Ecophysiology of Tree Species of the Tropical Rain Forest Under Enriched CO2 Atmosphere: A Successional Approach Using Different Functional Groups Among the Leguminosae
João
R.L.
Godoy, Instituto de Botânica São Paulo, jrlgodoy@usp.br
Marcos
P.M.
Aidar, Instituto de Botânica São Paulo, maidar@uol.com.br
(Presenting)
Mauro
Marabesi, Instituto de Botânica São Paulo, mauromarabesi@bol.com.br
Marcos
Silveira
Buckeridge, Instituto de Botânica São Paulo, msbuck@usp.br
The family Leguminosae is among the most representative in tropical biomes such as the rain forest. Its success seems to be related to the occurrence in the different functional groups along the entire successional continuum, from pioneer to early and late secondary species, playing key roles on the development of forest growth cycle. We have previously evaluated the potential for carbon sequestration of the tropical tree Hymenaea courbaril, a late secondary species. We found that they almost doubled their photosynthesis capacity, decreased the stomata index and raised the proportion of cellulose in leaves and stem. In this work, a group of legume species (Sesbania virgata, Schizolobium parahyba, Piptadenia gonoacantha and Dalbergia nigra) belonging to different ecological groups in the tropical forest succession, was chosen for studies of ecophysiolgical behaviour when growing under elevated [CO2] (720ppm) in open top chambers. The results obtained up to now indicate that under 720 ppm of CO2, Piptadenia gonoacantha, an early secondary species, showed higher growth (+10%) and photosynthesis (+29%), reaching maximum assimilation (Amax) of carbon dioxide earlier than plants growing under 360ppm. Plants under 720ppm reached values of Amax 16% higher than those under 360ppm and saturated almost in doubled atmospheric [CO2] (2140 and 1200 ppm, respectively) when AxCi curves were performed. These results suggest a good potential for carbon sequestration. Further comparisons among species of the different functional groups (on going experiments) may lead to a new understanding of forest succession under high CO2 atmospheric concentration. FAPESP; The Nature Conservancy; CNPq.
Submetido por Marcos Pereira Marinho Aidar em 18-MAR-2004
Tema Científico do LBA: CD (Armazenamento e Trocas de Carbono)