We have studied by in situ scanning tunneling microscopy the homoepitaxial electrodeposition on reconstructed and partially reconstructed Au(1 0 0) surfaces from chloride-containing solutions. Layer-by-layer, but strongly anisotropic, growth is observed on a completely reconstructed surface. On a partially reconstructed surface nucleation occurs on the unreconstructed areas, but the new islands formed tend to be pinned, growing anisotropically along the borders between reconstructed and unreconstructed areas. (C) 2011 Elsevier Ltd. All rights reserved.