The compensative effects of gravitation at the first stages of embryonic development stages have been investigated using slow clinorotation of embryoid bodies from mouse R1 stem cell lines. Semithin sections (1-2 microm) analysis and electron microscopy study of embryonic bodies cells allowed to reveal morphological features of cells at different maturation stages. Significant decrease in the number of embryonic stem cells undergoing apoptosis as well as noticeable reduction of "lacunas" relative areas were found in clinorotated embryonic bodies compared to control. We propose that large cyst absence may be caused by initial differentiation and morphogenesis stages delay associated with autophagy processes in embryonic bodies.