Abstract

Argan tree, the only representative species of the tropical family Sapotaceae in Morocco is distributed in arid and semi-arid areas. Tolerance to drought remains poorly described for this species; we applied five levels of drought stress and monitored growth variables and biomass production of seedlings in pot and in field propagated from seeds of eight genotypes from three geographical origins. Drought stress decreased seedlings height, basal diameter, leaf number, leaf area, and biomass production and water content but increased root / shoot length. Even under moderate or severe drought stress (1/4 and 0 FC), some genotypes (mother-trees) sustained shoot growth, they have taproots exceeding 50 cm, which are accompanied by a large number of lateral roots, more leaves and great leaf areas. But others showed an increase below-ground length and biomass indicating a higher root / shoot ratio under drought stress conditions. So, in order to enhance the survival rate and conserving rate of seedlings planting, appropriate human intervention is required to reduce the damage to Argan seedlings resulting from drought.

Key words: Argania spinosa, water stress, aridity, shoot, root, seedling biomass production.