生物炭对华北冬小麦根系形态和内生真菌多样性的影响

利用棉花秸秆生物炭,以冬小麦为试验对象,采用根系扫描法和Illumina MiSeq高通量测序技术探讨研究农田秸秆还田,施生物炭分别为4.5、9.0、13.5 t/hm~2后根系形态与内生真菌多样性的影响及其共生机制。试验结果表明,在生物炭施用量为4.5~13.5 t/hm~2时,在冬小麦成熟期提高初生根的直径和比根长,降低分支密度和生物量;降低次生根分支密度。在门水平,生物炭显著提高根内子囊菌门(Ascomycota)丰度,显著降低接合菌门(Zygomycota)、壶菌门(Chytridiomycota)和未鉴定杂菌(unidentified fungus)丰度,对球囊菌门影响不显著;在常见目水平,生物炭明显提高格孢菌目(Pleosporales)丰度,显著降低散囊菌目(Eurotiales)和被孢霉目(Mortierellales)丰度。在4.5~9.0 t/hm~2时,生物炭通过降低初生根内散囊菌目真菌丰度,促进初生根分支密度和生物量的生长;通过提高次生根内格孢菌目真菌丰度,抑制次生根直径和分支密度的生长。经综合比较,9.0 t/hm~2的生物炭处理对根系形态的优化效果优于其他处理,与对照处理相比,在成熟期,初生根直径和比根长分别提高5.00%、33.57%,分支密度和生物量分别降低67.26%、27.27%;次生根直径和分支密度分别降低13.16%、34.38%。

Effect of Biochar on Root Morphology and Endophytic Fungal Diversity of Winter Wheat in North China

The winter wheat was selected to study the effect of biochar of cotton straw on root morphology and endophytic fungal communities by using the method of root scanning and Illumina Miseq high-throughput sequencing. The symbiosis mechanism was found by the test. The treatments were amount of 4.5t/hm2, 9.0t/hm2 and 13.5t/hm2 of straw biochar, respectively applied to the soil, and the straw returning was taken as test control in the field experiment. The results showed that root diameter and specific root length were increased significantly, and branching density and biomass were decreased significantly in the primary root, and only the root branching density was decreased in the secondary root, when the amount of biochar was 4.5 ~ 13.5t/hm2 in the mature period of winter wheat. At the fungal phyla level, the abundance of Ascomycota was increased significantly, and the abundances of Zygomycota, Chytridiomycota and unidentified fungus was reduced greatly, and the abundance of Glomeromycota was not significant. At the common fungal order level, the abundance of Pleosporales was increased significantly, and the abundance of Eurotiales and Mortierellales was reduced greatly. With the amount of 4.5~9.0t/hm2 biochar promoted the primary root growth of root branch density and biomass by decreasing the abundance of Eurotiales, and inhibited the secondary root growth of diameter and branch density by increasing the abundance of Pleosporales. By comprehensive comparison, the effect of amount of 9.0t/hm2 biochar on root morphology was better than that of other treatments. The treatment with amount of 9.0t/hm2 significantly increased the primary root diameter by 5.00% and specific root length by 33.57%, and decreased root branch density by 67.26% and biomass by 27.27%, while also reduced the secondary root diameter by 13.16% and branch density by 34.38%, compared with the test control at maturity stage of winter wheat.