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Ivanov V.B.,RAS Timiryazev Institute of Plant Physiology | Dubrovsky J.G.,National Autonomous University of Mexico
Trends in Plant Science | Year: 2013

Despite the relative simplicity of Arabidopsis root organization, there is no general agreement regarding the terminology used to describe the longitudinal zonation pattern (LZP) of this model system. In this opinion article, we examine inconsistencies in the terminology and provide a conceptual framework for the LZP that may be applied to all angiosperms. We propose that the root apical meristem (RAM) consists of the cell-proliferation domain where cells maintain a high probability to divide and the transition domain with a low probability of cell division; in both domains cells grow at the same, relatively low, rate. Owing to stochastic termination of cell proliferation in the RAM, the border between the domains is 'fuzzy'. Molecular markers analyzed together with quantitative growth and cell analyses could help to identify developmental zones along the root and lead to a better understanding of the LZP in angiosperms. © 2012 Elsevier Ltd.


Ivanov V.B.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2011

A sound approach to the root usage as model objects for the assessment of biological activity of chemical substances and environmental stressors is suggested on the basis of the analysis of various inhibitor and radiation action on the root. It is analyzed on the cellular level, how steady growth is maintained under various stress action. Special attention is paid to the meristematic cell transition to elongation, which is controlled by the two groups of processes: the first ones determine the rate of cell proliferation and the second ones determine the cell life span in the meristem. The rate of cell proliferation is rather sensitive to various treatments; in contrast, the processes controlling the cell life span in the meristem are rather stable. It is shown that studying the kinetics of the root growth rate gives much more information than a single measurement of root length increment. A possibility of root usage for the search of efficient cytostatics is exemplified. The role of the quiescent center in growth resumption after various stressful treatments is considered. © 2011 Pleiades Publishing, Ltd.


Nosov A.M.,RAS Timiryazev Institute of Plant Physiology
Applied Biochemistry and Microbiology | Year: 2012

Bioactive substances (BAS) of plant origin are known to play a very important role in modern medicine. Their use, however, is often limited by availability of plant resources and may jeopardize rare species of medicinal plants. Plant cell cultures can serve as a renewable source of valuable secondary metabolites. To the date, however, only few examples of their commercial use are known. The main reasons for such a situation are the insufficient production of secondary metabolites and high cultivation costs. It is possible to increase the performance of plant cell cultures by one or two orders of magnitude using traditional methods, such as selection of highly productive strains, optimization of the medium composition, elicitation, and addition of precursors of secondary metabolite biosynthesis. The progress in molecular biology methods brought about the advent of new means for increasing of the productivity of cell cultures based on the methods of metabolic engineering. Thus, overexpression of genes encoding the enzymes involved in the synthesis of the target product or, by contrast, repression of these genes significantly influences the cell biosynthetic capacity in vitro. Nevertheless, the attempts of the production of many secondary metabolites in plant cell culture were unsuccessful so far, probably due to the peculiarities of the cell culture as an artificial population of plant somatic cells. The use of plant organ culture or transformed roots (hairy root) could turn to be a considerably more efficient solution for this problem. The production of plant-derived secondary metabolites in yeast or bacteria transformed with plant genes is being studied currently. Although the attempts to use metabolic engineering methods were not particularly successful so far, new insights in biochemistry and physiology of secondary metabolism, particularly in regulation and compartmentation of secondary metabolite synthesis as well as mechanisms of their transport and storage make these approaches promising. © 2012 Pleiades Publishing, Ltd.


Voronin P.Y.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2014

An original experimental installation is described to illustrate the unit-based principle in the open-mode design construction of a modern system for the combined fluorometric and CO2/H2O gas exchange measurements in the studies of the light and dark reactions of photosynthesis and the transpiration of a detached leaf. © 2014 Pleiades Publishing, Ltd.


Zorina A.A.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2013

This review presents the data on the role of eukaryotic-like serine/threonine protein kinases in the members of various groups of cyanobacteria. Information is provided for the two most studied model species (Anabaena and Synechocystis), differing in their morphology and ecophysiological features, and covers the entire period of study of this group of enzymes in cyanobacteria. © 2013 Pleiades Publishing, Ltd.


Solovchenko A.E.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2013

Some species of unicellular green algae accumulate under unfavorable conditions high amounts of secondary carotenoids (SCar), which are not involved in photosynthesis and localized outside thylakoids. Such algae are cultivated on an industrial scale for production of carotenoids with valuable pharmacological properties. This review summarizes recent experimental data on the importance of secondary carotenogenesis for stress tolerance of unicellular green algae (Chlorophyta). The peculiarities of SCar biosynthesis, its induction and regulation under the action of various stressors as well as their localization in the cell and physiological effects of the accumulation of high amounts of these pigments are considered. Particular attention is given to the relationships between SCar biosynthesis and stress-induced biosynthesis of neutral lipids as well as the role of ROS as universal inducers and regulators of SCar biosynthesis. Various aspects of SCar protective function in the micfroalgal cells are discussed. © 2013 Pleiades Publishing, Ltd.


