聚丙烯微塑料(PP-MPs),一种新兴的污染物,对水生植物恢复水体的能力产生不利影响,从而损害湿地生态系统的功能和完整性。本研究考察了微塑性应力对鱿鱼和虹膜脱氮除磷能力的影响,以及水生系统中的功能性微生物。研究结果表明,在PP-MP胁迫下,两种植物的氮和磷吸收能力均减弱。此外,植物中与氮和磷相关的代谢酶活性显着降低,伴随着叶片氮含量的显著下降。PP-MPs阻碍植物的营养吸收,影响其生长并间接降低其利用氮和磷的能力。具体来说,在10mg·L-1治疗组中,A.calamus和I.tectorum显示叶片氮含量降低了23.1%和31.0%,分别,200mg·L-1治疗组分别为14.8%和27.7%。此外,I.tectorum的叶片氮含量高于鱿鱼。使用荧光标记,PP-MP的分布可追溯到根部,茎,和植物的叶子,揭示了这两个物种的显著生长障碍。这包括光合色素合成的显著下降,增强氧化应激反应,和增加细胞膜的脂质过氧化。PP-MP暴露还显着降低了水生系统中在属水平上参与反硝化和除磷的功能微生物的丰度。生态功能预测显示,在两个处理组中,水微生物之间的氮循环功能(例如氮呼吸和亚硝酸盐反硝化)显着下降。在鱿鱼治疗组中具有较高的生态风险潜力。本研究为PP-MPs对参与水体修复的水生植物的潜在胁迫机制及其对湿地生态系统的影响提供了新的见解。
Polypropylene microplastics (PP-MPs), an emerging pollutant, adversely affect the ability of aquatic plants to restore water bodies, thereby compromising the functionality and integrity of wetland ecosystems. This study examines the effects of microplastic stress on the nitrogen and phosphorus removal capacities of Acorus calamus and Iris tectorum, as well as on functional microorganisms within the aquatic system. The findings indicate that under PP-MP stress, the nitrogen and phosphorus absorption capabilities of both plants were diminished. Additionally, there was a significant reduction in the metabolic enzyme activities related to nitrogen and phosphorus in the plants, alongside a notable decrease in leaf nitrogen content. PP-MPs hinder the nutrient uptake of plants, affecting their growth and indirectly reducing their ability to utilize nitrogen and phosphorus. Specifically, in the 10 mg L-1 treatment group, A. calamus and I. tectorum showed reductions in leaf nitrogen content by 23.1% and 31.0%, respectively, and by 14.8% and 27.7% in the 200 mg L-1 treatment group. Furthermore, I. tectorum had higher leaf nitrogen levels than A. calamus. Using fluorescent tagging, the distribution of PP-MPs was traced in the roots, stems, and leaves of the plants, revealing significant growth impairment in both species. This included a considerable decline in photosynthetic pigment synthesis, enhanced oxidative stress responses, and increased lipid peroxidation in cell membranes. PP-MP exposure also significantly reduced the abundance of functional microorganisms involved in denitrification and phosphorus removal at the genus level in aquatic systems. Ecological function predictions revealed a notable decrease in nitrogen cycling functions such as nitrogen respiration and nitrite denitrification among water microorganisms in both treatment groups, with a higher ecological risk potential in the A. calamus treatment group. This study provides new insights into the potential stress mechanisms of PP-MPs on aquatic plants involved in water body remediation and their impacts on wetland ecosystems.