Context :

Aims : We use catalogues of superclusters of galaxies from the 2dF Galaxy Redshift Survey to study the properties of galaxies in superclusters .

Methods : We compare the properties of galaxies in high and low density regions of rich superclusters , in poor superclusters and in the field , as well as in groups , and of isolated galaxies in superclusters of various richness .

Results : We show that in rich superclusters the values of the luminosity density smoothed on a scale of 8 h ^ { -1 } Mpc are higher than in poor superclusters : the median density in rich superclusters is \delta \approx 7.5 , in poor superclusters \delta \approx 6.0 .
Rich superclusters contain high density cores with densities \delta > 10 while in poor superclusters such high density cores are absent .
The properties of galaxies in rich and poor superclusters and in the field are different : the fraction of early type , passive galaxies in rich superclusters is slightly larger than in poor superclusters , and is the smallest among the field galaxies .
Most importantly , in high density cores of rich superclusters ( \delta > 10 ) there is an excess of early type , passive galaxies in groups and clusters , as well as among those which do not belong to groups or clusters .
The main galaxies of superclusters have a rather limited range of absolute magnitudes .
The main galaxies of rich superclusters have larger luminosities than those of poor superclusters and of groups in the field ( the median values are correspondingly M _ { bj } = -21.02 , M _ { bj } = -20.9 and M _ { bj } = -19.7 for rich and poor superclusters and groups in the field ) .

Conclusions : Our results show that both the local ( group/cluster ) environments and global ( supercluster ) environments influence galaxy morphologies and their star formation activity .