Evaluation of Morphological Diversity of Arbuscular Mycorrhizal Fungi in Soils Polluted with Heavy Metals (Zn and Pb) at Anguran Mining Region

The morphological diversity of arbuscular mycorrhizal fungi (AMF) at the Anguran Zn and Pb mining region (Zanjan province, Iran) were studied along a transect from the mine to 4500 m away. Within each plot, a composite sample of root and rhizospheric soil from a dominant indigenous plant was collected. The soil samples were analyzed for their physico-chemical characteristics. Spores were extracted, counted and after trap culturing, identified at species level. Isolatation frequency, spore density and relative abundance of AMF species were calculated for the soils with high, moderate and low levels of Zn and Pb as well as for non-polluted soils. A total of 10 AMF taxon were morphologically identified, which nine of them belonged to Glomus (Glomus mosseae, G. intraradices, G. versiforme, G. ambisporum,G. constrictum, G. fasciculatum, G. geosporum, G. sinosum and Glomus sp.) and one of them belonged to Acaulospora (Acaulospora sp.). Glomus was the dominant genus in all plots. Isolation frequency, spore density and relative abundance of AMF species were different in heavy metals (HMs) polluted and non-polluted sites. G. mosseae was the taxon most commonly observed in different plots, with higher spore density and relative abundance at high level of HMs pollution. G. mosseae, G. intraradices and G. versiforme were more abundant than other AMF species in the soils with moderate and low levels of Zn and Pb contents. Isolation frequency, spore density and relative abundance of G. intraradices were higher than those of other AMF in the non-polluted soils. The Shannon-Weiner index of AMF decreased from 1.55 to 0.52, but the evenness of species (distribution of individuals among the species) had not consideration variations, as the HMs contents of soils increased. The Sorenson similarity index of AM fungi and plant community between non-polluted soils with those of the other pollution levels decreased with increasing soil heavy metals contents and was higher for AM fungal populations than plant community