Adaptive leaf strategies of Miconia nervosa (Melastomataceae) in Amazon of Mato Grosso state

Abstract

The phenotype plasticity usually observed in morphological and anatomical leaf traits may be influenced by several factors, such as luminosity, soil nutrient availability, humidity and herbivory, among others. We tested leaf plasticity in Miconia nervosa (Melastomataceae) in a forest fragment in Southern Amazonia, Mato Grosso State - Brazil, seeking to verify morpho-anatomical strategies of light acclimation. We collected fully expanded leaves of 15 individuals exposed directly to sunlight, on a lake edge, and 15 under canopy shading. We evaluated quantitatively eight morphological variables and six anatomical variables, of which six and four, respectively, differed significantly between sun and shade leaves. Morphologically, sun leaves showed larger leaf and petiole sizes and anatomically, epidermal cells with slightly thickened walls, higher stomatal index and density. Shade leaves showed significantly thicker epidermis on both leaf faces. Leaves of M. nervosa exhibited medium to high degree of plasticity in morpho-anatomical traits, according to the plasticity index, with mixed characteristics of sun and shade environments. We suggest that the distribution of M. nervosa individuals in the forest is related to the availability of light and soil moisture.

Key words:
acclimation; environmental conditions; luminosity; plasticity; understory