The present study aims to elucidate the impact of arbuscular mycorrhizal fungi (AMF) inoculation and partial root drying (PRD), or regulated deficit irrigation (RDI) techniques on the growth, physiology and biochemistry of melon plants under three water regimes: control (100% of field capacity (FC) (C100%)), 75% of FC (PRD75%) and 50% of FC (PRD50% and RDI50%). The experiment was carried out under semi-controlled greenhouse conditions and the AMF inoculum used was a field-sourced native Aoufous consortium. Obtained results show an increase in shoot dry weight in inoculated plantss under PRD75% and PRD50% by 12 and 9% respectively, compared to C100%. Mycorrhizal plants under PRD75%, PRD50% and RDI50% maintained the highest relative water content, leaf water potential (Ψleaf) and stomatal conductance, as well as photosynthetic pigments, compared to their respective control plants. In addition, PRD75%+AMF and RDI50%+AMF recorded the highest values of evapotranspiration. AMF increased total soluble sugars, proteins, and proline contents in response to PRD and RDI. Our results demonstrate that PRD75%, PRD50% and RDI50% in combination with AMF were the most effective treatments for improving growth, physiological and biochemical traits of melon under water stress.

The impact of salt stress on the growth and phosphorus utilization efficiency (PUE) of two leguminous species: Retama monosperma and Acacia gummifera was studied. The effectiveness of arbuscular mycorrhizal fungi (AMF) to mitigate salt stress was furthermore assessed. Growth, N and P tissue concentrations, mycorrhizal root colonization frequency and intensity, and P utilization efficiency (PUE) in the absence or presence of AMF were evaluated under no salt (0 mM L⁻¹) and three salt (NaCl) concentrations of (25, 50 and 100 mM L⁻¹) using a natural sterilized soil. A significant difference in mycorrhizal colonization intensity, root-to-shoot ratio, P uptake, PUE, and N uptake was observed between the legume species. Salt stress inhibited the shoot and root growth, and reduced P and N uptake by the legume species. Mycorrhizal inoculation aided to mitigate the effects of salt stress with an average increase of shoot and root growth responses by 35% and 32% in the inoculated than in the non-inoculated A. gummifera treatments. The average shoot and root growth responses were 37% and 45% higher in the inoculated compared to the non-inoculated treatments of R. monosperma. Average mycorrhizal shoot and root P uptake responses were 66% and 68% under A. gummifera, and 40% and 95% under R. monosperma, respectively. Mycorrhizal inoculated treatments consistently maintained lower PUE in the roots. The results provide insights for further investigations on the AMF conferred mechanisms to salt stress tolerance response by A. gummifera and R. monosperma, to enable the development of effective technologies for sustainable afforestation and reforestation programs in the Atlantic coast of Morocco.

Two leguminous plant species: Retama monosperma and Acacia gummifera were selected for water deficit tolerance test for future use in reforestation programs of the Atlantic sand dunes forest of Essaouira region. Mycorrhizal fungal colonization was used to help plants amend the water deficit. To assess R. monosperma and A. gummifera response to water stress and the effectiveness of mycorrhizal formation alleviating it, two categories for each plant species were made, one inoculated with mycorrhizal fungi and the other not, were submitted to a hydric deficit treatment of four levels for 6 months. This treatment impact on the plants was assessed by comparing root/shoot dry weight ratios, levels of nitrogen and phosphorus, and by measuring mycorrhizal colonization frequencies and intensities. Results showed that these parameters were significantly affected by water deficit. The presence of the mycorrhizal fungi had significantly enhanced plants phosphorus uptake by 72–124% for Acacia gummifera and 87–161% for Retama monosperma. Nitrogen uptake was increased by 134–388% for Retama monosperma and 510–901% for Acacia gummifera. The colonization frequencies changed significantly only for the treatment extreme level and stayed between 80%-90% for the other levels. The mycorrhization intensities showed significant lessening between each treatment level decreasing from 35% to 10%.

This study focused on the mitigation of the negative impact of salinity stress over time on the growth and development of Phoenix dactylifera plants using compost and/or arbuscular mycorrhizal fungi (AMF). The experiment had eight treatments in a randomized design. The treatments consisted of a control, AMF (native consortium) and compost (produced from green waste). The treatments were applied separately or in combination in the presence of 240 mM NaCl (saline condition) or 0 mM NaCl (non-saline condition) after 10 and 14 months of cultivation. Our results show that saline stress increased toxic ion (sodium and chlorine), proline, soluble sugars and stress marker (H₂O₂ and MDA) contents. At the same time, it lowered growth traits, mycorrhizal colonization, leaf water potential and nutrients (nitrogen (N), potassium (K), phosphorus (P), calcium (Ca)) and photosynthetic pigment concentrations. The application of compost and AMF individually or in combination alleviated salt-induced effects through mechanisms such as an increase in nutrient absorption (P, N, K and Ca), photosynthetic pigment content, relative water content, stomatal opening, leaf water potential, photosystem II efficiency, organic osmolyte content (proline and soluble sugars) and antioxidant enzyme activities (SOD, APX, CAT and POD) and reduction in lipid peroxidation and H₂O₂ content. Our results also show that the tolerance strategies of date palm to salinity were progressively improved over time in treated plants and especially in date palms grown in the presence of the two biofertilizers. Between 10 and 14 months of cultivation, growth parameters increased with a significant improvement in nutrient contents, a reduction in the concentrations of toxic ions and stress markers, and regulation of the antioxidant system (antioxidant enzyme activity and osmolyte content) in both leaves and roots. In conclusion, this investigation highlights the effectiveness of dual application of compost and native AMF in mitigating the deleterious effects of salinity on date palm with an improvement in the tolerance over time.

Seasonal variation of mycorrhization attributes in a degraded ecosystem seems to be key information in conceiving rehabilitation programs that use mycorrhized plantations specific to that ecosystem. In order to record seasonality of arbuscular mycorrhizal fungi in an Atlantic sand dunes forest, root colonization and spores abundance alongside rhizospheric phosphorus and nitrogen of two plant species: Juniperus phoenicea and Retama monosperma, endemic to Essaouira sand dunes forest, were followed through three years. The findings were tested for statistical significance and correlated among each and to some meteorological variables: temperatures, precipitations, and humidity. Results showed that mycorrhization frequencies and intensities and spores densities changed seasonally. They had their peak at late winter-early spring and their low at summer. Phosphorus and nitrogen evolved significantly following seasons. Significant negative correlation was noted between phosphorus and mycorrhizal attributes evolution. Nitrogen correlated positively and significantly though weakly with R. monosperma mycorrhizal attributes. The correlations between mycorrhizal attributes and meteorological variables were not all evident except for temperatures and temperatures-precipitations combination, which had a direct negative impact on mycorrhizal attributes.