Different strategies of Cd tolerance and accumulation inArabidopsis halleriandArabidopsis arenosa

Pseudometallophytes are commonly used to study the evolution of metal tolerance and accumulation traits in plants. Within theArabidopsisgenus, the adaptation ofArabidopsis hallerito metalliferous soils has been widely studied, which is not the case for the closely related speciesArabidopsis arenosa. We performed an in-depth physiological comparison between theA.halleriandA.arenosapopulations from the same polluted site, together with the geographically close non-metallicolous (NM) populations of both species. The ionomes, growth, photosynthetic parameters and pigment content were characterized in the plants that were growing on their native site and in a hydroponic culture under Cd treatments.In situ, the metallicolous (M) populations of both species hyperaccumulated Cd and Zn. The NM population ofA.hallerihyperaccumulated Cd and Zn while the NMA.arenosadid not. In the hydroponic experiments, the NM populations of both species accumulated more Cd in their shoots than the M populations. Our research suggests that the twoArabidopsisspecies evolved different strategies of adaptation to extreme metallic environments that involve fine regulation of metal homeostasis, adjustment of the photosynthetic apparatus and accumulation of flavonols and anthocyanins.