The influence of selective light on the growth reaction and antioxidant system of seedlings Pisum sativum L.

Aim. Study of the effect of red (660 nm), green (530 nm) and blue (450 nm) light on the growth processes and the state of the antioxidant system in the axial organs of seedlings of pea plants. Methods. Etiolated seedlings of pea Maecenat variety were irradiated with selective light with different spectrum of RL (660 nm), GL (530 nm), BL (450 nm) to activate photoreceptor systems of plants. In 10-day-old seedlings, growth response was determined – linear growth and biomass accumulation, as well as indicators of antioxidant system – hydrogen peroxide content and activity of oxidases – catalase and nonspecific peroxidase in axial organs of seedlings: in the aboveground part and roots. Results. Irradiation of the RL and the GL stimulates the accumulation of seedling biomass in the aboveground part and roots. BL inhibits the growth response of seedlings. The maximum stimulating effect is shown by the GL. The state of the antioxidant system in etiolated seedlings is characterized by organ specificity. Under the action of selective light, the content of the main form of ROS – hydrogen peroxide and shoots and in the roots, significantly stimulates the activity of catalase and peroxidase enzymes in the aboveground part of the seedling and is inhibited in the roots. The maximum effect in the aboveground part is shown by the GL, in the roots of the RL and the BL. Conclusions. The established effects of selective light irradiation are manifested differently in the aboveground and underground parts of seedlings. Possible mechanisms of connection of a condition of antioxidant system with separate aspects of signaling in photomorphogenesis of plants are discussed. Keywords: Pisum sativum L., selective light, RL (660 nm), GL (530 nm), BL (450 nm), growth reaction, axial organs, H2O2, catalase, peroxidase.

Anatomical features of axial organs of the loganberry during apex reproduction

Выяснена особенность в анатомической структуре стебля ежемалины, размножающейся укоренением верхушек побега. В первый год жизни побега при его укоренении активизируется работа камбия, образуется второе годичное кольцо в зоне ксилемы. Стелющиеся побеги ежевик (и ежемалины) следует назвать дициклическими с многолетней верхушечной почкой. The peculiarity in the anatomical structure of the stalk of the loganberry, which reproduces by rooting the tops of the shoot, has been clarified. In the first year of the shoot's life, during its rooting, the work of the cambium is activated, and a second annual ring is formed in the xylem zone. Creeping shoots of blackberries (and loganberries) should be called dicyclic with a perennial apical bud.

The regulation of growth parameters of potato microclones by jasmonic acid

The microclones of potato (variety Lugovskoy) were grown on the modified Murashige-Skoog (MS) agar medium in the absence (control) or presence of JA at concentrations of 0.001, 0.1, and 10 µM. We evaluated plant growth parameters such as the length of the axial organs, the number of stolons, leaves, the area of the assimilating surface, and the wet and dry mass of aboveground and underground organs. For the first time, has been demonstrated, that jasmonic acid (0.1 and 10 µM) was showed a pronounced growth-stimulating effect on potato plants.

Mechanistic Insights into Plant Chiral Growth

The latent left–right asymmetry (chirality) of vascular plants is best witnessed as a helical elongation of cylindrical organs in climbing plants. Interestingly, helical handedness is usually fixed in given species, suggesting genetic control of chirality. Arabidopsis thaliana, a small mustard plant, normally does not twist but can be mutated to exhibit helical growth in elongating organs. Genetic, molecular and cell biological analyses of these twisting mutants are providing mechanistic insights into the left–right handedness as well as how potential organ skewing is suppressed in most plants. Growth direction of elongating plant cells is determined by alignment of cellulose microfibrils in cell walls, which is guided by cortical microtubules localized just beneath the plasma membrane. Mutations in tubulins and regulators of microtubule assembly or organization give rise to helical arrangements of cortical microtubule arrays in Arabidopsis cells and cause helical growth of fixed handedness in axial organs such as roots and stems. Whether tubulins are assembled into a microtubule composed of straight or tilted protofilaments might determine straight or twisting growth. Mechanistic understanding of helical plant growth will provide a paradigm for connecting protein filament structure to cellular organization.

