Similar to plant total biomass, total leaf area of oil palm
seedlings was also influenced by CO2 levels. Neither
progeny nor interaction effects between factors were
observed during all weeks of measurement (Fig. 2).
Although total leaf area in all treatments increased with age
due to ontogenical phase, seedlings enriched with elevated
CO2 significantly (P B 0.05) recorded higher total leaf area
compared to the control starting from week 6 after exposure
onwards. There was, however, no significant difference
on total leaf area obtained between the elevated CO2
treatments (800 and 1,200 lmol/mol). The lowest
enhancement of total leaf area in elevated treatments was
shown in week 3 where total leaf area was increased by
32% in elevated treatments (800 and 1,200 lmol/mol)
compared to control. Acute increase in total leaf area under
elevated CO2 was observed between week 9 (1,085 vs
2,299) and week 12 (2,981 vs 4,561) with respective 2.0-
and 1.5-fold enhancement compared to the control.