Stomata as foliar structures indicating climate changes in trees of the Atlantic Rainforest

• Grant number: 07/03477-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2007
• End date: August 04, 2009
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Marcos Silveira Buckeridge
• Grantee: Simone Godoi
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Levels of atmospheric CO2 concentrations markedly increased after the industrial revolution due to an increase in human activity, and levels around 450-600 ppm were forecasted for the next decades. It has been suggested that such type of climatic change could lead to considerable changes in the community composition of tropical forests. Among the several responses of plants to an increase in CO2 concentrations, those associated to changes in the number of stomata has received a growing attention in the past decades. Usually, the degree of flexibility of this response has been analysed through calculations of the stomatal index (or density), and some results pointed to a negative correlation between the decrease in stomatal index and an increase in CO2 concentrations. Notwithstanding the importance of these studies, such correlations were based on studies carried out with species from temperate ecosystems. Thus, to what extent this response is also observed among plants of tropical ecosystems is unknown. The main objective of the present project is to analyse the stomatal index of 5 species from the Family Leguminosae that are representative of tropical ecosystem and that are also associated with different successional stages. Stomatal index will be calculated from data collected for individuals of each species collected in the past 174 years using a methodology that will be developed in this study, as well as from freshly-collected individuals. The expected results are an increase in the stomatal index in freshly collected individuals as compared with data obtained from herborised individuals, and a variation in stomatal index as a function of the successional stages. Besides the validation of a new methodology to access stomatal index, these results can provide a better understanding of the phenotypic responses of plants to changing CO2 concentrations and, thus, could support predictions about the impact of this alteration in tropical ecosystems. (AU)