Research On Arbuscular Mycorrhizal Fungi Diversity In The Abandoned Mine Sites Of Ganluo Lead-zinc Mining Area

Abandoned mine sites not only encroach and/or damage a large amount of land resources,but also bring a series of environmental concernings such as heavy metal pollution and geological harzerd,and affect the health of local residents surrounding mining sites.However,ecological restoration and remediation of post-mining sites are extremely difficult due to its environmental stress conditions.Therefor,the best ways of accelerating remediation for abandoned mine land,and of realizing sustainable development of regional eco-economy,are to find a low-cost and environmental friendly ecological rehabilitation model.Arbuscular mycorrhiza fungi(AMF)are a mutualistic symbiosis between fungi and plant roots,which are ubiquitous in almost all habitats in nature.It forms an important constituent of soil-plant system that can affect plant community structure,soil stability and conservation through its physical and biological effects.Thus,screening AMF from stress environment and researching their application conditions,are important methods to achieve ecological restoration of abandoned mine sites.In this study,soil and plant samples were collected from the abandoned mine sites produced different mining periods in lead-zinc mining area of Ganluo.Those samples were used to isolate and identify of AMF species,and to observe the features of mycorrhizal infection,and to analyze soil properties influnec on AMF spores.The purpose of the study is to screen dominant AMF species suitable for ecological restoration,and to provide scientific basis for ecological restoration of abandoned mine sites.Main results are as follows:(1)In both Chipu and Muguzu mining areas,total 7 genera 16 species of AMF species from rhizosphere soils were isolated and identified,of which 7 species of Glomus,3species of Funneliformis,and 2 species of Acaulospora,while Claroideoglomus,Rhizophagus,Septoglomus,Scutellospora and Claroideoglomus was all noly 1 species.It indicates a relatively low diversity of AMF species.(2)The spores number of AMF in rhizosphere soil of the lead-zinic mining areawas quite small,which range from 9 to 149/100 g(soil),and the average spore density was only 54 ± 5/100 g(soil).The AMF spore number in soils of Muguzu mining area was significantly higher than that of Chipu mining area(p < 0.001).(3)The vegetation in abandoned mine sites of lead-zinc mine area were very sparse.Main plant has only Digitaria sanguinalis L.Scop,Imperata cylindrical,Acroptilon repens L.,Bidens pilosa L.,Conyza canadensis L.,Tridax procumbens L.,Rumex hastatus,Pteris cretica L.Apart from Rumex hastatus,the rest were funded to be infected with AMF,of which Digitaria sanguinalis had a higher infection rate of66.12%,followed by Pteris cretica of 64.25%,Digitaria sanguinalis(L.)of 58.75%,Conyza canadensis of 57.76% and Bidens pilosa of 43.17%.(4)The soils in the abandoned mine sites were extremely contaminated by heavy metals lead and zinic.Lead and zinic average content in soils were 26172.44 ±3941.22 mg/kg and 22936.84 ± 2653.77 mg/kg for Chipu mining area,respectively,and were 35558.26±6249.76 mg/kg and 20728.72 ± 3439.53 mg/kg for Muguzu mining area respectively.There was no significant difference in Pb and Zn content between two mining areas(p > 0.192).(5)The soils in the mining area were very poor.The content ranges of soil organic matter,and total nitrogen,phosphorus and potassium were 0.06 ~ 0.56%,8.26~188.41 mg/kg,154.86 ~1506.14 mg/kg and 28.50 ~ 501.00 mg/kg,respectively.There were not significantly differences in organic matter,in total nitrogen and phosphorus bewteen two mining area soils were not significantly different(p ? 0.087),except total potassium.The pH values in soils ranged from weakly acidic to weakly alkaline.(6)Some properties of soils in mining area influenced significantly on number of AMF species.The effects of lead and zinic contents in soils on the number of AMF spores showed a markedly negative correlation(p <-0.527,n =50),while soil pH manifest ed a significantly positive correlation(r = 0.273,n = 50).The rest of soil properties did not significant effect on the number of AMF spores.Main conclusions as follows:AMF in the two lead-zinc mining area soils of Ganluo shwed a relatively large genera diversity,and a small species richness and diversity.Glomus was dominant genera of AMF,which is preferred selection for screening AMF of resistant(resistant)heavy metal pollution.Imperata cylindrical and Tridax procumbens showed to be a higher rate infectedby AMF,and had a higher infection rate.The mutualistic symbiosis between fungi and plant roots are conductive to enhance adaptability and to increase in successful rate of plants colonization under stress environment.Therefor,Imperata cylindrical and Tridax procumbens should be preferential recommended for ecological restoration in abandoned mine lands.The soils in the abandoned minesites showed to be extremely contaminated by lead and zinic,which could be one of important factors that impact on plant colonization,carbon and nitrogen accumulation in soil and AMF species richness.Extreme heavy metal pollution and poor soil conditions could become restricted factors for natural vegetation restoration.