Effect of cold acclimation on the photosynthetic performance of two ecotypes of Colobanthus quitensis

The effects of cold acclimation of two ecotypes (Antarctic and Andes) of Colobanthus quitensis (Kunth) Bartl. Caryophyllaceae on their photosynthetic characteristics and performance under high light (HL) were compared. Non-acclimated plants of the Antarctic ecotype exhibited a higher (34%) maximal rate of photosynthesis than the Andes ecotype. In cold acclimated plants the light compensation point was increased. Dark respiration was significantly increased during the exposure to 4 °C in both ecotypes. Cold acclimated Antarctic plants showed higher PSm and qP compared with the Andes ecotype. In addition, the Antarctic ecotype exhibited higher heat dissipation (NPQ), especially in the cold-acclimated state, which was mainly associated with the fast relaxing compo