Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Key Laboratory of Integrated Pest Management in Crops, Ministry of Agriculture, Beijing, P. R. China.
J Environ Sci Health B. 2013;48(6):505-11. doi: 10.1080/03601234.2013.761915.
The objective of this study was to determine the effects of imazethapyr on soil microbial communities combined with its effect on soybean growth. A short-term field experiment was conducted, and imazethapyr was applied to the soil at three different doses [1-fold, 10-fold, and 50-fold of the recommended field rate (H1, H10, H50)] during the soybean seedling period (with two leaves). Soil sampling was performed after 1, 7, 30, 60, 90, and 120 days of application to determine the imazethapyr concentration and microbial community structure by investigating phospholipid fatty acids (PLFA) and microbial biomass carbon (MBC). The half-lives of the imazethapyr in the field soil varied from 30.1 to 43.3 days. Imazethapyr at H1 was innocuous to soybean plants, but imazethapyr at H10 and H50 led to a significant inhibition in soybean plant height and leaf number. The soil MBC, total PLFA, and bacterial PLFA were decreased by the application of imazethapyr during the initial period and could recover by the end of the experiment. The ratio of Gram-negative/Gram-positive (GN/GP) bacteria during the three treatments went through increases and decreases, and then recovered at the end of the experiment. The fungal PLFA of all three treatments increased during the initial period and then declined, and only the fungal PLFA at H50 recovered by the end of the treatment. A principal component analysis (PCA) of the PLFA clearly separated the treatments and sampling times, and the results demonstrate that imazethapyr alters the microbial community structure. This is the first systemic study reporting the effects of imazethapyr on the soil microbial community structure under soybean field conditions.
本研究旨在确定咪草烟与土壤微生物群落相互作用及其对大豆生长的影响。进行了一项短期田间试验，在大豆幼苗期（两叶期），分三个剂量[推荐田间施用量的 1 倍（H1）、10 倍（H10）和 50 倍（H50）]向土壤中施加咪草烟。在施药后 1、7、30、60、90 和 120 天进行土壤采样，通过磷脂脂肪酸（PLFA）和微生物生物量碳（MBC）调查来确定咪草烟浓度和微生物群落结构。田间土壤中咪草烟的半衰期为 30.1-43.3 天。H1 水平的咪草烟对大豆植物无害，但 H10 和 H50 水平的咪草烟导致大豆株高和叶片数显著抑制。施药初期土壤 MBC、总 PLFA 和细菌 PLFA 减少，试验结束时可恢复。三个处理的革兰氏阴性菌/革兰氏阳性菌（GN/GP）比值在处理初期呈先增加后减少的趋势，试验结束时恢复。三个处理的真菌 PLFA 在初期增加，然后减少，只有 H50 处理的真菌 PLFA 在处理结束时恢复。PLFA 的主成分分析（PCA）清楚地分离了处理和采样时间，结果表明咪草烟改变了微生物群落结构。这是首次系统研究咪草烟在大豆田间条件下对土壤微生物群落结构的影响。
