Andrea Carminati

Last Name

Carminati

First Name

Andrea

ORCID

0000-0001-7415-0480

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09732 - Carminati, Andrea / Carminati, Andrea

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Publications 1 - 10 of 82

Soil Hydraulic Constraints on Stomatal Regulation of Plant Gas Exchange
Wankmüller, Fabian; Carminati, Andrea (2024)
Progress in Botany ~ Progress in Botany
Terrestrial water fluxes are dominated by transpiration, with stomata exerting an important control by regulating transpirational water loss. Transpiration and stomatal conductance are in turn constrained by the hydraulic properties of the soil-plant-atmosphere continuum, thus providing a link between the physics of water flow (soil-plant hydraulics) and the gas exchange between vegetation and atmosphere (via stomatal regulation). In this article, we review the principles of water flow in soil and plants and the links to stomatal responses to decreasing soil water availability. We make use of a soil-plant hydraulic framework to define the physical constraints on transpiration and predict stomatal responses. We then discuss the role of soil-plant hydraulics for different plant water use strategies (i.e. degree of iso/anisohydry) with changing soil hydraulic properties, root hydraulic distribution and xylem vulnerability.
Unsaturated water flow across soil aggregate contacts
Carminati, Andrea; Kaestner, A.; Lehmann, Peter; et al. (2008)
Advances in Water Resources
Investigation of water imbibition in porous stone by thermal neutron radiography
Hassanein, R.; Meyer, H.O.; Carminati, Andrea; et al. (2006)
Journal of Physics D: Applied Physics
Analyzing the fabric of soil aggregates
Kaestner, A.; Lehmann, Peter; Carminati, Andrea; et al. (2005)
Stomatal regulation prevents plants from critical water potentials during drought: Result of a model linking soil–plant hydraulics to abscisic acid dynamics
Wankmüller, Fabian; Carminati, Andrea (2022)
Ecohydrology
Understanding stomatal regulation during drought is essential to correctly predict vegetation-atmosphere fluxes. Stomatal optimization models posit that stomata maximize the carbon gain relative to a penalty caused by water loss, such as xylem cavitation. However, a mechanism that allows the stomata to behave optimally is unknown. Here, we introduce a model of stomatal regulation that results in similar stomatal behaviour without presupposing an optimality principle. By contrast, the proposed model explains stomatal closure based on a well-known component of stomatal regulation: abscisic acid (ABA). The ABA level depends on its production rate, which is assumed to increase with declining leaf water potential, and on its degradation rate, which is assumed to increase with assimilation rate. Our model predicts that stomata open until the ratio of leaf water potential to assimilation rate, proportional to ABA level, is at a minimum. As a prerequisite, the model simulates soil-plant hydraulics and leaf photosynthesis under varying environmental conditions. The model predicts that in wet soils and at low vapour pressure deficit (VPD), when there is no water limitation, stomatal closure is controlled by the relationship between photosynthesis and stomatal conductance. In dry soils or at high VPD, when the soil hydraulic conductivity limits the water supply, stomatal closure is triggered by the sharp decline in leaf water potential as transpiration rate increases. Being adaptive to changing soil and atmospheric conditions, the proposed model can explain how plants are enabled to avoid critical water potentials during drought for varying soil properties and atmospheric conditions.
Transferability of pedotransfer functions for estimating soil hydraulic properties: An analysis of controlling factors for forest soils in Switzerland
Schoch, Julian; Nussbaum, Madlene; Walthert, Lorenz; et al. (2025)
Geoderma
Soil hydraulic properties (SHP) are essential for estimating fluxes in terrestrial ecosystems, plant available water, and root water uptake. To provide SHP for large scale applications, pedotransfer functions (PTFs) are used. Many PTFs are trained for a specific region and its applicability outside this region is controversial. In this study, we analyse the controlling factors affecting PTF transferability across forest soils in Switzerland, focusing on confounders, and the entire modelling framework that we denote as model-building-and-form-of-statistical-function (i.e., the statistical method used to link covariates and responses, as well as model training and selection). We trained parsimonious Lasso models and Random Forest models with data from 24 forest sites located in the Swiss Central Plateau to create new PTFs (SwiPT). These were then transferred, alongside existing European PTFs, to forest soils of another Swiss region (Valais), which is topographically, climatically, and geologically considerably different. Our key finding is that PTFs using fewer covariates (specifically, only sand and clay content) demonstrated in average higher predictive performance when transferred, compared to PTFs using up to 11 covariates. We identify the presence of covariates acting either as confounders or whose measurement uncertainty undermines any predictive gains they might offer, as the main contributors to the limited transferability of PTFs with many covariates. In the context of measurement uncertainty, we discuss how bias introduced by different methods and laboratories could potentially contribute to this limited transferability. In addition, based on our analyses related to model-building-and-form-of-statistical-function, we conclude that effectively limiting or reducing the number of covariates is essential for developing transferable PTFs. This work advances our understanding of the mechanisms limiting PTF transferability and highlights key aspects for improving their generalisation.
Microplastics in agricultural soils: The role of soil texture in modulating oxygen diffusivity and soil respiration
Nuñez, Jonathan; Jimenez-Martinez, Joaquin; Carminati, Andrea; et al. (2025)
Soil Biology and Biochemistry
