Preliminary Study On Saline-alkali Tolerance Of Endophytic Fungi From The Root Of Salix Linearistipularis

Soil salinization limits the sustainable development of agricultural economy.Salix linearistipularis,as a woody plant growing naturally in saline-alkali land,has been widely used in the study of saline-alkali land.There are a lot of endophytic fungi in the root system of Salix linearistipularis.We can explore the relationship between endophytic fungi that can be found in the root of Salix linearistipularis and saline-alkali resistance of its symbiotic plants.It is useful to further study.In this paper,we use endophytic fungi of Salix linearistipularis to isolate,identify and screen endophytic fungi with saline-alkali tolerance.Then,we analyze the relationship between the culture conditions and the growth of fungi and determin optimal conditions for culturing several salt-tolerant fungi.We nalysis of the effect of endophytic fungi on the growth and salt tolerance of Salix linearistipularis.The main findings are as follows:1.The optimal conditions for the induction and culture of endophytic fungi had been established.When we use 75%alcohol to disinfect for 10 seconds,and then use 30%H2O2 to disinfect for 30 seconds,the induction rate of endophytic fungi can reach 41.7%.The best induction medium in the process of fungi culture is PDA medium,and the induction rate can reache 50%.2?Seven species of endophytic fungi were obtained through artificial cultivation.They belong to 6 genera.These fungi are as follows:Trichoderma harizianum,Talaromyces variabilis,Nigrospora sp.,Arthrinium sp.,Penicillium expansum.Paraphaeosphaeria sp.and Talaromyces variabilis.3.Through the study of saline-alkali tolerance of endophytic fungi,we found that,the cultivable endophytic fungi of Salix linearistipularis are salt-tolerant but not alkali-tolerant.Among them,Arthrinium sp.has the strongest salt-tolerance.The salt tolerance of Talaromyces variabilis was low.Salt treatment with low concentration promotes the growth of fungi.Salt treatment with high concentration inhibits the growth of fungi.This promotion may be related to the active oxygen scavenging mechanism of mycelial cells.4.The results of the selection test of culture conditions show that:The optimum temperature for the growth of three fungi are both 25?.Nigraspora sp.and Arthrinium sp.can grow better on soluble starch and peptone medium,and Talamomyces variabilis and Trichodema harizanum can grow better on glucose and ammonium tartrate medium.The suitable pH value for the growth of Nigrospora sp.is eight.The suitable additive for the growth of Nigrospora sp.is insitol.The suitable pH value for the growth of the other three fungi is eight.The suitable additive for them are microorganism B1.5|.The results showed that four endophytic fungi both can improve the salt-tolerance of Salix linearistipularis by increasing biomass,root shoot ratio,plant height,leaf number,average root diameter and average root length of plants.The growth-promoting effect of Arthrinium sp.is the strongest,and Talaromyces variabilis is the weakest.In summary:The endophytic fungi that is Nigrospora sp.,Arthrinium sp.and Trichoderma harizianum have salt-tolerance.They can improve the growth and biomass of Salix linearistipularis.They can promote salt-tolerance of plants.