The Diversity And Improvement Salt-Resistance Of Host's Plant Of AM Fungi In Saline Alkaline Soil Of Inner Mongolia

The diversity and distribution of AM fungi of 13 dominant plants, such as Agropyron cristatum L., Achnatherum splendens Nevski., Kalidium foliatum Moq., Phragmites australis Trin., Carex duriuscula C.A.Mey., Saliconia europaea L., Zae mays L., Salix gordejevii Chang et Skv., Oryza sativa L., Populus euphratica Oliv., Triticum aestivum L., Allium fistulosum L., Iris lactea Pall., growing in saline alkaline soil of Inner Mongolia was reported in this research. The influence of inoculating arbuscular mycorrhizal fungi on sale-resistance and rhizospheric micro-ecological environment of maize(Zea mays L.) plant were investigated. Main research results are as follows:(1)AM fungi Diversity of Inner MongoliaOut of 13 dominant species of plants growing in saline alkaline soil in Inner Mongolia, 3 genera, 26 species of AM fungi were isolated. They are G. aggregatum, G. albidum,G. ambisporum, G. claroideum, G. clarum, G. constrictum, G. coronatum, G. etunicatum, G. fasciculatum, G. geosporum, G. intraradices, G. manihotis, G. microcarpum, G. monosporum, G. mosseae, G. multiforum, G. pansihalos, G. pustulatum, G. reticulatum, G. rubiform, G. versiforme, G. sp1, Archaeospora leptoticha, Acaulospora spinosa, Acaulospora sp1, Acaulospora sp2. The Glomus is preponderant genus in the rhizosphere-soil of plants in saline alkaline soil and Glomus geosporum and Glomus versiforme were the dominant ones in the region.(2)The Distribution of AM fungiAll the 13 species of plants were susceptible to infection of AM fungi, and Zae mays and Iris lactea were the highest in AM fungal colonization rate, reaching 100%; AM fungal spore density of rhizosphere soil ranged from 29 to 182 ind·g-1 dry soil, and among the 13 species, Oryza sativa was the highest (182 ind·g-1 dry soil). Furthermore, AM fungal colonization rate of the dominant plants varied with soil types, showing an decreasing order of meadow solonchak>alkalized solonchak>salined meadow soil>alkalized meadow soil, but in terms of AM fungal spore density, alkalized meadow soil was the highest (101 ind·g-1 dry soil), followed by Alkalized solonchak, Meadow solonchak and Salined meadow soil. No significant correlation was detected between AM fungal spore density and colonization rate.(3)AM fungi improved salt-resistance of maize plant. Our result showed that salt inhibited plant growth, reduced chlorophyll concentrations and increased proline and Malondialdehyde concentration and electrolyte leakage of maize leaves, while plants inoculated with G. mosseae had significantly heiger plant height, stem diameter, shoot dry weight, root dry weight and total biomass than nonmycorrhizal plants. At the same salt level, chlorophyll concentration of mycorrhizal plants increased by 4.65%~24.31%, proline concentration, Malondialdehyde concentration and electrolyte leakage rate respectively reduced by 16.34%~50.15%,13.67 %~25.17% and 3.03 %~24.49%, relative to non-mycorrhizal plants. Meanwhile, arbuscular mycorrhizal fungi inoculation significantly increased root activity. In the absence of added salt treatment, the root activity of mycorrhizal plants increased by 70.23% relative to nonmycorrhizal plants. In presence of salt at 0.4~1.6 g·kg-1, the root activity of mycorrhizal plants increased by 12.65%~53.54% relative to nonmycorrhizal plants.(4)AM fungi improved rhizospheric micro-ecological environment of maize plantWith salt concentration increase, the quantity of bacterium, fungus and actinomyces in maize rhizosphere descended after rising first. The growth of microorganism have been stimulated in presence of 0.4 g·kg-1 NaCl or Na2SO4. When salt concentration reached 1.6 g·kg-1, the quantity of bacterium, fungus and actinomyces were significantly lower than those under non-salt stress. Under the same salt level, the bacterium and actinomyces quantity of maize rhizosphere inoculated with G. mosseae were significantly higher than non-inoculated maize rhizosphere, while fungus quantity lower than non-inoculated maize rhizosphere. With salt concentration increase, soil urea enzymatic activity and soil sugar enzymatic activity in maize rhizosphere reduced gradually. The alkaline-phosphoric acid enzymatic activity in maize rhizosphere reduced along with NaCl concentration increased, while Na2SO4 concentration has little influence on the alkaline-phosphoric acid enzymatic activity. Under the same salt level, the soil urea enzymatic activity, soil sugar enzymatic activity and soil alkaline phosphatase activity of maize rhizosphere inoculated with G. mosseae were significantly higher than non-inoculated maize rhizosphere, while soil catalase activity was little higher than non-inoculated maize rhizosphere.