Photosynthetic Adaptive Strategies in Evergreen and Semi-Deciduous Species of Mediterranean Maquis During Winter.

Mediterranean-type ecosystems are characterised by a particular temperature and rainfallregime that limits plant growth in both summer and winter seasons (Mitrakos, 1980; Larcher, 2000). Mediterranean plant community is very heterogeneous and include many evergreen and semi-deciduous species that present a complex mixture of elements, some deriving from in situ evolution, others having colonized the area from adjacent regions in different periods in the past (Blondel & Aronson 1999; Gratani & Varone, 2004). The result of this evolution is that the Mediterranean maquis species are well adapted to environmental stress conditions and successfully overcome them (Sànchez-Blanco et al., 2002; Varone & Gratani, 2007). Our specific purposes were: 1) to focus on eco-physiological strategies adopted by the different species to optimize the carbon gain during winter and minimize the photoinhibitory damage risks; 2) to compare the behaviour of young and mature leaves under low winter temperature in order to elucidate if the photoprotective mechanisms may be influenced by the leaf age.