XVI International Botanical Congess

Photosynthetic performances were investigated for Alocasia odora, a shade tolerant herb species native to Asian tropical forest understories grown at a constant low irradiance of high R:FR ratio (NE) and low R:FR ratio light (FR) combined with an ambient CO2 of 400 (NE4, FR4) or elevated CO2 of 800 ppm (NE8, FR8). FR4-leaves measured at FR-light showed 13% reduction in photosynthesis as compared with NE4-leaves measured at NE-light. Photosynthesis in FR8-leaves was similar to that in NE4- and NE8-leaves. Acclimation to elevated CO2 significantly decrease Rubisco activity in leaves grown at both light regimes. Results consist with the hypothesis that elevated CO2 stimulated the spectral quality-limited photosynthesis in A. odora grown under low R:FR ratio light.