Epichloe内生真菌对禾草种子萌发影响研究进展

Effects of Epichloe endophytic fungi on the germination of grass seeds

种子是农业生产实践中最基本的生产资料,其萌发对植物物种的生存和繁衍起着决定性作用,但此过程易受到环境因素的影响,提高种子在胁迫环境下的萌发质量对禾草建植具有重要意义。Epichloe内生真菌与禾草形成互惠共生关系,可促进共生体种子萌发并提高对环境胁迫抗性,使其在植物群落中占据优势生态位,因此对动植物及微生物生态系统产生广泛影响。将国内外关于Epichloe属内生真菌在不同生境及处理下对宿主禾草种子萌发的影响进行综述,重点探讨Epichloe属内生真菌对宿主禾草种子在正常生长条件和胁迫环境下的萌发及化感效应等方面的作用,发现内生真菌在正常萌发条件和胁迫环境中均能促进种子萌发,而在化感作用下萌发响应不一致,同时,内生真菌的侵染能显著缓解贮藏时间对种子萌发的负效应。通过对前人研究的总结,建议今后应加强对Epichloe内生真菌促进禾草种子萌发及提高抗性生理生化等方面的研究,揭示内生真菌与禾草共生对种子萌发的影响机制,从而筛选出优良内生真菌菌株,以期利用内生真菌资源为禾草种质资源的创制开辟新途径。

Seeds are the most basic output generated in agricultural production,and seed germination plays a decisive role in survival and reproduction of species.However,the process of germination is easily affected by various environment factors.It is significant to improve germination quality in stress condition for grass planting.The establishment of the symbiotic relationship in plants with Epichloe endophyte confers on the symbiosis higher germination rate,stronger resistance to adverse stress,and leads to the occupation of a more favourable ecological niche in the phytocoenosis.Hence,the Epichloe endophyte has a wide impact in ecosystems,with ramifications affecting animals,plants and microorganisms within an ecosystem.This study reviewed the influence of Epichloeendophyte infection on host grass germination under different habitats and treatments,with a focus on roles of endophyte in seed germination under natural growth conditions and various stress conditions,including allelopathy.It was found that endophyte promotes seed germination under both natural and stress conditions.However,germination responses were inconsistent in the presence of allelopathic effects.Additionally,the negative effect on germination caused by extended storage time is alleviated by endophyte infection.Building on previous research,we should prioritize research into the physiology and biochemistry of promoting germination and enhancing resistance to biotic and abiotic stresses in grass infected with Epichloe endophyte,and on defining the mechanism whereby endophyte fungi influence germination,in order to identify excellent endophytic strains and explore novel ways of creating grass germplasm resources using Epichloe endophyte.