Cr‘S POLLUTION AFFECTED CONTENT OF ELEMENTS IN THE LEAVES OF TRAPA BISPINOSA EFFECTS OF Cd2+ ,Hg2+ ON GROWTH AND ACTIVITY OF SUPEROXIDE DISMUTASE AND PEROXIDASE IN TRAPA BISPINOSA ROXB.SEEDLINGS Phytotoxicity of Cu2+ on Physiolodical Indices and Ultrastructural Responses in Leaves of Trapa bispinosa Roxb.