不同丛枝菌根真菌对青藏高原高寒草原优良牧草垂穗披碱草生长的促生效应

Effects of Various Arbuscular Mycorrhizal Fungi on the Growth of Elymus nutans in Tibetan Plateau Alpine Meadow Ecosystem

丛枝菌根(Arbuscular mycorrhizae,AM)真菌能侵染绝大多数陆生高等植物的根系,形成菌根共生体结构;在生态系统中,AM真菌能调节植物间的营养分配和竞争关系,对增加植物群落的产量、维持植物群落动态的稳定性具有重要意义。目前,青藏高原高寒草原生态系统面临严重退化,研究利用AM真菌开展受损高寒草原的恢复具有重要意义,但不同AM真菌对优良牧草生长的促生效应是否一致尚待深入研究。为此,本研究在盆栽条件下接种5种不同的AM真菌菌剂:地表球囊霉(Glomus versiforme)、光壁无梗囊霉(Acaulospora laevis)、单孢球囊霉(Glomus monosporum)、根内球囊霉(Glomus intraradices)和土著AM真菌,研究不同的AM菌剂与高寒草原主要优良牧草之一垂穗披碱草(Elymus nutans)之间的共生关系及其对垂穗披碱草的促生效应。结果显示,5种AM真菌均能成功侵染垂穗披碱草根系,但对垂穗披碱草生长的促进作用存在差异,其中,根内球囊霉和土著AM真菌对垂穗披碱草地上部分的生长(总生物量、地上生物量、株高、分蘖数)、地下部分的生长(地下生物量、根长)均具有显著的促进效应(P<0.05),而地表球囊霉、单胞球囊霉、光壁无梗囊霉对垂穗披碱草地上部分生物量没有显著的促进效应(P>0.05)。以综合效应而言,根内球囊霉和土著AM真菌的促生效应最显著。可见,不同的AM真菌对同一宿主植物的促生效应不同,只有选择合适的AM真菌才能产生最佳的促生效应。

Arbuscular mycorrhizal （AM） fungus is one of the most important microorganisms in soil ecosystem,which could be form symbiotic association with host plants.In ecosystem,AM fungi could enhance nutrition and water absorption,increase the ability to stress condition and regulate the intraand inter-competitive relationship between plants.It is also could increase the productivity and maintain the stability of plant community.Nowadays,the grassland in Tibetan Plateau Alpine meadow ecosystem has been serious damaged.The quantity and quality of many grasses have been decreased,and many poisonous plants spread very quickly.In order to recovery the damaged grassland,AM fungi was been selected as a bio-fertilizer to carried out the bioremediation of Tibetan Plateau Alpine meadow ecosystem.Based on this,five AM fungi inoculums,Glomus versiforme,Acaulospora laevis,Glomus monosporum,Glomus intraradices and indigenous AM fungi,were selected to test their effects on the growth of Elymus nutans.Results showed that all the five AM fungi could colonize and form symbiosis with E.nutans roots.However,the effects of various AM fungi on E.nutans growth performance were totally different.Although the five AM fungi could improve the root biomass and root length of E.nutans significantly （P 〈 0.05）,G.intraradices and indigenous AM fungi have more promoting effects.They could enhanced the total biomass,shoot biomass,plant height and tiller number of E.nutans significantly （P 〈 0.05）.In a word,G.intraradices and indigenous AM fungi has the most significant effects on the growth of E.nutans,which means that different AM fungi has different effects on the same host plants.