Intensive production of juvenile cuttings by mother microplant culture in Hydrangea macrophylla "Leuchtfeuer"

International audienc

Using architectural analysis to compare the shape of two hybrid tea rose genotypes

In the area of ornamental horticulture, it is necessary to compare individuals to assess the effect of an experimental treatment or to distinguish between two genotypes. This is especially true for the hybrid tea rose, a plant species widely used throughout the world as a garden rose and represented by a very large number of cultivars. Normally, this diversity is approached by a more or less Subjective analysis of the shape, with terms such as upright or spreading, and compact vs. laxly branched. Even when evaluated by a panel or experts, this approach quickly reaches its limits when it is necessary to objectively quantify the differences observed. The architectural analysis proposed here allows us to satisfy this objective. Two rose genotypes were studied: Rosa hybrida 'Radrazz' Knock-Out(R) (KO) and 'Meiratcan', Lovely Meilland(R) (LM). These two genotypes share both architectural similarities and differences. As for the similarities: (i) the axes ire of two highly differentiated types, long and short: (ii) the proportions of each type of axis vary from 100% of long axes for order 1, to 100% of short axes for the last branching order: and (iii) all of the flowering axes have a comparable profile, with the continuous development of their morphological components, from their base to their extremity. Despite these similarities, the two genotypes are very clearly differentiated. The number of orders and axes is greater for KO, whereas axis length and the number of metamers per axis are much greater for LM. The architectural analysis proposed here makes it possible to effectively quantify the major shape components of an ornamental plant like the rose. As a result, it provides a truly effective tool for objectively assessing plant shape. (C) 2008 Elsevier B.V. All rights reserved

De la reconstitution à la construction de sols à partir de déchets

International audienceLes sols urbains présentent une grande variabilité spatiale et verticale et sont influencés plus ou moins intensément par les activités humaines. Ils ont des horizons de surface souvent massifs, fortement modifiés par l’Homme via des mélanges, de l’incorporation et/ou de l’exportation de matériaux technogéniques[1], souvent grossiers et potentiellement contaminés. Les sols urbains ont donc la particularité d’être généralement peu fertiles pour la croissance des végétaux : tassement, scellement des surfaces, volume restreint et confiné, faible surface d’échange sol-atmosphère, ruissellement, circulation de l’eau et de l’air réduite, fertilisation faible, pollution fréquente et potentiellement forte. Améliorer les propriétés des sols urbains est nécessaire si l’on veut y planter et cultiver du végétal, afin que ces sols puissent assurer leurs fonctions et rendre les services attendus

Effect of organic amendment for the construction of favourable urban soils for tree growth

International audienceOrnamental tree planting and establishment in cities is a great challenge because urban soil physical properties are unfavourable to the development of root systems. Our objectives were to measure (i) the effects of organic matter on soil physical properties and tree development, and (ii) the effects of ensuing root development on soil physical properties. Using twenty-four 600-L planted or bare soil containers, we monitored physical properties such as dry bulk density, aggregate stability and near-saturated hydraulic conductivity of our reconstituted soils over a 5.5-year period. A 28-cm thick top layer of sandy loam amended with 40% (v/v) sphagnum peat or organic composts was laid on top of a 28-cm thick layer of sandy loam. Bare-root Ostrya carpinifolia trees were planted in half of the 24 containers, and we monitored shoot development and root biomass and distribution. After 5.5 years, trunk diameter had increased from 59 mm for the control soil to 66 mm for soil mixed with green waste compost, and 74 mm for soil mixed with co-compost of sewage sludge and wood chips. After 4.5 years, trunk diameter was strongly correlated with the total number of axes (r = 0.94) and fine root length density (r = 0.98), and was confirmed as a good indicator of tree development. Fine root development increased stable aggregate formation in all treatments as compared to bare soil. After 4.5 years after planting, the tree root system induced by a high organic matter input had significantly improved near-saturated hydraulic conductivity and was fit to support fertile urban soils

