Wang Qi, Meng Lingzuo, Liu Weitao, Zeb Aurang, Shi Ruiying, Lian Yuhang, Su Chen
Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education (MOE), College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
College of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China.
Sci Total Environ. 2023 May 10;872:162291. doi: 10.1016/j.scitotenv.2023.162291. Epub 2023 Feb 16.
Nanoplastics (NPs) and heavy metals are widely distributed in aquatic ecosystem, posing a potential threat to ecosystem function. Submerged macrophytes play an important role in water purification and maintaining ecological functions. However, the coupled effects of NPs and cadmium (Cd) on submerged macrophytes physiology and the mechanisms involved are still unclear. Here, the potential effects of single and co-Cd/PSNPs exposure on Ceratophyllum demersum L. (C. demersum) were explored. Our results showed that NPs aggravated the inhibition of Cd on plant growth ate (a decrease of 35.54 %), reduced chlorophyll synthesis (a decrease of 15.84 %), and disrupted the antioxidant enzyme system (a decrease of 25.07 % on SOD activity) of C. demersum. Massive PSNPs adhered to the surface of C. demersum when exposed to co-Cd/PSNPs while they did not adhere when exposed to single-NPs. The metabolic analysis further demonstrated that co-exposure down-regulated plant cuticle synthesis and that Cd exacerbated the physical damage and shadowing effects of NPs. In addition, co-exposure upregulated pentose phosphate metabolism, leading to the accumulation of starch grains. Furthermore, PSNPs reduced Cd enrichment capacity of C. demersum. Our results unraveled distinct regulatory networks for submerged macrophytes exposed to single and composite of Cd and PSNPs, providing a new theoretical basis for assessing the risks of heavy metals and NPs in the freshwater environment.
纳米塑料（NPs）和重金属广泛分布于水生生态系统中，对生态系统功能构成潜在威胁。沉水植物在水体净化和维持生态功能方面发挥着重要作用。然而，NPs与镉（Cd）对沉水植物生理的联合影响及其作用机制仍不清楚。在此，研究了单一及Cd/聚苯乙烯纳米塑料（PSNPs）共同暴露对金鱼藻的潜在影响。我们的结果表明，NPs加剧了Cd对金鱼藻生长的抑制作用（降低了35.54%），减少了叶绿素合成（降低了15.84%），并破坏了其抗氧化酶系统（超氧化物歧化酶（SOD）活性降低了25.07%）。暴露于Cd/PSNPs共同作用时，大量PSNPs附着在金鱼藻表面，而暴露于单一NPs时则不会附着。代谢分析进一步表明，共同暴露下调了植物角质层合成，且Cd加剧了NPs的物理损伤和遮蔽效应。此外，共同暴露上调了磷酸戊糖代谢，导致淀粉粒积累。此外，PSNPs降低了金鱼藻对Cd的富集能力。我们的结果揭示了沉水植物暴露于单一及Cd与PSNPs复合物时不同的调控网络，为评估淡水环境中重金属和NPs的风险提供了新的理论依据。
