摘要:为了研究聚乙烯类微塑料对玉米根际土壤微生物群落结构的影响，以玉米为试材，以平均分子量为2000、5000、10万的聚乙烯粉末模拟土壤中的微塑料污染，设置5个处理：不添加聚乙烯（CK）、添加分子量为2000（T1）、5000（T2）、10万以上（T3）的聚乙烯且种植玉米、未添加聚乙烯未种植玉米（CK0），分析玉米抽穗期各部位矿质元素代谢和根际土壤微生物群落结构差异。结果显示，矿质元素含量在玉米各部位存在差异，Fe、Cu主要集中在玉米根部，Ca、Mn、Mg在叶中分布最多，K主要集中在茎中；添加不同分子量聚乙烯微塑料后，不同部位的矿质元素较CK增加，且T1处理下增加最多。微生物多样性分析显示，不同分子量聚乙烯微塑料对玉米根际微生物群落组成影响不同。T1处理下除变形杆菌纲、伯克氏菌科细菌丰度增加外，其他细菌丰度较CK均减少；T3处理下，细菌和真菌的丰度较CK都有较大幅度的增加。总体来看，添加聚乙烯后，玉米不同部位矿质元素含量较CK显著增加，2000分子量聚乙烯能够显著降低土壤中细菌和真菌的丰度，10万以上分子量聚乙烯使得土壤中细菌和真菌丰度增加，各处理中与环境污染物降解相关的微生物增多。
关键词:微塑料/
聚乙烯/
分子量/
根际微生物/
群落结构/
矿质元素/
玉米
Abstract:The use of agricultural polyethylene films results in polyethylene microplastic accumulation in the soil, causing microplastic pollution, which has attracted the attention of scholars worldwide. To study the effects of polyethylene microplastics on the microbial community structure of crop rhizosphere soil, corn was grown with different polyethylene powders (average molecular weights:2000, 5000, and ≥ 100 000) to simulate microplastic pollution in agricultural soil. There were five treatments in this experiment:planting maize without polyethylene (CK), planting maize with 2000 (T1), 5000 (T2), and ≥ 100 000 (T3) molecular weight polyethylene powder, and non-planting maize without polyethylene (CK0). Differences in mineral element metabolism in different parts of maize plant at the heading stage and variation in the rhizosphere soil microbial community structure were analyzed. The results showed that the mineral element content differed in different parts of maize. Iron and copper were mainly concentrated in the roots; calcium, manganese, and magnesium were most abundant in the leaves; and potassium was mainly concentrated in the stems. After adding the polyethylene microplastics of different molecular weights, the mineral elements in different parts of the plant increased compared with CK; the increase was greatest under the 2000 molecular weight polyethylene treatment. Microbial diversity analysis showed that the polyethylene microplastics had different effects on the microbial community composition in the maize rhizosphere. Except for Proteobacteria and Burkholderiaceae, the abundance of bacteria decreased under the 2000 molecular weight polyethylene treatment compared to CK. The abundance of bacteria and fungi increased under the ≥ 100 000 molecular weight polyethylene treatment compared to CK. In general, the mineral elements contents in different parts of the maize plant increased compared with CK after the addition of polyethylene. Two-thousand molecular weight polyethylene reduced the abundance of bacteria and fungi in the soil, whereas ≥ 100 000 molecular weight polyethylene increased the abundance of bacteria and fungi in the soil; the number of microorganisms related to the degradation of environmental pollutants in each treatment increased, which helped the soil cope with microplastics stress.
Key words:Microplastics/
Polyethylene/
Molecular weight/
Rhizosphere microorganism/
Community structure/
Mineral elements/
Corn
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