whe a glass rod is rubbed with silk rod glass rod posses +ve and silk posses -charge . how the mass of each body be effected?

Positive charge in glass means some electrons from the glass rod's surface has been shifted to the silk cloth. Now since electrons has got mass, albeit very small, so the glass rod has lost mass while the silk cloth that had a negative charge has gained mass. But due to the very low mass of the electrons, this mass difference may not be detected.