Physiological responses of Quercus suber to the effect of water deficit in presence of ectomycorrhizal fungi

Abstract

The Moroccan Maamora forest is one of the largest cork oak forests in the Mediterranean area. In this important forest, characterized by sandy soils, water disturbance is the major factor that leads to the degradation and destruction of cork oak stands. Ectomycorrhizal symbiosis is a good alternative and can induce functional and structural modi ications that alleviate Quercus suber plants from water stress. This study was carried out to assess the response of young cork oak plants inoculated by nine fungal isolates (Russul sp. Lactar controversus, Amanita pantherina, Cortinarius sp., Hebeloma sp., Boletus sp., Lactarius volemus, Inocybe sp. and Scleroderma sp.) to water de icit. The results showed that controlled mycorrhization improves signi icantly plants tolerance to drought stress. Boletus sp. was the most ef icient isolate that procured to cork oak seedlings a better stomatacal conductance, root and shoot dry weight and chlorophyll content. Also, the leaf water potential, proline and anthocyanin accumulation were lower in seedlings with Boletus inoculation. After drought stress stage, cork oak plants have been rehydrated and again, Boletus sp. produced a mean recovery of 60% while it was only 1% in plants control. These data clearly show that the inoculation of cork oak plants with ectomycorrhizal isolates, such as Boletus sp. could be a very interesting pathway in the sandy soils of Maamora and subsequently in determining the success of its regeneration programmes.