Effects of Different Arbuscular Mycorrhizal Fungi on Physiology of Viola prionantha under Salt Stress

Arbuscular mycorrhizal(AM)fungi distribute widely in natural habits and play a variety of ecological functions.In order to test the physiological response to salt stress mediated by different AM fungi,Viola prionantha was selected as the host,the dominant AM fungus in the rhizosphere of V.philippica growing in Songnen saline-alkali grassland,Rhizophagus irregularis,and their mixtures were used as inoculants,and NaCl stress was applied after the roots were colonized.The results showed that V.philippica could be colonized by AM fungi in the field and the colonization rate ranged from 73.33%to 96.67%,and Claroideoglomus etunicatum was identified as the dominant AM fungi species in the rhizosphere of V.philippica by morphology combined with sequencing for AM fungal AML1/AML2 target.Inoculation with both the species resulted in the formation of mycorrhizal symbiosis(the colonization rate was more than 70%)and AM fungi significantly enhanced plants’tolerance to salt stress of varying magnitude.Higher activity of antioxidant enzymes and augmented levels of proline and other osmoregulators were observed in AM plants.The content of MDA in CK was higher than that in the inoculations with the stress of 100,200,and 250 mM.All indices except soluble protein content and MDA content were significantly correlated with AM fungal colonization indices.The analysis for different AM fungal effects showed that the mixtures and R.irregularis worked even better than C.etunicatum.These results will provide theoretical support for the exploration and screening of salt-tolerant AM fungi species and also for the application of AM-ornamental plants in saline-alkali urban greening.

Colonization Characteristics and Diversity of Arbuscular Mycorrhizal Fungi in the Rhizosphere of Iris lactea in Songnen Saline-alkaline Grassland

To understand arbuscular mycorrhizal(AM)fungi resources and develop AM fungal species in ornamental plants with saline-alkaline tolerances,Iris lactea,which grows in the Songnen saline-alkaline grassland with a high ornamental value,was selected as the experimental material,and the colonization characteristics of its roots and the AM fungal diversity in its rhizosphere were explored.The results of the observations and calculations of mycorrhizae from ten different samples showed that AM fungi colonized the roots of I.lactea and formed Arum-type mycorrhizal structures.There was a significant correlation between soil spore density and pH value,while the colonization rate showed a fluctuating trend with increasing pH values.The observed colonization intensities were of Levels II(1%–10%)or III(11%–50%),and the vesicle abundances were of grades A2 or A3 among different sites.AM fungi produced a large number of mycelia and vesicles in the roots of I.lactea after colonization.Thirty-seven species belonging to 15 genera of AM fungi were isolated from the rhizosphere of I.lactea and identified by morphological identification.Funneliformis and Glomus were the dominant genera,accounting for 21.79%and 20.85%of the total number,respectively.F.mosseae and Rhizophagus intraradices were isolated in all samples with importance values of 58.62 and 51.19,respectively.These results are expected to provide a theoretical basis for the analysis of the salt tolerance mechanism of I.lactea and for the discovery,exploration and further screening of AM fungal resources with salinity tolerances in saline-alkaline soils.

Isolation and species diversity of arbuscular mycorrhizal fungi in the rhizosphere of Puccinellia tenuiflora of Songnen saline-alkaline grassland,China

Salinization has led to the deterioration of the ecological environment,affected the growth of plants,and hindered the development of agriculture and forestry.Arbuscular mycorrhizal(AM)fungi,as important soil microorganisms,play significant physiological and ecological roles in promoting plant nutrient absorption and improving soil structure.Puccinellia tenuiflora(Turcz.)Scribn.et Merr.in Songnen saline-alkaline grassland was selected as the research object to observe AM fungal colonization of the roots and explore the species and diversity of AM fungi in symbiotic association with P.tenuiflora.This study showed that AM fungi colonized in P.tenuiflora roots and formed a typical Arum-type mycorrhizal structure.A significant correlation was observed between vesicular abundance and the colonization intensity of mycorrhiza.Isolation and identification revealed 40 species of AM fungi in the rhizosphere of P.tenuiflora,belonging to 14 genera,of which two species could not be identified.The richness of the genus Glomus was the highest,accounting for 30%of the total species.Funneliformis mosseae and Rhizophagus intraradices were isolated from all the samples and were the species with the widest distribution in the rhizosphere of P.tenuiflora.Correlation analysis showed that pH only had a significant impact on the distribution of a few species,such as Glomus pustulatum,Diversispora spurca,Glomus aggregatum,Rhizophagus clarum,and Acaulospora foveata.The present study provides a theoretical basis for further exploring the resources of AM fungi in saline-alkaline soil.