State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Hangzhou, 311300, Zhejiang, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A & F University, Hangzhou, 311300, Zhejiang, China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Hangzhou, 311300, Zhejiang, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A & F University, Hangzhou, 311300, Zhejiang, China.
Environ Pollut. 2024 Nov 1;360:124626. doi: 10.1016/j.envpol.2024.124626. Epub 2024 Jul 29.
Microplastic (MP) contamination in soil severely impairs plant growth. However, mechanisms underlying the effects of MPs on plant nutrient uptake remain largely unknown. In this study, we revealed that NO content was significantly decreased in shoots and roots of wheat plants exposed to high concentrations (50-100 mg L) of MPs (1 μm and 0.1 μm; type: polystyrene) in the hydroponic solution. Isotope labeling experiments demonstrated that MP exposure led to a significant inhibition of NO uptake in wheat roots. Further analysis indicated that the presence of MPs markedly inhibited root growth and caused oxidative damage to the roots. Additionally, superoxide dismutase and peroxidase activities in wheat roots decreased under all MP treatments, whereas catalase and ascorbate peroxidase activities significantly increased under the 100 mg L MP treatment. The transcription levels of most nitrate transporters (NRTs) in roots were significantly downregulated by MP exposure. Furthermore, exposure to MPs distinctly suppressed the activity of nitrate reductase (NR) and nitrite reductase (NiR), as well as the expression levels of their coding genes in wheat shoots. These findings indicate that a decline in root uptake area and root vitality, as well as in the expression of NRTs, NR, and NiR genes caused by MP exposure may have adverse effects on NO uptake and assimilation, consequently impairing normal growth of plants.
土壤中的微塑料（MP）污染严重损害了植物的生长。然而，MP 对植物养分吸收的影响机制在很大程度上仍不清楚。在这项研究中，我们揭示了在水培溶液中暴露于高浓度（50-100mg/L）MP（1μm 和 0.1μm；类型：聚苯乙烯）的小麦植株中，茎和根中的 NO 含量显著降低。同位素标记实验表明，MP 暴露导致小麦根中 NO 摄取显著受到抑制。进一步分析表明，MP 的存在明显抑制了根的生长，并对根造成了氧化损伤。此外，在所有 MP 处理下，小麦根中的超氧化物歧化酶和过氧化物酶活性降低，而过氧化氢酶和抗坏血酸过氧化物酶活性在 100mg/L MP 处理下显著增加。根中大多数硝酸盐转运蛋白（NRTs）的转录水平因 MP 暴露而显著下调。此外，MP 暴露明显抑制了硝酸盐还原酶（NR）和亚硝酸盐还原酶（NiR）的活性，以及它们在小麦茎中的编码基因的表达水平。这些发现表明，MP 暴露导致根吸收面积和根活力下降，以及 NRTs、NR 和 NiR 基因的表达下调，可能对 NO 摄取和同化产生不利影响，从而损害植物的正常生长。
