玉米秸秆还田对土壤丛枝菌根真菌群落的影响

为揭示农业管理活动对土壤丛枝菌根(AM)真菌的影响机制,基于Illumina Miseq高通量测序平台以及脂肪酸指纹图谱方法,研究了连续4年玉米秸秆还田后,AM真菌群落组成、AM真菌生物量及其与土壤环境因子间的相互关系.结果表明: 所获得的2430个AM真菌OTUs从门到种依次分类,共分为1门、3纲、4目、8科、10属、143种,但不同处理间AM真菌群落丰富度(Chao1指数和ACE指数)、多样性(Shannon、Simpson多样性指数)没有显著差异.AM真菌中类球囊霉属、球囊霉属为优势属.随秸秆还田量的增加,球囊霉属丰度降低;3000、9000 kg·hm^-2秸秆还田量下,类球囊霉属、无梗囊霉属的丰度与对照(0 kg·hm^-2)间差异达极显著水平;原囊霉属、类球囊霉属、球囊霉属在3000 kg·hm^-2秸秆还田量下与对照间差异显著.非度量多维尺度(NMDS)分析表明, 9000、12000 kg·hm^-2的秸秆还田量下土壤AM真菌β多样性与对照间聚集度较其他处理相差较远,秸秆还田量对AM真菌β多样性的影响显著.多元分析结果能在累积变量82.8%上揭示土壤主要理化性状与AM真菌丰富度、多样性的空间变化关系. 土壤全氮、碱解氮是影响以磷脂脂肪酸表征的土壤主要微生物类群生物量以及以中性脂肪酸表征的AM真菌生物量的主要因子.持续玉米秸秆还田改变了AM真菌属水平上的分类学组成;随秸秆还田量的增加,AM真菌特有的微生物种类减少,AM真菌群落组成间的相似度下降;秸秆还田增加了土壤AM真菌生物量及其占土壤微生物总生物量的比例.

Effects of maize straw returning on arbuscular mycorrhizal fungal community structure in soil

To understand the effects of agricultural management activities on soil arbuscular mycorrhizal (AM) fungi diversity, the high-throughput sequencing based on Illumina MiSeq platform, and the fatty acids fingerprints were used to examine the effects of maize straw returning on soil arbuscular mycorrhizal fungi. The relationships between AM fungal community composition, AM fungal biomass and soil factors after maize straw returning were examined for four continuous years. A total of 2430 operational taxonomic units (OTUs) of AM fungi were classified into 10 genera and 143 species, respectively, which belonged to 1 phylum, 3 classes, 4 orders, 8 families. There was no significant difference in AM fungal community richness (Chaoles index and ACE index) and diversity (Shannon, Simpson diversity indices) in different treatments. Paraglomus and Glomus were dominant genera among all AM fungal communities. With the increase of the maize straw returned amounts, the abundance of Glomus reduced. Under the treatments of 3000 and 9000 kg·hm^-2 straw returned, the abundance of Glomus and Acaulospora had significant differences with the control (0 kg·hm^-2). Compared with the control, there were significant differences between Archaeospora, Paraglomus and Glomus in the treatment of 3000 kg·hm^-2 straw returned. Results from non-metric multi-dimensional scale (NMDS) analysis showed that under 9000 and 12000 kg·hm^-2 straw returning treatments, the difference between the β diversity of soil AM fungi and the spatial distance of controls was farther apart than the other treatments. The effect of straw returning on the β diversity of AM fungi was significant. The multivariate analysis results revealed the relationship of the spatial variation between the soil physicochemical properties and AM fungi richness and diversity could be explained at 82.8% cumulative variables. The total nitrogen and available nitrogen were the most important factors driving soil microbial communities biomass marked by PLFAs and AM fungal biomass (NLFAs). The continuous maize straw returning to the field changed the genera composition of AM fungi. With the increases of straw returning amounts, the specific species of AM fungi decreased and the similarity between AM fungi community composition decreased. Straw returning increased soil AM fungi biomass and its contribution to soil total microbial biomass.