| Arbuscular mycorrhizal fungi (arbuscular mycorrhizal, AM) is a kind of symbiotic fungi which widely existing in the soil eco-system, can significantly reduce the damages to plants by strengthening the resistance under the salt adversity conditions, has received wide attention. This article has preliminary investigate the Songnen saline-alkaline grassland in southwest Zhaodong, Heilongjiang Province, analyzed the relationship of AM fungi species colonization, diversity, resources distribution, soil factor together with AM fungi. we collected and identified the advantageous variety AM fungi in experimental plot, and then we carried out to study the infection rate of AM fungi of Medicago sativa and effect of AM fungi on the Medicago sativa under aqueous sodium chloride salt stress. The results can accumulate information for the bioremediation and reconstruction of songnen saline-alkaline grassland degraded ecosystem, at the same time provided reference for Medicago sativa will be widely used certain salinity botanical garden green space. The main research achievements are as following:(1)Twenty six species in eleven families were colonized by AM fungi, among which Rosaceae plants got the highest colonization rate of 100%. Taraxacum mongolicum has got the highest colonization, diversity and distribution of resources, which has the strongest affinity with AM fungi, While Polygonum plants has the worst affinity with AM fungi, Polygonum aviculare is the most typical.(2)From twenty six species of Songnen saline-alkaline grassland in southwest Zhaodong, Heilongjiang Province, we collected 40 AM fungal species belonging to five genera,38 AM fungal species has been identified,2 AM fungal species were unascertained. There were 21 species of Glomus,52.5% of all speices; 12 species of Acaulospora,30% of all speices; 4 species of Scutellospora,10% of all speices; 2 species of Gigaspora,5% of all speices; 1 species of Pacispora boliviana. Glomus and Acaulospora were the dominant genera and Glomus intraradices and Glomus versiforme were the prevalent AM fungi.(3) There are different physical and chemical properties in rhizosphere soil of twenty six species. Taraxacum mongolicum got the highest organic matter content, total nitrogen, total phosphorus content of 24.32,1.72 and 0.37g·kg-1, while Polygonum aviculare got the lowest value of only 19.06,1.38,0.45 and g·kg-1. The organic matter contents and total nitrogen contents of soil had a significant influence on the forming of AM fungi. Meanwhile, significant positive correlations were found between organic matter content and total nitrogen content of rhizosphere soil and the mycorrhizal colonization rate, colonization intensity, vesicle abundance, arbuscule abundance, spore density and species richness of AM fungi, significant correlation with Shannon-Weiner(H). Total phosphorus content and total potassium also has certain degree positively correlation with colonization and Shannon-Weiner(H), whereas pH value and total salt content only had a certain influence on AM fungi.(4) With the enhancing level of aqueous sodium chloride salt stress(0%,0.5%,1.0%), the growing conditions of Medicago sativa is gradually weakening. Inoculating AM fungi can significantly improve Medicago sativa salt resistance, three different types of AM fungi could significantly increase the colonization rate, individual biomass and chlorophyll content of Medicago sativa. When the salinity level is 1.0%, AM fungi enhanced Medicago sativa in POD, SOD, CAT activity of antioxidant enzymes is more significant, when the salinity level is 0.5%, AM fungi promote Medicago sativa in the absorption of N, P, K is more obvious, Inoculating Glomus intraradices and Glomus versiforme mixed AM fungi work best, Glomus versiforme take second place. |
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