摘要
为探讨长期施氮对作物运输根和吸收根内生真菌群落特征的影响及其机制。以农田长期定位施肥试验(1995—2019年)为基础,通过高通量测序技术,研究长期5个施氮肥处理(CK、N1、N2、N1P、N2P。其中CK、N1、N2施氮量分别为0,55.2,110.4 kg/hm^(2))对谷子不同功能根内生真菌群落组成和结构的影响。结果表明:CK处理中吸收根的OTUs数和真菌多样性(shannon指数和Chao 1指数)均显著高于运输根(P<0.05)。门水平上,吸收根的Ascomycota和Glomeromycota丰度显著高于运输根(P<0.05),但Mortierellomycota和Basidiomycota丰度显著低于运输根(P<0.05)。在属水平上,优势菌属Mortierella和Bipolaris在吸收根内的相对丰度显著低于运输根(P<0.05),但Fusarium和Minimedusa显著高于运输根(P<0.05)。高氮施肥吸收根和运输根的OTUs数、Chao 1指数分别提高了23.62%,23.87%,其他施肥则相反。施肥运输根的shannon指数提高了7.12%~19.62%,吸收根则相反。施肥吸收根致病菌属(Bipolaris、Fusarium、Magnaporthiopsis、Microdochium)的相对丰度分别增加了52.99%,40.74%,133.06%,200.00%,运输根中抗病菌属(Minimedusa)的相对丰度提高了40.16%~97.11%。施肥谷子根系碳、氮、磷含量分别提高了2.33%~11.63%,13.30%~94.66%,3.89%~263.92%,氮磷肥配施处理的影响尤为显著(P<0.05)。施肥运输根生物量提高了106.67%~336.41%,吸收根的生物量降低了35.20%~60.20%。长期施肥通过提高土壤速效磷、全磷、可溶性氮和根系碳含量而提高吸收根内生真菌丰度,通过提高根系生物量而降低运输根内生真菌丰度,低氮磷配施肥(N1P)对土壤养分含量及菌群发展影响最大。探明长期施氮肥对黄土丘陵区谷子不同功能根系内生真菌分布格局变化的影响,为作物的高产优质及农田土壤生态环境的良好构建提供理论依据。
The purpose of this study was to explore the effect and its mechanism of long-term nitrogen application on the characteristics of endophytic fungi community in crop transport roots and absorbing roots.Based on the field long-term location fertilization experiment(1995-2019),through the high-throughput sequencing technology,the long-term 5 nitrogen fertilizer treatments(CK,N1,N2,N1P,N2P)were studied.Among them,the CK,N1,N2 nitrogen application rates were respectively:0,55.2,110.4 kg/hm 2)on the composition and structure of endophytic fungi community in different functional roots of millet.The results showed that the number of OTUs and fungal diversity(shannon index and Chao 1 index)of absorbing roots in CK treatment were significantly higher than those of transporting roots.At the phylum level,the abundance of Ascomycota and Glomeromycota of absorbing roots was significantly higher than that of transporting roots,but the abundance of Mortierellomycota and Basidiomycota was significantly lower than that of transporting roots.At the genus level,the relative abundance of the dominant genus Mortierella and Bipolaris in absorbing roots was significantly lower than that in transporting roots,but Fusarium and Minimedusa were significantly higher than transporting roots.The number of OTUs and Chao 1 index of absorbing root and transport root of high nitrogen fertilization increased by 23.62%,23.87%,respectively,while other fertilization was just the opposite.The Shannon index of fertilization and transporting roots increased by 7.12%~19.62%,but the absorbing roots were the opposite.The relative abundance of fertilization-absorbing root pathogenic bacteria(Bipolaris,Fusarium,Magnaporthiopsis,Microdochium)increased by 52.99%,40.74%,133.06%,200.00%,respectively,and the relative abundance of pathogen-resistant bacteria(Minimedusa)in transporting roots increased 40.16%~97.11%.The carbon,nitrogen,and phosphorus contents of the millet root system increased by 2.33%~11.63%,13.30%~94.66%,3.89%~263.92%,respectively.The effect of combined application of nitrogen and phosphorus was particularly significant.The biomass of fertilization and transport roots increased by 106.67%~336.41%,and the biomass of absorbing roots was reduced by 35.20%~60.20%.Long-term fertilization increased the abundance of endophytic fungi in absorbing roots by increasing soil available phosphorus,total phosphorus,soluble nitrogen and root carbon content,and reducing the abundance of endophytic fungi in transporting roots by increasing root biomass,and applying phosphorus fertilizer with low nitrogen(N1P)has the greatest impact on the soil nutrient content and the development of the flora.In short,long-term nitrogen application could change root endophytic flora by affecting the soil or root chemical composition,which might lead to the changes in plant survival strategies and ultimately affect farmland ecosystems.
作者
高小峰
景航
闫本帅
吴春晓
王国梁
GAO Xiaofeng;JING Hang;YAN Benshuai;WU Chunxiao;WANG Guoliang(State Key Laboratory of Soil Erosion and Dryland Agriculture on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences,Ministry of Water Resources,Yangling,Shaanxi 712100;University of Chinese Academy of Sciences,Beijing 100049;Institute of Soil and Water Conservation,Northwest A&F University,Yangling,Shaanxi 712100)
出处
《水土保持学报》
CSCD
北大核心
2021年第5期303-311,共9页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(K3010217050)。
关键词
长期施肥
氮磷
运输根
吸收根
内生真菌
long-term fertilization
nitrogen and phosphorus
transport roots
absorbing roots
endophytic fungi
