ANATOMICAL CHANGES IN PROSOPIS-TAMARUGO PHIL SEEDLINGS GROWING AT DIFFERENT LEVELS OF NACL SALINITY

Seedlings of Prosopis tamarugo were grown in artificial substrates with additions, of 200, 400 and 600 mM NaCl, and without salt treatment. Salinity induced anatomical changes in the roots, stems and leaflets. The diameters of the roots of seedlings grown in the increasing salt concentrations (up to 400 mM) were progressively smaller and differentiation of the stelar tissues was delayed. At an NaCl concentration of 600 mM, the root structure was strongly altered. On the contrary, stem diameter increased as salinity rose. In the stems of seedlings grown in a concentration of 200 mM NaCl, secondary xylem differentiation appeared earlier than in the controls. At a concentration of 400 mM NaCl, disorganization of the vascular cylinder of the stem was evident. Leaflets of seedlings grown in 200 mM NaCl showed a delay in structural differentiation: no water-storage cells or 'special cells' could be seen. The leaflets from plants grown in 400 mM NaCl, had larger numbers of intercellular air spaces; probably an indication of the beginning of tissue disorganization. A progressive decrease in cell size of leaflets as salinity rose was also demonstrated. © 1991 Annals of Botany Company.