Yang Jie, Tu Chen, Li Ruijie, Li Lianzhen, Liu Ying, Liu Zijian, Chi Meiting, Luo Yongming
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2025 Aug 18;497:139608. doi: 10.1016/j.jhazmat.2025.139608.
The effects of nanoplastics (NPs) on crop plants are receiving increasing attention. Studies have demonstrated that many crop plants can internalize and transport NPs to their aboveground tissues. However, the effect of ubiquitous soil clay minerals on NP uptake remains unclear. This study investigated the interaction between two common clay minerals (kaolinite and montmorillonite) and 200 nm polystyrene (PS) NPs during uptake by wheat seedlings. Our results revealed that both kaolinite and montmorillonite formed heterogeneous aggregates with PS NPs in the rhizosphere. Furthermore, clay minerals were observed to co-localize with NPs within lateral root cracks, suggesting potential competition for entry pathways. Quantification of PS NPs demonstrated that co-exposure with clay minerals significantly reduced NP accumulation: specifically, kaolinite decreased root and shoot accumulation by 44.9 % and 17.4 %, respectively, while montmorillonite induced greater reductions of 69.1 % in roots and 17.5 % in shoots. Sequential exposure (clay minerals followed by NPs) also resulted in decreased uptake, with reductions of 37.5 % (roots) and 4.7 % (shoots) for kaolinite, and 44.4 % (roots) and 7.2 % (shoots) for montmorillonite. The stronger uptake limitation observed with montmorillonite, compared to kaolinite, is attributed to its larger aggregate size and greater surface area. These findings demonstrate that both kaolinite and montmorillonite reduce the uptake of 200 nm PS-NPs in wheat seedlings through dual mechanisms: (1) hetero-aggregation in the rhizosphere and (2) competitive occupation of lateral root crack-entry pathways. This study reveals the important role of clay minerals in mitigating NP uptake by crop plants, provides insights into how clay minerals can alter the environmental risk posed by NPs, and establishes a foundation for future research on plant interactions with complex environmental particles.
纳米塑料（NPs）对农作物的影响正受到越来越多的关注。研究表明，许多农作物能够将纳米塑料内化并运输到地上组织。然而，普遍存在的土壤粘土矿物对纳米塑料吸收的影响仍不清楚。本研究调查了两种常见粘土矿物（高岭石和蒙脱石）与200纳米聚苯乙烯（PS）纳米塑料在小麦幼苗吸收过程中的相互作用。我们的结果表明，高岭石和蒙脱石在根际均与PS纳米塑料形成异质聚集体。此外，观察到粘土矿物与纳米塑料在侧根裂缝内共定位，表明在进入途径方面存在潜在竞争。PS纳米塑料的定量分析表明，与粘土矿物共同暴露显著降低了纳米塑料的积累：具体而言，高岭石分别使根和地上部的积累减少了44.9%和17.4%，而蒙脱石对根和地上部的减少幅度更大，分别为69.1%和17.5%。顺序暴露（先粘土矿物后纳米塑料）也导致吸收减少，高岭石使根减少37.5%、地上部减少4.7%，蒙脱石使根减少44.4%、地上部减少7.2%。与高岭石相比，蒙脱石表现出更强的吸收限制，这归因于其更大的聚集体尺寸和更大的表面积。这些发现表明，高岭石和蒙脱石均通过两种机制减少小麦幼苗对200纳米PS纳米塑料的吸收：（1）根际异质聚集和（2）对侧根裂缝进入途径的竞争性占据。本研究揭示了粘土矿物在减轻农作物对纳米塑料吸收方面的重要作用，深入了解了粘土矿物如何改变纳米塑料带来的环境风险，并为未来关于植物与复杂环境颗粒相互作用的研究奠定了基础。
