Photosynthetic traits of five neotropical rainforest tree species: interactions between light response curves and leaf-to-air vapour pressure deficit

measurements of leaf gas exchange at different photosynthetic photon flux density (ppfd) levels were conducted in order to compare the photosynthetic traits of five neotropical rainforest tree species, with a special emphasis on empirical mathematical models to estimate the light response curve parameters incorporating the effects of leaf-to-air vapour pressure deficit (d) on the saturated photosynthetic rate (amax). all empirical mathematical models seemed to provide a good estimation of the light response parameters. comparisons of the leaf photosynthetic traits between different species needed to select an appropriate model and indicated the microenvironmental conditions when the data were collected. when the vapour pressure deficit inside the chamber was not controlled, the incorporation of linear or exponencial functions that explained the effects of d on leaf gas exchange, was a very good method to enhance the performance of the models.