生物炭对微塑料污染下普通白菜生长和土壤细菌群落结构的影响

Effects of Biochar Application on Growth of Pakchoi and Soil Bacterial Community Structure under Microplastic Pollution

采用盆栽试验,以四季小白菜为试材,研究了施用生物炭对不同微塑料类型(PP、PE、PVC)污染下普通白菜生长、土壤细菌群落结构和丰度的影响,并进行了功能预测分析。结果表明,微塑料污染对普通白菜鲜质量和叶片数有抑制作用,施用生物炭对微塑料污染下的普通白菜鲜质量、株高和根长均有促进作用。微塑料及其与生物炭共存处理显著增加了土壤细菌丰度,其中PER处理土壤细菌丰度最大;PE、PVC及其与生物炭共存处理均显著促进土壤细菌Chao1指数和ACE指数增加。在门水平上,放线菌门、变形菌门、绿弯菌门、厚壁菌门、酸杆菌门为优势类群;微塑料及其生物炭共存处理促进了放线菌门相对丰度的增加,抑制了变形菌门、酸杆菌门相对丰度。土壤p H以及有机碳、铵态氮、硝态氮、速效钾含量是土壤细菌群落结构变化的主要影响因素。PICRUSt分析表明,施用生物炭提高了微塑料污染下土壤新陈代谢、环境信息处理和有机系统等有益细菌代谢通路的相对丰度。综上,施用生物炭对微塑料污染下土壤微生物影响较大,但其影响程度因微塑料类型而异。

Pot experiments were conducted using‘Sijixiaobaicai’to study the effects of biochar application on the growth of pakchoi on soils contaminated by different microplastics(PP,PE,and PVC)and on soil bacterial community structure and abundance.Functional prediction of soil bacterial community was also conducted.The results showed that microplastic contamination inhibited the fresh mass and leaf number of pakchoi.Biochar application increased the fresh mass,plant height,and root length of pakchoi grown on microplastic-contaminated soils.Co-treatment with microplastics and biochar significantly increased soil bacterial abundance.The highest soil bacterial abundance was found in PER treatment.Co-treatment with PE or PVC and biochar significantly increased the Chao1 index and ACE index of soil bacteria.On the phylum level,Actinobacteria,Proteobacteria,Chlorobacteria,Firmicutes,and Acidobacteria are dominant taxa.Co-treatment with microplastics and biochar increased the relative abundance of Actinobacteria,but decreased the relative abundances of Proteobacteria and Acidobacteria.Soil pH value and organic carbon,ammonium nitrogen,nitrate nitrogen,and available potassium contents were primary influence factors for changes in soil bacterial community structure.Functional prediction of soil bacterial community using PICRUSt showed that biochar application increased the relative abundances of several metabolic pathways of beneficial bacteria,including soil metabolism,environmental information processing,and organic system.To conclude,biochar application had a significant impact on the bacterial community in microplastic-contaminated soils,though the degree of influence varied with the type of microplastics.