congress pant science and biosecurity 2019

Pteris vittata, a fern able to hyperaccumulate arsenic (As) in its fronds, has been object of a number of studies aimed to understand the mechanisms involved in As absorption and tolerance. This study has been focused on a new mechanism, As leaching, already observed, but not explained, in P. vittata, based on the possible involvement of hydathodes, not yet described in this fern. P. vittata has two types of fronds: trophophylls, the first fronds that develop from the gametophyte with only trophic function, and trophosporophylls, mature fronds that combine the trophic function with spore reproduction. Stereomicroscopic observations showed in trophosporophylls the presence of swollen veins in their terminal parts, associated with specialized adaxial epidermal cells. SEM-EDX analysis showed that in presence of As, secretions occurred on the adaxial epidermal cells of trophosporophylls; EDX analyses showed that these secretions contained high As levels. TEM analysis reported that the structures identified in trophosporophylls fronds were hydathodes. These results, useful in basic research, also suggest that in phytoremediation processes under field conditions, there is the need to know the atmospheric conditions before harvesting plants, to avoid the loss of As in the environment.