Plasticity in leaf characters of three olive cultivars growing in an experimental field in northern Italy

In northern Italy, several local varieties are grown in regional field trials with the aim of selecting the best cultivars for specific environments. In this paper, two northern varieties from Liguria (Razzola and Taggiasca) are compared to a widespread cultivar (Frantoio) to test the degree of plasticity and adaptation in leaf characters. Leaf gas exchange, N content and morphological parameters were measured throughout the growing season. Daytime gas exchange ranked cultivars more effectively than light response curves. The highest values of photosynthesis and stomatal conductance were observed in ‘Frantoio’, while ‘Razzola’ a n d ‘ Ta g g i a s c a ’ did not show consistent diff e rences in gas exchange. Diff e rences in leaf N content as well as leaf mass/area ratio among the three cultivars were small. Differences between cultivars in foliage structural plasticity and gas exchange, and correlations among leaf N content, photosynthetic parameters and morphological traits are discussed in relation to the seasonal course.