Spatiotemporal regulation of lateral root organogenesis in Arabidopsis by cytokinin

The architecture of a plant's root system, established postembryonically, results from both coordinated root growth and lateral root branching. The plant hormones auxin and cytokinin are central endogenous signaling molecules that regulate lateral root organogenesis positively and negatively, respectively. Tight control and mutual balance of their antagonistic activities are particularly important during the early phases of lateral root organogenesis to ensure continuous lateral root initiation (LRI) and proper development of lateral root primordia (LRP). Here, we show that the early phases of lateral root organogenesis, including priming and initiation, take place in root zones with a repressed cytokinin response. Accordingly, ectopic overproduction of cytokinin in the root basal meristem most efficiently inhibits LRI. Enhanced cytokinin responses in pericycle cells between existing LRP might restrict LRI near existing LRP and, when compromised, ectopic LRI occurs. Furthermore, our results demonstrate that young LRP are more sensitive to perturbations in the cytokinin activity than are developmentally more advanced primordia. We hypothesize that the effect of cytokinin on the development of primordia possibly depends on the robustness and stability of the auxin gradient

Characterization of Biostimulant Mode of Action Using Novel Multi-Trait High-Throughput Screening of Arabidopsis Germination and Rosette Growth

Environmental stresses have a significant effect on agricultural crop productivity worldwide. Exposure of seeds to abiotic stresses, such as salinity among others, results in lower seed viability, reduced germination, and poor seedling establishment. Alternative agronomic practices, e.g., the use of plant biostimulants, have attracted considerable interest from the scientific community and commercial enterprises. Biostimulants, i.e., products of biological origin (including bacteria, fungi, seaweeds, higher plants, or animals) have significant potential for (i) improving physiological processes in plants and (ii) stimulating germination, growth and stress tolerance. However, biostimulants are diverse, and can range from single compounds to complex matrices with different groups of bioactive components that have only been partly characterized. Due to the complex mixtures of biologically active compounds present in biostimulants, efficient methods for characterizing their potential mode of action are needed. In this study, we report the development of a novel complex approach to biological activity testing, based on multi-trait high-throughput screening (MTHTS) of Arabidopsis characteristics. These include the in vitro germination rate, early seedling establishment capacity, growth capacity under stress and stress response. The method is suitable for identifying new biostimulants and characterizing their mode of action. Representatives of compatible solutes such as amino acids and polyamines known to be present in many of the biostimulant irrespective of their origin, i.e., well-established biostimulants that enhance stress tolerance and crop productivity, were used for the assay optimization and validation. The selected compounds were applied through seed priming over a broad concentration range and the effect was investigated simultaneously under control, moderate stress and severe salt stress conditions. The new MTHTS approach represents a powerful tool in the field of biostimulant research and development and offers direct classification of the biostimulants mode of action into three categories: (1) plant growth promotors/inhibitors, (2) stress alleviators, and (3) combined action

Novel Cytokinin Derivatives Do Not Show Negative Effects on Root Growth and Proliferation in Submicromolar Range

BACKGROUND: When applied to a nutrition solution or agar media, the non-substituted aromatic cytokinins caused thickening and shortening of the primary root, had an inhibitory effect on lateral root branching, and even showed some negative effects on development of the aerial part at as low as a 10 nanomolar concentration. Novel analogues of aromatic cytokinins ranking among topolins substituted on N9-atom of adenine by tetrahydropyranyl or 4-chlorobutyl group have been prepared and tested in standardized cytokinin bioassays [1]. Those showing comparable activities with N(6)-benzylaminopurine were further tested in planta. METHODOLOGY/PRINCIPAL FINDINGS: The main aim of the study was to explain molecular mechanism of function of novel cytokinin derivatives on plant development. Precise quantification of cytokinin content and profiling of genes involved in cytokinin metabolism and perception in treated plants revealed several aspects of different action of m-methoxytopolin base and its substituted derivative on plant development. In contrast to standard cytokinins, N9- tetrahydropyranyl derivative of m-topolin and its methoxy-counterpart showed the negative effects on root development only at three orders of magnitude higher concentrations. Moreover, the methoxy-derivative demonstrates a positive effect on lateral root branching and leaf emerging in a nanomolar range of concentrations, in comparison with untreated plants. CONCLUSIONS/SIGNIFICANCE: Tetrahydropyranyl substitution at N9-position of cytokinin purine ring significantly enhances acropetal transport of a given cytokinins. Together with the methoxy-substitution, impedes accumulation of non-active cytokinin glucoside forms in roots, allows gradual release of the active base, and has a significant effect on the distribution and amount of endogenous isoprenoid cytokinins in different plant tissues. The utilization of novel aromatic cytokinin derivatives can distinctively improve expected hormonal effects in plant propagation techniques in the future

