Trends between abundances and atmospheric parameters in the dwarfs of the sample. Upper left: no apparent trend between [Fe/H] and T_eff (correlation coefficient ρ = 0.03, with p value = 0.49). Upper middle: weak trend between [Na/H] and T_eff (ρ = −0.09, with p value = 0.03). Upper right: weak trend between [Al/H] and T_eff (ρ = −0.17, with p value close to zero). Lower left: a moderate trend (ρ = −0.34, with p value close to zero) between [Na/Fe] and T_eff appears for stars cooler than 5400 K (red dashed line). Lower middle: a moderate trend between [Al/Fe] and T_eff (ρ = −0.37, with p value close to zero). In red circles, we show the stars with [Fe/H] <−0.20 selected to understand whether the correlation with T_eff would affect the chemical evolution discussion. Lower right: the trend between [Al/Fe] and [Fe/H] thought to appear from the Galactic chemical evolution. We selected the stars with [Fe/H] <−0.20 (left of the red dashed line) to test whether they are the stars mainly affected by the correlation of [Al/Fe] with T_eff.