Changes in assimilation capacity during leaf development in broad-leaved Prunus persica and sclerophyllous Olea europaea

SummaryNet photosynthesis, dark respiration, chlorophyll and carbohydrate content, and leaf growth in plants of deciduous peach (Prunus persica (L.) Batsch.) and evergreen olive (Olea europaea L.) grown in controlled environmental conditions were measured to assess changes in carbon balance during leaf development at the 6th, 12th and 16th nodes (first flush) from the beginning of expansion to full maturity. A simulation model was written including growth traits, physiological measurements and meteorological data. In both species, gas exchange varied with the percentage of leaf expansion, regardless of the node examined. The relationships between net daily CO2 assimilation (24 h), chlorophyll content, and the ratio of leaf mass per area, across all nodes, differed between species. Photosynthetic capacity differed significantly between different degrees of leaf expansion in both species. The model predicted differences in leaf carbohydrate balance between peach and olive. The onset of carbohydrate export from individual leaves varied with species, being 18 – 19 d and 28 – 29 d from emergence in peach and olive, respectively.