Dynamics of arbuscular mycorrhizal fungi associated with desert ephemeral plants in Gurbantunggut Desert

Previous studies documented that most desert plants can be colonized by arbuscular mycorrhizal （AM） fungi, however, little is known about how the dynamics of AM fungi are related to ephemerals in desert ecosystems. The dynamics of AM fungi with desert ephemerals were examined to determine the effects of host plant life stages on the development of AM fungi. Mean colonization of ephemeral annual plants was 45% lower than that of ephemeral perennial plants. The colonizations were much higher in the early part of the growing season than in later parts, peaking at flowering times. The phenology of AM fungi in root systems varied among different ephem- erals. The density of AM fungal spores increased with the development of ephemeral annual plants, reached its maximum at flowering times, and then plateaued about 20 days after the aboveground senescence. A significant positive correlation was found between AM fungi spore density and biomass of ephemeral annual plants. The life cycles of AM fungi associated with desert ephemerals were very shod, being about 60-70 days. Soil temperature and water content had no direct influence on the development of AM fungal spores. We concluded that the development of AM fungi was in response to desert ephemeral phenology and life history strategy.

Isolation and Identification of Arbuscular Mycorrhizal Fungi from Agricultural Fields of Vietnam

The rising claim for more environmental friendly and healthy agriculture is a strong incentive to find alternative strategies to replace the use of mineral fertilizer and pesticide. Arbuscular mycorrhizal fungi (AMF), a main component of soil microbiota, represent a promising tool as providers of key ecological services. The present work represented one of the first attempts to study, under a morphological and molecular point of view, the AMF communities associated to some strategic crops in Vietnam. The findings about the AMF morphotypes dominant in different crop systems could be a starting point for the development of well performing and adapted inocula suitable for the application in field.

A Preliminary Survey of Arbuscular Mycorrhizal Fungi Associated with Marsh Plants in Lhalu Wetland,Suburban Lhasa,South Tibet

A survey was made of the spore community of arbuscular mycorrhizal fungi (AMF) and root colonization by AMF in 16 plant species in Lhalu wetland on the outskirts of Lhasa city in Tibet. It was found that 13 of the 16 plant species investigated (81. 5% ) formed arbuscular mycorrhizal structures and dark septate endophytic fungi colonized the roots of most species. Total AMF colonization ranged from 0 to 82. 6% in dicots and 0 to 54. 5% in monocots. Both total AMF and arbuscular colonization were greater in dicots than that in monocots. A total of 48 taxa representing 7 genera of AMF were isolated and identified. Of these,9 species belonged to Acaulospora,2 to Appendicispora,34 to Glomus,and 1 each to Pacispora,Paraglomus and Scutellospora. Spores of Glomus aggregatum,G. deserticola and G. etunicatum were most common and abundant in the spore survey. Spores of 8 to 26 AMF species were isolated from the rhizosphere soil of individual plant species. Spore densities in soil associated with the 16 plant species ranged from 20 to 475 per 20 g soil,with an average of (92. 3 ± 14. 6). Species richness of AMF ranged from 6 to 12. 7. There were no significant differences between dicots and monocots in AMF spore density or species richness. Future work directed towards under- standing the response of the wetland plants to AMF may provide some insight into the role that these fungal symbionts may play in influencing plant diversity in this important urban wetland.

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.

Exclosures restored the density and root colonization of arbuscular mycorrhizal fungi in Tigray, Northern Ethiopia

Introduction:Exclusion of grazing animals and tree plantations were among the methods used for the restoration of degraded lands in tropical semiarid areas.Exclosures can foster secondary forest succession by improving soil conditions and modifying microclimate for understory growth.This paper compared the arbuscular mycorrhizal fungi(AMF)spore density,root colonization of woody plants and soil chemical properties under exclosure with increasing age,and grazing land at different slope positions.Methods:The study was conducted in northern Ethiopia from 12 exclosure sites paired each with adjacent grazing land in total from 24 sites with four treatments replicated three times.In the entire study,216 plots were examined of which 108 were in exclosures and 108 in communal grazing lands.There were four age classes and three slope positions in each of the land uses.Composite soil and root samples were collected using nested plots measuring 100m2 from four sides of 1763 plants for spore enumeration and root colonization.Soils for chemical properties were collected from the four corners and center of 5 m×5 m plots.Results:All the 61 woody plant species that belong to 41 families were colonized by AMF.Spore density and root colonization were significantly higher in exclosures as compared to grazing land and increased with increasing ages of exclosures.Foot slope had significantly higher spore density and root colonization than middle and upper slopes.Soil chemical properties were significantly higher in the exclosure,oldest age of exclosure,and foot slope position(except P).AMF spore density and root colonization were significantly positively correlated with soil chemical properties.Conclusions:Exclosures are helpful to restore the AMF spore density and root colonization of woody species and soil fertility.

Identification of Arbuscular mycorrhizal multiplicity in the saline-sodic soils

This study focused on the Arbuscular mycorrhizal(AM)fungal diversity in the saline-sodic soils based on native spore density and most probable number(MPN)assay.Identification through spore morphology showed existence of five genera in the various crop rhizospheres.The physico-chemical analysis of the native soils revealed that they were saline-sodic with pH ranging from(8.7±0.5)to(9.5±0.6)and habituated five different genera of AM fungi including Glomus,Scutellospora,Acaulospora,Sclerocystis and Gigaspora.Each location revealed presence of varied species of AM fungus namely Acaulospora and Glomus in rhizosphere of maize;Scutellospora and Glomus in tulsi;four isolates of Glomus in onion;Glomus and Sclerocystis in guava;three isolates of Glomus in rice;Glomus in neem and Gigaspora and Glomus in bamboo.The molecular identification through nested PCR analysis showed amplification of 600 bp size in SSU rDNA gene in samples A and C(predominated by Acaulospora and Glomus mosseae respectively).