Phytosociological, phenological and photosynthetic analyses of the vegetation of a highly polluted site

This work describes an ecological study on the vegetal component in a pilot area (hill A5) of a highly contaminated site (ACNA Cengio, Savona, Italy). The following analyses were performed: (i) phytosociological analysis of the vegetal component; (ii) phenological and synphenological analyses; (iii) evaluation of photosynthetic efficiency; and (iv) evaluation of the degree of mycorrhization. Most representative phytocoenoses belonged to the Artemisietea vulgaris , Galio-Urticetea and Molinio-Arrhenatheretea classes; the site was completely and densely covered by vegetation, but characterized by a rather poor floristic richness. Most plants were visibly suffering, as confirmed, at the physiological level, by fluorescence analysis of photosynthetic rate. Some important phenological phases were shorter than normal or even absent. Most plants were modestly colonized by arbuscular - mycorrhizal fungi, but the fungal structures within the roots were normal. Species belonging to the Leguminosae were, together with those belonging to the Graminaceae , the most representative; the former showed an almost normal photosynthetic efficiency, whereas other families did not.