Efecto de las bajas temperaturas sobre la ultra estructura de la hoja de diferentes especies de Eucalyptus

The effect of cold temperature on the leaves of different species of Eucalyptus was studied after treating the leaves at -200 during 24 h. Different alterations of the ultrastructure occurred; the chloroplasts lost their normal parallel arrangement to the cell walls in al1 of the species and the c1oroplast membranes were broken by different points. The cel1 wal1s desintegrated in Eucalyptus viminalis and Eucalyptus globulus, while in other species remained without visible alterations. Eucalyptus fastigata was the specie less affected by the cold, although sorne ultraestructural alterations of chloroplasts were also noticed. K. W.: Chloroplast; Cel1 wall; Ultraestructural alterations.