Comparison of two shrub rose genotypes using architectural analysis

 The aesthetic value of an ornamental plant is highly dependant on its shape. This is primarily determined by the characteristics of its axes at the following levels: (1) morphological (size of the different constituent elements) (2) topological (branching relationships) and (3) spatial (position of the axes in space). Architectural analysis therefore appears to be an interesting method for characterising plant shape and for assessing its aesthetic value. This method seems to be particularly well adapted to an ornamental shrub such as the rose bush that has a visibly complex architecture. The analysis took place on two cultivars of the shrub rose Rosa hybrida, Knock Out® cv Radrazz and Lovely Meilland® cv Meiratcan. Quantitative experimental data (morphological and topological) were obtained on plants grown from metamers cuttings in a greenhouse for five months. Fifteen plants per cultivar were fully described. Data was analysed using the Multi Tree Scale method (MTG) (Godin C. and Caraglio Y. 1998). This method made it possible to obtain a database for each cultivar that included the different related architectural scale levels, morphological entities and variables (attributes). By analysing this database, we were able to clearly identify the dominant architectural elements common to the two cultivars, such as the existence of two types of axes (long and short) and the position of these axes according to branching order. Moreover, it also allowed us to identify the architectural characteristics that differentiate the two genotypes, such as the number of branching orders, the number of flower-bearing branches and their length. This precise and quantitative analysis of shrub architecture is a powerful method for describing shrub shape. It may therefore be an invaluable tool for breeders, for example, who want to accurately characterise the architecture of different genotypes in order to impose selection pressure on objective criteria. The same is true for the researcher who would like to assess the effect of various treatments on plant shape, such as in the case of pruning or the application of a growth regulator

Effect of mechanical stimulation on the growth and branching of garden rose

International audienceOne of the main criteria for the visual quality of an ornamental potted plant is its shape, which should be compact and branched. In the case of rose, like that of many other ornamental plants, it is essential to be able to control both growth and branching. The most common method used is the application of chemical growth regulators. However, their toxicity in relation to health and their impact on the environment cast doubts on their use. Mechanical stimulation is one of the alternative methods proposed to replace these chemical regulators. It was applied to young rose plants, Rosa hybrida 'Radrazz' Knock-Out (R), at two different frequencies: once a day, three times per week, for seven weeks (Exp. 1), and five times a day, four times per week, for five weeks (Exp. 2). It consisted of passing a horizontal bar over the upper part of the plants. Significant results were obtained in the two trials, with an increase in the number of branchings from the most proximal metamers (of 102% and 97% in Exps. 1 and 2, respectively) and a reduction of the length of metamers of order 1 axes (of 8% and 9% in Exps. 1 and 2, respectively), resulting in a significant reduction in axis length in Exp. 2. A reduction in the length of order 2 axes during growth was also observed in the two trials. These results lead the way to interesting potential horticultural applications for controlling plant growth, in particular, the elongation of branches, and for promoting basitone branching

Evaluation de la qualité ornementale d’une collection d’Hydrangea paniculata Sieb CD Rom: Euro-trials 2006-2007

évaluation sensorielle de collections de buissons ligneux d'ornement à l'échelle européenne. Outils d'aide au choix des végétaux par les différents acteurs de la filière horticole.National audienceLes essais d'évaluation de taxons du programme européen Euro-Trial permettent d'apprécier le comportement d'un genre, d'une espèce dans différentes conditions pédo-climatiques. La présente synthèse rapporte les résultats de comportement de 29 cultivars d'Hydrangea paniculata obtenus par l'évaluation, par un jury européen, de caractères morphologiques (foliaires et floraux) à différents stades de développement

ROSE-X: an annotated data set for evaluation of 3D plant organ segmentation methods

International audienceBackgroundThe production and availability of annotated data sets are indispensable for training and evaluation of automatic phenotyping methods. The need for complete 3D models of real plants with organ-level labeling is even more pronounced due to the advances in 3D vision-based phenotyping techniques and the difficulty of full annotation of the intricate 3D plant structure.ResultsWe introduce the ROSE-X data set of 11 annotated 3D models of real rosebush plants acquired through X-ray tomography and presented both in volumetric form and as point clouds. The annotation is performed manually to provide ground truth data in the form of organ labels for the voxels corresponding to the plant shoot. This data set is constructed to serve both as training data for supervised learning methods performing organ-level segmentation and as a benchmark to evaluate their performance. The rosebush models in the data set are of high quality and complex architecture with organs frequently touching each other posing a challenge for the current plant organ segmentation methods. We report leaf/stem segmentation results obtained using four baseline methods. The best performance is achieved by the volumetric approach where local features are trained with a random forest classifier, giving Intersection of Union (IoU) values of 97.93% and 86.23% for leaf and stem classes, respectively.ConclusionWe provided an annotated 3D data set of 11 rosebush plants for training and evaluation of organ segmentation methods. We also reported leaf/stem segmentation results of baseline methods, which are open to improvement. The data set, together with the baseline results, has the potential of becoming a significant resource for future studies on automatic plant phenotyping