CO2 Assimilation Characteristics of Five Prunus Tree Fruit Species1

Abstract

Photosynthetic CO 2 assimilation characteristics of 5 Prunus species were compared with respect to leaf nitrogen content and water use. The mean maximum CO 2 assimilation rates of peach, plum, and cherry were all very similar when expressed on a leaf area, leaf nitrogen, and water use basis (1.33–1.37 nmol CO 2 cm −2 s −1 , 6.17–6.75 nmol CO 2 mgN −l s −1 , 0.19–0.21 nmol CO 2 µgH 2 O −1 ). In comparison, the mean maximum CO 2 assimilation rate of almond was higher when expressed on a leaf area basis (1.80 nmol CO 2 cm −2 s −1 ), the same when expressed on a leaf N basis (6.47 nmol CO 2 mgN −1 s −1 ), and lower when expressed on a water use basis (0.16 nmol CO 2 µgH 2 O −1 ). The mean maximum rate of CO 2 assimilation in apricot leaves was lower than that of peach, plum, and cherry when expressed on a leaf area (0.67 nmol CO 2 cm −2 s −1 ) and leaf N basis (3.76 nmol CO 2 mgN −1 s −1 ) but the same when expressed on a water use basis (0.19 nmol CO 2 µgH 2 O −1 ). The interspecific relationship between leaf N content and leaf CO 2 assimilation rate was found to be similar to that described previously for leaves of a single cultivar of peach.