Lesquerella growth and selenium uptake affected by saline irrigation watercomposition

A greenhouse study was conducted to determine the effects of waters differi ng in salt composition on growth and selenium (Se) accumulation by lesquere lla (Lesquerella fendleri Gray S. Wats.). Plants were established by direct seeding into sand cultures and irrigated with solutions containing either (a) Cl- as the dominant anion or (b) a mixture of salts of SO42- and Cl-. F our treatments of each salinity type were imposed. Electrical conductivitie s of the irrigation waters were 1.7, 4, 8, and 13 dS m(-1). Two months afte r salinization, Se (1 mg l(-1), 12.7 muM) was added to all solutions as Na2 SeO4. Shoot growth was significantly reduced by increasing Cl-salinity. Reg ardless of salinity type, concentrations of Ca2+, Mg2+, Cl-, total-S, and S e were higher in the leaves than the stems, whereas K+ and Na+ were higher in the stem. Leaf-Se concentrations were not significantly affected by Cl-b ased irrigation waters, averaging 503 mg Se kg(-1) dry wt across salinity l evels, whereas leaf-Se decreased consistently and significantly from 218 to 13 mg kg(-1) as mixed salt salinity increased. The dramatic reduction in S e was attributed to SO42-:SeO42- competition during plant uptake. The stron g Se-accumulating ability of lesquerella suggests that the crop should be f urther evaluated as a potentially valuable phytoremediator of Se-contaminat ed soils and waters of low to moderate salinity in areas where the dominant anion in the substrate is Cl-. Published by Elsevier Science B.V.