title: Assessing the effects of architectural variations on light partitioning within virtual wheat-pea mixtures.
abstract: OBJECTIVE
  Predicting light partitioning in crop mixtures is a critical step in improving the productivity of such complex systems, and light interception has been shown to be closely linked to plant architecture. The aim of the present work was to analyse the relationships between plant architecture and light partitioning within wheat-pea (Triticum aestivum-Pisum sativum) mixtures. An existing model for wheat was utilized and a new model for pea morphogenesis was developed. Both models were then used to assess the effects of architectural variations in light partitioning.
  
  
  METHODS
  First, a deterministic model (L-Pea) was developed in order to obtain dynamic reconstructions of pea architecture. The L-Pea model is based on L-systems formalism and consists of modules for 'vegetative development' and 'organ extension'. A tripartite simulator was then built up from pea and wheat models interfaced with a radiative transfer model. Architectural parameters from both plant models, selected on the basis of their contribution to leaf area index (LAI), height and leaf geometry, were then modified in order to generate contrasting architectures of wheat and pea.
  
  
  RESULTS
  By scaling down the analysis to the organ level, it could be shown that the number of branches/tillers and length of internodes significantly determined the partitioning of light within mixtures. Temporal relationships between light partitioning and the LAI and height of the different species showed that light capture was mainly related to the architectural traits involved in plant LAI during the early stages of development, and in plant height during the onset of interspecific competition.
  
  
  CONCLUSIONS
  In silico experiments enabled the study of the intrinsic effects of architectural parameters on the partitioning of light in crop mixtures of wheat and pea. The findings show that plant architecture is an important criterion for the identification/breeding of plant ideotypes, particularly with respect to light partitioning.
authors.forename: Romain
authors.initials: R
authors.lastname: Barillot
authors.forename: Abraham J
authors.initials: AJ
authors.lastname: Escobar-Gutiérrez
authors.forename: Christian
authors.initials: C
authors.lastname: Fournier
authors.forename: Pierre
authors.initials: P
authors.lastname: Huynh
authors.forename: Didier
authors.initials: D
authors.lastname: Combes
mesh_terms: D003198:Computer Simulation; D008027:Light; D008954:Models, Biological; D018532:Pisum sativum / Q000033:anatomy & histology* / Q000254:growth & development / Q000528:radiation effects; D018515:Plant Leaves / Q000033:anatomy & histology / Q000254:growth & development / Q000528:radiation effects; D014908:Triticum / Q000033:anatomy & histology* / Q000254:growth & development / Q000528:radiation effects