植物内生固氮菌及其固氮机理研究进展

氮素是植物生长必不可少的元素，植物内生固氮菌不仅能够在植物体内产生氮素以供植物利用，而且在自然界氮素循环过程中发挥积极作用，对农业可持续发展具有重要意义。近年来，植物内生固氮菌逐渐成为研究热点。由植物内生固氮菌的发现、作物共生、侵入途径、固氮机理、促生作用机制等方面系统地综述了植物内生固氮菌的研究进展，探讨了植物内生固氮菌新的研究思路以及一些尚未解决的问题，以期为植物内生固氮菌及生物固氮研究提供参考。

Research Progress on Plant Endophytic Nitrogen-fixing Bacteria and Their Nitrogen Fixation Mechanism

Nitrogen is an essential element for plant growth. Plant endophytic nitrogen-fixing bacteria can not only produce nitrogen in the plant body for plant utilization， but also play an active role in the natural nitrogen cycle， which has important significance for the sustainable development of agriculture. The research on endogenous nitrogen-fixing bacteria has gradually become research hotspot in recent years. This article systematically reviewed the research progress of plant endophytic nitrogen-fixing bacteria from many aspects， such as the discovery of plant endophytic nitrogen-fixing bacteria， crop symbiosis， invasion pathways， nitrogen-fixing mechanism， and growth-promoting mechanism. In addition， new research ideas of plant endophytic nitrogen-fixing bacteria and some unresolved problems were discussed. This paper was expected to provide reference for research on plant endophytic nitrogen-fixing bacteria and biological nitrogen fixation.