Acclimatization capacity of leaf traits of species co-occurring in restinga and seasonal semideciduous forest ecosystems

Abstract

Restingas and seasonal semideciduous forests (SSF) are phytophysiognomies of the Atlantic Forest that have many co-occurring species. However, the microclimatic and edaphic conditions of these phytophysiognomies are quite different. Restingas are characterized by low water availability, high irradiance and temperatures, and sandy and nutrient poor soil, which contrasts with the soil conditions of forests. In this sense, these environmental divergences would have forced species to become acclimatized in order to co-occur in these two distinct environments. The present study aimed to determine the main functional leaf traits that enabled Maytenus obtusifolia, Manilkara subsericea and Inga laurina to co-occur in both restinga and SSF. Morphological, physiological, nutritional and biochemical traits of the leaves of these three species in the restinga and SSF were analyzed. The results showed that in the restinga the species possess thicker leaves with a greater thickening of mesophyll cells; the adaxial and abaxial epidermis and cuticle. In addition, restinga leaves had higher specific leaf mass and greater stomatal density, as well as less leaf area than species in the SSF. The restinga species invested in the biosynthesis of osmoregulatory and photoprotective molecules. Photosynthetic performance was similar between phytophysiognomies for M. obtusifolia and M. subsericea, but I. laurina had lower photosynthetic performance in the restinga. We conclude that the species invested in structural, physiological and biochemical adjustments in the restinga in response to conditions of low water availability and high irradiance.