低密度聚乙烯微塑料对空心菜生长和生理特征的影响

Effects of Low-density Polyethylene Microplastics on the Growth and Physiology Characteristics of Ipomoea aquatica Forsk

土壤中微塑料污染及其毒理学效应逐渐引起关注,但微塑料对农作物生长和生理的影响机制研究仍相对匮乏.为探讨微塑料对农作物生长和生理生化的影响,选用不同质量分数(0%、0.2%、5%和10%)的低密度聚乙烯(LDPE MPs)进行盆栽试验,研究了其对柳叶空心菜(Ipomoea aquatica Forsk)种子发芽率、光合色素含量、生物量、抗氧化酶活性、可溶性蛋白和可溶性糖含量等的影响效应.结果表明,LDPE MPs显著抑制了(P<0.05)空心菜种子活力,且质量分数越高抑制效果越显著.然而,5%LDPE MPs显著促进空心菜地上生物量;0.2%LDPE MPs显著促进空心菜叶片超氧化物歧化酶(SOD)活性,而10%LDPE MPs则显著提高了过氧化氢酶(CAT)和过氧化物酶(POD)的活性;丙二醛(MDA)含量随LDPE MPs质量分数的增加呈梯度式下降,较对照处理降低了15.53%~27.39%.LDPE MPs显著提高了空心菜叶片可溶性糖含量.综上可知,LDPE MPs可抑制空心菜种子活力,但会促进其生物量累积;空心菜可通过调节抗氧化酶活性和可溶性蛋白含量来缓解LDPE MPs造成的氧化胁迫.研究结果可为评估微塑料对蔬菜生产的影响提供参考依据.

Microplastic pollution in soil and its toxicological effects have attracted increasing attention from researchers,but the mechanisms of microplastics affecting crop growth and physiology remain unclear.A pot experiment was conducted to evaluate the impacts of various mass concentrations(0%,0.2%,5%,and 10%)of low-density polyethylene microplastics(LDPE MPs)on the germination rate,photosynthetic pigment content,biomass,antioxidant enzyme activity,soluble protein,and soluble sugar content of water spinach(Ipomoea aquatica Forsk).The results showed that LDPE MPs significantly inhibited(P<0.05)the seed vigor of water spinach,and the inhibitory effect increased with increasing concentration of LDPE MPs.However,the 5% LDPE MPs significantly promoted the aboveground biomass of water spinach.The 0.2% and 10% LDPE MPs significantly improved the superoxide dismutase(SOD)activity and catalase(CAT)and peroxidase(POD)activities,respectively.Further,malondialdehyde(MDA)content decreased with increasing concentration of LDPE MPs,and the reductions reached 15.53%-27.39% in comparison to that in the control.The LDPE MPs also significantly increased the soluble sugar content of water spinach leaves.In summary,LDPE MPs could inhibit the seed vigor and promote biomass accumulation in water spinach.Water spinach could relieve the oxidative stress caused by LDPE MPs by regulating antioxidant enzyme activity and soluble protein content.Therefore,this study may provide basic information for assessing the influences of microplastics on vegetables.