Obroucheva N.V.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2012

It is generally believed that seed dormancy release is terminated by germination and that this process is controlled by phytohormones. Most attention was paid to gibberellins (GAs) because treatment with GAs is most frequently applied for seed dormancy breaking. The review characterizes the hormonal regulation of seed dormancy and its release, as exemplified by arabidopsis seeds possessing non-deep physiological dormancy. Dormancy release occurs under the influence of low temperature and/or illumination with red light. Two main trends are typical of this process: (1) a decrease in ABA content and blocking of signal transduction from ABA, and (2) GA synthesis and activation of GA signaling pathway. Dormancy release ends with the GA-induced syntheses of some proteins, enzymes in particular, required for the start of germination. Quiescent seeds are capable of realizing the germination program without hormonal induction, due to nothing but seed hydration. In imbibing seeds, the triggering role of water lies in the successive activation of basic metabolic systems after attaining the water content thresholds characteristic of these systems and in preparing cells of embryo axial organs for germination. Thus, seed dormancy release is controlled by phytohormones, whereas subsequent germination manifesting itself as the initiation of cell elongation in embryo axes is controlled by water inflow. © 2012 Pleiades Publishing, Ltd.


Solovchenko A.E.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2012

In the studies of lipid metabolism of unicellular photoautotrophic eukaryotes (microalgae), the main attention is commonly paid to polar membrane lipids and their fatty acid (FA) composition, whereas neutral lipids, represented predominantly by triacylglycerols (TAG), are insufficiently studied. As was reported recently, the role of these compounds in microalgae is not limited to their storage function. It was found that TAG are frequently involved in adaptation to environmental conditions. This review summarizes experimental data obtained so far allowing to distinguish at least three aspects of TAG adaptive function in microalgae. First, these compounds are the source of long-chain FA, the building blocks for membranes necessary for rearrangements of the photosynthetic apparatus. Second, TAG biosynthesis consumes excessive photoassimilates preventing photooxidative injuries under stresses which reduce cell capacity of photosynthesis product utilization. Third, TAG deposited as cytoplasmic oil bodies form a depot for secondary carotenoids in carotenogenic microalgae producing an optical screen protecting the cell against photodamage by excessive PAR. © 2012 Pleiades Publishing, Ltd.


Obroucheva N.V.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Developmental Biology | Year: 2014

The modern concept of the hormonal regulation of fruit set, growth, maturation, and ripening is considered. Pollination and fertilization induce ovule activation by surmounting the blocking action of ethylene and ABA to be manifested in auxin accumulation. Active fruit growth by pericarp cell division and elongation is due to the syntheses of auxin in the developing seed and of gibberellins in the pericarp. In climacteric fleshy fruits, the maturation is controlled by ethylene via so-called System 1 combining the possibilities of autoinhibition and autocatalysis by ethylene of its own biosynthesis. Transition of tomato fruits from maturation to ripening is characterized by highly active synthesis of ethylene and its receptors due to the functioning of regulatory System 2 resulting in the up-regulation of much greater number of ethylene-inducible genes. In peach fruits, the hormonal regulation of ripening includes also an active auxin involvement in the ethylene biosynthesis, which is combined with the ethylene-induced expression of genes encoding both auxin biosynthesis and the response to auxin. Ethylene induces the expression of genes responsible for the fruit softening, its taste, color, and flavor. Nonclimacteric fleshy fruits produce very small amounts of ethylene; its evolution increases only by the very end of ripening and can be described by a reduced System 1. The ripening of nonclimacteric fruits only weakly depends on ethylene but is stimulated by abscisic acid. © 2014 Pleiades Publishing, Inc.


Sidorov R.A.,RAS Timiryazev Institute of Plant Physiology | Tsydendambaev V.D.,RAS Timiryazev Institute of Plant Physiology
Russian Journal of Plant Physiology | Year: 2014

Triacylglycerols (TAGs) are one of the most important storage compounds of higher plants; they are the basis for essentially all plant oils and are used by the cell as a reserve source of energy and carbon. Therefore, as a rule, plants store oils almost exclusively in their seeds. Plant oils are not only a major food and feed products, but also the raw material for obtaining many nonfood products from drying oils and lubricants to biofuel. TAGs differ from other storage compounds in that in the course of fruit ripening their quantitative and qualitative composition does not remain constant, but undergoes significant changes. Therefore, the biosynthesis pathways of TAGs in living organisms have been actively studied for the past several decades, and today enough data can be presented to outline as how and where these processes occur in the plant cell. The present review is devoted to a brief description of current ideas about the ways and mechanisms of TAG formation and accumulation in higher plants. © 2014 Pleiades Publishing, Ltd.

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