucial role in the N fixation and preservation process. In summary, the utilization of g-CN offers a novel approach to ensure safe crop production in Cd-contaminated soils. The results of this study provide valuable data and a theoretical foundation for the remediation of Cd polluted soils.
石墨相氮化碳（g-CN）是一种很有前途的重金属修复候选材料，主要由碳（C）和氮（N）组成。研究表明，g-CN 可以调节根际理化条件，特别是氮条件，从而减轻大豆对镉（Cd）的吸收和积累。然而，g-CN 通过诱导氮变化来减轻植物对 Cd 吸收的机制尚不清楚。本研究通过盆栽实验研究了 g-CN 介导的氮条件变化对大豆 Cd 积累的影响，探讨了 g-CN 引起大豆根际氮循环变化的微生物学机制。研究发现，g-CN 显著增加了大豆根际的氮含量（p<0.05），特别是硝酸盐和铵盐的有效氮（AN）。植物吸收了更多的铵态氮（NH₄⁺-N），根中 NH₄⁺-N 的含量与植物中 Cd 浓度呈显著负相关（p<0.05）。此外，g-CN 通过增加固氮功能基因 nifH 的比例和降低硝化功能基因 amoA 和 nxrA 的比例，显著影响了与氮循环相关的根际功能基因（p<0.05）。这增强了大豆的固氮潜力，抑制了根际的反硝化潜力，从而保留了 NH₄⁺-N。Niastella、Flavisolibacter、Opitutus 和 Pirellula 可能在氮固定和保护过程中发挥关键作用。综上所述，g-CN 的利用为在 Cd 污染土壤中确保安全作物生产提供了一种新方法。本研究结果为 Cd 污染土壤的修复提供了有价值的数据和理论基础。