Linguistic forms of expressivity An analysis of Bild-journal language

This bachelor's thesis deals with expressivity and its formulation. Subsequent inspection of this term is conducted using analysis of the daily journal Bild-Zeitung. At first there is a definition of term lexicology and then the work focuses on expressivity itself. The accent is put on all language levels in connection with this term. Further other close related elements are mentioned such as stylistics and history of the Bild-Zeitung journal. The practical part is devoted to analysis of particular examples set in individual language levels. The empirical part is concluded with well-arranged tables of the analysed phenomenona

Evaluation of quality management system implementation in selected company

The goal of this work is to evaluate the implementation of quality management system in the organization, identification of bottlenecks, including a proposal to remove them. The diploma thesis reports on the quality norms ISO according to their transformation into the requirements of company practical form. I analyse the ways in which the requirements of the standard ISO 9001:2008 the organization can be utilized in the activities, processes and quality requirements. The thesis deals with the various fundamental points of standards and the standard met in the organization is described.The final part is concerned with current state. I consider the pre-certified quality system and finally the possible way for improvement is suggested

Current Tendencies of Technical Language in the Field of Ecology

The following Master thesis is based on the technical language of recycling and plastic processing taking into consideration the relevant language and text attributes. Characteristic features are analysed on the basis of leaflets acquired at the international trade fair Fakuma focussing on this particular industry. First, the Master thesis concentrates on the definition of technical language itself presenting different points of view of this issue. Furthermore, the thesis focuses on the technical language of technology, chemistry and ecology which is employed in the analysed leaflets. Of major importance for the flyers is also the element of advertising which is elaborated in the second chapter. The empirical part of the thesis concentrates on a text analysis of each of the language subsystems: textual, stylistic, lexical and morphological. To conclude with, the thesis provides table overviews and a summarizing chapter

An Automated Method for High-Throughput Screening of Arabidopsis Rosette Growth in Multi-Well Plates and Its Validation in Stress Conditions

High-throughput plant phenotyping platforms provide new possibilities for automated, fast scoring of several plant growth and development traits, followed over time using non-invasive sensors. Using Arabidopsis as a model offers important advantages for high-throughput screening with the opportunity to extrapolate the results obtained to other crops of commercial interest. In this study we describe the development of a highly reproducible high-throughput Arabidopsis in vitro bioassay established using our OloPhen platform, suitable for analysis of rosette growth in multi-well plates. This method was successfully validated on example of multivariate analysis of Arabidopsis rosette growth in different salt concentrations and the interaction with varying nutritional composition of the growth medium. Several traits such as changes in the rosette area, relative growth rate, survival rate and homogeneity of the population are scored using fully automated RGB imaging and subsequent image analysis. The assay can be used for fast screening of the biological activity of chemical libraries, phenotypes of transgenic or recombinant inbred lines, or to search for potential quantitative trait loci. It is especially valuable for selecting genotypes or growth conditions that improve plant stress tolerance

CKs content in maize leaves after exogenous application of 1 μM 3MeOBAP and 3MeOBA9THPP compared to controls.

<p> Samples were processed in the same way as the samples from root tissue.</p

CKs content in maize roots after exogenous application of 1 μM 3MeOBAP and 3MeOBA9THPP compared to controls.

<p>CK quantitative analysis was performed by UPLC/MS 1 hour (<b>A</b>), 3 hours (<b>B</b>), 24 hours (<b>C</b>) and 72 hours (<b>D</b>) after treatment with 3MeOBAP (black bars), 3MeOBA9THPP (grey bars) and DMSO-treated plants (white bars). All values are derived from three biological replicates that were determined in at least two technical replicates. <b>3MeOBAPR</b> – 3-methoxy(-6-benzylamino)purine riboside; 3OHBAP – 3-hydroxy(-6-benzylamino)purine; <b>3OHBAPR</b> – 3-hydroxy(-6-benzylamino)purine riboside; <b>3OHBAP9G</b> – 3-hydroxy(-6-benzylamino-9-glucosyl)purine; <b>(OG)3OHBAP</b> – 3-<i>O</i>-glucosyl-6-benzylaminopurine; <b>unknown</b> – 3MeOBA9THPP with additional hydroxyl group; <b>All tZ metabolites</b> – sum of <i>trans</i>-zeatin, its <i>N9</i>-riboside, <i>N9</i>-glucoside, 5′-monophosphate nucleotide, <i>O-</i>glucoside and <i>N9</i>-riboside-<i>O</i>-glucoside; <b>All cZ and DHZ metabolites</b> – sum of above listed <i>cis</i>-zeatin and dihydrozeatin derivatives, respectively; <b>All iP metabolites</b> – sum of 6<i>-</i>isopentenylaminopurine, its <i>N9</i>-riboside, <i>N9</i>-glucoside and 5′ -monophosphate nucleotide. Absolute concentration of unknown metabolite can be misinterpreted as deuterium labeled standard is not available.</p