Resistance mechanisms of Hydrocotyle ranunculoides to Cr(VI): A biolfilter plant

Hydrocotyle ranunculoides is an aquatic macrophyte with natural ability for removing heavy metals from environment. The understand of the mechanisms that makes this plant species tolerant and able to remove Cr(VI) is essential for proposing biofilters devices for watercourses decontamination. Therefore, this research aimed to identify the main effects of H. ranunculoides that could explain its tolerance to this heavy metal. For such, treatment with K2Cr2O7 with 7 days exposure was performed, along with evaluation regarding growth parameters, photosynthetic pigment, lipid peroxidation via TBARS assay, total phenolic compounds, antioxidant enzymes, FT-IR, chromium and nutrients contents, phytoremediation indexes, surface and cytological observations along with TGA analysis. The results found suggested that H. ranunculoides demonstrated adaptive response to chromium, as the plant seems to present photosynthetic pigment restoration, alteration in functional groups, and alteration in epidermal cells. Considering all the tolerance and excellent removal potential by this plant, it is then proposed a floating biofilter device in order to apply this plant species for chromium decontamination purposes. [Display omitted] •H. ranunculoides is as a high potential phytoremediation plant.•H. ranunculoides tolerates high amounts of Cr(VI).•H. ranunculoides developed mechanisms to chromium resistance.•The plant present great potential for use in floating biofilter device.