Application of Arbuscular Mycorrhizal Fungi Isolates from Semi-arid Mediterranean Ecosystems as Biofertilizers in Argan Tree Development

In semi-arid Mediterranean ecosystems, biotic and abiotic constraints have led to intense forest destruction and ecosystem deterioration and particularly to limitation in the production of Argan tree. Reforestation is thus more than ever a major challenge and an absolute necessity. The use of arbuscular mycorrhizal fungi (AMF) is of great importance in the processes of sustainable regeneration of the vegetation cover, given their roles in the improvement of plant growth and in the protection of soils. In the current study, Argan seedlings were inoculated with five arbuscular mycorrhizal fungi complexes and six arbuscular mycorrhizal fungi monospecific isolates. Growth, nutrition, photosynthetic pigments, and mycorrhizal colonization were under study. The soil samples were obtained from different ecosystems. Trap culture with Maize (Zea mays L.) was used for the production of mycorrhizal inoculum directly for complexes. Monospecific isolates were then produced from spore suspension using the technique of micropipette tips. Germinated seeds of Argan tree were inoculated separately with eleven fungal inoculants, under nursery conditions. Eight-month aged seedlings were compared for their growth and nutritional status. All the considered AMF inoculants stimulated significantly the growth of Argan seedlings; an increase in plant height between 33 and 70% was recorded. The aerial dry weight showed an increase of 62 to 124%, and the root dry weight showed an increase of 24 to 86% compared to the control. Similarly, the mineral contents in inoculated seedlings were significantly increased compared to the control non-inoculated seedlings. The analysis of the chlorophyll contents in leaves showed a significant improvement in inoculated seedlings. In conclusion, this first use of arbuscular mycorrhizal fungi isolates had shown that either complexes or monospecific isolates could improve significantly growth, mineral nutrition, and photosynthesis of Argan seedlings under nursery conditions. Hence, the use of inoculation with suitable consortium from these isolates is a recommended eco-friendly strategy for the restoration of degraded Argan ecosystems.

Automated summary

In semi-arid Mediterranean ecosystems, constraints have led to intense forest destruction and ecosystem degradation, particularly affecting the production of the Argan tree. The use of arbuscular mycorrhizal fungi has been shown to significantly improve the growth, mineral nutrition, and photosynthesis of Argan seedlings, making it a recommended eco-friendly strategy for the restoration of degraded ecosystems.