Impact of life history traits on physiological attributes of canopy species growing under different light regimes

CAMPANELLO P.; GATTI M.G.; GOLDSTEIN G.

Miami, USA

Congreso; Reunión anual sobre biología tropical; 2004

Association of Tropical Biology and Conservation

The ability of plants to modify the internal allocation of carbon and resources under different light environments is an important factor determining growth and survival in tropical forests where large microclimatic changes occur as a result of canopy gap formation. The way morphological and physiological attributes change and correlate across a range of potential environments could lead to a better interpretation of plastic responses in relation to life history traits. The study of the relationships between hydraulic architecture and carbon uptake may improve our understanding of plasticity responses, as long as photosynthetic capacity represents a measure of the maximum demand for water in the leaves and has proved to correlate with water transport capacity across species and habitats. In this context, the effects of different light environments on hydraulic architecture and photosynthetic capacity were studied in saplings of seven canopy species of the Atlantic Forest in Northern Argentina. Measurements of hydraulic conductivity, leaf to sapwood area ratio, xylem vulnerability to cavitation, wood density, maximum photosynthetic rate, carbon stable isotope composition of leaves, specific leaf area, and growth rate were obtained in saplings acclimated to different light environments. The response for these attributes varied among the species. Their ability to coordinate morphological and physiological changes, and whether plastic responses enhanced growth rate, were fundamental questions addressed in this study.