15 research outputs found

    Identification of relevant morphological, topological and geometrical variables to characterize the architecture of rose bushes in relation to plant shape

    Get PDF
    Plant shape is a major component of the visual quality of ornamental plants. It is the result of their architectural construction. It can be analyzed by breaking down the plant into entities (axis, metamer) that can be characterized morphologically, topologically and geometrically. Eight bush rose cultivars were selected for their contrasting shapes (from upright to spreading) and their architecture was digitized at two scales, the plant and the axis, differentiating between short and long axes. Thirty-five variables were measured. Measurement acquisition is nevertheless tedious and time-consuming and not really compatible with an analysis involving a large number of individuals. To diminish these constraints, our approach aimed at reducing the number of variables measured, limiting ourselves to the ones most relevant for describing the architecture. A selection of variables was made using the following criteria: to represent the different categories of variables describing the plant architecture; to explain the variability observed; to present the weakest correlation between them. Seven variables were selected: at the plant scale, the number of determined axes, the number of long axes of order 3 and the branching order number; at the long axis scale, the number of metamers and the length of the axis; and at the short axis scale, the basal diameter of the axis and the branching angle of the cord in relation to the vertical axis. Four architectural profiles were differentiated based on these seven variables. Moreover, a high correlation was revealed between some of these architectural variables and a shape descriptor

    Assessing the visual aspect of rotating virtual rose bushes by a labeled sorting task

    Get PDF
    Aesthetics is one of the major parameters for consumers when buying a rose bush. Therefore, managing this quality is important for agronomists. Tools are needed to assess visual characteristics and to find links with architectural plant parameters. Sensory analyses were developed using real plants and photographs as stimuli. With technology and modeling improvements, using virtual plants could presents numerous advantages. This study demonstrated the feasibility of using rotating virtual rose bush videos as stimuli for a labeled sorting task. The virtual rose bush reflected a natural within-crop variability of one cultivar based on bud breaks location and axes length. Two panels of subjects closely linked to the horticulture sector sorted and described 40 rotating virtual rose bush videos. Non-metric Multidimensional Scaling (MDS) results for both panels were similar and allowed us to highlight five groups of virtual rose bushes with their specific sensory characteristics and their own most representative products using a combination of the paragons and the most typical products. This approach revealed that subjects detected high visual differences between products, and that by using rotation, they were able to integrate 3D properties about variations around plant facets. Finally, a labeled sorting task is a powerful method for preliminary exploration of the visual aspect of virtual plants

    Sugars are under light control during bud burst in Rosa sp.

    Get PDF
    Bud burst in certain species is conditioned by the luminous environment. With roses, the requirement for light is absolute, and darkness totally inhibits bud burst. Few studies have looked into understanding the action of light on the physiological bud burst processes. Here, we show the impact of light on certain components of glucidic metabolism during bud burst. Measurements were taken on decapitated plants of Rosa hybrida L. ‘Radrazz’ exposed either to darkness, white, blue or R light. Results show that a mobilization of bud and the carrying stem sucrose reserves only takes place in light and accompanies the bud burst. Furthermore, the activity of the RhVI vacuolar acid invertase which contributes to the breakdown of sucrose in the buds, as well as the transcription of the RhVI gene, is reduced in darkness, although it is strongly stimulated by light. The same analysis concerning the RhNAD-SDH gene, coding an NAD-dependent sorbitol dehydrogenase, shows, on the contrary, a strong induction of its transcription in darkness that could reflect the use of survival mechanisms in this condition

    Intérêt du CGA 245704, stimulateur des défenses naturelles des plantes, dans la lutte contre la tâche bactérienne de la mâche, due à Acidovorax valerianellae

    No full text
    Intérêt du CGA 245704, stimulateur des défenses naturelles des plantes, dans la lutte contre la tâche bactérienne de la mâche, due à Acidovorax valerianellae. 5ème Congrès de la S.F.P

    Localizing Starch Reserves in Mandevilla sanderi (Hemsl.) Woodson Using a Combined Histochemical and Biochemical Approach

    No full text
    Mandevilla sanderi is a plant of tropical origin of great horticultural interest because of its abundant flowering and its persistent foliage. Vegetative propagation requires the removal of leafy branches on the mother plant to produce cuttings. This loss of biomass must be compensated for by the growth of new branches thanks to the mobilization of reserves within the plant. Lack of knowledge about the physiology of this species therefore makes it necessary to characterize its different organs both at the level of their anatomic organization as well as at the level of their ability to store starch. After histological characterization of the different organs (leaves, stems, and roots), starch reserves were localized by histochemical analysis and quantified by biochemical analysis. Starch grains are mainly found in the parenchymatous cortex, the parenchymatous pith and xylem parenchyma cells, in tuberous roots and stems, and in the palisade and spongy mesophyll of leaves. In 22-week-old plants, the greatest quantity of starch is found in the leaves, whereas the tuberous roots have the highest concentration. The histological description of the different organs of Mandevilla sanderi and the localization of starch reserves allow us to assess the potential role of the different organs in plant growth and development. In the particular case of mother plant management, it is hoped that this knowledge will make it possible to optimize conditions for removing leafy branches

    Discriminative Strategies to Integrate Multiword Expression Recognition and Parsing

    No full text
    The integration of multiword expressions in a parsing procedure has been shown to improve accuracy in an artificial context where such expressions have been perfectly pre-identified. This paper evaluates two empirical strategies to integrate multiword units in a real constituency parsing context and shows that the results are not as promising as has sometimes been suggested. Firstly, we show that pregrouping multiword expressions before parsing with a state-of-the-art recognizer improves multiword recognition accuracy and unlabeled attachment score. However, it has no statistically significant impact in terms of F-score as incorrect multiword expression recognition has important side effects on parsing. Secondly, integrating multiword expressions in the parser grammar followed by a reranker specific to such expressions slightly improves all evaluation metrics
    corecore