Coordinated developement of the architecture of the primary shoot in bush rose

The development of the architecture of ornamental bushes needs to be explicitly described because it defines both their visual appearance and their interface with the environment. The aim of this work was to describe the dynamics of organ development in the primary shoot of rose bushes and their coordination. Rosa hybrida L. \u27Radrazz\u27 was grown in a glasshouse in two seasons. Internodes and leaflets were measured frequently and elongation curves were fitted to a linear-plateau model. The number of leaflets per leaf displayed clear patterns of organization along the shoot. Allometric relationships linked all leaf dimensions to terminal leaflet length. The differences in internode length between successive phytomers resulted from differences in the extension rate and the duration of extension. Conversely, the differences in the terminal leaflet size resulted almost solely from differences in extension rate. Internodes and terminal leaflets extensions were closely coordinated. This work provides the basic elements for establishing a virtual plant model

Rose bush leaf and internode expansion dynamics: analysis and development of a model capturing interplant variability

Rose bush architecture, among other factors, such as plant health, determines plant visual quality. The commercial product is the individual plant and interplant variability may be high within a crop. Thus, both mean plant architecture and interplant variability should be studied. Expansion is an important feature of architecture, but it has been little studied at the level of individual organs in rose bushes. We investigated the expansion kinetics of primary shoot organs, to develop a model reproducing the organ expansion of real crops from non-destructive input variables. We took interplant variability in expansion kinetics and the model\u27s ability to simulate this variability into account. Changes in leaflet and internode dimensions over thermal time were recorded for primary shoot expansion, on 83 plants from three crops grown in different climatic conditions and densities. An empirical model was developed, to reproduce organ expansion kinetics for individual plants of a real crop of rose bush primary shoots. Leaflet or internode length was simulated as a logistic function of thermal time. The model was evaluated by cross-validation. We found that differences in leaflet or internode expansion kinetics between phytomer positions and between plants at a given phytomer position were due mostly to large differences in time of organ expansion and expansion rate, rather than differences in expansion duration. Thus, in the model, the parameters linked to expansion duration were predicted by values common to all plants, whereas variability in final size and organ expansion time was captured by input data. The model accurately simulated leaflet and internode expansion for individual plants (RMSEP = 7.3 and 10.2% of final length, respectively). Thus, this study defines the measurements required to simulate expansion and provides the first model simulating organ expansion in rosebush to capture interplant variability

Assessing the Impact of Pollen-mediated Gene Flow from GM Herbicide Tolerant Brassica Napus into Common Wild Relatives in Ireland

Although now we have had many years of research completed on assessing the potential environmental impact of GM crops, concern remains over their potential impact on biodiversity in the rural landscape. In particular, issues have arisen in regards to the modification of crops with traits that could introgress into sexually compatible wild relatives. In contrast to wheat, barley, potato and maize, Brassica napus (oilseed rape) is the only commercial crop grown in Ireland at present with the potential to successfully transfer its DNA, via pollen-mediated gene flow, into inter-related weed species. This review details the species in question and by examining the relevant literature that relates to Irish agronomic conditions, demonstrates that gene flow is likely to occur, especially to an earlier used cultivar, Brassica rapa. However, the critical factor remains not that GM traits will flow from the commercial source but what might the consequences of said gene flow events be. This review indicates that the conferred trait in question (in this case, herbicide tolerance) can only impact on weed diversity in the presence of selecting herbicide action. In the absence of the herbicide, the GM traits will be lost from the wild species over time and will not confer any selective advantage that could facilitate population growth.Author has checked copyrightNames J