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Where do leaf water leaks come from? Trade‐offs underlying the variability in minimum conductance across tropical savanna species with contrasting growth strategies

2020; Wiley; Volume: 229; Issue: 3 Linguagem: Inglês

10.1111/nph.16941

1469-8137

Renan Machado, Lucas Loram Lourenço, Fernanda dos Santos Farnese, Rauander Douglas Ferreira Barros Alves, Leticia F. Sousa, Fabiano Guimarães Silva, Sebastião Carvalho Vasconcelos Filho, José Manuel Torres Ruiz, Hervé Cochard, Paulo Eduardo Menezes‐Silva,

Plant and animal studies

Summary Plants continue to lose water from their leaves even after complete stomatal closure. Although this minimum conductance ( g leaf‐res ) has substantial impacts on strategies of water use and conservation, little is known about the potential drivers underlying the variability of this trait across species. We thus untangled the relative contribution of water leaks from the cuticle and stomata in order to investigate how the variability in leaf morphological and anatomical traits is related to the variation in g leaf‐res and carbon assimilation capacity across 30 diverse species from the Brazilian Cerrado. In addition to cuticle permeance, water leaks from stomata had a significant impact on g leaf‐res . The differential pattern of stomata distribution in the epidermis was a key factor driving this variation, suggesting the existence of a trade‐off between carbon assimilation and water loss through g leaf‐res . For instance, higher g leaf‐res , observed in fast‐growing species, was associated with the investment in small and numerous stomata, which allowed higher carbon assimilation rates but also increased water leaks, with negative impacts on leaf survival under drought. Variation in cuticle structural properties was not linked to g leaf‐res . Our results therefore suggest the existence of a trade‐off between carbon assimilation efficiency and dehydration tolerance at foliar level.