Screening Of Highly-effective AM Fungi Of Pteris Vittata L.

Southwest China,especially Guangxi,is seriously polluted by As,and has a high proportion of limestone-developed soil,high p H,and strong arsenic?As?activity,which threatens food safety.Pteris vittata L has a good enrichment effect on soil As,but the remediation efficiency in moderate to light As contaminated soil needs to be improved.Arbuscular mycorrhizal fungi has great application potential in improving Pteris vittata L.to repair As-contaminated soil.However,different types of AM fungi have great effects on the growth of Pteris vittata L.and the absorption of As.At present,AM strain resources are limited,and it is urgent to select excellent strains to improve the repair efficiency of Pteris vittata L.Our research team previously investigated AM fungal resources in the root system and soil of the centipede grass in the high-As mining area and surrounding areas in Dan County,Guangxi.In order to screen out highly effective strains adapted to the soil and climate of the subtropical region,soil samples of the Pteris vittata L root area of 4 plots with different As concentrations were collected.The AM fungal spores of 4 plots isolated by wet sieve decantation were inoculated into the root system of Pteris vittata L,and a sand culture pot experiment was carried out.Add 30 mg·L^-1Na₃As O₄·12H₂O?aq?as the source of As to study the effects of AM flora and its dominant species on the growth and As absorption of centipede in 4 plots under arsenic stress.The infection rate of dominant species,P,As absorption promotion rate were evaluated,and AM efficient strains were screened out,and the strains of AM efficient strains were identified by morphological and molecular methods.The main findings are as follows:1.The AM fungal communities?S1,S2,S3,S4?from the four site can infect the Pteris vittata L root system,and the infection rates of S1 and S3 are12.80%and 10.62%,which are significantly higher than S2?7.47%?and S4?5.35%?.The spore density and spore production of S1 were significantly higher than S2,S3 and S4.Inoculated with S1,S2,S3,and S4,the fresh weight of the centipede grass roots increased by 12.3%,13.8%,9.1%,and 48.8%,respectively.the fresh weight of the shoot part of the Pteris vittata L inoculated with S2decreased by 4.0%,when inoculation with S1,S3,and S4 increased,respectively 7.7%,11.2%and 24.8%.The inoculation effect of S4 on Centipede grass is the most significant.Inoculation with S1,S2,S3,S4 increased the phosphorus?P?content in the shoot part of the Pteris vittata L by 17.5%,48.4%,6.0%,and 28.4%,respectively.Inoculation with S2 significantly increased the P content in the root of the Pteris vittata L.The content of P in the root of Centipede grass had no significant effect.Inoculation with S1,S2,S3,S4increased the As content and As accumulation of the upper centipede grassland by 73.14%,20.58%,2.20%,9.43%,and 64.77%,16.65%,5.79%,and 26.15%,respectively.Inoculation of S1,S2,S3,S4 reduced the As contentration of the Pteris vittata L root system,but promoted the transfer of As in the Pteris vittata L root system to the shoot.As transport coefficient and As effective transport coefficient increased by 57.17%,8.83%,14.13%,14.37%,and 82.04%,59.92%,50.31%,11.17%,respectively.S1 from low-concentration As-contaminated soil has the most significant effect on promoting As absorption and transport of Pteris vittata L.2.The nine dominant AM fungal strains have different effects on the growth of Pteris vittata L and the absorption of arsenic.Compared with CK,inoculation of K45,F20,K54,F65,B13 increased the fresh weight of the shoot of the Pteris vittata L,respectively increased by 18.68%,14.77%,8.68%,6.92%,1.28%;inoculation of G20,G3-3 and K50 decreased the fresh weight of the shoot of the Pteris vittata L by 6.61%,13.16%,21.76%and 20.51%,respectively.The nine dominant AM fungus all promoted the absorption of nitrogen?N?and P by the root of Pteris vittata L,and all increased the content of N and P in the upper part of the grass centipede,except K54.Inoculation with G20,K54,F20,B13,K50and F65 significantly increased the As content in the shoot of the Pteris vittata L by 36.00%,30.77%,23.70%,23.44%,20.32%and 17.10%,respectively.Inoculation of K54,B13,F20,K50,G20,F65,Ce,B1 and K45 significantly increased the accumulation of As in the shoot of the Pteris vittata L,increasing by 62.49%,47.60%,34.23%,34.07%,33.95%,31.65%,31.38%,23.97%and19.40%.In addition to K45,the inoculation advantage and bacteria increased the As absorption promotion rate of Pteris vittata L.Among them,G20,K54,K50,F20,B13 inoculated As absorption promotion rate is greater than 20%,and G20As absorption promotion rate is significantly higher than other AM fungus.In addition to K54,inoculation of dominant AM fungus increased the P absorption promotion rate of Pteris vittata L,among which K50,B13,G3-3,F20,G20 had a P absorption promotion rate higher than 20%.3.Combining the infection rate and the absorption promotion rate of P and As,F20 and G20 are high-efficiency AM fungi of Pteris vittata L.The infection rates of F20 and G20 were 19.56%and 17.14%,which were significantly higher than other other dominant AM fungus.The promotion rate of P and As absorption of F20 and G20 were significantly higher than that of Ce.Compared with CK and Ce,inoculation with G20 and F20 significantly increased the As content in the shoot of the Pteris vittata L by 36.00%,23.70%and 31.09%,19.24%,respectively.Compared with Ce,the accumulation of As in the shoot of F20 and G20 Pteris vittata L increased by 2.16%and 1.95%,respectively.G20 has the highest arsenic content and the most significant Mycorrhizal As effect.The absorption promotion rate of As and As effective transport coefficient of F20 are greater than CK and Ce,which effectively promotes the migration of As in Pteris vittata L.4.Analysis of the 18S r DNA AML1-AML2 region sequence shows that F20has high sequence homology with various species of Funneliformis,and can cluster into a cluster with Funneliformis fragilistratum with a homology of up to98%.G20 has high sequence homology with various species of Claroideoglomus,and can be clustered with Claroideoglomus etunicatum with a homology of up to 99%.Comprehensive morphological characteristics,F20 was identified as Funneliformis fragilistratum,G20 was identified as Claroideoglomus etunicatum.