Abstract: Arbuscular mycorrhizal fungi (AMF) and rhizobia are two important symbiotic microorganisms in nature. They could form symbiotic systems of arbuscular mycorrhiza and root nodules with host plants respectively,which have an important impact on the growth of host plants. In this study,the symbiosis of arbuscular mycorrhizal fungi-gramineous forage and arbuscular mycorrhizal fungi-legume-rhizobium were established to study the effects of AMF and rhizobium inoculation on the forage biomass of alfalfa and smooth brome in mixed sowing. The results showed that,compared with CK,the aboveground biomass of alfalfa inoculated with rhizobium in pure and mixed sowing increased by 65.42% and 53.41%,and the belowground biomass increased by 96.66% and 114.42%,respectively,for each individual. The aboveground biomass of alfalfa per individual increased by 35.33% and 23.20% respectively,and the belowground biomass increased by 40% and 46.45%,respectively,when inoculated with AMF. The aboveground biomass of alfalfa inoculated with AMF and rhizobium increased by 105.66% and 185.64% in pure and mixed sowing for each individual,and the belowground biomass increased by 167% and 121%,respectively. It can be seen that the double inoculation of mycorrhizal fungi and rhizobia has a synergistic effect on the biomass of alfalfa.

Key words: Arbuscular mycorrhizal fungi (AMF), Rhizobia, Alfalfa, Smooth brome, Mixed sowing

摘要： 丛枝菌根真菌（Arbuscular mycorrhizal fungi，AMF）和根瘤菌是自然界存在的两类重要的共生微生物，分别能与宿主植物形成丛枝菌根和根瘤的共生体系，对宿主植物的生长具有重要影响。本研究通过建立丛枝菌根真菌-禾本科牧草和丛枝菌根真菌-豆科牧草-根瘤菌的共生体，研究AMF和根瘤菌接种对混播中紫花苜蓿（Medicago sativa）和无芒雀麦（Bromus inermis Leyss）生长的影响。结果表明：与CK相比，单独接种根瘤菌处理下单播和混播的紫花苜蓿地上单株生物量分别提高了65.42%和53.41%，地下单株生物量提高了96.66%和114.42%。单独接种AMF处理下单播和混播的紫花苜蓿地上单株生物量分别提高了35.33%和23.20%，地下单株生物量提高了40.00%和46.45%。而AMF和根瘤菌双接种处理下单播和混播的紫花苜蓿地上单株生物量分别提高了105.66%和185.64%，地下单株生物量分别提高了167%和121%。综上所述，AMF和根瘤菌双接种对紫花苜蓿生物量的促进作用具有协同效应。

关键词: 丛枝菌根真菌(AMF), 根瘤菌, 紫花苜蓿, 无芒雀麦, 混播