Study On Salt-alkali Tolerance And Growth-promoting Effect Of Endophytic Trichoderma Of Salix Linearistioularis Roots

There are a large number of endophytic fungus in terrestrial and aquatic plants.A mutually beneficial symbiotic relationship has developed over a long period of evolution.Research has shown that plant endophytes not only have biocontrol functions to help plants resist pathogens,but also enhance the host plant resilience.Studies have shown that plant endophytes not only have biological control function,and help plants resist pathogen damage,but also enhance the stress resistance of host plants.It has important research value.In this study,the roots of Salix linearisttpularis grown in the saline alkali soils of the Songnen Plain were used as materials to isolate endophytic fungus by direct root cultivation and molecular biology methods.1.Using Salix linearisttpularis roots as experimental material,colony morphology and molecular biology were used.A total of 71 endophytic fungus were obtained after isolation by using MEA and MMN mediums.Dominant bacteria genus are Trichoderma sp.、Fusarium sp.、Penicillium sp.A total of five endophytic Trichoderma were isolated from the roots of Salix linearisttpularis,and these five Trichoderma were morphologically and molecularly identified.2.Study on the salt and alkali resistance characteristics of Trichoderma.According to the size of the colony diameter and the sporulation ability of Trichoderma on different saline-alkali concentration medium,Trichoderma with the strongest saline-alkali tolerant ability was screened out.According to the p H value of the saline-alkali soil under different vegetation,the soil filtrate was prepared.The p H value of the soil filtrate was very different from the five kinds of Trichoderma experiment.Trichoderma No.4,which is both resistant to saline and alkali and can improve the p H value of saline-alkali soil,was screened for the next experiment.3.Growth-promoting effect of Trichoderma on rice under saline-alkali conditions:(1)Trichoderma increases the germination rate and potential of rice seeds,and promotes the development of rice genn and radica.(2)After the seedlings were treated with Trichoderma,the plant height,the fresh weight,the dry weight,the root length of the aboveground and underground parts,were all significantly increased.(3)In terms of physiology and biochemistry,the contents of Malondialdehyde,superoxide dismutase,peroxidase,catalase decreased and proline increased in rice leaves after inoculation.(4)In terms of photosynthetic parameters,these indexs after inoculation were significantly improved.4.The growth-promoting effect of Trichoderma on Salix linearisttpularis: Trichoderma can increase the dry weight,fresh weight,plant height,root length,and number of leaves of the aboveground and underground parts of Salix linearisttpularis through the inoculation experiment of Trichoderma spore suspension.In summary,the endophytic Trichoderma in the root of Salix linearisttpularis is resistant to saline and alkali stress,and can reduce the p H value of saline soil at the same time.Under saline-alkali stress,Trichoderma can increase the biomass and enhance the salt-alkali tolerance of rice.