In addition, the two set of plants (2- and 5-yearold plants) were exposed to summer drought and mature leaves were collected prior (18 May, control) and during summer drought (29 July, stress) to compare the physiology of leaves in terms of water contents, photosynthetic pigment and anthocyanin levels and the Fv/Fm ratio. Monthly rainfall during June and July was of 25.2 and 34.1mm, respectively, so that a summer drought typical of the Mediter- ranean climate occurred during the experiment.