Ultrastructural organization of cells in soybean root tips in microgravity.

Root apex cells of higher plants have unique structure and functions. In particular, the central cells of root cap are considered as the site of gravity perception in roots and are characterised by structural polarity, including directional sedimentation of amyloplasts with to gravity. Past studies have shown that root growth, structural organisation of the cells, and structural polarity of statocytes were affected in microgravity. Microgravity-grown plants also exhibited enhanced production of ethylene and decreased production of starch relative to ground controls. In this paper, the effects of microgravity and ethylene on ultrastructural organisation of the cells in soybean root apices are presented.