Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory.
Bottom Line: AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the circadian-driven photosynthetic oscillations observed in plants.Growth and dieback events often occurred simultaneously and were tightly coupled with soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment.Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying soil carbon sequestration, nutrient cycling and host plant success.
Affiliation: Department of Environmental Earth System Science, Stanford University, Stanford, CA, 94305, USA; Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, 94305, USA; Center for Conservation Biology, University of California, Riverside, CA, 92521, USA.Show MeSH
Mentions: Lastly, to showcase the rather complex set of factors influencing the sub-daily dynamics of AM fungal hyphae, we characterized the properties of the mycelium environment that may exogenously influence (or entrain endogenous circadian oscillators that control) the observed diurnal temporal variation in the production of AM fungal hyphae. We created a conceptual model, informed from this and previous studies (Liu & Bell-Pederson, 2006; Smith & Read, 2008), to describe these potential diurnal-scale controls of AM fungal hyphae (Fig.6). In this model, factors impacting on the productivity of AM fungal hyphae include fungivory, photosynthate input, soil nutrient availability, Ts and SWC. Changes in fine root density and porosity impact on AM fungi at coarser periods of time, but are relatively constant over this time scale, and thus are not dynamic model factors. The size of the bulge of each potential factor corresponds to its impact on the hyphal network. These impacts will probably vary across time and space in the mycorrhizosphere, and can be facilitating (i.e. promoting elongation; upward slope) or limiting (i.e. promoting dieback; downward slope).
Affiliation: Department of Environmental Earth System Science, Stanford University, Stanford, CA, 94305, USA; Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, 94305, USA; Center for Conservation Biology, University of California, Riverside, CA, 92521, USA.