Ecotypic variation in selenium accumulation among populations of Stanleya pinnata

Abstract

• Ecotypic variation in selenium (Se) hyperaccumulation in plants is reported here among populations of Stanleya pinnata (Brassicaceae), which has a broad biogeographical range in the western USA. • In a glasshouse study, Se and sulfur accumulation were examined in 16 populations of S. pinnata. Plants grown from seed (collected from sites representing the species range) were subjected to five treatments differing in selenate (SeO₄²⁻) and sulfate (SO₄²⁻) concentrations. • The populations differed in shoot Se concentration by 1.4- to 3.6-fold, depending on the treatment, and these concentrations were positively correlated with the indigenous soil Se levels at the collection sites. Shoot S concentrations varied by less than two-fold, and did not correlate with the shoot Se levels. All populations accumulated SeO₄²⁻ preferentially over SO₄²⁻. By contrast, Brassica juncea seedlings grown in a similar solution series consistently accumulated SO₄²⁻ preferentially over SeO₄²⁻. Biomass production differed up to three-fold between populations. • S. pinnata is a primary Se accumulator, but populations exhibit significant ecotypic differences in Se accumulation. Environmental concerns about Se are common, and the broad adaptation of S. pinnata makes it an attractive candidate for phytoremediation.