Project Details
Projekt
SP06: Tracing regulation of root water uptake depth and (evapo)-transpiration in response to plant-plant interaction of European beech and small-leaved lime
Subject Area
Ecology and Biodiversity of Plants and Ecosystems
Term
since 2026
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 538902328
Plants have developed a plethora of adaptation mechanism to abiotic stress factors, such as drought or heat. However, we are still lacking important information about belowground mechanisms, such as dynamics in root water uptake, contributing and shaping the stress response of plants. In detail, it is unclear how different rooting and root water uptake depths (i.e. belowground water access) shape the relationship of transpiration, soil and leaf water potential (i.e. the E(Ψleaf - Ψsoil) surface). Furthermore, it remains elusive if interactions of species of different isohydricity and different soil types impact root water uptake dynamics, and thus, potentially influence E(Ψleaf - Ψsoil). To illuminate belowground processes, tracers, such as water stable isotopes, provide an ideal, minimal-invasive tool. With the recent advancements in continuous measurement systems, data on belowground isotope dynamics can be provided on a (sub-)daily basis, which significantly enhances our insights into the plasticity of root water uptake and its impact on E(Ψleaf - Ψsoil). With this project, we will investigate root water uptake dynamics under drought in two species of different isohydricity (Fagus sylvatica and Tilia cordata) in a controlled mesocosm experiment applying intra- and interspecific interaction treatments in two different soil types with different soil water holding capacity and physical properties. This mesocosm experiment will serve as central experimental platform for the research unit, with all partners contributing and profiting from the experimental set-up. In WP1, we will develop an automated switching unit for continuous measurements of gas exchange and in-situ water stable isotopes in transpiration and soil water, complemented by a series of eco-physiological and edaphic measurements. In WP2, saplings of both species will be planted in intra- and interspecific interaction design in 18 self-built weighing lysimeters and subjected to a severe drought treatment, closely tracking changes in root water uptake and E(Ψleaf - Ψsoil) in response to the interaction type. In a second experiment (WP3), mixtures of both species will be planted in two different soil types (sandy vs. loamy) and subjected to the same drought treatment as in WP2, to elucidate the role of soil type for root water uptake dynamics during dry-down. All experiments, will be conducted in close collaboration with all partners, by joint harvest of root and leaf material for further analysis and data for model input, evaluation and validation. In WP4, root water uptake depths of saplings in the mesocosm experiments will be compared to data obtained from mature trees under natural conditions. Finally, WP5 will lay a special focus on data analysis and integrating the effect of plant-plant interactions and soil type under drought on E(Ψleaf - Ψsoil).
DFG Programme
Research Units
Subproject of
FOR 5820:
Soil-plant hydraulics impacting transpiration and plant growth in response to drought [SOPHY]
Major Instrumentation
Cavity Ring-down Spectrometer
Instrumentation Group
1520 Meßgeräte für Gase (O2, CO2)
