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Expansion and stimulation of the rhizosphere during hydraulic redistribution

Active Dates 9/1/2022-7/31/2024
Program Area Environmental Systems Science
Project Description
Plant root systems can act as conduits for water from wet regions of soil to dry regions of soil, a phenomenon known as hydraulic redistribution (HR). HR plays a variety of ecological roles, including preventing root desiccation, increasing plant resilience to drought, and providing water to soil organisms.  This is one of the many ways that roots shape the soil environment. Another important way is through the release of sugars and other photosynthesis products into the soil, which fuels the metabolisms of soil microbes. This process is called exudation and is known to be an important control on soil microbial activity and soil health.

In this project, we propose to examine the interplay between HR and root exudation. We hypothesize that HR will increase exudation during drought conditions, acting to stimulate microbial activity and sustain soil biogeochemical processes during drought. To examine this hypothesis, we will perform an integrated suite of experiments and modeling to determine how HR modifies the quantity and quality of root exudates and how this in turn impacts microbial activity in the soil. We will quantify changes in exudate quantity and composition using state-of-the-art high-resolution mass spectrometry techniques. We will determine if HR alters spatial patterns of root exudation using mass spectrometry imaging. Further, we will track the transport and fate of exudates in the soil with isotopic imaging techniques. These experiments will inform two cutting-edge models. The first model simulates the transport and microbial uptake of exudates from the root into the soil at the scale of individual roots. The second model simulates the incorporation of these root-scale processes into a model of whole plant-soil ecophysiology, allowing us to determine how HR impacts plant performance and soil health. Results from this study will enhance our ability to predict ecosystem responses to drought and better plan for extreme climatic events.
Award Recipient(s)
  • State University of New York Buffalo (PI: Marinos, Richard)