摘要
土壤微塑料与重金属污染的植物毒理效应是普遍关注的环境问题之一。为明确土壤常见污染物聚乙烯(PE)微塑料与重金属铅(Pb)复合暴露对种子发芽的影响,以小麦和大豆种子为实验对象进行了种子发芽实验,研究了单一PE微塑料(0,100,300,500,1000,1500 mg/L),单一Pb(0,50,100,200,400 mg/L),以及PE微塑料(300,500 mg/L)与Pb(100,200 mg/L)复合作用对小麦种子和大豆种子的萌发与根伸长的影响。实验结果表明:不同浓度单一PE微塑料暴露(100~1500 mg/L)小麦与大豆种子发芽率分别为84.83%~100.00%和76.67%~100.00%,根长度分别为7.32~9.18 cm和10.90~12.30 cm,小麦和大豆种子的萌发及根伸长整体呈现“低浓度促进,高浓度抑制”;不同浓度单一Pb污染(50~400 mg/L)对小麦和大豆种子的萌发具有抑制作用,随Pb浓度增高其发芽率降低,而根伸长则呈现先增大再减小趋势;其中,PE微塑料和Pb污染对大豆种子的萌发和根伸长的影响更为显著。PE微塑料与Pb复合暴露对小麦和大豆种子的萌发与根伸长的抑制强度随PE微塑料和Pb浓度的增加而加大;PE微塑料可促进种子萌发与根伸长,拮抗Pb污染对小麦种子和大豆种子萌发与根伸长的影响,但拮抗作用强度随PE微塑料浓度和Pb浓度的增加而减弱。微塑料疏水、粒径小、比表面积大,易被种子表面吸附,影响种子吸收水分与种子呼吸是抑制种子萌发与根伸长的可能机制;微塑料带有负电荷、与Pb^(2+)静电吸附力强,通过与种子竞争吸附降低Pb^(2+)与种子可接触性是PE微塑料拮抗Pb对小麦与大豆种子毒性的可能原因。
The phytotoxic effects of soil contaminated by microplastics and heavy metal are one of the environmental issues of widespread concern.In order to clarify the effects of composite exposure of polyethylene(PE)microplastics and heavy metals(Pb),the common pollutants in soils,on seed germination,the germination experiments were conducted on wheat seeds and soybean seeds;the effects of single PE microplastics(0,100,300,500,1000 and 1500 mg/L)and the effects of single Pb(0,50,100,200,and 400 mg/L),as well as the combined effects of PE microplastics and Pb(300 mg/L^(-1) +100 mg/L,300 mg/L+200 mg/L^(-1),500 mg/L+100 mg/L,500 mg/L+200 mg/L)on the germination and root elongation of wheat seeds and soybean seeds were studied.The experimental results show that the germination rates of wheat seeds and soybean seeds respectively were 84.83%-100%and 76.67%-100%,and the root lengths respectively were 7.32-9.18 cm and 10.90-12.30 cm when PE microplastics were from 100 mg/L to 1500 mg/L.The germination and root elongation of wheat seeds and soybean seeds overall were promoted at low concentration of PE microplastics,and inhibited at high concentration of PE microplastics.Single Pb contamination inhibited the germination of wheat seeds and soybean seeds,and as the concentration of exposed Pb increases,the germination rates decreased,while the root elongation increased first and then decreased.Among them,PE microplastics and Pb pollution had more significant effects on soybean seed germination and root elongation.The inhibition strength of PE microplastics and Pb combined exposure on seed germination and root elongation of wheat and soybean increased with the increase of PE microplastics and Pb concentrations.PE microplastics can promote seed germination and root elongation,and antagonizing the effect of Pb pollution on seed germination and root elongation.However,the intensity of the antagonistic effect weakens with the increase of PE microplastics concentration and Pb concentration.Microplastics are hydrophobic,small in particle
出处
《环境保护与循环经济》
2024年第6期70-76,共7页
environmental protection and circular economy
关键词
PE微塑料
PB
小麦
大豆
种子发芽
polyethylene microplastics
lead
wheat
soybean
seed germination
