Germination and seedling survival of Argan (Argania spinosa) under experimental saline conditions

Solutions of NaCl at various concentrations (0, 2(.)5, 5, 7(.)5 and 10 gl(-1)) were used to treat argan (Argania spinosa (L.) Skeels) at germination and as container-grown seedlings. We assessed germination percentage, radicle length and dry weight as well as seedling survival and number of days before seedling collapse. Increasing salt concentration did not delay the beginning of germination but it lowered the germination rate and reduced the final germination percentage. At the seedling stage, increasing salinity levels resulted in decreasing growth, increasing ionic toxicity symptoms and reduced survival as compared to the control. Argan did not behave as a salt-tolerant species showing damage at as low as 2-5 gl(-1), the upper limit for survival being 7-5 gl(-1). However the effect mother-tree was highly significant indicating that much selective potential is probably available for breeding for salt tolerance within natural argan populations. (C) 2001 Academic Press.