Magnetic flux tubes reaching from the solar convection zone into the chromosphere have to pass through the relatively cool, and therefore highly non-ideal (i.e. resistive) photospheric plasma. It is shown that stationary MHD equilibria of magnetic flux tubes which pass through this region require an inflow of plasma into the tube and a deviation from isorotation along the tube axis. Although for characteristic parameters of thick flux tubes the effect is negligible, a scaling law indicates its importance for small-scale structures. The relevance of this inflow for the expansion of flux tubes above the photosphere is discussed.