From in field to in vitro: response to heavy metal environmental pollution in Leptodyctium riparium

This study evaluated the biological effects of heavy metal pollution of the heavily contaminated channels Regi Lagni, running through the so-called “terra dei fuochi” (South Italy), using the aquatic moss L. riparium. This species is a efficient bioindicator of heavy metal pollution, accumulating different heavy metals taken from the aquatic environment (Basile et al, .2011). Biological effects of heavy metal pollution were assessed by studying metal bioaccumulation, ultrastructural damage, oxidative stress, and stress gene expression. Experiments were performed both on samples exposed in field in moss bags and in vitro-cultured in conditions reproducing the heavy metal pollution. Three sites were chosen as representative of the extreme polluted conditions. In vitro samples were exposed to the same HM concentrations as measured in the 3 sites. The results showed severe ultrastructural damage, increase of ROS production, induction of antioxidant enzymes and expression of stress gene. Those changes were observed both in the samples collected from the polluted sites and in those in vitro treated with the same heavy metal concentrations as in the field. In the in vitro test all the considered parameters were severely affected, although at a lower extent in comparison with the field experiment. The results showed that in vitro studies are useful indicators of the role exerted by the different stressors in environmental conditions. In addition, these results suggest L. riparium as a model organism in biomonitoring projects and the ultrastructural, enzymatic and genetic responses as promising biomarkers of heavy metal toxicity.