The effect of leaf age on CO2 assimilation and stomatal conductance of field-grown olive trees

The effect of leaf age on CO2 assimilation was measured in field-grown olive trees of cv. Frantoio over two growing seasons. Two to four age classes (from approx. 3-week old to 1-year-old) of fully-expanded leaves were measured in different periods of the year by infrared gas analysis. Maximum photosynthetic rates and stomatal conductance were measured in leaves between one and four months of age. CO2 assimilation tended to be lower in leaves of about 12 months or older. Differences depended on both and the environmental conditions prevailing when leaves had developed.