RESUMO
Tropical high mountain plants have different adaptations to survive extreme daily temperature fluctuations and specially freezing night conditions. In winter plant species, survival to low temperatures is related to the ability of the cell to produce specific low molecular weight proteins (antifreezing proteins) and to export them to the apoplast. In order to see if high mountain tropical plants survive to low temperatures through the same mechanism we collected, during a 24 hourperiod, leaves from Senecio niveoaureus growing at 3,300 and 3,600 m.o.s.l, in the Páramo de Palacio, Chingaza, Colombia. Leaf apoplast proteins had MW between 3512 kDa. Electrophoretic patterns were different depending on the altitude and the time of sampling. However the observed variations could not be linked to changes in temperature or to the altitudinal gradient. Antifreeze activity was detected in leaf apoplast of plants at different altitudes. This is the first report of antifreeze activity in a high mountain tropical species.