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Agricultural yields are under constant jeopardy as climate change and abiotic pressures spread worldwide. Using rhizospheric microbes as biostimulants/biofertilizers is one of the best ways to improve agro-agriculture in the face of these things. The purpose of this experiment was to investigate whether a native arbuscular mycorrhizal fungi inoculum (AMF-complex) might improve caper (Capparis spinosa) seedlings’ nutritional status, their morphological/growth performance and photosynthetic efficiency under water-deficit stress (WDS). Thus, caper plantlets inoculated with or without an AMF complex (+AMF and −AMF, respectively) were grown under three gradually increasing WDS regimes, i.e., 75, 50 and 25% of field capacity (FC). Overall, measurements of morphological traits, biomass production and nutrient uptake (particularly P, K+, Mg2+, Fe2+ and Zn2+) showed that mycorrhizal fungi inoculation increased these variables significantly, notably in moderate and severe WDS conditions. The increased WDS levels reduced the photochemical efficiency indices (Fv/Fm and Fv/Fo) in −AMF plants, while AMF-complex application significantly augmented these parameters. Furthermore, the photosynthetic pigments content was substantially higher in +AMF seedlings than −AMF controls at all the WDS levels. Favorably, at 25% FC, AMF-colonized plants produce approximately twice as many carotenoids as non-colonized ones. In conclusion, AMF inoculation seems to be a powerful eco-engineering strategy for improving the caper seedling growth rate and drought tolerance in harsh environments.

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The date, the palm tree (Phoenix dactylifera L.) is an important component of arid and semi-arid Mediterranean ecosystems, particularly in Morocco where it plays a considerable socio-economic and ecological role. This species is largely affected by desertification, global warming, and anthropic pressure. Salinity is a very worrying problem that negatively affects the growth and the physiological and biochemical activities of the date palm. In these arid zones, the main challenge is to develop new environmentally friendly technologies that improve crop tolerance to abiotic restraints including salinity. In this sense, Arbuscular mycorrhizal fungi (AMF) have received much attention due to their capability in promoting plant growth and tolerance to abiotic and biotic stresses. It is thus fitting that the current research work was undertaken to evaluate and compare the effects of native AMF on the development of the growth and tolerance of date palm to salt stress along with testing their role as biofertilizers. To achieve this goal, two complexes and two monospecific isolates of native and non-native AMF were used to inoculate date palm seedlings under saline stress (0 g·L−1 Na Cl, 10 g·L−1, and 20 g·L−1 Na Cl). The obtained results showed that salinity drastically affected the physiological parameters and growth of date palm seedlings, whilst the application of selected AMF significantly improved growth parameters and promoted the activities of antioxidant enzymes as a protective strategy. Inoculation with non-native AMF complex and monospecific isolates showed higher responses for all analyzed parameters when compared with the native complex and isolate. It therefore becomes necessary to glamorize the fungal communities associated with date palm for their use in the inoculation of Phoenix dactylifera L. seedlings.

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.