【摘要】 土壤环境中微塑料污染及毒理学效应逐渐引起关注,但微塑料对植物的毒性及其机制研究仍十分匮乏.为探究微塑料对陆生高等植物小麦(Triticum aestivum)的毒性作用,选用100 nm和5μm聚苯乙烯微塑料(PS-MPs)进行土培处理,结合水培生长试验,研究了PS-MPs对小麦生长及叶片光合色素、可溶性蛋白含量和抗氧化酶活性等的影响.结果表明,水培试验中,高浓度(200 mg·L-1) PS-MPs显著抑制小麦根、茎的伸长,5μm PS-MPs较100 nm PS-MPs表现出更大的毒性效应,小麦根和茎的长度抑制率分别为67. 15%和56. 45%.土培条件下,10 mg·kg-1PS-MPs对小麦生长影响最为显著.在试验含量范围内(0～100 mg·kg-1),随PS-MPs含量的增加,小麦叶片光合色素和可溶性蛋白含量先升后降,提示PS-MPs对小麦叶片光合系统产生了损害,抑制其蛋白的合成;超氧化物歧化酶(SOD)活性下降,过氧化氢酶(CAT)活性先降后升,表明PS-MPs对小麦毒性的可能机制涉及氧化应激.本研究结果将为土壤环境中微塑料的生态风险评价提供依据.更多还原

【Abstract】 The toxicological effects of microplastics in the soil environment have gradually attracted widespread attention,while less is known about the influence of microplastics on plants. The growth of wheat,photosynthetic pigment content,soluble protein content,and the antioxidant enzyme activities of leaves were investigated to explore the toxic effects of microplastics on wheat( Triticum aestivum). In this study,100 nm and 5 μm polystyrene microplastics( PS-MPs) were used for soil culture treatment combined with hydroponic growth. The results showed that in hydroponic experiment,high concentrations( 200 mg·L-1) of PS-MPs significantly inhibited the elongation of wheat roots and stems,and 5 μm PS-MPs showed a greater toxicity effect than 100 nm PS-MPs. Roots and stem length inhibition rates were 67. 15% and 56. 45%,respectively. In the soil culture tests,10 mg·kg-1 PS-MPs had the most significant effect on wheat growth. Within the test content range( 0-100 mg·kg-1),with an increase in PS-MPs exposure,the content of photosynthetic pigment and soluble protein in wheat leaves increased first and then decreased. This indicated that PS-MPs damaged the photosynthetic pathway of wheat leaves and inhibited protein synthesis. SOD activity decreased,and CAT decreased first and then increased,indicating that the possible mechanism of toxicity to wheat involves oxidative stress. The results provide a basis for the ecological risk assessment of microplastics in the soil environment.更多还原