Papers by Delphine Luquet
2006 Second International Symposium on Plant Growth Modeling and Applications, 2006
Most classic ecophysiological models rely on crude representations of canopies as stacks of veget... more Most classic ecophysiological models rely on crude representations of canopies as stacks of vegetation layers. Therefore, their use in complex canopies implies complicated adaptations as well as simplifying assumptions that are difficult to validate. Alternatively, the ARCHIMED simulation platform uses 3D virtual stands as a support for numerical simulations of biophysical processes such as leaf irradiation, transpiration and temperature and ultimately carbon assimilation. By doing so, detailed information can be integrated from the individual leaf scale up to the individual plant scale, even within complex stands such as agroforestry systems.
Annals of botany, 2008
Cotton shows a marked plasticity vs. density in terms of branch development and geometry, interno... more Cotton shows a marked plasticity vs. density in terms of branch development and geometry, internode elongation and leaf expansion. This paper proposes interpretations for observed plasticity in terms of light quantity and quality. 3-D virtual plants were reconstructed from field observations and 3-D digitization and were used to simulate the light regime in cotton stands of different densities. All densities showed the same linear relationship between LAI and the sum of light intercepted by the canopy, from seedling emergence up to flowering. Simulated R : FR ratio profiles can very likely explain (1) the longer first internodes on main stem and branches and (2) the azimuthal re-orientation of branches toward the inter-row. Simulation tools were used to analyse plant plasticity in terms of light quantity and quality. The methodology applied here at the stand scale will now be continued at the plant scale to further strengthen the above hypotheses.
Crop model assisted characterization of appropriate traits for the rice TPE in Brazilian Cerrados
Environmental and genetic control of morphogenesis in crops: towards models simulating phenotypic plasticity
Australian Journal of Agricultural Research, 2005
... area of morphogenesis. Additional keywords: sourcesink relationships, competition for resour... more ... area of morphogenesis. Additional keywords: sourcesink relationships, competition for resources, carbohydrate reserves, rice, peach, plant architecture, organogenesis, crop models, SARRAH, GREENLAB. Introduction There ...
Functional Plant Biology, 2006
Because of rapid advances in functional genomics there is an increasing demand for models simulat... more Because of rapid advances in functional genomics there is an increasing demand for models simulating complex traits, such as the physiological and environmental controls of plant morphology. This paper describes, validates and explores the behaviour of the structural-functional model EcoMeristem, developed for cereals in the context of the Generation Challenge Program (GCP; CGIAR). EcoMeristem constructs the plant on the basis of an organogenetic body plan, driven by intrinsic (genetic) behavioural norms of meristems. These norms consist of phenological-topological rules for organ initiation and pre-dimensioning (sink creation) and rules enabling feedbacks of the plant's resource status on the organogenetic processes. Plant resource status is expressed by a state variable called Internal Competition Index (Ic) calculated daily as the ratio of assimilate source (supply) over the sum of active sinks (demand). Ic constitutes an internal signal analogous to sugar signalling. Ic affects potential phytomer size, tiller initiation, leaf senescence, and carbohydrate storage and mobilisation. The model was calibrated and tested on IR64 rice grown in controlled environments, and validated with field observations for the same cultivar (Philippines). Observed distributions and dynamics of soluble sugars and starch in plant organs supported the model concepts of internal competition and the role of reserves as a buffer for Ic fluctuations. Model sensitivity analyses suggested that plant growth and development depend not only on assimilate supply, but also on organogenesis-based demand. If true, this conclusion has important consequences for crop improvement strategies.
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Papers by Delphine Luquet