Ecophysiology of Antarctic vascular plants.

Most of the ice and snow-free land in the Antarctic summer is found along the Antarctic Peninsula and adjacent islands and coastal areas of the continent. This is the area where most of the Antarctic vegetation is found. Mean air temperature tends to be above zero during the summer in parts of the Maritime Antarctic. The most commonly found photosynthetic organisms in the Maritime Antarctic and continental edge are lichens (around 380 species) and bryophytes (130 species). Only two vascular plants, Deschampsia antarctica Desv. and Colobanthus quitensis (Kunth) Bartl., have been able to colonize some of the coastal areas. This low species diversity, compared with the Arctic, may be due to permanent low temperature and isolation from continental sources of propagules. The existence of these plants in such a permanent harsh environment makes them of particular interest for the study of adaptations to cold environments and mechanisms of cold resistance in plants. Among these adaptations are high freezing resistance, high resistance to light stress and high photosynthetic capacity at low temperature. In this paper, the ecophysiology of the two vascular plants is reviewed, including habitat characteristics, photosynthetic properties, cold resistance, and biochemical adaptations to cold.