What is the role of nutrient availability in the autotrophic respiratory cost?

The terrestrial biosphere mitigates climate change through carbon sequestration into plant biomass and soil. The way in which plants use the carbon assimilated during photosynthesis, ultimately determines the carbon sink strength of the ecosystem. However, the mechanisms driving variation in carbon allocation are still poorly understood. Previous research has reported large variation in the fraction of photosynthates used for autotrophic respiration, but the underlying mechanisms are still uncertain. Evidence is growing, however, that nutrient availability plays a key role. The main aim of the research proposal is to determine the impact of soil nutrition on the fraction of photosynthates used in autotrophic plant respiration. This will be studied via both chamber and leaf scale measurements in an experimental setup where GPP is measured and also NPP is being assessed completely. Given that observations in a mesocosm experiment require testing in more realistic conditions, I will also study autotrophic respiration in an ongoing nutrient manipulation field experiment. Further, I will study whether the process of nutrient retranslocation and light-induced inhibition of plant respiration depend strongly enough on nutrient availability such that they can explain additional variation in the autotrophic respiratory cost. If successful, this project will provide important benchmarking datasets to the modelling community that will allow further testing of the observed mechanisms.

Keywords:CARBON SEQUESTRATION

Disciplines:Plant biology

Project type:Collaboration project