Various abiotic stresses cause the appearance of reactive oxygen species (ROS) in plant cells, which seriously damage the cellular structures. The engineering of transgenic plants with higher production of ROS-scavenging enzyme in plant cells could protect the integrity of such a fine intracellular structure as the cytoskeleton and each cellular compartment. We analyzed the morphological changes in root tip cells caused by the application of iso-osmotic NaCl and Na2SO4 solutions to tomato plants harboring an introduced superoxide dismutase gene. To study the roots of tomato plants cultivar Belyi Naliv (WT) and FeSOD-transgenic line, we examined the distribution of ROS and enzyme-linked immunosorbent detection of α-tubulin. In addition, longitudinal sections of the root apexes were compared. Transmission electronic microscopy of atypical cytoskeleton structures was also performed. The differences in the microtubules cortical network between WT and transgenic plants without salt stress were detected. The differences were found in the cortical network of microtubules between WT and transgenic plants in the absence of salt stress. While an ordered microtubule network was revealed in the root cells of WT tomato, no such degree of ordering was detected in transgenic line cells. The signs of microtubule disorganization in root cells of WT plants were manifested under the NaCl treatment. On the contrary, the cytoskeleton structural organization in the transgenic line cells was more ordered. Similar changes, including the cortical microtubules disorganization, possibly associated with the formation of atypical tubulin polymers as a response to salt stress caused by Na2SO4 treatment, were also observed. Changes in cell size, due to both vacuolization and impaired cell expansion in columella zone and cap initials, were responsible for the root tip tissue modification.

The toxicity of high concentrations of sodium chloride creates significant difficulties in realizing the productivity potential of wheat. The development of effective test systems for the identification and selection of resistant genotypes is an urgent task given the global increase in soil salinity in agricultural land. To identify the characteristics of the plant’s reaction to the toxic effect of sodium chloride, wheat genotypes with different resistance to ionic toxicity (the Orenburgskaya 10 and Orenburgskaya 22 varieties) were used. In model experiments, we used fluorescence, light-optical and electron microscopy to characterize the structural and functional features of the cells of the roots of wheat seedlings, and cytological markers suitable for creating a test system for the early diagnosis of the sensitivity of wheat genotypes to sodium chloride were established. The response of the plants to the effects of sodium chloride was assessed by changes in biometric data, respiration rate, peculiarities in the accumulation of reactive oxygen species (ROS) and mitochondrial staining, and the quantitative assessment of coleoptile cell viability as putative sensitivity markers. In the sodium chloride-sensitive genotype (Orenburgskaya 10), toxic effects resulted in oxidative damage in the root cells, while in the resistant genotype (Orenburgskaya 22), oxidative damage to the cells was minimal. A high level of expression of mitochondrial superoxide dismutase (MnSOD) was found in the roots of the Orenburgskaya 22 variety. The identification and functional analysis of cytological and molecular markers provide the basis for further studies of the resistance of wheat to sodium chloride stress.

Exogenous short biologically active peptides epitalon (Ala-Glu-Asp-Gly), bronchogen (Ala-Glu-Asp-Leu), and vilon (Lys-Glu) at concentrations 10-10 M significantly influence growth, development, and differentiation of tobacco (Nicotiana tabacum) callus cultures. Epitalon and bronchogen, in particular, both increase growth of calluses and stimulate formation and growth of leaves in plant regenerants. Because the regulatory activity of the short peptides appears at low peptide concentrations, their action to some extent is like that of the activity of phytohormones, and it seems to have signaling character and epigenetic nature. The investigated peptides modulate in tobacco cells the expression of genes including genes responsible for tissue formation and cell differentiation. These peptides differently modulate expression of CLE family genes coding for known endogenous regulatory peptides, the KNOX1 genes (transcription factor genes) and GRF (growth regulatory factor) genes coding for respective DNA-binding proteins such as topoisomerases, nucleases, and others. Thus, at the level of transcription, plants have a system of short peptide regulation of formation of long-known peptide regulators of growth and development. The peptides studied here may be related to a new generation of plant growth regulators. They can be used in the experimental botany, plant molecular biology, biotechnology, and practical agronomy.

S u m m a r yThe authors investigated the effect of light-emitting diode irradiator with maximum in the region of red (λ max 6305 nm, 6605 nm) and blue (λ max 4505 nm, 4705 nm) light on growth processes and activity of photosynthetic apparatus in potato plants of the Nevskii early variety. It was made a conclusion, that application of light-emitting diode irradiators in controllable conditions of phytotron may be useful technique during potato growing subject to changes of spectrum composition in plant ontogenesis.Keywords: potato, photosynthesis, growth, light diodes.In natural conditions of plant vegetation, daylight provides illumination of quite variable intensity and spectral composition. Controlled environment with adjustable lightning allows setting the parameters required by a plan of experiment and provide an optimum light program for improved efficiency of plant growth.Photoculture commonly uses different types of electric lamps (1). For plants it is essential that light must include all visible spectral regions with prevailing red, green, blue, and violet rays, as well as a small proportion of ultraviolet and infrared light. Currently, the most widely used lamps are high-pressure gas-discharge lamps -metal-halide lamps (MHL, maximum emission at 450 nm) and high-pressure sodium lamps (HPS, maximum emission at 590 nm) of 400 and 600 W (1, 2). However, using gas-discharge lamps in plant growing is associated with significant energy expenditure and insufficient spectral properties of light emitters. A possible solution of this problem is low-energy light-emitting diodes (LEDs).LEDs can be used as supplement light sources, though they are expected to completely replace traditional lamps in photoculture (3, 4), especially in enclosed cultivation systems. Today the authors are developing new approaches to production of improved planting material of potato in aeroponics with LED illumination (5, 6).Main effects of broadband red and blue light on photosynthetic apparatus and metabolic processes of plants were discovered in 1960-1980ies (7, 8), but many issues are still unclear -particularly, the effect of narrowband red and blue light on basic parameters of photosynthesis and productivity. The available scientific literature describes the effects of LED light on primary stages of photosynthesis (4) and growth processes (9).The purpose of this work was studying growth and development of potato plants improved against phytopathogens during vegetation under LED illumination, as well as the study of the activity of photosynthetic apparatus and individual elements of carboxylation cycle.Technique. Experiments were performed on plants grown in factor-static conditions at 18-20 C and 16 hour photoperiod. Improved minitubers of potato cv Nevsky were planted in a 5-liter vegetation containers filled with soil substrate and placed under different light sources: HPS-600 W ("Phillips", the Netherlands) and LEDs (developed in the All-Russia Research and Development Institute of Agricultural Biotechnology in collaborat...