STRUCTURAL AND ECOPHYSIOLOGICAL PLASTICITY OF SOME EVERGREEN SPECIES OF THE MEDITERRANEAN MAQUIS IN RESPONSE TO CLIMATE

The most representative evergreen shrub species growing in the lowmediterranean maquis modified their leaf characteristics during theyear, but the response to climate varied among the species. The realsclerophyllous species, Quercus ilex L., Phillyrea latifolia andPistacia lentiscus, showed a convergence in higher leaf thickness andlower, net photosynthetic rate (PN) compared with Arbutus unedo L. andCistus incanus L. Under summer stress they maintained a substantialpositive carbon balance. Pistacia was one of the most tolerant speciesto the drought, it maintained a substantial positive balance over a widerange in temperature. Arbutus and Cistus had relatively thin leaves witha higher succulence index and higher PN over the more characteristicsclerophyllous species. The superiority of Cistus in carbon uptake overall the spacies was maintained throughout most of the year by itsmorphological leaf properties. low leaf thickness, high chlorophyllcontents. Besides, Cistus shed most of its leaves before summer, thusreducing its evaporative surface.