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 f or the productive recovery of arid and salt-affected areas. The effect s of salinity on germination and seedling growth of this species were studied. Salt tolerance during germination was examined in seeds colle cted 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 wer e observed above 0.2 M NaCl. Variability was higher among individual t rees than between populations and highest at 0.4 M NaCl. Salt toleranc e at the seedling stage was analysed in 20-day-old seedlings, grown in pots with soil, treated for 90 days with NaCl solutions ranging betwe en 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 tre atment with 0.4 M NaCl, where substrate in the pots had reached a fina l salt concentration of nearly 1 M NaCl. In Prosopis flexuosa, salt to lerance at the seedling stage appears to be greater than at the germin ation stage, suggesting that seedlings could be used for afforestation of salt-affected areas.