ALTERACIONES ULTRAESTRUCTURALES EN LOS CLOROPLASTOS Y NÓDULOS DE LAS RAÍCES DE PLANTAS DE FRIJOL CAUPÍ DESARROLLADAS BAJO CONDICIONES DE ESTRÉS SALINO.

The ultrastructure of leaves chloroplast and root nodules from cowpea plants (Vigna unguiculata (L.) Walp.), var. IT 86 D-715, subjected to saline stress was evaluated by Transmission Electron Microscopy (TEM). Plants were exposed at 150 and 0,02 mM of NaCl treatments, considering 0,02 mM salt level as control. Native strain VIBA-1 (Bradyrhizobium liaoningense) isolated from saline soils of Cauto Valley (Cuba) was inoculated at sowing. Forty days after germination, samples of the same age and position from leaves and root nodules were taken for microscopy observations. Some ultrastructural modifications were detected by the salt effect in chloroplasts, mainly triggered by the great increase in the size of the starch granules. These modifications produced altered grana distribution. In nodule structure, when saline stress was applied, a weakness of peribacteroid membrane and high number of vesicles into infected cells were noted. Symbiosomes started deteriorating with some broken peribacteroidal membranes. A high vesiculation and degradation of some cellular organelle into uninfected cells were observed. [ABSTRACT FROM AUTHOR]