Observations of the Photosynthetic Physiology of Tree Species within the C3 Monocotyledon Genus Pandanus, and Comparison with Dicotyledon C3 Tree Species

Abstract

Photosynthetic characteristics of tree species from the tropical C₃ monocotyledon genus Pandanus were compared with C₃ dicotyledon species growing in similar environments. The Pandanus species had similar maximum photosynthetic rates (A_max) to dicotyledon tree species in leaves from both sun and shaded environments when A_max was expressed on an area basis. Because of the low specific leaf area of the schlerophyllous leaves of the Pandanus compared to the dicotyledon species, the similarity in A_max was no longer evident when A_max was expressed on a dry-weight basis. Leaf dark respiration rates of the Pandanus on a leaf area and weight basis were generally lower than the shade-intolerant dicotyledons and similar to the shade-tolerant dicotyledon species. Low dark respiration rates and low specific leaf area of the Pandanus may be important characteristics for growth and survival in environments where resource levels are low and the likelihood of tissue damage is high.