A comparative analysis of tomato roots regenerated in vitro on media supplemented with different NaCl concentrations (0–250 mM) has been carried out. A morphogenetic study performed at the organ level has determined rhizogenesis-inhibiting NaCl concentrations, while the morphometric analysis of regenerated roots in juvenile seedlings has registered such characteristics as their number, length, and fresh/dry weight. A cytological study has revealed some tissue disorders, such as changes in the vacuolization of root cap cells and root cortex cells (RCC) under salinity conditions. At some NaCl concentrations, significant changes in the cells of these tissues have been observed in relation to such parameters as the root cap length (50–100 and 250 mM NaCl), the number of root cap layers (50, 75, 150–250 mМ NaCl), the area of central cylinder cells (CCCs, 75–150 and 250 mM NaCl), the RCC area (100–200 mM NaCl), and the nucleolus to nucleus ratio (25, 50, and 200 mM NaCl). Using cytophotometry, we have shown there to be an increase in the number of interphase cells of the root meristem in the G2 phase with a simultaneous decrease of this parameter in the G1 phase. Immunofluorescent labeling has revealed various disorganizations in the alpha-tubulin cytoskeleton of interphase root meristem cells. Using transmission electron microscopy, we have revealed structural changes in plastids of root cap cells, RCC, and CCC, as well as changes in the organization of a nuclear compartment in RCC occurred in the presence of 150 mM NaCl. The studied characteristics can be used for a comparative evaluation of tomato genotypes under salinity at different levels of their organization. The proposed approach can be also used for crops that have no difficulties with induced rhizogenesis in vitro.

Improving plant resistance to unfavorable environmental factors is one of the important tasks of modern agricultural production.The cultivated tomato is highly sensitive to salinity.Understanding the physiological, biochemical, molecular and genetic adaptive mechanisms of tomato resistance to salinity as a complex trait is an essential part of most fundamental studies, the results of which are increasingly finding practical application during the last decade.However, the data on the effect of sodium chloride on cell organization of different tomato tissues and organs are scarce.Thus, the purpose of the study was to investigate cell organization of the epidermis and parenchyma cortical tissues of tomato hypocotyl (Solanum lycopersicum L. line YaLF and cultivar Rekordsmen) under chloride salinity in vitro.Fragments of 10-12-day-old aseptically germinated tomato seedlings, whose roots have been removed, were transferred on root induction medium ( 1 /2 МS, 2 % sucrose, 0.2 mg/l indole-3-butyric acid) supplemented with 0-250 mМ NaCl.After 8 days in culture, middle part of hypocotyls were excised from rooted seedlings and prepared for light microscopy.Histological examination revealed significant differences between genotypes in shape and average cross-sectional areas of the epidermal and cortical parenchyma cells of hypocotyl.The addition of Na+ and Cl  ions to culture medium significantly affected the size of the intercellular spaces in the cortical parenchyma as well as the average cross-sectional areas and shape epidermal and cortical parenchyma hypocotyl cells of both tomato genotypes.The average cross-sectional areas of epidermal and cortical parenchyma hypocotyl cells of tomato line YaLF under 50 mM NaCl were significantly less (1.2 and 1.6 times, respectively) compared with control conditions (medium without NaCl).Epidermal and cortical parenchyma hypocotyl cells of tomato cultivar Rekordsmen decreased in size at higher concentrations of NaCl in the culture medium (100 and 150 mM NaCl, respectively).Dramatic increase in the cells areas of both tissue types of tomato line YaLF were observed under 250 mM NaCl salinity.In addition, under high salinity treatments there was a considerable change in the shape of epidermal (cells obtained angular contours) and cortical parenchyma hypocotyl cells (cell flattening) of line YaLF.Unlike line YaLF, the cross-sectional areas of epidermal and cortical parenchyma hypocotyl cells of tomato cultivar Rekordsmen was no significant differences between 0 and 250 mM NaCl treatment.The dramatic difference between the two tomato genotypes was observed by a change in the cross-sectional areas of intercellular spaces in cortical parenchyma hypocotyl cells under salt treatments.Epidermal and cortical parenchyma cells of tomato hypocotyls cultivar Rekordsmen were less sensitive to the presence of NaCl in the culture medium, compared with the line YaLF.The revealed changes in shape and size of epidermal and cortical parenchyma hypocotyl cells can be used as cytological markers for comparative evaluation of tomato genotypes in sensitivity and/or resistance to salinity.

Исследовано влияние типа экспланта, а также вида и концентрации регуляторов роста на индукцию процессов каллусообразования и соматического органогенеза побегов in vitro четырех генотипов томата российской селекции. Проведено цитологическое изучение каллусной ткани. Установлено, что сорта томата обладают существенно большей способностью к непрямому органогенезу побегов по сравнению с гибридом F1. Для большинства исследуемых генотипов наибольшая частота соматического органогенеза побегов, а также их число на один эксплант были отмечены при культивировании семядольных листьев на питательной среде Мурасиге–Скуга, содержащей 2 мг/л зеатина в сочетании с 0.1 мг/л 3-индолилуксусной кислоты. Разработана эффективная методика непрямого соматического органогенеза побегов из различных эксплантов сортов томата с частотой >80%.

Ultrastructural organization of chloroplasts and mitochondria of transgenic tomato plants expressing the FeSOD1 gene from Arabidopsis thaliana (L.) Heynh. with the pea rbcS gene leader sequence under chloride and sulfate salinity has been studied. Dark respiration of transgenic tomato regenerants under stress conditions has been estimated. It has been established that expression of the FeSOD1 gene in transgenic tomato plants under salinity leads to a decrease in damage of ultrastructure organization of plastids and mitochondria and affects the size and shape of their inclusions, suggesting a protective effect of this gene under salinity. The obtained experimental data show the effectiveness of using a genetic engineering strategy of redirection and subsequent accumulation of cytoplasmic Fe-dependent SOD from Arabidopsis thaliana (L.) Heynh. in chloroplasts for increasing the tolerance of crops to salt stress.

The influence of explant type as well as of the type of growth regulators and concentration on callus induction and somatic organogenesis of shoots was studied in vitro on four tomato genotypes of Russian breeding. Cytological study of callus tissue was conducted. It was established that tomato varieties have a substantially greater ability to indirect shoot organogenesis compared with the F1 hybrid. The highest frequency of somatic organogenesis of shoots, as well as their number per explant, was observed for most of the genotypes studied during the cultivation of cotyledons on Murashige-Skoog culture medium containing 2 mg/L of zeatin in combination with 0.1 mg/L of 3-indoleacetic acid. An effective protocol of indirect somatic organogenesis of shoots from different explants of tomato varieties with a frequency of more than 80% was developed.

Исследовано влияние типа экспланта, а также вида и концентрации регуляторов роста на индукцию процессов каллусообразования и соматического органогенеза побегов in vitro четырех генотипов томата российской селекции. Проведено цитологическое изучение каллусной ткани. Установлено, что сорта томата обладают существенно большей способностью к непрямому органогенезу побегов по сравнению с гибридом F1. Для большинства исследуемых генотипов наибольшая частота соматического органогенеза побегов, а также их число на один эксплант были отмечены при культивировании семядольных листьев на питательной среде Мурасиге–Скуга, содержащей 2 мг/л зеатина в сочетании с 0.1 мг/л 3-индолилуксусной кислоты. Разработана эффективная методика непрямого соматического органогенеза побегов из различных эксплантов сортов томата с частотой >80%.

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.