Lafont et al. 2023 (Article) Aechmea, Light

Light intensity mediates phenotypic plasticity and leaf trait regionalisation in a tank bromeliad

Author(s):—T. Lafont Rapnouil, M. Gallant Canguilhem, F. Julien, R. Céréghino & C. Leroy

Publication:—Annals of Botany 131: mcad126 (online). (2023) — DOI

Abstract:—Background and aims: Phenotypic plasticity allows plants to cope with environmental variability. Plastic responses to the environment have mostly been investigated at the level of individuals (plants) but can also occur within leaves. Yet, the later has been underexplored, as leaves are often treated as functional units with no spatial structure. We investigated the effect of a strong light gradient on plant and leaf traits and examined whether different portions of a leaf show similar or differential responses to light intensity.
Methods: We measured variation in 27 morpho-anatomical and physiological traits at the rosette and leaf portions (i.e., base and apex) of the tank-bromeliad Aechmea aquilega (Bromeliaceace), when naturally exposed to a marked gradient of light intensity.
Key Results: The light intensity received by A. aquilega had a strong effect on the structural, biochemical, and physiological traits of the entire rosette. Plants exposed to high-light intensity were smaller and had wider, shorter, more rigid, and more vertical leaves. We found significant differences between the apex and basal portions of the leaf under low light conditions, and the differences declined or disappeared for most of the traits as light intensity increased (i.e., leaf thickness, adaxial trichome density, abaxial and adaxial trichome surface, and vascular bundle surface and density).
Conclusions: Our results reveal a strong phenotypic plasticity in A. aquilega, particularly in the form of a steep functional gradient within the leaf under low-light conditions. Under high-light conditions, trait values were relatively uniform along the leaf. This study sheds interesting new light on the functional complexity of tank-bromeliad leaves, and on the role of environmental conditions on leaf trait regionalisation.

Keywords:—Aechmea aquilega, functional traits, leaf anatomy, leaf morphology, leaf regionalisation, light intensity gradient, phenotypic plasticity, tank bromeliad