ContentSnapshots

Plant growth modelling and applications (Viewpoint)

Modelling plant growth allows the testing of hypotheses and simulation of experiments that could otherwise take years in field conditions. Fourcaud et al. (pp. 1053–1063) propose that plant architecture and sink activity should be pushed to the centre of plant growth models.

Models for forest ecosystem management: a European perspective (Review)

Growth models are the most innovative planning tools available. They integrate system knowledge and scale it to levels relevant for management. Pretzsch et al. (pp. 1065–1087) identify five different paradigms, assess models suitable for goal setting or decision support, and develop guidelines for practical operation.

Modelling carbohydrate allocation to defence-related metabolites

Variation in the concentrations of defence-related metabolites depends on internal source and sink strengths for carbon and nitrogen. Gayler et al. (pp. 1089–1098) use the plant growth model PLATHO to simulate the dynamics of carbohydrate allocation to secondary compounds and present model equations and simulation results for juvenile apple, beech and spruce.

Sink functions of wheat organs derived from GREENLAB model

The functional–structural plant model GREENLAB is calibrated for wheat by Kang et al. (pp. 1099–1108). They fit model outputs to measured mass of roots, leaf parts, internodes and ears of tillers and main stems at four sampling stages. The resulting parameters give sink functions of the various organs.

Combined rule-based model of morphogenesis, shading and hormone signal transduction

Using an interactive modelling platform, Buck-Sorlin et al. (pp. 1109–1123) integrate different models combining gibberellic acid signal transduction, phytochrome-based shade detection and object avoidance in barley at different hierarchical scales. The outcome shows the suitability of this new formalism for multi-scaled functional–structural plant modelling.

AmapSim: a structural plant architecture simulator designed to host external functional models

This model and related software include botanical knowledge to simulate realistic plant shapes. A specific software open interface designed by Barczi et al. (pp. 1125–1138) allows the growth engine to be optionally driven by functional computing that is plugged into it.

A 3-D virtual model estimates light capture in sunflower

Light capture at organ, plant and plot levels is estimated by characterizing the light environment and using 3-D virtual plants built from plant architectural characteristics (Rey et al., pp. 1139–1151). Blades and the capitulum are shown as major contributors to light interception while contributions of petioles, stem or by heliotropism are negligible.

Light-foraging efficiency of low-density cotton

How plants forage for light is addressed by Dauzat et al. (pp. 1153–1166) using 3-D virtual plants reconstructed from field experiments planted at 1, 2 or 4 plants m^–2. These plants optimize light capture through photomorphogenetic responses but produce leaf area in proportion to intercepted light in a manner similar for all densities.

Modelling grapevine canopy structure

Based on simple field measurements, Louarn et al. (pp. 1167–1184) describe and validate a statistical model for reconstructing 3-D virtual canopies for various genotypes and training systems. They highlight how such a statistical approach can provide more reliable outputs at the stand level than exhaustive architectural records of a limited number of plants.

Validation of GREENLAB model for field-grown maize at different densities

Parameter values describing variation of organ sink function in GREENLAB are shown by Ma et al. (pp. 1185–1194) to vary little between years and at different planting densities. This strengthens the hypothesis that one set of equations can govern dynamic organ growth in the GREENLAB model.

Modelling phenotypic plasticity using a structure–function model

The structure–function model GREENLAB allows resource-dependent plasticity of plant architecture to be simulated. Using tomato, a crop exhibiting marked morphogenetic responses to plant spacing, Dong et al. (pp. 1195–1206) examine strengths and weaknesses of the current version of GREENLAB in accounting for the plasticity of response to spacing.

Simulation of tree growth and development at different densities

A functional model of light competition is proposed by Cournède et al. (pp. 1207–1219) based on an empirical model of foliage spatial repartition and on the Beer–Lambert law of light extinction. The model shows that plant density strongly influences tree architectural development through interactions with source–sink balance during growth.

Modelling morphological plasticity in trees

Three-dimensional modelling is used by Vincent and Harja (pp. 1221–1231) to assess effects of morphological plasticity on tree performance. Simulations conducted in various competitive environments (contrasting planting density, stand composition, site fertility) all show significant competitive advantage of crown-shape plasticity in light-demanding species.

Modelling of alternating patterns

Mathieu et al. (pp. 1233–1242) formalize interactions between architecture and functioning using the GREENLAB mathematical model that permits theoretical studies of plant growth as well as simulations of alternating patterns, such as rhythms in fruiting or branch production. Emergent properties of the model are shown to simulate observed patterns faithfully.

Simulation of QTL detection for functional–structural model parameters

Letort et al. (pp. 1243–1254) introduce genetics into the GREENLAB functional–structural growth model. This gives access to fundamental traits for quantitative trait loci (QTL) detection. Computation of a genetic algorithm holds promise for detecting the allelic combination optimizing maize yield. The potential of GREENLAB to represent environment/genotype interactions is outlined.

Modelling cell–cell interactions during plant morphogenesis

During the development of multicellular organisms, cells interact with each other using a range of biological and physical mechanisms. Dupuy et al. (pp. 1255–1265) describe a new generic model of plant cellular morphogenesis that expresses interactions explicitly amongst cellular entities.

Numerical analysis of roots and tree overturning

A 2-D finite element analysis by Fourcaud et al. (pp. 1267–1280) couples the influence of root morphology and soil type on tree anchorage, and reveals the relative effects of lateral roots and the distal tap root on tree overturning. The contribution of secondary root growth to acclimation to mechanical stress is discussed.

Three-dimensional evaluation of roots in unstable sloping sites

Vegetation can stabilize landslide-prone sites. Danjon et al. (pp. 1281–1293) use 3-D digitized images to assess root-system architecture of woody plants growing on slopes and show that such data can be used to obtain accurate estimates of factors affecting safety.