摘要
Epichloë内生真菌存在于许多禾草的地上部分组织中,地上内生真菌和地下土壤微生物都能影响植物的生长,但关于二者同时对植物生长和竞争力影响的研究却很少。本文旨在研究地上部分内生真菌对宿主禾草的生长和竞争能力的作用是否受到土壤微生物的影响。本文以感染Epichloë内生真菌(EI)和不感染内生真菌(EF)的羽茅(Achnatherum sibiricum)以及大针茅(Stipa grandis)为植物材料,采用湿筛法获得具有不同多样性的微生物接种物。试验采用3因素随机区组设计:一是羽茅的内生真菌感染状况,包括EI和EF;二是土壤接种物的微生物组成,包括混合微生物组分(高多样性)和小型微生物组分(低多样性);三是种植方式,包括单独种植、单种和混种。植物种植16周后测定了植物生长和竞争状况。当羽茅单株或单种种植时,内生真菌对羽茅的生长和种内相互作用无显著影响,但内生真菌显著缓解了土壤微生物对羽茅单株种植时的抑制作用。当羽茅与大针茅混种时,内生真菌和土壤微生物对羽茅的种间竞争力具有显著的交互作用,当接种小型微生物组分时,内生真菌显著提高了宿主植物的种间竞争力;而当接种包含大型微生物的混合微生物组分时,内生真菌对宿主种间竞争力无显著影响。方差分析表明,内生真菌和土壤微生物交互作用对羽茅种间竞争力的贡献比内生真菌和土壤微生物的贡献均大。
Many grasses are infected by systemic fungal endophytes that occur in aboveground plant tissues.Both aboveground endophytic fungi and belowground soil microbes can influence plant growth,but studies on their simultaneous effects on plant growth and competitiveness are limited.This study aims to investigate whether the role of aboveground endophytic fungi in the growth and competitive ability of the host grasses was influenced by soil microbes.In this study,we used Epichloëendophyte-infected and endophyte-free Achnatherum sibiricum as plant materials.A wet sieving method was adopted to obtain microbial inocula with different diversities(com,combined microbe fraction,high diversity;sm,small microbe fraction,low diversity).A three-factor randomized block design was used.The first factor was the endophyte infection status of A.sibiricum.The second factor was the microbial composition of the soil inocula.The third factor was the planting type.Growth and competitive characters were measured after 16 weeks.The results showed that a soil microbe inoculation was detrimental to the growth of A.sibiricum.Epichloëendophytes significantly mitigated the inhibitory effect of soil microbes on A.sibiricum planted alone.When A.sibiricum was planted with Stipa grandis,there was a significant interaction between Epichloëendophytes and soil microbes on the interspecific competition of A.sibiricum.When inoculated with small microbial community fraction,Epichloëendophytes significantly improved the interspecific competitive ability of host plants.When inoculated with combined microbial community fraction,however,Epichloëendophytes had no significant effect on host competition.The results showed that the interaction between Epichloëendophytes and soil microbes contributed more to the interspecific competitive ability than either Epichloëendophytes or soil microbes alone.
基金
supported by the National Natural Science Foundation of China(31971425)。
