Nucleolar structure and function under clinorotation.

A nucleolus is the dynamic part of a cell nucleus where rDNA transcription, rRNA precursor processing and transport are proceeding. Investigations of the influence of microgravity and clinorotation on the structure and function of nucleolus began more than thirty years ago but, unfortunately, now there are only some articles concerning the nucleolar peculiarities in altered gravity. Available data about alterations of nucleolar morphology and function under the influence of high and low temperature, hypoxia and UV-microbeam irradiation allow us to put intent attention to the study of the nucleolus reactions on clinorotation. Therefore, the aim of our work was to investigate the ultrastructural organization and functional activity of nucleoli in Lepidium sativum root meristematic cells under clinorotation in order to understand whether a nucleolus can react to gravity.