Tridimensional representation of the FP according to the fit given in Eq. (1), the color scale of the plane is related with the stellar mass. Light color symbols are located above the plane, while the dark ones are below it. Dots represent the SDSS local sample described in Sect. 2, diamonds correspond to the Erb et al. (2006) data at , and circles symbolise the data at from Maiolino et al. (2008). The yellow triangle represents the data of Rodrigues et al. (2008) at . The iso-density contours are subject to a projection of the SDSS data cloud onto the metallicity-SFR plane, and they are given only as a visual aid.