s+d pairing in orthorhombic phase of copper-oxides

A microscopical theory of electronic spectrum and superconductivity is form ulated within the two-dimensional anisotropic t-J model with t(x) not equal t(y) and J(x) not equal J(y). Renormalization of electronic spectrum and s uperconductivity mediated by spin-fluctuations are investigated within the Eliashberg equation in the weak coupling approximation. The gap function ha s d + s symmetry with the extended s-wave component being proportional to t he asymmetry t(y) - t(x). Some experimental consequences of the obtained re sults are discussed.