Leaf rolling as indicator of water stress in Cistus incanus from different provenances

The relationship between leaf rolling and physiological traits under imposed water stress conditions was analyzed in C. incanus representative saplings collected at different altitudes (i.e. Castelporziano, 0 m a.s.l. and Natural Park of Monti Lucretili, 750 m a.s.l) and grown ex-situ. The hypothesis that leaf rolling reflected physiological changes occurring during water stress irrespective to the different acclimation to cope with water stress was tested. On the whole, the results show that leaf rolling is associated to an increased sub-stomatal CO2 concentration (Ci) and a decreased carboxylation efficiency (Ce). Moreover, leaf rolling in C. incanus leaves might be involved in protecting the PSII complex under water stress during the progressive inhibition of photosynthetic metabolism.