Arbuscular mycorrhizal fungi in degraded typical steppe of inner Mongolia

Abstract

Arbuscular mycorrhizal (AM) fungi may have some potential use in the restoration of degraded grassland through beneficial effects on plant growth and soil quality. A field investigation was conducted in three grassland sites of typical steppe in Inner Mongolia. The three plant communities, one of which was undegraded, one moderately degraded and the third severely degraded, were studied by collecting soil samples and samples of four plant species that occurred in all three sites. The percentage of root length colonized by AM fungi was estimated and the species composition and diversity of AM fungus spores recovered from the soil were determined using spore morphological characteristics. Although differences between the sites may have been due partly to other factors, it is likely that the degree of degradation was an important factor. No decline was found in the AM colonization of the roots of the indicator plant species in the moderately or severely degraded plant communities, and two plant species showed higher colonization status in the two degraded areas. Glomus geosporum and Scutellospora calospora were the dominant AM fungi in the undegraded steppe, while G. geosporum and Glomus aggregatum dominated the two degraded sites which also had low spore densities, species richness and diversity indices. However, different AM species showed different distributions among the three plant communities and the results indicate that both biotic and abiotic factors were important in determining the AMF communities, with biotic factors possibly the more important.

The relationship between the diversity of arbuscular mycorrhizal fungi and grazing in a meadow steppe

“…Mycorrhizal species probably remain at the same root colonization levels in spite of changes in AMF community composition. Indeed, Tian et al (2009) reported that the AMF root colonization of four indicator plants did not decline in the grazed area, while the AMF species composition changed substantially with increasing grazing pressure in a typical steppe of Inner Mongolia. There are previous reports of Fig.…”

“…The composition and abundance of AMF spore species varied among sites with different grazing pressures. Glomus was the dominant genus in the Reserve and grazed sites, as has been found in other arid and semiarid areas (Su and Guo 2007;Tian et al 2009 The characters of the AMF community differed among the sites with different grazing pressures (Table 1). There was higher spore density, AMF species richness and root colonization in the lightly and moderately grazed sites than in the other heavily grazed sites and the Reserve.…”

“…In various grazing ecosystems, shifts in AMF spore species and abundance were found to be related to abiotic factors such as soil moisture, nitrogen availability and soil carbon, which influenced the growth of the dominant and subdominant species under different grazing intensities (Mendoza et al 2011;Murray et al 2010). In a semiarid grassland of Inner Mongolia, the species distribution of AMF spores was influenced by soil pH (Tian et al 2009), while in winter rainfall areas of western South Africa, mycorrhizal colonization in grasses was significantly correlated with pH (Uhlmann et al 2004). Moreover, electric conductivity had weak or negative effects on the spore numbers (Mohammad et al 2003;Uhlmann et al 2004).…”

“…Grazing can reduce the abundance of AMF spores and community diversity (Eom et al 2001), particularly under over-grazing condition (Su and Guo 2007;Tian et al 2009). In various grazing ecosystems, shifts in AMF spore species and abundance were found to be related to abiotic factors such as soil moisture, nitrogen availability and soil carbon, which influenced the growth of the dominant and subdominant species under different grazing intensities (Mendoza et al 2011;Murray et al 2010).…”

Arbuscular mycorrhizal fungi associated with citrus orchards under different types of soil management, southern China

“…The P Olsen , AN and AK were positively correlated with the second axis, but the P Olsen had the higher degree of correlation with AMF distribution. Tian et al (2009) also reported that pH, C ox and P Olsen had severe influences on the distribution of AMF community. The results indicated that the soil environment modification caused by different SM practices should be a major factor impacting the AMF spore communities in citrus orchards.…”