丛枝菌根真菌与根瘤菌对3种豆禾混播植物种间互作的影响

Arbuscular Mycorrhizal Fungi and Rhizobia Regulate Plant Interspecific Interaction of Three Legumes and Grasses Species

丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)和根瘤菌是两类重要的土壤微生物,可与宿主植物形成互利共生关系。本研究通过对多年生黑麦草(Lolium perenne)、鸭茅(Dactylis glomerata)和白三叶(Trifolium repens)构建的混播组合接种AMF和根瘤菌,探讨两种微生物对3种植物竞争关系的调控机制。结果表明,混播处理中鸭茅和多年生黑麦草的株高及生物量显著高于各自的单播处理,白三叶的株高及生物量显著低于其单播处理;接种AMF提高了混播中白三叶的株高、生物量、根系结瘤数,但AMF抑制了群落中优势种鸭茅的生长,缓解了鸭茅对白三叶的竞争排除作用。综上所述,双接种AMF和根瘤菌进一步提高了混播中白三叶的地下生物量及结瘤数,促进白三叶生长固氮并调节了3种植物的种间竞争关系,从而有利于豆禾混播群落功能性和稳定性的维持。

Arbuscular mycorrhizal fungi(AMF)and rhizobia are well-known microbes which can influence plant coexistence and grassland productivity,due to their complementary roles in meeting plant nutritional needs.However,the effect of these two microbial symbionts on the component of a plant community varies with the mycorrhizal dependence of different species.Our study was conducted to measure the effects of AMF,rhizobia and their potential interactions on the productivity and interspecific competition of different plant species.Trifolium repens,Lolium perenne and Dactylis glomerata were used to establish legumes-grasses mixture,associated with AMF/rhizobia or both AMF and rhizobia.The plant height and biomass of T.repens were greater in monocultures than polycultures,whereas the plant height and biomass of L.perenne and D.glomerata were greater in polycultures than their monocultures respectively.Compared to non-AMF inoculated treatments,AMF inoculation significantly promoted plant height,aboveground biomass and root nodulation of T.repens,but decreased the biomass of D.glomerata in polycultures.This resulted in the decreased competitive exclusion from dominant grass,D.glomerata.Co-inoculated with AMF and rhizobia typically altered interspecies competitive relationship between legumes and grasses,significantly increased the root development and N 2 fixing capability of T.repens,and enhanced soil nutrient availability for neighbouring grasses.Our study promise that these two microbial symbioses are critical drivers of productivity and stability of legumes-grasses mixture.