Leaf photosynthetic rate (PR) and related characters in sago palms were determined under field conditions at three different locations in Indonesia: Kendari, Bogor and Jayapura. The results were as follows: First, diurnal changes in PR revealed that the maximum values of PR in sago palms were in the range of 25-27 mg CO
2 dm
-2 h
-1 in a palm after trunk formation that was grown in Kendari, values which were much higher than those recorded at younger stages in previous reports (8-15 mgCO
2 dm
-2h
-1) . The PR values in palms prior to trunk formation that were grown in Bogor were in the range of 16-18 mg CO
2 dm
-2h
-1. Similar values were observed for the average PR of some folk varieties grown in Jayapura (17.2 mg CO
2 dm
-2h
-1) . Second, the PR was saturated at the light intensity of about 500 μE m
-2s
-1, suggesting that low light saturation plays an important role in maintaining the levels of CO
2 fixation required for a high starch yield under the low light conditions caused by the canopy cover. Third, the PR was closely related to the mesophyll conductance (Gm), an indicator of CO
2 fixation ability: the decrease in the PR values of the lower leaves was due to the decrease in Gm. However, the lower PR values recorded in Bogor than those in Kendari were associated with stomatal conductance (Gs), rather than with Gm.
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