Asymmetry of Plant Cell Divisions under Salt Stress

Salt stress causes several damaging effects in plant cells. These commonly observed effects are the results of oxidative, osmotic, and toxic stresses. To ensure normal growth and development of tissues, the cellular compartments of multicellular plants have a unique system that provides the specified parameters of growth and differentiation. The cell shape and the direction of division support the steady development of the organism, the habit, and the typical shape of the organs and the whole plant. When dividing, daughter cells evenly or unevenly distribute the components of cytoplasm. Factors such as impaired osmotic regulation, exposure to toxic compounds, and imbalance in the antioxidant system cause disorders associated with the moving of organelles, distribution transformations of the endoplasmic reticulum, and the vacuolar compartment. In some cases, one can observe a different degree of plasmolysis manifestation, local changes in the density of cytoplasm. Together, these processes can cause disturbances in the direction of cell division, the formation of a phragmoplast, the formation of nuclei of daughter cells, and a violation of their fine structural organization. These processes are often accompanied by significant damage to the cytoskeleton, the formation of nonspecific structures formed by proteins of the cytoskeleton. The consequences of these processes can lead to the death of some cells or to a significant change in their morphology and properties, deformation of newly formed tissues and organs, and changes in the plant phenotype. Thus, as a result of significant violations of the cytoskeleton, causing critical destabilization of the symmetric distribution of the cell content, disturbances in the distribution of chromosomes, especially in polyploid cells, may occur, resulting in the appearance of micronuclei. Hence, the asymmetry of a certain component of the plant cell is a marker of susceptibility to abiotic damage.

Promising Isotope Effect in Pd77Ag23 for Hydrogen Separation

Pd–Ag alloys are largely used as hydrogen separation membranes and, as a consequence, the Pd–Ag–H system has been intensively studied. On the contrary, fewer information is available for the Pd–Ag–D system; thus, the aim of this work is to improve the knowledge of the isotope effect on the commercial Pd77Ag23 alloy, especially for temperature above 200 °C. In particular, deuterium absorption measurements are carried out in the Pd77Ag23 alloy in the temperature range between 79 and 400 °C and in the pressure range between 10−2 and 16 bar. In this exploited pressure (p) and composition (c) range, above 300 °C the pc isotherms display the typical shape of materials where only a solid solution of deuterium is present while at lower temperatures these curves seem to be better described by the coexistence of a solid solution and a deuteride in a large composition range. The obtained results are compared and discussed with the ones previously measured with the lightest hydrogen isotope. Such a comparison shows that the Pd77Ag23 alloy exhibits a clear inverse isotope effect, as the equilibrium pressure of the Pd–Ag–D system is higher than in Pd–Ag–H by a factor of ≈2 and the solubility of deuterium is about one half of that of hydrogen. In addition, the absorption measurements were used to assess the deuteration enthalpy that below 300 °C is ΔHdeut = 31.9 ± 0.3 kJ/mol, while for temperatures higher than 300 °C, ΔHdeut increases to 43 ± 1 kJ/mol. Additionally, in this case a comparison with the lighter isotope is given and both deuteration enthalpy values result lower than those reported for hydrogenation. The results described in this paper are of practical interest for applications operating above 200 °C, such as membranes or packing column, in which Pd77Ag23 has to interact with a gas stream containing both hydrogen isotopes.

Use the Force: Review of High-Rate Actuation of Shape Memory Alloys

Typical shape memory alloy actuators provide a unique combination of large stresses and strains that result in work-per-volume larger by more than two orders of magnitude than all other actuation methods that are based on active materials. High-rate actuation of shape memory alloys can provide improved energy efficiency, and shorter response and total actuation times, along with large travel-per-wire-length, with respect to slow-rate SMA applications. In this article, we review the different aspects of high-rate actuation of shape memory alloy wires in the high-driving-force regime. We briefly survey previous experimental results about the kinetics and thermodynamics of the phase transformation in view of its practical implications. New experimental results, regarding energy efficiency, total actuation time, repeatability, and fatigue, are presented and discussed. The paper provides general design guidelines for obtaining high actuator performance, as well as guidelines for selecting the source of the electric pulse and its parameters. Finally, we construct and solve detailed simulations of actuator response that can serve as accurate design tools.

First instar nymphs of two peltoperlid stoneflies (Insecta, Plecoptera, Peltoperlidae)

The first instar nymphs of two peltoperlid stoneflies, i.e., Microperla brevicauda Kawai, 1958 of Microperlinae and Yoraperla uenoi (Kohno, 1946) of Peltoperlinae, were examined and described. Additionally, the phylogeny and groundplan of the first instar nymphs of Peltoperlidae and Plecoptera were considered. The first instar nymphs of M. brevicauda have a slender body with a prognathous head of typical shape; they represent a groundplan in Plecoptera. On the other hand, the first instar nymphs of Y. uenoi have a broad, cockroach-like body with an orthognathous and shortened head, the latter being regarded as a potential autapomorphy of Peltoperlinae. Such differences in body shape between the subfamilies are speculated to arise from heterochrony. The three-segmented cerci of Y. uenoi are characteristic to Systellognatha, whereas the four-segmented cerci of M. brevicauda were independently acquired within Microperlinae. The structure and distribution pattern of chloride cells in the first instar nymphs of Plecoptera were also discussed. The presence of coniform chloride cells is a potential groundplan of Arctoperlaria. One to two pairs of chloride cells are distributed on the first nine abdominal segments of M. brevicauda; this represents a groundplan character of Systellognatha. On the other hand, one to four pairs of chloride cells are found on the second to ninth abdominal segments of Y. uenoi; this distribution pattern may be an apomorphic groundplan of Peltoperlinae.

