[Cellular differentiation and proliferation in corn roots grown in microgravity (Biocosmos 1985)]

A cytological study was performed on Maize roots (Zea mays) which were grown in space (flight Biocosmos 1985) and on control roots on earth. Two criteria were selected: cell elongation in the cortical zone in the four mm of the extremity of the root and mitotic activity of the meristem. The results show that in microgravity the length of the meristem is reduced of 1/3 and that its mitotic activity increases of about twofold comparatively to the synchronous control. In parallel the cell differentiation begin closer to the root cap junction. These results are discussed relative to the influence of gravistimulation on cell proliferation and cell differentiation in roots.