Research Of The Effect Of Dominant AM Fungi From Inula Japonica Rhizosphere On Salt-alkali Tolerance Of Trifolium Repence

AM fungi (arbusular mycorrhiza fungi) is the most important types of endomycorrhizal fungi which can symbiosis and form arbuscular mycorrhiza with more than 90% of root system of higher plants under natural conditions. AM fungi plays an important role on plants resistance improved and growth promoted. AM fungi has been applied in horticultural crops at present. The roots of Inula japonica and the soil surroundings that collected from salt-alkal glassland of songnen plain were as the material in this test. The colonization of AM fungi in the roots of Inula japonica,the infection characteristics,the AM fungal diversity and the 25S ribosomal DNA sequences analysis of predominant bacterias were carried as the experimental contents in this test. With Trifolium repens as host plants, the influences of predominant AM fungi to growth、photosynthetic and physiological of Trifolium repens under different salt and alkali mixed stress were exploration contents inthistest. The main results are as follows:1.The roots of Inula japonica from salt-alkal glassland of songnen glassland were infected and formed typical Arum arbuscular mycorrhiza. The roots of Inula japonica were all infected by AM fungi under different pH value (pH= 8.13-9.30) soil habitat,the infection rates were different obviously under different soil pH. The infection rate was 100% and vesicular abundance,arbuscular abundance reached maximum values which are 75.67% and 74.32% respectively when the soil pH value is 8.76.2.37 species belong to 8 genera of AM fungi were identified by morphological analysis in 10 soil samples collected by the roots of Inula japonica surroundings in this test.There were 21 species belong to Glomus accounted for 56.7% of the total and the Glomus is preponderant genera, G.intraradices which were separated from 8 soil samples was the most widely distributed specie, G.etunicatum which were separated from 7 soil samples took second place, G. intraradices and G.etunicatum were predominant AM fungi species in salt-alkal glassland of songnen plain. The 25S ribosomal DNA sequences analysis of predominant AM fungi species were through the method of Nested-PCR and got the received sequence number:KT826604, KT993572 by NCBI.3.Trifolium repens that inoculated different types of AM fungi under different salt and alkali mixed stress(Glomus intraradices,Glomus etunicatum,Glomus intraradices+Glomus etunicatum) was formed symbiotic relationship with AM fungi after growing for 60 days,the highest infection were concentrated on young root tips. Inoculation of AM fungi improved water status of Trifolium repens under salt and alkali mixed stress and also had a positive effection on growth and material accumulation of Trifolium repens.4.With the increase of salt and alkali mixed concentration, The inoculation of AM fungi could obviously improve net photosynthetic rate, stomatal conductance, transpiration rate, and decreased intercellular CO2 concentration.The content of soluble protein chlorophyll content of inoculated Trifolium repens were higher than unvaccinated plants significantly,In addition, the SOD, POD and CAT activity of Trifolium repens that inoculated with AM fungi were also higher than unvaccinated Trifolium repens under different salt and alkali mixed stress.5.Trifolium repens itself had certain salt-tolerance, low concentration of salt and alkali ions(salt content of soil below 0.788%) can promote its growth,but the growth of Trifolium repens was restrained under high concentration of salt and alkali ions. Glomus intraradices+Glomus etunicatum mixed AM fungi were predominant infection strain to Trifolium repens under the condition of different salt and alkali mixed stress.The aims of this study were to carry out the research about AM fungi in salt-alkali grassland of Songnen plain and then guide the inoculation of them on garden plants and economic crops in order to find out the the best combination of soil-plant-arbuscular mycorrhiza. At the same time, the research also could provide reference value to generalize the use of Innula japonica and Trifolium repens in urban landscape with a certain salt and alkali mixed concentration.