DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI IN MEDITERRANEAN AGROECOSYSTEMS AS AFFECTED BY AGRICULTURAL PRACTICES

摘要

Arbuscular mycorrhizal (AM) fungi (Glomeromycota) are obligate symbionts, living in association with the roots of most land plants, including the large majority of crops (Smith and Read, 2008). AM fungi (AMF) are key organisms of the soil/plant system, fundamental for soil fertility and plant nutrition, which is facilitated by the large extraradical mycelial network spreading from mycorrhizal roots into the soil, able to actively absorb, translocate and transfer mineral nutrients, such as P, N and Zn from the soil to their host plants (Smith & Read, 2008). In agroecosystems, agricultural practices such as ploughing and chemical inputs affect the composition and structure of AM fungal communities, with negative effects on soil biological activity, as revealed by AMF spore occurrence and DNA sequences extracted from plant roots (Helgason et al., 1998; Oehl, 2003). As a consequence, any assessment of soil quality - the capacity of a soil to sustain biological productivity, maintain environmental quality, and promote plant health (Doran and Parkin, 1994) - should include the evaluation of AM fungal populations.