Biology subjects

Schuler, P.

Publications and source records attributed to Schuler, P..

3 recordsLinked to original sources

bioRxiv2025

Decoupling of stomatal conductance from net assimilation at high temperature as a mechanism to increase transpiration

O_LIPhotosynthetic assimilation (Anet) and stomatal conductance (gs) are usually strongly coupled, but this relationship is decreased or even lost at high temperatures (Tair). The contributions of environmental drivers (Tair, vapour pressure deficit (VPD), and soil moisture) in interaction with the physiological mechanisms behind this process are still unclear. C_LIO_LIWe exposed saplings of three temperate and tropical species to rising Tair (20 to 40{degrees}C) at low (1.2 to 1.9 kPa) and increasing VPD (1.1 to 5.6 kPa), and at stable Tair (35{degrees}C) to increasing VPD (1.4 to 4.3 kPa) under well-watered or chronic soil drought conditions ([≤]10 %). Anet, gs, and transpiration (E) in the light and the dark and leaf thermoregulation were tracked throughout the experiment. C_LIO_LIWhen VPD remained low, gs continued to increase while Anet decreased at Tair > 35{degrees}C, leading to stomatal decoupling. In contrast, under rising VPD, trees maintained the coupling between Anet and gs at high Tair. C_LIO_LIWhile a decoupling of Anet and gs only occurred when VPD was low, Anet and E decoupled under both VPD regimes at high Tair. C_LIO_LIOur results indicate that, since gs and VPD collectively drive E, stomatal decoupling is needed to increase E when VPD is not sufficiently high. C_LI

plant biology↗

bioRxiv2025

PANDA: A simple and affordable chamber system for measuring the whole-plant net CO2 flux

The carbon (C) balance of plants is the sum of all source and sink processes. However, due to methodological limitations, most studies focus predominantly on measurements of leaf-level assimilation and respiration, with less attention given to these processes in heterotrophic organs or the whole-plant level. As a result, knowledge of the whole-plant net C balance is scarce, limiting our understanding of the dynamics between C source and sink activities. Therefore, we developed an easily reproducible chamber system for continuous measurements of whole-plant net CO2 fluxes. We present the obtained dynamics of net CO2 fluxes of several C3 and CAM species, including germinating Quercus robur, over several days, as well as the whole-plant net CO2 flux temperature response of Q. robur seedlings, identifying the temperature thresholds at which they shift from a net CO2 sink to source. We show distinct diel patterns of net CO2 fluxes in C3 plants, likely driven by a dynamic diurnal up- and downregulation of sink activities in woody C3 plants. These patterns appear temperature-driven, suggesting a dynamic response of plants sink and source activity to environmental drivers. Our results highlight the importance of whole-plant C balance measurements for understanding plant responses to environmental conditions.

plant biology↗

bioRxiv2024

Modulation of Neuronal Excitability and Plasticity by BHLHE41 Conveys Lithium Non-Responsiveness

Many bipolar disorder (BD) patients are non-responsive to lithium. The mechanisms underlying lithium (non-)responsiveness are largely unknown. By using gene-set enrichment analysis methods, we found that core clock gene-sets are significantly associated with lithium response. Among the top hits was BHLHE41, a modulator of the molecular clock and homeostatic sleep. Since BHLHE41 and its paralog BHLHE40 are functionally redundant, we assessed chronic lithium response in double-knockout mutant mice (DKO). We demonstrated that DKOs are non-responsive to lithiums effect in various behavioral tasks. Cellular assays and patch clamp recordings revealed lowered excitability and reduced lithium-response in prefrontal cortical layer 2/3 DKO neurons and on hippocampal long-term potentiation. Single-cell RNA sequencing identified that lithium deregulated mitochondrial respiration, cation channel and postsynapse associated gene-sets specifically in upper layer excitatory neurons. Our findings show that lithium acts in a highly cell-specific way on neuronal metabolism and excitability and modulates synaptic plasticity depending on BHLHE40/41.

neuroscience↗