Revision and description of six species of Choeradoplana (Platyhelminthes, Tricladida), with an emendation to the genus

Living representatives of the Neotropical genus Choeradoplana Graff, 1896 (Geoplaninae, Tricladida, Platyhelminthes) are easily recognized by the typical shape of the head which is laterally expanded, rolled-up, and ventrally provided with two glandular cushions. In this study, the morphology and phylogeny (cytochrome C oxidase subunit I gene) of several species of land planarians are taxonomically investigated. Four of the six species studied are new to science, namely: Ch. eudoxiae Silva & Carbayo, sp. nov., Ch. claudioi Lago-Barcia & Carbayo, sp. nov., Ch. onae Lago-Barcia & Carbayo, sp. nov., and Ch. riutortae Lago-Barcia & Carbayo, sp. nov. The species Choeradoplana albonigra and Ch. eudoxiae deviate from the usual body shape pattern in that the head does not present lateral expansions nor glandular cushions, becoming indistinguishable from its sister genus Cephaloflexa. Pseudogeoplana tristriata (Schultze & Müller, 1857) is also redescribed from a newly collected specimen and was discovered to be a member of Choeradoplana. Graff (1899) also studied another specimen that was considered to be conspecific with P. tristriata; however, in this new it is concluded that it is not conspecific but rather a new species. The name Pseudogeoplana aevipandemiae Lago-Barcia & Carbayo, sp. nov. is suggested for Graff’s specimen.

Genetic dependence of poplar species specificity on starch content in shoots tissues

We studied the hereditary conditionality of species specificity of 8 poplar species by the starch content in the tissues of their shoots. The objects of research were: white pyramidal poplar: (P. alba L., f. piramidalis); black poplar (P. nigra L.); Italic poplar (P. nigra, var. italica Münchh.); Chinese poplar (P. Simonii Carr.); balsamic poplar (P. balsamifera L.); poplar larrity (P. laurifolia Ledeb.); white poplar (P. alba L.); aspen (P. tremula L.). Starch concentration in various tissues of annual shoots were established during microscopic studies with histochemical staining of preparations. Statistical processing of the actual material was performed using one-way and two-way anova. It was found that the types of poplars differed in the presence of starch in different tissues. The white pyramidal poplar and its typical shape showed similarities in its content. Aspen differed from them in a somewhat large amount of this substance. The species included in one section were more similar to each other, with a noticeable difference from the representatives of other sections. The difference in ratings between sections of black and balsamic poplars is less noticeable than between each of these sections and white poplars. The influence of the genotype on the formation of physiological differences reaches 72 %. Differences between accounting trees of the same species are less pronounced than between the taxonomic groups compared, and do not reach the level of significant ones. The species specificity of poplars growing in the Nizhny Novgorod region, according to the physiological characteristics associated with the starch content in the tissues of their shoots, is hereditary.

Towards modelling ghostly damped Ly αs

ABSTRACT We use simple models of the spatial structure of the quasar broad-line region (BLR) to investigate the properties of so-called ghostly damped Ly α (DLA) systems detected in Sloan Digital Sky Survey (SDSS) data. These absorbers are characterized by the presence of strong metal lines but no H i Ly α trough is seen in the quasar spectrum indicating that, although the region emitting the quasar continuum is covered by an absorbing cloud, the BLR is only partially covered. One of the models has a spherical geometry, another one is the combination of two wind flows, whereas the third model is a Keplerian disc. The models can reproduce the typical shape of the quasar Ly α emission and different ghostly configurations. We show that the DLA H i column density can be recovered precisely independently of the BLR model used. The size of the absorbing cloud and its distance to the centre of the AGN are correlated. However, it may be possible to disentangle the two using an independent estimate of the radius from the determination of the particle density. Comparison of the model outputs with SDSS data shows that the wind and disc models are more versatile than the spherical one and can be more easily adapted to the observations. For all the systems, we derive log N(H i)(cm−2) > 20.5. With higher quality data, it may be possible to distinguish between the models.

On the Nature of Exotic Matter in Morris-Thorne Wormholes

It is well known that phantom energy, which is characterized by the equation of state p = ωρ, ω < −1, can support Morris-Thorne wormholes since it leads to a violation of the null energy condition. The purpose of this note is to show that the converse is also true in the following sense: for a typical shape function, the equation of state of exotic matter in the vicinity of the throat is given by p↓r = ωρ, ω < −1, where pr is the radial pressure.

