Ecotypic variation in selenium accumulation among populations of Stanleya pinnata

Ecotypic variation in selenium (Se) hyperaccumulation in plants is reported here among populations of Stanleya pinnata (Brassicaceae), which has a bro ad biogeographical range in the western USA. In a glasshouse study, Se and sulfur accumulation were examined in 16 popul ations of S. pinnata. Plants grown from seed (collected from sites represen ting the species range) were subjected to five treatments differing in sele nate (SeO42-) and sulfate (SO42-) concentrations. The populations differed in shoot Se concentration by 1.4- to 3.6-fold, dep ending on the treatment, and these concentrations were positively correlate d with the indigenous soil Se levels at the collection sites. Shoot S conce ntrations varied by less than two-fold, and did not correlate with the shoo t Se levels. All populations accumulated SeO42- preferentially over SO42-. By contrast, Brassica juncea seedlings grown in a similar solution series c onsistently accumulated SO42- preferentially over SeO42-. Biomass productio n 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 ar e common, and the broad adaptation of S. pinnata makes it an attractive can didate for phytoremediation.