Research On Diversity And Function Of AM Fungi From The Rhizosphere Of Potentilla Anserine In Songnen Salt-alkali Grassland

Potentilla anserina is a perennial herb belonging to the genus Potentilla of the Rosaceae family.It is a garden cover flower with high ornamental value and one of the main pioneer species in the early stage of restoration of degraded pine and tender saline-alkali grassland.Arbuscular Mycorrhizal(AM)fungi can form a symbiotic system with 80%of plants.After the AM fungi and plants have established a symbiotic system,the plants provide them with photosynthetic products.The hyphae networks of AM fungi were used to assist host plants to extract water and nutrients,they help each other to form symbiotic organisms in various habitats such as drought,saline and alkali.AM fungi and its large mycelial network are of great significance for maintaining the fragile ecological balance in saline-alkali soil regions.Potentilla anserina has salt and alkali tolerance and can be symbiotic with AM fungi,but the AM fungi diversity in its roots has not been reported.This study intends to study the types and infection characteristics of AM fungi in the rhizosphere of Potentilla anserina in Songnen saline-alkali grassland,and to explore the effects of it on the salt tolerance of Potentilla anserina.The aim is to develop and utilize AM fungal resources in the Songnen saline-alkali grassland to obtain more AM fungal strains with strong saline-alkali tolerance,and to lay a theoretical foundation for the application.of promote the use of Potentilla anserina-AMF symbiotic organisms in the restoration of saline-alkali land and the greening of saline-alkali cities.In this study,after observing the symbiotic structure and its infection status,the species of AM fungi in the roots of Potentilla anserina were identified by morphological identification method.In order to further investigate the effects of AM fungi on the salt-tolerance physiology of Potentilla anserina,it was inoculated with Glomus etunicatum.After 90 days of culture,the plants were irrigated with different concentrations of NaCl and NaHCO3 for 10 days,and then its root infection index and leaf physiological index were measured.The test results are as follows:1.Observation and research results on AM fungi in the roots of Potentilla anserina in Songnen saline-alkali grassland showed that:The root system of Potentilla anserina can form a good symbiotic relationship with AM fungi.A-type arbuscular structure,vesicles,and root hyphae were observed in the root system of Potentilla anserina.Of the 10 alkaline saline soil plots,the infection rate of Potentilla anserina in 7 plots reached 100%.Infection intensity and arbuscular abundance reached the maximum at the highest pH of 8.39,and the lowest root infection rate was at the lowest pH of 7.60.At pH 7.70,the vesicle abundance reached a maximum of 21.94%.Compared with the sample with lower pH,the infection intensity of AM fungi was higher in the sample with higher pH.2.A total of 38 AM fungi from 8 genera were isolated from the sample by the method of morphological identification.Among them,the important values of Glomus and Acaulospora were 67.45%and 55.98%,which are the dominant genera.Archaeospora is the most common genus;Entrophospora and Scutellospora are the common genus;Claroideoglomus,Rhizophagus and Septolomus is the rare genus.The important value of G.melanosporum is 60.38%,which is the dominant AM fungal species in the rhizosphere of Potentilla anserina in Songnen saline-alkali grassland.3.After 90 days of cultivation and treatment of NaCl and NaHCO3 for 10 days of Potentilla anserina,its root was tested for infection characteristics.It was found that AM fungi had coexisted with Potentilla anserina and formed arbuscular structure,vesicle structure and hypha.The results showed that:With the increase of NaCl and NaHCO3 concentrations,the root infection rate,arbuscular abundance,vesicle abundance,and infection intensity all decreased,and all reached the lowest value at the concentration of 300mM.Except for vesicle abundance,all other indicators had significant differences(P<0.05),and the infection index under NaHCO3 stress decreased even more.Potentilla anserina has strong mycorrhizal dependency after symbiosis with AM fungi.Under NaCl and NaHCv3 stress,as the concentration increased,the mycorrhizal dependency also increased.The mycorrhizal dependency reached the highest when the concentration of NaCl was 300 mM,the grade was ?,and the other grades were all grade ?;under NaHCv3 stress,the mycorrhizal dependency reached the highest when the concentration was 225 mM,the grade was ? which was the same as the concentration of 300mM.The mycorrhizal dependency of other NaHCO3 concentrations were grade ?.4.In this test,the effects of inoculation with Glomus etunicatum on the physiological status of Potentilla anserina were determined from aspects of antioxidant enzyme system,water status,osmolytes,membrane system,and chlorophyll content.The test results showed that under NaCl and NaHCO3 stress,inoculation with Glomus etunicatum increased the activities of three antioxidant enzymes SOD,POD and CAT,increased the tissue moisture content of the leaves and reduced the water saturation deficit of the leaves;inoculation with Glomus etunicatum also increased the content of proline,soluble sugar,soluble protein and chlorophyll,and reduced the content of malondialdehyde.