Arsenic alters uptake and distribution of sulphur in P teris vittata

Low‐molecular‐weight thiol ( LMWT ) synthesis has been reported to be directly induced by arsenic ( A s) in P teris vittata , an A s hyperaccumulator. Sulphur ( S ) is a critical component of LMWTs . Here, the effect of A s treatment on the uptake and distribution of S in P . vittata was investigated. In P . vittata grown under low S conditions, the presence of A s in the growth medium enhanced the uptake of SO 4 2− , which was used for LMWT synthesis in fronds. In contrast, A s application did not affect SO 4 2− uptake in N ephrolepis exaltata , an A s non‐hyperaccumulator. Moreover, the isotope microscope system revealed that S absorbed with A s accumulated locally in a vacuole‐like organelle in epidermal cells, whereas S absorbed alone was distributed uniformly. These results suggest that S is involved in A s transport and/or accumulation in P . vittata . X ‐ray absorption near‐edge structure analysis revealed that the major A s species in the fronds and roots of P . vittata were inorganic A s( III ) and A s( V ), respectively, and that A s– LMWT complexes occurred as a minor species. Consequently, in case of A s accumulation in P . vittata , S possibly acts as a temporary ligand for A s in the form of LMWTs in intercellular and/or intracellular transport (e.g. vacuolar sequestration).