Deschampsia antarctica Desv. and Colobanthus quitensis Kunth Bartl. are the only two plant species that have naturally colonized the Maritime Antarctica. What special features do these two species have to be the only vascular plants widespread in this harsh environment?, has been an enigmatic question for scientists. These plant have developed different strategies to deal with low temperature associated stresses. For instance, D. antarctica is more freezing tolerant than C. quitensis exhibiting high capacity to withstand freezing temperatures way below the ice nucleation temperatures, C. quitensis maintains supercooling capacity but exhibited damage at temperatures close to its ice nucleation temperature (tolerance vs avoidance of freezing). This is related with interspecific differences associated to accumulation of different cryoprotectants and also with different mechanism able to protect functional integrity of these plant from damaging reactive oxygen species and finally, their differential capability to produce cryoprotective and antifreeze proteins. But it is not only freezing tolerance which account for their survival and population expansion in Antarctica, there are also morphological and reproductive traits of these species that play an important role. For instance, prostrated habit of both plants leaf size and morphology, plus some particular attributes such as special salt glands in D. antarctica and vivipary observed in C. quitensis are also remarkable. But all this cold adaptation is now challenged by the regional warming experienced by The Antarctic Peninsula in the last century. Many questions have been raised about plant performance and their fate in this new scenario. Results from an in situ warming experiment will be discussed and provide further insights.
Acknowledgments: PIA-CONICYT ART-1102, FONDECYT 1151173, NEXER NXR17-0002