Title

Forest Canopy Precipitation Partitioning: An Important Plant Trait Influencing the Spatial Structure of the Symbiotic Soil Microbial Community

Document Type

Contribution to Book

Publication Date

2015

Publication Title

Plant Microbe Interactions, Advances in Botanical Research

DOI

10.1016/bs.abr.2015.09.005

Abstract

Diversity and structure of the symbiotic soil microbial community significantly influences essential soil ecosystem services including nutrient cycling, C-mineralization and stabilization/formation of soil structure. The overall structure and function of the symbiotic microbial community can also impact trees' ability to acquire nutrients, potentially influencing its overall fitness. Interestingly, factors affecting below-ground signalling pathways between tree hosts and their symbiotic microbes (e.g. soil moisture and chemistry) can be altered by the tree's canopy structure partitioning precipitation. In fact, canopy precipitation partitioning produces persistent patterns in the receipt of meteoric water (and the solutes it carries) to soils via two pathways: throughfall (drips from canopy surfaces) and stemflow (the funnelling of droplets to an infiltration area around the trunk). If these above-ground, tree-directed mechanisms (throughfall and stemflow) altered edaphic conditions in the active zone surrounding the roots, it may be possible for canopy-derived hydrologic fluxes to influence host–symbiont signalling communication. In this chapter, we discuss and evaluate past research that indicates canopy precipitation partitioning may alter how microbial symbionts (specifically N-fixing bacteria and mycorrhizal fungi) interact with tree roots by changing soil characteristics (pH, micro–macronutrient status and concentration of allelopathic compounds). The potential for throughfall and stemflow to influence tree-symbiotic microbe communication has not been previously explored, but past literature indicate it could significantly alter the profile, and perhaps even the function, of root microbial symbiont communities. Our literature synthesis and evaluation concludes with suggested directions for future efforts to evaluate the existence (and extent of biogeochemical implications) of this process.