This study compares leaf anatomy, chlorophyll content and photosynthetic induction rates for seedlings
of five dipterocarp species growing both by a path and in the understorey of a Bornean heath forest. Hemispherical
photographs were used to estimate the light level. Although three of the five species showed significantly higher
photosynthetic capacity in high light conditions, there were no significant within-species differences in induction rates.
Average induction times to reach 50% (T50%) and 90% (T90%) of maximum photosynthetic rate (Amax) were about
1.5 and 9 min for Shorea pachyphylla. In contrast, these were 18 and 37 min respectively for Dipterocarpus borneensis,
and 12 and 25 min for Shorea multiflora. Intermediate values were recorded for Hopea pentanervia and Cotylelobium
burckii. There was an overall weak and negative correlation of induction rate with stomatal density. Three species
showed more rapid induction loss in their leaves from the path edge vs. the understorey. The results suggest that
photosynthetic acclimation can influence some aspects of a leaf's dynamic response to sunflecks, such as Amax and
induction loss, while not affecting overall induction rates. This study also shows significant differences among diptero carp species in photosynthetic capacity, induction responses and leaf structure, and in acclimation on these traits.