Lahcen Ouahmane

Improvement of Cupressus atlantica Gaussen growth by inoculation with native arbuscular mycorrhizal fungi

Aims: The study aimed to determine whether inoculation with native arbuscular mycorrhizal (AM) fungi could improve survival and growth of seedlings in degraded soils of Morocco.

High potential of symbiotic interactions between native mycorrhizal fungi and the exotic tree Eucalyptus camaldulensis for phytostabilization of metal-contaminated arid soils.

Abstract Waste dumps generated by mining activities contain heavy metals that are dispersed into areas leading to significant environmental contamination. The objectives of this study were (i) to survey native plants and their associated AM fungal communities from waste soils in a Moroccan mine site and (ii) to follow Eucalyptus growth in soil collected from the waste-mine. AM spores from native plant species were collected from the mining site and the surrounding uncontaminated areas were multiplied and inoculated onto Eucalyptus camaldulensis. The results showed that (i) the native plant species recorded in the waste did not show an active metal uptake, (ii) the selected native plant species are associated with AM mycorrhizal fungi and (iii) the use of AM fungi adapted to these drastic conditions can improve the growth of the fast-growing tree, E. camaldulensis and its tolerance to high soil Cu content. In conclusion, it is suggested that in order to define efficient low-cost phytostabilization processes, the use of native resources (i.e., mixtures of native mycorrhizal fungi) in combination with fast-growing tree species such as Eucalyptus, could be used to optimize the establishment of a permanent cover plant in contaminated areas.

Monitoring the development of nurse plant species to improve the performances of reforestation programs in Mediterranean areas

In the Mediterranean basin, a millenarian history of overexploitation has lead to the loss of most primeval forests and an increase of the surface area covered by shrublands that represent stages of degradation of mature forests. In this situation, and since environmental characteristics act as barriers to succession, human intervention is usually necessary to improve recovery of woodlands. Reafforestation is a common practice in Mediterranean areas to achieve this aim but its performances are very low with high rates of early mortality making this practice unprofitable in ecological as well as in economic terms.

Seasonality of mycorrhizal attributes, soil phosphorus and nitrogen of Juniperus phoenicea and Retama monosperma boiss. in an Atlantic sand dunes forest

ABSTRACT 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.