Element abundance ratios [X/Fe] versus [Fe/H] for the samples of stars without planets (green empty squares), stars with planets (red empty triangles), BD-host stars (blue filled circles), stars without known BD companions from the CORALIE sample (blue empty circles), and stars with discarded BD candidates (violet filled circles). At the top-left corner of each panel, the mean standard deviation of the abundance measurements are shown for the stars without planetary companion (σ_NP), stars with planets (σ_WP), and stars with confirmed BD companions (σ_BD).