511 research outputs found
Changes of AM Fungal Abundance along Environmental Gradients in the Arid and Semi-Arid Grasslands of Northern China
Arbuscular mycorrhizal (AM) fungi are ubiquitous symbionts of higher plants in
terrestrial ecosystems, while the occurrence of the AM symbiosis is influenced
by a complex set of abiotic and biotic factors. To reveal the regional
distribution pattern of AM fungi as driven by multiple environmental factors,
and to understand the ecological importance of AM fungi in natural ecosystems,
we conducted a field investigation on AM fungal abundance along environmental
gradients in the arid and semi-arid grasslands of northern China. In addition
to plant parameters recorded in situ, soil samples were collected, and soil
chemo-physical and biological parameters were measured in the lab. Statistical
analyses were performed to reveal the relative contribution of climatic,
edaphic and vegetation factors to AM fungal abundance, especially for
extraradical hyphal length density (HLD) in the soil. The results indicated
that HLD were positively correlated with mean annual temperature (MAT), soil
clay content and soil pH, but negatively correlated with both soil organic
carbon (SOC) and soil available N. The multiple regressions and structural
equation model showed that MAT was the key positive contributor and soil
fertility was the key negative contributor to HLD. Furthermore, both the
intraradical AM colonization (IMC) and relative abundance of AM fungi, which
was quantified by real-time PCR assay, tended to decrease along the increasing
SOC content. With regard to the obvious negative correlation between MAT and
SOC in the research area, the positive correlation between MAT and HLD implied
that AM fungi could potentially mitigate soil carbon losses especially in
infertile soils under global warming. However, direct evidence from long-term
experiments is still expected to support the AM fungal contribution to soil
carbon pools
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