Comparison of the metallicity scale derived with lists MASH and ASPL as a function of the T_eff obtained with ASPL list for M1 (upper panel) and M2 (lower panel). In each plot, the null, ±0.1 and ±0.2 abundance differences are represented by the continuous, the dotted and the dashed lines respectively. Red dots refer to the giants while black squares refer to the dwarfs.