As plant total biomass increased, total leaf area also
increased and this was solely influenced by CO2 enrichment,
particularly in weeks 6, 9, 12 and 15 after the start of
treatments. Throughout these weeks, elevated CO2 (800
and 1,200 lmol/mol) resulted in higher total leaf area
compared to the control palms. Elevated CO2 improved
light harvesting component of oil palm seedlings as
increased biomass produced under elevated CO2 is being
partitioned to the leaves as manifested by the positive
linear relationships between total leaf area and RGR and
NAR. Although total leaf area was enhanced by elevated
CO2, significant reduction in SLA occurred more with
increasing CO2 than with the ambient. SLA had shown to
be negatively correlated with RGR and NAR. This implies
that the leaves of oil palm seedlings enhanced with
2 9 and 3 9 than ambient CO2 were thicker than control,
probably due to thicker mesophyll layer under elevated
CO2, which results in more efficient photosynthesis per
area basis (Beadle 1998).