[Not Available].

An overview on the effects of real and simulated microgravity on certain cell components and processes, including new information obtained recently, is presented. Attention is focused on the influence of microgravity on the cytoplasmic membrane state, transcriptome and proteome, cell wall remodeling, and Ca2+-signaling in plant cells that are not specialised to gravity perception. It is emphasized the exceptional significance of the data on the organ-specific remodeling of the transcriptome and proteome in response to space flight, that discovers new advanced approaches to implement the fundamental and applied problems of plant space biology.

[Double fertilization in flowering plants: 1898-2008].

A short review of the results of investigations in the field of plant embryology in vivo and in vitro which are directly connected with the discovery of double fertilization in flowering plants by S.G. Navashin is presented.

[The growth and differentiation of root cap columella cells and the proper root grown in the stationary conditions and under clinorotation].

The results of light- and electron-microscopic investigations of root apices of Beta vulgaris 3-day-old seedlings grown in the stationary conditions and under clinorotation are presented. It was shown that ultrastructure and topography of organelles in root cap statocytes (graviperceptive cells) and in the cells of distal elongation zone clearly reflected the different direction in their growth and differentiation in space and time in dependence on specialization and functions. Cell growth and genetically determined differentiation occur similarly to control, although certain differences in ultrastructure are evident on metabolism changes.

[Alterations of nucleolar DNA localization caused by simulated microgravity].

The functions of the nucleolus responsible for the biosynthesis of ribosomes in altered gravity are still unclear. The location of nucleolar DNA both in control and simulated microgravity has been investigated using fluorescent and immunogold cytochemistry. We have determined the redistribution of rDNA in the nucleolar components accompanied by their ultrastructure changes.

[Altered gravity affects subnucleolus localization of fibrillarin and NopA64, the most important proteins of rRNA processing].

Fibrillarin and plant nucleolin homologue NopA64 are two important nucleolar proteins involved in pre-rRNA processing. To understand better the effects of the altered gravity environment on the nucleolus functioning we have investigated the location of fibrillarin and NopA64 in nucleolar subcomponents of cress (Lepidium sativum L.) root meristematic cells grown under simulated microgravity that was compared to the control cells grown in normal conditions at I g.