Effect of Soil Contamination on Biological Activities of Plant Species Growing in Peripheral Industrial Areas in Southeastern Tunisia

摘要

In recent decades industrial encroachment has affected many ecosystems including air, water and vegetation. Many plant species have revealed a strong capacity to survive in neighbourhoods of contaminated soil. Despite this, previous studies have emphasized the response of vegetation to heavy metals contamination, but none have examined those related to a cement plants industrial effect. This study was conducted in Gabes cement plant peripheries in southeastern Tunisia, where Lygeum spartum, Gymnocarpos decander, Atractylis serratuloides and Stipa retorta were found to grow abundantly. The aim of this work is to assess the physiological response of these species that was carried out along four sites: S1, (1 km), S2 (3 km), S3 (6 km) and the control site SC (12 km) to evaluate their tolerance to heavy metals and to select the most appropriate species for a phytoremediation attempt. Significant variation (p0.05) was evidenced between sites in Mg2+ content, CAT, POD, GST, APX activities, proline and water content. Understanding the effect of heavy metals contamination on the physiological response was carried out through a correlations test. A strong positive correlation was marked between enzymatic activities and heavy metals as well as minerals. An increase of heavy metals content in plants was correlated by calcium content, which was followed by rising POD, APX and GST activities. Lygeum spartum enzymatic response was unaffected between sites with a slight decrease in the control site except for the APX activity reflecting a better adaptation and tolerance to contaminated conditions where the accumulation of heavy metals were revealed to be higher than in other plants.