© 1994 Heron Publishing—Victoria, Canada
Photosynthesis of a tropical canopy tree, Ceiba pentandra, in a lowland forest in Panama
Gerhard Zotz and Klaus Winter
Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Republic of Panama / Received December 1, 1993
Summary
Diel (24 h) courses of CO2 and water-vapor exchange of Ceiba pentandra (L.) Gaertn. (Bombacaceae) were studied under natural tropical conditions in the semi-evergreen moist forest of Barro Colorado
Island, Panama. Measurements were conducted from early February 1991 (dry season), shortly after new leaves emerged, until
mid-October 1991 (wet season), when leaves were shed. Rates of net CO2 uptake were significantly higher in the dry season than in the wet season, and showed a linear decrease with leaf age. Leaf
nitrogen concentrations and contents also decreased with age. Our estimate of annual carbon gain (2640 g CO2 m–2 year–1 or 21 g CO2 gDW–1 year–1) is considerably higher than estimates available for temperate forest trees.
Keywords:
carbon balance, CO2 exchange, nitrogen, tropical rain forest, water vapor exchange.
