C:N stoichiometry in plant-soil interactions: effects on plant metabolism and processes in the rhizosphere

(Co)investigator from the Department: Eva Kaštovská
Funding provider: Grantová agentura České republiky
Duration: 2016 -2018

Project goals: 
The overarching aim of the project is to determine the mechanisms relating plant C:N stoichiometry to plant and microbial activities in the rhizosphere and how shifts in plant C:N ratios and related physiological changes will impact C and N cycling in soil.

Project description: 
We want to study the connection between The C:N stoichiometry of plant tissue and root-released compounds, and their effects on rhizosphere microbial activity and soil C and N sequestration. The C:N stoichiometry of root exudation was recognized as the important factor constraining microbial performance in soil. Likely, the C:N ratio of root exudation is closely related to root C:N and the C:N ratio and composition of the plant metabolome. However, neither of these relations nor their effects on soil microbial activity have been directly studied yet. We will study these relations for two plant species, conservative versus competitive, using a manipulative mesocosm experiment. We will shift plant C:N stoichiometry through foliar N application thus maintaining the same initial conditions of N availability in the soil with the only input of additional N via the plant. Then we will determine the relations between increased plant N and other plant functional traits, and soil C and N cycling using biochemical and analytical methods including stable isotope probing and plant metabolomics.