Research Of Deversity And Function Of AM Fungi From Puccinellia Tenuiflora Rhizosphere In Songnen Alkaline Grassland

AM Arbuscular mycorrhizal fungi is the most widely distributed,the most common type of soil microorganisms,form a mutually beneficial symbiotic symbiosis-mycorrhizal structure with more than 90% of the plant.Under stress conditions,AM fungi promote plant uptake of mineral nutrients,improve the osmotic adjustment ability of plants,and promote plant absorption of water,the change of plant physiological metabolism,thereby reducing stress damage to the plant,which has been concerned by the vast number of environmental workers in environmental remediation.Puccinellia Tenuiflora is a kind of high quality forage grass which has a strong ability to salt stress,the roots of P.tenuiflora and the soil surroundings that collected from Zhaodong city in salt-alkal glassland of songnen plain were as the material in this thesis.the diversity and infection characteristics of AM fungi in the rhizosphere of P.tenuiflora was investigated preliminarily,the dominants AM fungi in the rhizosphere of P.tenuiflora were Isolated and identified by the method of combination of morphology and molecular biology,and on the basis,the effects of these two dominant AM fungi on the salt and alkali resistance of star grass were studied by inoculation test.Aimed at screening salt tolerance of AM fungi,and the use of mycorrhizal technology to further improve the salt tolerance of P.tenuiflora,provide an important theoretical basis to promote the application of P.tenuiflora in Songnen grassland in restoration and landscaping in saline areas.The results are as follows:The test collected 9 copies roots and rhizosphere soil of P.tenuiflora on July 2015 in the southwest of Heilongjiang Province,Zhaodong city in Songnen alkaline grassland.The infection rate were 80% and 40%,the infection density was 15.60% and 19.20%,when the soil pH value was the lowest value of 8.35 and the highest value of 9.81.When the soil pH value was 9.72,the infection rate reached the maximum value of 93.33%,the infection density reached 30%.When the soil pH was 9.50,the vesicle abundance and infection density reached the maximum value respectively was 13.31% and 30.87%,the vesicle abundance and infection density reached the minimum value were respectively 0.05% and 4.30%,when the soil pH was9.59.40 species belong to 11 genera of AM fungi were identified by morphological analysis,the Glomus is preponderant genera,which were identified 14 species accounted for 35% of the total.There was 1 specie of Scutellospora?Pacispora?Diversispora?Claroideoglomus and Racocetra,accounted for 2.5% of the total.Funneliformis mosseae and Rhizophagus intraradices is the dominant species identified,important values were 61.53% and 64.58%.F.mosseae ? R.intraradices ? Claroideoglomus etunicatum and G.sp 1 were isolated and identified by the method of combination of morphology and molecular biology.Sequencingresults obtained in NCBI serial reception numbers respectively are KU376499,KT881238,KU144882 and KT952460.P.tenuiflora that inoculated by Funneliformis mosseae and Rhizophagus intraradices was formed symbiotic relationship with AM fungi after growing for 80 days,and the infection was relatively high,FM and RI infection rate were 80.86% and 85.91%.Then P.Tenuiflora were treated by different concentration of NaCl and NaHCO3 for 10 days.The results showed that under different concentrations of saline alkali stress,P.Tenuiflora all had higher mycorrhizal dependence on AM fungi,especially RI,the MD value was as high as 300.25% and the infection grade reached grade III,when the salt concentration reached 400mmol/L.The low concentration of saline alkali treatment promoted growth of P.tenuiflora because of its own saline alkali characteristics,With the increase of NaCl or NaHCO3 stress concentration,the growth of P.tenuiflora was weakened,but the inoculation with AM fungi significantly improved the ability of saline alkali tolerance and reduced the content of proline and MDA.And reduce the relative conductivity,to maintain stable cell membrane permeability,increase soluble protein content and increase absorption capacity of N,P,K.No matter the control group or the NaCl or the NaHCO3 processing group,urease in rhizosphere soil of plants inoculated,invertase and hydrogen peroxide activity are higher than the uninoculated plants at the same level.The improvement function is most significant when salt or alkali concentration is 200mM(p<0.05).