EFFECTS OF SALINITY ON GERMINATION AND SEEDLING GROWTH OF PROSOPIS-FLEXUOSA (DC)

Prosopis flexuosa, the most widespread arboreal legume found on saline soils in Argentina, is regarded as an especially attractive species for the productive recovery of arid and salt-affected areas. The effects of salinity on germination and seedling growth of this species were studied. Salt tolerance during germination was examined in seeds collected from two populations growing either on saline or non-saline soil. Germination was assessed under various NaCl concentrations: 0, 0.2, 0.4, 0.6 and 0.8 M. Significant decreases in germination percentage were observed above 0.2 M NaCl. Variability was higher among individual trees than between populations and highest at 0.4 M NaCl. Salt tolerance at the seedling stage was analysed in 20-day-old seedlings, grown in pots with soil, treated for 90 days with NaCl solutions ranging between 0 and 0.4 M. The average seedling survival percentage for the trial was above 96%. A 50% decrease in final height was observed in the treatment with 0.4 M NaCl, where substrate in the pots had reached a final salt concentration of nearly 1 M NaCl. In Prosopis flexuosa, salt tolerance at the seedling stage appears to be greater than at the germination stage, suggesting that seedlings could be used for afforestation of salt-affected areas.