The presence of microplastics (MPs) in soils impacts nutrient cycling and soil respiration. However, the mechanisms underpinning the direction and magnitude of these effects on soil are uncertain. We hypothesized that the presence of MPs affects pore connectivity, leading to changes in oxygen (O2) diffusivity and soil respiration. Furthermore, we anticipated that the magnitude of the effects would be dependent on both soil texture and MPs morphology. 1 % (w/w) PET MPs fibers (500 μm length) and fragments (125–250 μm) were spiked into rhizotrons filled with either clay or sandy loam soils. O2 diffusivity differences were determined in microcosm using an oxygen-free chamber. The O2 concentration in the soil was also measured in optimal conditions for respiration. O2 diffusivity and concentration were measured using optode imaging. Respiration was estimated from cumulative CO2 and changes in the size of the water-extractable carbon pool. Adding MPs decreased O2 concentration in the sandy loam soil (167.4 ± 6.1 mg L−1 air), with a greater reduction observed for fragments (15 %) compared to fibers (12 %). Soil respiration decreased by 40 % in both fragment and fiber treatments in alignment with the reduction in oxygen concentration. Conversely, in the clay soil, the addition of fibers and fragments resulted in a 13 and 7 % increase in O2 concentration compared to the control (177.9 ± 3.8 mg L−1 air). Both changes in oxygen concentration and diffusivity, show a similar response to MPs for the two soils. These findings indicate that the effects of MPs on soil respiration are likely driven by changes in O2 dynamics. However, the MPs' impact on O2 dynamics depends on soil particle size distribution. Future research should consider MP size, morphology, and soil particle distribution interactions to assess MPs' impacts on soil functions.
On the importance of rhizosphere conductance and soil-root contact in drying soils
Koch, Axelle; Cai, Gaochao; Ahmed, Mutez Ali; et al. (2025)
Annals of Botany
Background and Aims Root water uptake (RWU) is influenced by rhizosphere conductance and soil–root contact, which vary with soil texture and root structure, including root hairs. Current simplified models often fail to capture the spatial complexity of these interactions in drying soils. The aim of this study was to examine how rhizosphere conductance, soil–root contact and root hairs affect RWU. Methods We used an explicit three-dimensional functional–structural model to investigate how root and rhizosphere hydraulics influence the transpiration rate–leaf water potential relationship of two maize (Zea mays) genotypes (with and without root hairs) grown in two contrasting soil textures (loam and sand) during soil drying. The model incorporated rhizosphere resistance in series with radial root resistance, with the latter being influenced by maturation (development of apoplastic barriers with age). It considered two critical processes: (1) the decrease in soil water potential between bulk soil and the soil–root interface; and (2) the extent of soil–root contact. Key Results The simulations revealed that RWU was highly soil texture specific. In loam, the non-linearity in the transpiration rate–leaf water potential relationship was attributable primarily to localized uptake fluxes and high rhizosphere resistance as soil dried. In sand, however, where soil–root contact was less effective, rhizosphere conductance became a significant limiting factor for RWU, even at relatively higher soil water potential in comparison to loam. Root hairs did not make a significant contribution to rhizosphere conductance, probably owing to the dominant effect of soil–root interaction. Additionally, variations in root hydraulic conductance and its change with root tissue age impacted the accuracy of the model. Conclusions The explicit three-dimensional model provides a more precise representation of RWU dynamics by pinpointing exact uptake locations and primary limiting factors and by quantifying the proportion of root surface actively engaged in RWU. This approach offers notable improvements over conventional models for understanding the spatial dynamics of water uptake in different soil environments.
Contrasting the soil-plant hydraulics of beech and spruce by linking root water uptake to transpiration dynamics
Martinetti, Stefano; Molnar, Peter; Carminati, Andrea; et al. (2025)
Tree Physiology
Tree water status is mainly determined by the amount of water taken up from roots and lost through leaves by transpiration. Variations in transpiration and stomatal conductance are often related to atmospheric conditions and leaf water potential. Yet, few experimental datasets exist that enable to relate leaf water potential, transpiration dynamics and temporal variation of root water uptake from different depths during soil drying. Here we explored the soil-plant hydraulic system using field measurements of water potentials and fluxes in soils, roots, stems and leaves of beech (Fagus sylvatica) and spruce (Picea abies) trees. Spruce maintained less negative water potentials than beech during soil drying, reflecting a more stringent stomatal control. While root water uptake depths were similar between species, water potentials in plant tissues of spruce were rather constant and less correlated across roots and the stem, possibly because of large water storage and hydraulic capacitance in these tissues. Root water uptake from deep soil layers increased during dry periods, particularly for beech. Our data suggest that species-specific root hydraulic conductance, capacitance and water uptake strategy are linked and affect transpiration dynamics. Thus, it is important to include such species-specific hydraulics when predicting transpiration rates based on plant water status.
Author Correction: Global influence of soil texture on ecosystem water limitation
Wankmüller, Fabian; Delval, Louis; Lehmann Grunder, Peter Ulrich; et al. (2025)
Nature
In the version of this article initially published, incorrect values were shown in the “hb/[cm]” column of Supplementary Table 1, and the last sentence of the legend for Extended Data Fig. 3 had an error where “pale colours” now replaces “dotted area, AI > 1” in the description. The colours for loamy sand and clay in Fig. 1 have been updated to match usage in other figures, while the full names of the authors have now been spelled out. The changes have been made in the Supplementary information and HTML and PDF versions of the article.

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Andrea Carminati

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