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The cork oak (Quercus suber L.) is a tree which forms important forests that play a vital socioeconomic and environmental value in the Mediterranean basin. The multiple factors of overgrazing, biological invasion by introducing acacia trees, and repeated fires weaken the cork oak ecosystem and affect its natural regeneration. The purpose of this study is to increase the production of cork oak. With this aim, a test of controlled mycorrhization was carried out on the nursery where two commercial inocula--the arbuscular mycorrhizal (Symbivit) (S) and ectomycorrhizal (Ectovit) (E)--were brought separately and combined on cork oak seedlings cultivated on sterilized or non-sterilized soil. Statistical models revealed that the controlled inoculation improved the growth of the plants inoculated by IE, which had significantly increased mycorrhizal root colonization levels and cork oak growth compared to the treatments of the Symbivit (IS) and the non-inoculated plants (NI); these rates were lower in both substrates: sterile and non-sterile. It is known that the best mycorrhizal partners of cork oak are ectomycorrhizae, however, in the presence of arbuscular mycorrhizae, the mycorrhizal root colonization levels and the growth parameters were considerably enhanced compared to previous treatments IE, IS and NI. The dual colonization had shown positive effects on the improvement of the mycorrhizal potential of the soil. Indeed, EM % colonization was the most strongly correlated with growth parameters compared to other mycorrhizal parameters. This research underlines that the use of controlled inoculation based on commercial inoculum can be an effective alternative in the case where the local inoculum is not available, and thus time saving. [ABSTRACT FROM AUTHOR]

Desert truffles are hypogeous fungi, with an important role in the folklore and cuisine of many countries. They are mycorrhizal fungi belonging to the Ascomycetes and forming symbiotic associations with several species of the family Cistaceae. The plant-desert truffle association has been the subject of numerous studies. The main purpose of the present research was to characterise the mycorrhizal system between Tuberaria guttata (L.) Fourr and Terfezia arenaria (Moris) Trappe. Plants of T. guttata were grown in pots under greenhouse conditions. They were inoculated in vivo with a solution containing spores of T. arenaria. The mycorrhizal level was assessed after root staining. T. guttata roots were also collected from littoral dunes in northeastern Algeria in order to compare the mycorrhizal status under both natural and in vivo conditions. Two principal ectomycorrhizal morphotypes were observed: branched mycorrhizae and club-shaped mycorrhizae. Root staining and observations of semi-thin sections showed that the in vivo produced roots had an ectomycorrhiza with Hartig net and extracellular hyphae more or less organised in a “real” sheath. The less-developed sheath was seen in the branched mycorhhiza and the well-developed one in the club-shaped mycorrhiza. This is the first report of a sheathing ectomycorrhiza formed by a desert truffle species associated with herbaceous plant. [ABSTRACT FROM AUTHOR]

In arid and semi-arid lands, the spiny prickly pear (Opuntia ficus-indica) is an outstanding plant for soil conservation and restoration. To determine the role of Opuntia ficus-indica on vegetation recovery process in desertified areas of Southern Tebessa (Northeast Algeria), we investigated the effect of prickly pear plantation age and some soil properties (grain size, pH, electrical conductivity, organic matter, total nitrogen, available phosphorus, and CaCO3 equivalents) on native plant community. Vegetation cover and plant diversity were assessed by calculating the number of individual plants (N), species richness (S), their ratio (N/S), Shannon index, and Evenness in prickly pear plantation plots of different ages (control, 5 and 20 years). Even if surveyed soil parameters did not differ significantly among O. ficus-indica plantations, results of ANOVA testing the effect of Opuntia plantations on native vegetation traits revealed significant variation for plant abundance (P < 0.0001), N/S ratio (P = 0.003) and vegetation cover (P < 0.0001). Vegetation cover differed significantly with both prickly-pear plantation age (P = 0.031) and seasons (P = 0.019). Tukey's tests revealed that all vegetation traits were significantly higher on prickly pear plantations than in control plots. Multiple comparisons also showed that plant abundance, N/S ratio and vegetation cover were significantly different between both young and old plantations and the controls. Prickly pear cultures facilitated the colonization and development of herbaceous species by ameliorating the severe environmental conditions. In conclusion, the facilitative effect of O. ficus-indica has been clearly demonstrated for both abundance and cover of native vegetation. [ABSTRACT FROM AUTHOR]