Effect of weak magnetic field and low positive temperature on chromatin and nucleolus ultrastructure of rye and barley

Using two crops (rye, barley) we have demonstrated a fundamental difference in the structural organization of condensed chromatin, nucleolus and chromatin-RNP complexes in the experiments with the weakening (spherical ferromagnetic shield) and the enhancing (constant magnet) of magnetic field at low positive (−3-+1°C) and room temperatures (+24°C). As a model we used the spring and winter varieties of cereals placed after imbibition in the experimental conditions. We used the classic regime of seed vernalization (12 and 42 days at temperatures ranging from 0 to +4°C) for winter cereals and temperate climate zones of germination at room temperature in the control and experimental conditions.After experimental exposure the plants visually were observed during the growth until the transition to generative development. It is shown that the effect of a weak constant magnetic field (shielding) leads to a change in the ultrastructural organization of the nuclei that has been manifested in chromatin decondensation and formation of complicated chromatin-RNP complexes. There were three types of previously not described structures: 1 (A)-alternate, parallel stretches of condensed chromatin associated with the RNP and fully consisted with the peripheral component of the nucleolus, and then divided between a bright area, which can be traced thin thread-like formation, indicating a relationship with RNP condensed chromatin, 2 (B)-single strands of condensed chromatin in conjunction with the RNP and the characteristic separation, and 3 (C)-some parallel RNP complexes of chromatin extending from the nucleolus in the form of “pseudopods of amoeba”.The plating of imbibed seeds into a spherical shield conditions, and also under influence of enhanced magnetic field caused by constant magnet at room temperature and at low positive temperatures led to changes of chromatin compartmentalization, and of the nucleolus and chromatin-RNP complexes structure. Decondensation of chromatin and the appearance of RNP-chromatin complexes under shielding of magnetic field are reversible.