A method of separating fluid-suspended plant embryos from immature embryogenic tissue comprising the steps of: a) providing a suitable separator container, said container containing fluid having a density lower than of the embryos to be separated, being essentially cylindrical in shape, having an essentially flat bottom wall and an essentially vertical axis, and further comprising a conduit in communication with the fluid in the container at the axial region of the bottom wall during operation and means for inducing an axisymmetric rotating flow being a rotating object positioned inside the container; b) creating a sink vortex at the axial region of the bottom wall by draining fluid from said conduit; and inducing an axisymmetric rotating flow in the fluid relative to the bottom wall by the rotation means, thus: i) creating a viscous boundary layer at the bottom wall; and ii) creating a radial pressure gradient in the separator container; c) introducing the fluid-suspended embryos and immature embryogenic tissue to be separated into the fluid present in the separator container at a location away from the bottom wall, thus: i) sedimenting the embryos faster than the immature embryogenic tissue; ii) allowing the embryos to enter the viscous boundary layer while not allowing the immature embryogenic tissue to enter the viscous boundary layer; iii) drawing the embryos entering the viscous boundary layer into the axial region of the bottom wall; and d) collecting embryos from said axial region of the bottom wall in the fluid drained from the conduit, whereby the embryos collected are essentially separated from immature embryogenic tissue. a) providing a suitable separator container, said container containing fluid having a density lower than of the embryos to be separated, being essentially cylindrical in shape, having an essentially flat bottom wall and an essentially vertical axis, and further comprising a conduit in communication with the fluid in the container at the axial region of the bottom wall during operation and means for inducing an axisymmetric rotating flow being a rotating object positioned inside the container; b) creating a sink vortex at the axial region of the bottom wall by draining fluid from said conduit; and inducing an axisymmetric rotating flow in the fluid relative to the bottom wall by the rotation means, thus: i) creating a viscous boundary layer at the bottom wall; and ii) creating a radial pressure gradient in the separator container; i) creating a viscous boundary layer at the bottom wall; and ii) creating a radial pressure gradient in the separator container; c) introducing the fluid-suspended embryos and immature embryogenic tissue to be separated into the fluid present in the separator container at a location away from the bottom wall, thus: i) sedimenting the embryos faster than the immature embryogenic tissue; ii) allowing the embryos to enter the viscous boundary layer while not allowing the immature embryogenic tissue to enter the viscous boundary layer; iii) drawing the embryos entering the viscous boundary layer into the axial region of the bottom wall; and i) sedimenting the embryos faster than the immature embryogenic tissue; ii) allowing the embryos to enter the viscous boundary layer while not allowing the immature embryogenic tissue to enter the viscous boundary layer; iii) drawing the embryos entering the viscous boundary layer into the axial region of the bottom wall; and d) collecting embryos from said axial region of the bottom wall in the fluid drained from the conduit,