A comparison of nickel and zinc uptake and translocation in three species of Brassicaceae: The Ni hyperaccumulator Odontarrhena corsica and two non-hyperaccumulators, Aurinia saxatilis and Lobularia maritima

The uptake and translocation of nickel (Ni) and zinc (Zn) were compared in hydroponics in three species of Brassicaceae, Lobularia maritima, Aurinia saxatilis, and Odontarrhena corsica at 2 and 10 μM Ni or Zn in the nutrient solution. Odontarrhena corsica, which is a known hyperaccumulator of Ni, but not of Zn, accumulated significantly more Ni in its roots and shoots than did L. maritima and A. saxatilis, which are both non-hyperaccumulators. The Ni translocation factor and Ni uptake were by far the highest in O. corsica, compared to L. maritima and A. saxatilis. The Zn translocation factor was significantly higher in L. maritima than in A. saxatilis and O. corsica. In the 10-μM Zn treatment, the Zn uptake was strongly and significantly higher in O. corsica than in L. maritima and A. saxatilis. Aurinia saxatilis is clearly an excluder, with low uptake and translocation, both for Ni and Zn. Of all the species, L. maritima showed by far the highest Zn translocation levels, both at 2 and 10 μM Zn in the nutrient solution (TF = ±0.4, compared to ±0.1 in A. saxatilis and O. corsica). Also its Ni translocation approached hyperaccumulator-like level (TF = ±1), though only in the 10-μM Ni treatment and still much lower than in O. corsica.