Arsenic accumulation and distribution in Pteris vittata fronds of different maturity: Impacts of soil As concentrations.

Arsenic (As) hyperaccumulator Pteris vittata is efficient in As uptake, translocation and accumulation, but the impacts of soil As concentrations on As accumulation and distribution in P. vittata are still unclear. The impacts of soil As (7.3, 63 and 228 mg kg^-1) on plant growth and As accumulation in P. vittata after 6 months of growth were evaluated. Arsenic concentrations in the roots, midribs and pinna margin of P. vittata fronds of different maturity were determined by inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy coupled with an energy dispersive spectrometer (SEM-EDS). While moderate As level at As₆₃ didn't impact P. vittata growth, higher As at As₂₂₈ decreased plant biomass by 38%. Under As stress, more As was accumulated in the senescing fronds (47%) and mature fronds (11%) than the young fronds. In senescing fronds, As concentrations in pinna margin were 2.3 times that of the midribs, consistent with As-induced necrotic symptom. Arsenic distribution based on SEM-EDS analysis revealed good correlation between Si and As in the pinnae (r = 0.49). Our data showed that As accumulation in pinna margin caused necrosis and Si may have a potential role in As detoxification in P. vittata.