A Study of Ryegrass Architecture As a Self-Regulated System, Using Functional-structural Plant Modelling (original) (raw)

The canopy structure of grasslands is a major determinant of their use-value, as it affects the quantity and quality of the forage removed when mowed or grazed. The structure of this canopy is determined by individual plant architecture, which is highly sensitive to both environmental variations and management practices such as cutting regimes. This architectural plasticity may partially be mediated by a self-regulation process, i.e. the actual state of the architecture (e.g. length of the pseudostem) may control the determination of morphogenetic processes such as cell production. To test the robustness of this hypothesis, we designed a functional-structural model of ryegrass plant morphogenesis exhibiting this type of cybernetic behavior. The model is based on the L-system formalism. It was able to capture satisfactorily the major quantitative architectural traits of ryegrass under non-limiting growing conditions and under a cutting constraint. From these simulation results it appears that i) self-regulation rules could be of practical use to ryegrass modeling and ii) when activated in an integrated model, they are not markedly incompatible with reality.