Stripes and spin incommensurabilities are favored by lattice anisotropies.

Structural distortions in cuprate materials give a natural origin for anisotropies in electron properties. We study a modified one-band t-J model in which we allow for different hoppings and antiferromagnetic couplings in the two spatial directions (t(x) not equal to t(y) and Jx not equal to J(y)). Incommensurate peaks in the spin structure factor show up only in the presence of a lattice anisotropy, whereas charge correlations, indicating enhanced fluctuations at incommensurate wave vectors, are present but almost unaffected with respect to the isotropic case.