Evaluation of arsenic phytoextraction efficiency of Pteris vittata under field conditions

The Chinese brake fern Pteris vittata is a well known arsenic hyperaccumulator plant and possesses features that can make it an ideal species for phytoremediation of As contaminated sites: fast growth rate, high biomass production and a high efficiency of As translocation from roots to fronds. Extensive research has been carried out using this plant under laboratory and greenhouse conditions, while more limited information is available on the behaviour of P. vittata when plants are grown directly in the field. This study summarizes and compares the results of field experiments conducted with this plant in contaminated sites located in northern Italy, characterized by different levels of contamination and soil characteristics. The research was aimed not only at estimating As extraction efficiency, but also at evaluating the most critical parameters for plant growth, since P. vittata is not a native species. Various experimental conditions have been tested, such as plant age, presence of other contaminants, influence of agronomic practices. In addition, the effect of mycorrhizal symbioses on plant growth and on arsenic phytoextraction efficiency was also investigated. P. vittata showed in general a high phytoextraction efficiency, but plant growth and survival were strongly affected by adverse pedoclimatic conditions. Mycorrhization had a positive effect on plant growth; however, it was not possible to point out a clear influence of mycorrhization on As phytoextraction.