干旱胁迫下丛枝菌根真菌对羊草功能性状的影响

Effects of Arbuscular Mycorrhizal Fungi on Functional Traits of Leymus chinensis under Drought Stress

羊草是欧亚温带草原的主要优势植物,在生态系统保护及恢复利用中起着至关重要的作用。丛枝菌根真菌与植物共生,能够提高植物的抗旱能力,但目前干旱胁迫下AMF与羊草共生机理仍不明晰。基于此,采用盆栽试验研究轻度干旱(田间持水量56.25%)和重度干旱(田间持水量37.50%)下接种摩西斗管囊霉、幼套近明球霉菌及混合接种对羊草功能性状的影响,结果表明:(1)与对照(田间持水量75%)相比,轻度干旱处理下地上生物量、地下生物量分别降低了24.00%、17.02%,重度干旱处理则分别降低了53.00%、34.04%。(2)在重度干旱下,幼套近明球霉菌显著增加了两种羊草的叶片数、叶宽及根长(P<0.05);在轻度干旱下,混合接种显著增加了羊草的叶片数、叶宽及根长(P<0.05)。(3)叶片数、株高、叶面积、叶宽、茎高度性状对地上生物量变化的解释率为78.52%,是地上生物量主要调控因子;根表面积、根体积、根分叉数、根长性状对地下生物量变化的解释率为67.10%,是地下生物量主要调控因子。

Leymus chinensis is the main dominant plant in the Eurasian temperate grassland,which plays a vital role in the protection and recovery of the ecosystem.Arbuscular Mycorrhiza Fungi(AMF)are symbiotic with plants,which can improve the drought resistance of plants.However,the mechanism of how AMF and Leymus chinensis symbiosis change the functional traits of Leymus chinensis under drought stress is still unclear.Thus,pot experiments were carried out to study the effects of inoculation of Funneliformis mosseae,Claroideoglomus etunicatum,mixed inoculation and non inoculation on the functional properties of Leymus chinensis under drought free(75%of field capacity),mild drought(56.25%of field capacity)and severe drought(37.50%of field capacity).The results showed that:(1)The aboveground biomass and underground biomass decreased by 24.00%and 17.02%respectively under mild drought,while the aboveground biomass and belowground bio⁃mass decreased by 53.00%and 34.04%respectively under severe drought.(2)Under severe drought,Claroideoglomus etunicatum increased the leaf number,leaf width,and root length(P<0.05);Under mild drought,mixed inoculation significantly increased leaf number,leaf width and root length of Leymus chinensis(P<0.05).(3)Number of leaves,plant height,leaf area,leaf width,stem height explained 78.52%of the variation in aboveground biomass and were the main regulators of aboveground biomass;root surface area,root volume,root bifurcation number,root length explained 67.10%of the variation in belowground biomass and were the major regulators of belowground biomass.Our study confirms that AMF resists drought stress through symbiosis with Leymus chinensis and altering its functional traits.