Plant Phenotypic Plasticity in Response to Environmental Factors
Figure 3
Physiological, morphological, and anatomical leaf trait variations of Quercus ilex ecotypes from different provenances in Italy, grown from seeds collected in the native environments. Seedlings from the more xeric provenance (Frassanito, 40°13′N, 18°26′E, at sea level, site C) have a larger tolerance to drought by a larger leaf mass area (LMA) and leaf tissue density (LTD) and a higher stomatal sensitivity to changes in leaf water potential at predawn () contributing to a better water use efficiency (WUE) than the other seedlings [58]. In particular, the reduced leaf area (LA) appears to be the best adaptive trait in response to the winter stress at the northern distribution limit (Nago, 45°55′N, 10°53′E, 260 m a.s.l., site A) while the larger shoot and leaves production of Castelporziano seedlings reflects the favorable climatic condition of this locality (41°45′N, 12°26′E, at sea level, site B). The favorable environmental conditions at Castelporziano are expressed throughout a larger phenotypic plasticity while the cold stress at Nago and the drought stress at Frassanito allow specialization. Moreover, Q. ilex phenotypic plasticity is larger for physiological than for morphological and anatomical traits due to the capability of this species to grow in full sun as well as in shade conditions and colonize successfully new areas after fire by vegetative regeneration [142]. Frassanito shrubs by their larger tolerance to high temperature and limited water availability might have an advantage in response to the forecasted increase of air temperature and drought in the Mediterranean Basin. Net photosynthesis (), stomatal conductance (), leaf transpiration (E), and specific leaf area (SLA) are shown.
