Variations in photosynthetic rate and associated parameters with age of oil palm leaves under irrigation

Net photosynthetic rate (P _N), transpiration rate (E), and stomatal conductance (g _s) in an adult oil palm (Elaeis guineensis) canopy were highest in the 9^th leaf and progressively declined with leaf age. Larger leaf area (LA) and leaf dry mass (LDM) were recorded in middle leaves. P _N showed a significant positive correlation with g _s and a negative relationship with leaf mass per area (ALM). The oil palm leaf remains photosynthetically active for a longer time in the canopy which contributes significantly to larger dry matter production in general and greater fresh fruit bunch yields in particular.