A causal trait model for explaining foliar water uptake capacity

• Published in: Journal of vegetation science Vol. 35; no. 3
• Main Authors: Matos, Ilaíne Silveira, Rifai, Sami Walid, Gouveia, Walquíria Felipe, Oliveras, Imma, Mantuano, Dulce, Rosado, Bruno H. P.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.05.2024; Wiley
• Subjects: Bayesian analysis; Campos de altitude; Cell walls; Climate change; Conductance; Drought; Environmental Sciences; Graph theory; Grasslands; iso/anisohydric behaviour; leaf water absorption; leaf wettability; leaf‐wetting; Leaves; Moisture content; montane grassland; plant hydraulics; Plant species; Species; Stomata; Stomatal conductance; Water content; Water potential; Water storage; Water uptake; Wettability; Wetting; Plant hydraulics; Leaf water absorption; Montane grassland; Campos de altitude; Brazil; Leaf-wetting; Iso/anisohydric behaviour; Drought; Leaf wettability
• ISSN: 1100-9233; 1654-1103
• DOI: 10.1111/jvs.13258

Questions Plants largely vary in their capacity for foliar water uptake (FWU), that is, the capacity to increase leaf water content by directly absorbing water from leaf‐wetting events. Climate change will reduce leaf wetting and increase drought events. Therefore, we need a better understanding of the underlying traits and mechanisms that facilitate FWU. Location Seasonally dry tropical montane grasslands in Brazil (Campos de Altitude). Methods We measured FWU and leaf traits related to wettability, surface conductance, water potential and water storage on up to 55 plant species. By using Direct Acyclic Graph theory and Bayesian modelling, we tested how those leaf traits affect FWU. Results We found that stomatal conductance largely explained interspecific variation in FWU, which was also favoured in species with hydrophilic leaves, high cuticular conductance, more negative leaf water potentials, low dry‐matter content, isohydric behaviour, and more elastic cell walls. Conclusions Due to the existence of trade‐offs, not all species exhibit an optimal combination of traits that favours FWU. Instead, co‐occurring species have achieved a similar capacity for FWU through distinct trait combinations. Consequently, species engaged in FWU may exhibit differential vulnerabilities to climate change as they can cope with drought using other strategies beside FWU. Plants vary in their capacity to absorb atmospheric sourced water through their leaves (i.e., foliar water uptake, FWU). Here, we reveal the main foliar traits responsible for interspecific differences in FWU, and also discuss the implications of our findings for plants' responses to future drier conditions.