Modelling of grains’ shoots formation

The processes of seed germination and shoots formation of crops caused by environmental factors are investigated. Also existing approaches to the modelling of this period, modelling of processes taking place in a seed during its germination, shoots formation are investigated, the structure of the developed model of the period of sowing - rise of shoots is described, as well as the results of numerical experiments. The specified model is aimed at overcoming the disadvantages and improving previous models of the period of sowing - rise of shoots. Development of this model is based on the achieved level of modelling of shoots formation with introduction of certain modifications. The model takes into account both physical processes taking place in a seed prior to germination of shoots and physiological and biochemical processes such as hydrolysis of endosperm reserves, respiration, distribution of hydrolysis products within axial organs and their growth. The model is implemented on a PC using Microsoft Office Excel. Many numerical experiments were carried out in order to investigate sensitivity of the model to changes of environmental conditions during germination of seeds. It was found that main agrometeorological factors affecting the time of emergence and completeness of germination are temperature, humidity and soil density. Influence of soil moisture becomes the most apparent at the stage of absorption and accumulation of moisture by a seed starting from sowing to beginning of growth process. Provided that there are optimum moisture and temperature, density of soil appears to be limiting factor affecting shoots formation: if soil density increases duration of shoots emergence increases as well. Developed dynamic model allows determining the date of shoots emergence, their field germination rate, distribution of particular number of plants of with different depth of seeds covering and a number of plants per particular unit of area.

Metabolism of excised embryos of Lupinus luteus L. VI. An electrophoretic analysis of some dehydrogenases in cultured embryos as compared with the normal seedling axes

The electrophoretic patterns (disc electrophoresis) of the studied dehydrogenases: glucose-6-phosphate - (A), malate - (B), glutamate - (C), alcohol - (D) and lactate dehydrogenase (E), in the axial organs of isolated <i>Lupinus luteus</i> embryos and seedlings cultivated over 12 days are characterized by great similarities. With time, after the third day of cultivation the patterns begin to become less deyeloped. Analyses performed during the first 10 hours of imbibition of seed parts indicate that the maximal development of isozyme patterns occurs during the third hour after which the patterns become poorer. The most uniform type of pattern. and the lowest number of isozymes was shown by glutamate dehydrogenase, the richest pattern was shown by malate dehydrogenase. No band common for a 11 the 27 experimental elements was found.

Metabolism of excised embryos of Lupinus luteus L. VII. An electrophoretic analysis of esterases and peroxidases in cultured embryos and normal seedling axes

A rich and active spectrum of esterases (E) exists already in the organs of a dry seed. The isolation of axes from the cotyledons exerts a considerable influence on the pattern of E. In the axial organs of a seedling the spectra and activity become impoverished starting from the 3rd day of culture in the dark. On the other hand in the axial organs isolated from the cotyledons from that moment onwards the spectra become richer and more active, particularily in the root. It appears that the enhancement of spectra in the detached axes is not dependent on the elimination with the cotyledons of a source of inhibitors, since in the cotyledons, until the end of the culture period (12 days), a rich pattern of E is maintained. Peroxidase (P) appears starting from the third day giving impoverished spectra, in general development similar to E. The removal of the seed coat from dry seeds exerts during the first two days of imbibition a strong influence on the spectra of axial and cotyledonary enzyms.

The “seeds” on Padgettia readi are insect galls: reassignment of the plant to Odontopteris, the gall to Ovofoligallites n. gen., and the evolutionary implications thereof

The Early Permian (Asselian) Euramerican plant Padgettia readi Mamay is reassigned to Odontopteris Brongniart, as O. readi (Mamay) Stull et al. n. comb. Distinctive elongate structures on neuropteroid pinnules of this plant, previously interpreted as fructifications, are herein reinterpreted as foliar histoid galls, structurally analogous to blister or vein galls, and probably induced by an early lineage of hemipterans or mites. These distinctive features are assigned to the new gall ichnogenus Ovofoligallites Labandeira, n. ichnogen. n. ichnosp, as O. padgetti Labandeira. The Early Permian association between an Odontopteris host and Ovofoligallites gallers probably originated during the Middle Pennsylvanian as a similar, antecedent association between Macroneuropteris scheuchzeri (Hoffmann) Cleal, Shute, and Zodrow and the maker of U-shaped surface features long known as a distinctive, unattributed damage type, but now recognizable as a likely gall. The persistence of this association between the galler and certain medullosan pteridosperms into the Permian adds to the morphological richness of the Permian galler insect fauna. The Permian ecological expansion of galling insects resulted in colonization of new host plants, primarily through a shift from the consumption of entire, mostly pteridophyte axial organs during the Pennsylvanian to the partitioning of seed plant tissues in leaves and small branches in the Permian. The Ovofoligallites galler was part of a diverse Permian galler guild involving a variety of plant taxa, organs and tissues that overwhelmingly targeted multiple lineages of seed plants.