Аннотация:Stellar populations (SPs) in Galactic globular clusters (GCs) exhibit specific dissimilarities as compared to those in open clusters. These are the manifestations of so-called multiple SPs in monometallic GCs, which are not observed in other environments, neither in open clusters nor in the field. We focus on stellar collisions, an unexplored factor which could at least be one of the key contributors to these dissimilarities. The stellar collisions do occur in the densest part of GCs but are of much lower probability in open clusters or improbable at all in the field. We draw attention and argue that the collisional blue stragglers (CBSs) observed in GCs are just the top of the iceberg of main sequence stars modified via collisions and accumulated in GCs during the cluster lifetime. We consider the expected impact of stellar collisions/merging on the characteristics of the modified stars in GCs and discuss the observed effects compatible with this process.