© 2006 Heron Publishing—Victoria, Canada
Changes in photosynthesis and leaf characteristics with tree height in five dipterocarp species in a tropical rain forest
Tanaka Kenzo (1, 2, 7), Tomoaki Ichie (3, 4), Yoko Watanabe (5), Reiji Yoneda (2), Ikuo Ninomiya (6) and Takayoshi Koike (5)
1. The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, 790-8566, Japan / 2. Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan / 3. Center for Tropical Forest Science - Arnold Arboretum, Asia Program, NIE-NTU, 637616, Singapore / 4. Faculty of Agriculture, Kochi University, Nankoku, 783-8502, Japan / 5. Hokkaido University Forests, FSC, Sapporo, 060-0809, Japan / 6. Faculty of Agriculture, Ehime University, Matsuyama, 790-8566, Japan / 7. Corresponding author (mona@affrc.go.jp) / Received April 11, 2005; accepted September 15, 2005; published online April 3, 2006
Summary
Variations in leaf photosynthetic, morphological and biochemical properties with increasing plant height from seedlings to
emergent trees were investigated in five dipterocarp species in a Malaysian tropical rain forest. Canopy openness increased
significantly with tree height. Photosynthetic properties, such as photosynthetic capacity at light saturation, light compensation
point, maximum rate of carboxylation and maximum rate of photosynthetic electron transport, all increased significantly with
tree height. Leaf morphological and biochemical traits, such as leaf mass per area, palisade layer thickness, nitrogen concentration
per unit area, chlorophyll concentration per unit dry mass and chlorophyll to nitrogen ratio, also changed significantly with
tree height. Leaf properties had simple and significant relationships with tree height, with few intra- and interspecies differences.
Our results therefore suggest that the photosynthetic capacity of dipterocarp trees depends on tree height, and that the trees
adapt to the light environment by adjusting their leaf morphological and biochemical properties. These results should aid
in developing models that can accurately estimate carbon dioxide flux and biomass production in tropical rain forests.
Keywords:
Dipterocarpaceae, leaf morphology, nitrogen content, palisade layer, photosynthetic capacity, Sarawak.
