Growth promotion and mycorrhizal colonization of Argan (Argania spinosa (L.) Skeels) inoculated with the edible desert truffle Tirmania nivea (Desf.) Trappe.

This study presents the first evidence of the mycorrhizal compatibility between the edible desert truffle Tirmania nivea and the valuable fruit tree Argania spinosa. Seed germination trials demonstrated that soaking pre-treatment of argan seeds in hydrogen peroxide (9%) for five days combined with the application of a fungicide treatment on an inert sowing material maximized the seed germination of this tree species. The mycorrhizal synthesis was conducted under greenhouse conditions by inoculating, in vivo, the host plant seedlings with spores of T. nivea. The growth and mycorrhizal status of A. spinosa was assessed 15.5 months after inoculation. The desert truffle mycorrhization significantly promoted all the investigated morphological parameters of growth and improved the physiological performances of the host plant through enhancing plant water status and chlorophyll concentration. The mycorrhizal symbiosis led to the formation of typical desert truffle endomycorrhizae with intracellular coils. The resistance of A. spinosa to the harsh environmental conditions of desert habitats makes it a potential candidate for cultivation of desert truffles.