Content and balance of spare substances in the tissues of poplar shoots in the Nizhny Novgorod Volga region

В формировании состава искусственных насаждений немаловажную роль играют основные физиологические характеристики деревьев. Цель исследования – установить видоспецифичность тополей (Populus L.) по содержанию и балансу запасных веществ. Объект исследования – 8 видов тополей: т. белый пирамидальный (P. alba L., f. piramidalis); т. черный (P. nigra L.); т. черный пирамидальный (P. nigra, var. italica Münchh.); т. китайский (P. Simonii Carr.); т. бальзамический (P. balsamifera L.); т. лавролистный (P. laurifolia Ledeb.); т. белый (P. alba L.); осина (P. tremula L.). Выполнены микроскопические исследования тканей для выявления крахмала и жиров. Применен дисперсионный и кластерный анализ. Виды из разных секций дифференцированы по наличию и балансу запасных веществ. Тополь белый пирамидальный и его типичная форма проявили сходство между собой по общему количеству крахмала: 7,37±0,13 и 7,79±0,17 балла. Осина имела большее количество: 9,13±0,13 балла. Наибольшие оценки содержания жиров характерны для представителей секции черных тополей: тополя черного (7,67±0,13 балла) и тополя итальянского (9,59±0,12 балла). Дисперсионный анализ подтвердил существенность различий между сравниваемыми группами тополей. Влияние генотипа на их формирование по разным признакам неодинаково и достигало 71,81±0,41%. Кластерный анализ установил соответствие группировки представителей секций белых, черных и бальзамических тополей таксономическому устройству рода тополь в отношении широкого спектра физиологических параметров. Представители секции белых тополей продемонстрировали комплексное сходство между собой при заметном отличии от других секций. The main physiological characteristics of trees play an important role in the formation of the composition of artificial plantings. The purpose of the research is to establish the species specificity of poplars (Populus L.) by the content and balance of spare substances. The object of research were 8 species of poplar (P. alba L., f. piramidalis); black poplar (P. nigra L.); Populus italica (P. nigra, var. italica Münchh.); Chinese poplar (P. Simonii Carr.); balsamic poplar (P. balsamifera L.); poplar larrity (P. laurifolia Ledeb.); white poplar (P. alba L.); aspen (P. tremula L.). Performed microscopic examination of tissues for the detection of starch and fats. Applied ANOVA and cluster analysis. Species from different sections are differentiated by the presence and balance of spare substances. The white pyramidal poplar and its typical shape showed similarities in the total amount of starch: 7.37±0.13 and 7.79±0.17 points. Aspen had a higher number: 9.13±0.13 points. The highest estimates of fat content are typical for representatives of the black poplar section: black poplar (7.67±0.13 points) and Italian poplar (9.59±0.12 points). The ANOVA confirmed the significant differences between poplars. The influence of the genotype on their formation by different characteristics is not the same and reached 71.81±0.41%. Cluster analysis has established that the grouping of representatives of sections of white, black and balsam poplars corresponds to the taxonomic structure of the genus poplar in relation to a wide range of physiological parameters. Representatives of the white poplar section demonstrated a complex similarity with each other, while noticeably different from other sections.

PSVIII-4 Bone marrow architectonics of turkeys hybrid cross «Converter»

The aim of this research was to study bone marrow architectonics and the peculiarities of hematopoiesis of turkeys cross «Converter». To study the hemopoiesis at the age of 50 days, the samples of the red bone marrow from the femur were selected. Samples were prepared according to standard methods for histological and cytological examination. Four lineages of hematopoiesis (erythrocytic, monocytic, granulocytic and platelet) were isolated from the bone marrow of turkeys. The erythrocytic lineage was represented by erythroblasts, rubricytes and mature erythrocytes. In the process of maturation, the erythroblast initially uniformly decreased, turning into rubricyte. Then the cytoplasm and nucleus enlarged and acquired an oval shape. A mature erythrocyte was formed. Hematopoiesis of eosinophils and basophils in turkeys was similar to hematopoiesis in mammals. They also formed from myeloblasts. At the stage of promyelocyte, granularity of the cytoplasm appeared. At the stage of myelocyte, the number of granules increased, and the granularity acquired a typical shape and color. Then the nucleus acquired a rod-shaped form, and after it was segmented into 2–5 segments. Heterophiles were divided into two types (with rounded and elongated granules). Heterophile granules were about 2 times bigger than eosinophils, and cytoplasm granularity was significantly sparser. Monocytes in turkeys had a rounded cytoplasm, in which small granules were sometimes present, and the nucleus was shifted to the periphery. Mature monocytes differed from promonocytes in a smaller nuclear-cytoplasmic ratio. Platelets had a centrally located nucleus and an oval cytoplasm with granules inside. Prothrombocytes were approximately 1.5 times larger than mature platelets. The lymphoid lineage is not represented, which indicates an extramedullary lymphopoiesis. A significant difference was the absence of megakaryocytes and the development of platelets from thromboblasts. Granulocytic and monocytic lineages were similar to those in mammals, and erythroid one was represented only by nucleated erythrocytes.