Effects of Inoculation with Indigenous and Exogenous Arbuscular Mycorrhizal Fungi on Drought Resistance of Pyrus betulaefolia and Its Adaptation Mechanism
[Objective]Arbuscular mycorrhizal(AM)fungi play a significant role in enhancing plant growth and improving resistance to environmental stress.The aim of this study was to screen AM fungi that can withstand drought stress in pear seedlings,so as to establish a theoretical foundation and technical approach for pear mycorrhizal cultivation.[Method]In this study,a pot experiment and high-throughput sequencing technology were employed to investigate the effects of single and mixed inoculation with indigenous AM fungi,including Claroideoglomus lamellosum(Cl),the exogenous fungus Funneliformis mosseae(Fm),Rhizophagus intraradices(Ri),and Acaulospora mellea(Am),on the growth of Pyrus betulaefolia seedlings under normal and drought conditions.The changes in the AM fungal community in the roots and rhizosphere soil of P.betulaefolia seedlings were analyzed under mixed inoculation(Mix)after 0,3,and 6 weeks of drought treatment.[Result]Under normal and drought conditions,the single inoculation with Cl,Ri,and Mix significantly increased the plant height,stem diameter,leaf area,and relative water content of the leaves of pear seedlings,resulting in a dry weight increase of 35.26％to 52.20％.Additionally,the uptake of phosphorus,potassium,calcium,and magnesium in the aboveground part of the seedlings was enhanced,especially phosphorus uptake,with a mycorrhizal phosphorus uptake effect of up to 1.0.The exogenous fungus Am showed less effectiveness,while Fm inhibited the growth of P.betulaefolia seedlings under normal water supply conditions.Regression analysis indicated that the growth and element absorption effects of mycorrhizal fungi increased with the degree of infection.Under drought stress,AM fungal inoculation significantly reduced the MDA(malondialdehyde)content in the leaves of P.betulaefolia seedlings and increased the activity of antioxidant enzymes and the content of proline to varying degrees.Sequencing results demonstrated that the structure of the AM fungal community in the roots and rhizosphere soil of P.betulaefolia seedlings changed significantly under drought stress compared with normal water conditions.The exogenous fungus Ri dominated the community,followed by Cl and Am,while Fm was the least abundant.The abundance of Ri in the roots significantly increased with the degree of drought stress.[Conclusion]In conclusion,the different AM fungi had varying effects on the growth of P.betulaefolia seedlings,with the indigenous strain Cl and the exogenous strain Ri showing strong growth-promoting effect and drought resistance.The increase in Ri abundance in the AM fungal community was an important adaptation mechanism for P.betulaefolia seedlings to withstand drought stress.
万方数据
维普
