Biology subjects

Devidal, S.

Publications and source records attributed to Devidal, S..

3 recordsLinked to original sources

bioRxiv2026

Severe warming alters biomass allocation and enhances ecosystem respiration in an alpine grassland: evidence from a short-term mesocosm experiment

Background and aims Alpine ecosystems are highly sensitive to climate change, with rising temperatures threatening ecosystem structure and function. This study examined the short-term responses of alpine grassland ecosystems (Mont Blanc, Italy) to projected climate scenarios using an Ecotron mesocosm experiment. Methods Ecosystem monoliths were exposed to current (~420 ppm CO2) and future CO2; concentrations (~550 and ~800 ppm) under RCP 4.5 and RCP 8.5 scenarios, incorporating changes in temperature, precipitation, humidity, and radiation. CO2; fluxes (NEP, GPP, Reco), soil chemistry, vegetation coverage, above- and belowground biomass, and plant functional traits were assessed throughout the experiment. Results Alpine grassland ecosystems withstood moderate warming (RCP 4.5), while under severe warming (RCP 8.5), GPP, vegetation cover and biomass increased with a shift toward aboveground allocation, although daytime NEP remained stable as gains were offset by higher Reco, with no detectable water and nutrients limitations. On a diel basis, higher GPP was offset by enhanced Reco, indicating a potential towards net C loss. Salix herbacea exhibited functional trait adjustments-higher LMA and Na, and elevated delta15N-reflecting greater leaf longevity, water-use efficiency, and altered nitrogen metabolism, suggesting potential community reorganization. Conclusion Over a single growing season, alpine ecosystems appeared relatively stable under moderate warming. However, under the more severe RCP 8.5 scenario, biomass allocation shifted toward greater aboveground and reduced belowground investment, leading to altered C fluxes that, if sustained over the long-term, could drive the ecosystem C balance from a sink to a source. Responses were plant species-specific, indicating uneven acclimation within the community.

plant biology↗

bioRxiv2023

Natural genetic variation underlying the negative effect of elevated CO2 on ionome composition in Arabidopsis thaliana

The elevation of atmospheric CO2 leads to a decline in the plant mineral content, which might pose a significant threat to food security in the coming decades. To date, very few genes have been identified as having a role in the negative effect of elevated CO2 on plant mineral composition. Yet, several studies have shown a certain degree of diversity in the ionomes response to elevated CO2, associated with genotypic variation. This suggests the existence of genetic factors controlling the effect of CO2 on ionome composition. However, no large-scale studies have been carried out to date to explore the genetic diversity of the ionome responses to elevated CO2. Here, we used six hundred Arabidopsis thaliana accessions, representing geographical distributions ranging from worldwide to regional and local environments, to analyze the natural genetic variation underlying the negative effect of elevated CO2 on the ionome composition in plants. We show that the growth under elevated CO2 leads to a global and important decrease of the ionome content whatever the geographic distribution of the population. We also observed a high range of genetic diversity in the response of the ionome composition to elevated CO2, and we identified sub-populations, showing effects on their ionome ranging from the most pronounced to resilience or even to a benefit in response to elevated CO2. Using genome-wide association mapping on the response of each mineral element to elevated CO2 or on integrative traits, we identified a large set of QTLs and genes associated with the ionome response to elevated CO2. Finally, we demonstrate that the function of one of these genes is associated to the negative effect of elevated CO2 on the plant mineral composition. This resource will contribute to understand the genetic mechanisms underlying the negative effect of elevated CO2 on plant mineral nutrition, and could help towards the development of crops adapted to a high-CO2 world.

plant biology↗

bioRxiv2017

Does circadian regulation lead to optimal gas exchange regulation?

Optimal stomatal theory is an evolutionary model proposing that leaves trade-off Carbon (C) for water to maximise C assimilation (A) and minimise transpiration (E), thereby generating a marginal water cost of carbon gain ({lambda}) that remains constant over short temporal scales. The circadian clock is a molecular timer of metabolism that controls A and stomatal conductance (gs), amongst other processes, in a broad array of plant species. Here, we test whether circadian regulation contributes towards achieving optimal stomatal behaviour. We subjected bean (Phaseolus vulgaris) and cotton (Gossypium hirsutum) canopies to fixed, continuous environmental conditions of photosynthetically active radiation, temperature and vapour pressure deficit over 48 hours. We observed a significant and self-sustained circadian oscillation in A and in stomatal conductance (gs) which also led to a circadian oscillation in{lambda} . The lack of constant marginal water cost indicates that circadian regulation does not directly lead to optimal stomatal behaviour. However, the temporal pattern in gas exchange, indicative of either maximizing A or of minimizing E, depending upon time of day, indicates that circadian regulation could contribute towards optimizing stomatal responses. More broadly, our results add to the emerging field of plant circadian ecology and show that molecular controls may partially explain leaf-level patterns observed in the field.

ecology↗