增施摩西管柄囊霉对甜玉米氮肥增效及土壤丛枝菌根真菌多样性的影响

Effects of Funneliformis mosseae Application on Nitrogen Utilization by Sweet Corn and AM Fungi Diversity in soil

【目的】研究增施摩西管柄囊霉(Funneliformis mosseae)对甜玉米氮肥减量效果及根际土壤AM真菌多样性的影响,揭示AM真菌对甜玉米氮肥减量增效的土壤微生物学机制,为AM真菌在甜玉米氮肥减量上的推广应用提供参考。【方法】试验共设4个施氮水平:(1)不施氮肥(N0);(2)优化施肥,施氮肥330 kg·hm-2(N22);(3)优化施肥减氮10%,施氮肥297 kg·hm-2(N19.8);(4)优化施肥减氮20%,施氮肥264 kg·hm-2(N17.6)。同一施氮水平下设增施摩西管柄囊霉315 kg·hm-2和不增施2个裂区,试验共8个处理3个重复。利用土壤常规理化分析方法和Illumina Hiseq 2500测序平台,对8个处理甜玉米根际土壤氮肥增效及AM真菌进行扩增子测序,进而对AM真菌的群落结构多样性进行分析。【结果】增施摩西管柄囊霉处理,在N0、N17.6、N19.8和N22等4个施氮水平上,甜玉米鲜苞产量较不施菌裂区组分别增加了32.6%、16.7%、8.0%和0.8%,氮素生理利用率较不施菌裂区组分别增加了5.51%、4.14%、6.19%。通过Illumina Hiseq 2500测序平台共获得1 558 461个有效序列,在97%的相似水平下聚类后获得15 771个OTUs,分属于1纲4目5科5属。在属水平上,球囊霉属(Glomus)、近明球囊霉属(Claroideoglomus)和类球囊霉属(Paraglomus)是8个处理共有的菌属,其中,球囊霉属是8个处理的优势菌属,占各处理相对丰度≥1%物种的21.82%以上。N22AM处理的Chao1和Richness指数显著高于其他处理(P<0.05),而N0AM处理的Dominance指数最大,Shannon指数和Simpson指数最小。增施摩西管柄囊霉后,显著增加了Shannon指数、 Simpson指数与侵染率、孢子密度和4种氮素利用率(NAE、 PFP、 NRE、 NPE)之间的相关性(P<0.05)。【结论】增施摩西管柄囊霉可显著提高甜玉米的氮肥利用效率,改变AM真菌群落结构,提高甜玉米产量,是甜玉米氮肥减量的有效途径。

【Objective】 By adding Funneliformis mosseae to the sweet corn field, roles of AM fungi play on the nitrogen(N)utilization and the fungal diversity in rhizosphere soil were studied.【Method】 Various N applications including no N(N0),330 kg N·hm-2(N22), 297 kg N·hm-2(N19.8), and 264 kg N·hm-2(N17.6) were used. In addition, at a same level of N, two split-plots with(AM+) or without(AM-) 315 kg·hm-2 of F. mosseae were included for the experimentation. Thus, 8 treatments with 3 replicates each were performed. Rhizosphere soil were sampled for chemical analysis and Illumina Hiseq2500 sequencing to determine the diversity and community structure of the AM fungi.【Result】 Among the AM+ treatments,the fresh bud yield of the corn plants increased by 32.6% at N0, 16.7% at N17.6, 8.0% at N19.8, and 0.8% at N22. In comparison to AM-, the N utilization of the plants on the AM+ plots with N17.6, N19.8, and N22 improved by 5.51%, 4.14%,and 6.19%, respectively. From the 1 558 461 valid sequences obtained, 15 771 OTUs were clustered at 97% similarity level to show a result of one class, 4 orders, 5 families, and 5 genera. Among the common genera, Glomus, Claroideoglomus, and Paraglomus, Glomus predominantly presented in the rhizosphere accounting for more than 21.82% of all species with a relative abundance ≥1%. The N22/AM+ treatment yielded higher Chao1 and richness indices than others(P< 0.05). The greatest abundance index as well as the lowest Shannon and Simpson indices were found with the N0/AM+ treatment. The addition of F. mosseae significantly increased the correlations between Shannon index, Simpson index and infection rate, spore density,and utilization rates of 4 types of N(NAE, PFP, NRE, and NPE)(P<0.05).【Conclusion】 The addition of F. mosseae in corn field altered the AM fungal community in the rhizosphere resulting in an increased crop yield. This study confirmed the significant promotional effect of AM fungi on the N utilization efficiency by sweet corn plants, which would effectively reduce the need for N fertilizer in the field.