2,276 research outputs found

    Abnormal flowers and pattern formation in floral

    Get PDF
    “From our acquaintance with this abnormal enabled to unveil the secrets that normal us, and to see distinctly what, from the regular we can only infer.” - J. W. von Goethe (1790

    Genetic interactions among floral homeotic genes of Arabidopsis

    Get PDF
    We describe allelic series for three loci, mutations in which result in homeotic conversions in two adjacent whorls in the Arabidopsis thaliana flower. Both the structure of the mature flower and its development from the initial primordium are described by scanning electron microscopy. New mutations at the APETALA2 locus, ap2-2, ap2-8 and ap2-9, cause homeotic conversions in the outer two whorls: sepals to carpels (or leaves) and petals to stamens. Two new mutations of PISTILLATA, pi-2 and pi-3, cause second and third whorl organs to differentiate incorrectly. Homeotic conversions are petals to sepals and stamens to carpels, a pattern similar to that previously described for the apetala3-1 mutation. The AGAMOUS mutations, ag-2 and ag-3, affect the third and fourth whorls and cause petals to develop instead of stamens and another flower to arise in place of the gynoecium. In addition to homeotic changes, mutations at the APETALA2, APETALA3 and PISTILLATA loci may lead to reduced numbers of organs, or even their absence, in specific whorls. The bud and flower phenotypes of doubly and triply mutant strains, constructed with these and previously described alleles, are also described. Based on these results, a model is proposed that suggests that the products of these homeotic genes are each active in fields occupying two adjacent whorls, AP2 in the two outer whorls, PI and AP3 in whorls two and three, and AG in the two inner whorls. In combination, therefore, the gene products in these three concentric, overlapping fields specify the four types of organs in the wild-type flower. Further, the phenotypes of multiple mutant lines indicate that the wild-type products of the AGAMOUS and APETALA2 genes interact antagonistically. AP2 seems to keep the AG gene inactive in the two outer whorls while the converse is likely in the two inner whorls. This field model successfully predicts the phenotypes of all the singly, doubly and triply mutant flowers described

    Control of flower development in Arabidopsis thaliana by APETALA1 and interacting genes

    Get PDF
    Mutations in the APETALA1 gene disturb two phases of flower development, flower meristem specification and floral organ specification. These effects become manifest as a partial conversion of flowers into inflorescence shoots and a disruption of sepal and petal development. We describe the changes in an allelic series of nine apetala1 mutants and show that the two functions of APETALA1 are separable. We have also studied the interaction between APETALA1 and other floral genes by examining the phenotypes of multiply mutant plants and by in situ hybridization using probes for several floral control genes. The results suggest that the products of APETALA1 and another gene, LEAFY, are required to ensure that primordia arising on the flanks of the inflorescence apex adopt a floral fate, as opposed to becoming an inflorescence shoot. APETALA1 and LEAFY have distinct as well as overlapping functions and they appear to reinforce each other's action. CAULIFLOWER is a newly discovered gene which positively regulates both APETALA1 and LEAFY expression. All functions of CAULIFLOWER are redundant with those of APETALA1. APETALA2 also has an early function in reinforcing the action of APETALA1 and LEAFY, especially if the activity of either is compromised by mutation. After the identity of a flower primordium is specified, APETALA1 interacts with APETALA2 in controlling the development of the outer two whorls of floral organs

    Study of the bottom diatoms of a fertilized sea loch

    Get PDF

    Cluster of galaxies Abell 1060

    Get PDF
    This thesis describes the implementation and results of a prograunue of photometry of the relatively nearby southern cluster of galaxies and X -ray source, Abell 1060 = Hydra I.Photographic photometry in B and V wavebands of galaxies in a ~22 degree² region centred on this cluster have been obtained on the basis of measurements of four U.K. Schmidt telescope plates by the COSMOS measuring machine at the Royal Observatory, Edinburgh. The feasibility of using the COSMOS machine to derive reliable isophotal magnitudes of bright and faint galaxies is demonstrated.Multiaperture photoelectric (U, B, V and R -band) photometry has been secured of sixteen galaxies in the field of the cluster, including seven NGC and IC systems. Besides providing photometric calibration, these observations permit the total magnitudes and colours of several galaxies to be derived.The positions and magnitudes of over 5000 galaxies, supplemented in many cases by morphological classifications, by micrometric measurements of dimensions and alignment, and by redshift data, have been analysed to determine the static and dynamical properties of A1060. The cluster is symmetric, centrally condensed, and rich in disk galaxies; members segregate radially by morphological type, with spiral galaxies generally farthest from the centre.The V -band luminosity function of A1060 has been constructed. It is similar in form but different in detail from those of other clusters. The colour -magnitude relation of early -type galaxies in A1060 is outlined, and is shown to be inconsistent with one prediction of a standard theory of the morphological evolution of galaxies and clusters.Visual searches for low surface brightness members of A1060 are described. It is suggested that fewer such galaxies exist than an extrapolation of the luminosity function for all galaxy types to faint magnitudes would predict.Peculiar properties of four galaxies near the centre of the cluster are interpreted in terms of the influence of their environments. Three are anaemic spirals, for which there is strong evidence that an era of gas depletion has recently begun. The first- ranked member, N3311, is an extended system of low mean surface brightness, and may represent a D galaxy in the early stages of evolution. These observations suggest that the cluster Abell 1060 is relatively young in dynamical terms

    Developing a dynamic regional brand - focus on flavour.

    Get PDF
    This project has delivered technical sensory language that accurately and precisely describes the flavour and texture of key seafood species to the seafood industry of the Eyre Peninsula. Industry members and producers have been trained on the sensory properties of their products and are equipped with knowledge of how to apply sensory language to their products for their customers. The seafood industry of the Eyre Peninsula has embraced the “Eyre Peninsula Seafood Flavour wheel” and is already using it in the promotion of their products. In addition local, national and international seafood producers and end-users have indicated a strong interest in the results and outputs of this project and the potential application of the seafood flavour wheel in their respective businesses

    Case Study Experience of a Collaborative and Responsible Form of Professional Development for Teachers

    Get PDF
    The argument in this paper is that teachers\u27 interpretations and theories about what works in classrooms, can and should constitute the basis of change. Teachers have the capacity to engage in practical reflection through collaboration that enriches their sense of what is feasible and possible as well as transforming their understanding of those realities. Critical reflection, however, requires various forms of assistance, and in this case it occurred through the provision of a paradigm, the Cogan (1973)/Goldhammer (1969) notion of clinical supervision

    Class, dispositions and radical politics -- A rejoinder

    Get PDF
    This paper is a rejoinder to James Avis' paper: "A Note on Class, Dispositions and Radical Politics" which is, in turn, a critique of the opening chapter of the book "Education and Working-Class Youth: Reshaping the Politics of Inclusion," written by the authors of this article. Here we deal with each of the criticisms raised by Avis, including his accusation that our position is reductionist and fails to recognise the complex nature of social class in contemporary society. In doing this, we re-emphasise our relational perspective on education and social class

    "Phrases and proverbs of speach proper to this hundred."

    Get PDF
    Glosario. -- Gloucestershire. -- Pertenece a la Colección Varia 1500-1699 de The Salamanca Corpus. -- John Smyth, 1567-1640. -- "Phrases and proverbs of speach proper to this hundred". -- 1639.[ES]Glosario del dialecto de Gloucestershire. [EN]Glossary of Gloucestershire dialect
    corecore