Computational Models

Two decades of “virtual” plant simulations: what’s next?

The FSPM approach has demonstrated considerable progress, but has yet to reach its full potential in terms of integration and heuristic knowledge production.

Put on a mathematician’s glasses and look at a plant. The aim of Functional-Structural Plant Modelling (FSPM) is to understand the growth and development of plants in modules (e.g. organs or groups of organs) whilst interacting with their environment. 

Drs Gaëtan Louarn and Youhong Song at the Anhui Agricultural University (China) reviewed the development in FSPM over two decades, contributing to a new special issue of Annals of Botany journal. The scientists discussed the achievements, major challenges and set out new horizons and opportunities for FSPM in the future. The researchers argue that FSPM is yet to reach its full potential in terms of scaling models up from a single plant to modelling whole communities for both belowground and aboveground organs. Many previous Botany One articles highlighted recent studies using FSPM, such as simulating mango tree growth and predicting its yield, rice root growth in response to fertilisers and tree growth in relation to soil water deficit and carbon assimilation.

The FSPM approach originates from James White in 1979 and after decades of working out the computational methods and standards, Guédon and colleagues established the first methods to simulate “virtual” plants which respond to their environment in 2001. The different mechanistic models are based on carbon-driven trophic regulations or the integration of non-trophic signalling.

FSPMs integrate models from gene to community levels and their interactions with abiotic environments. Source: Louarn and Song, 2020

Whilst FSPM was first advocated for linking plant genotype and phenotype but much more progress is needed. As FSP models are highly complex and platform development is costly, they are not often open-source. Louarn and Song highlight the need for better communication and more data sharing as well as scaling up the models from single plants to plant communities. The models could simulate how plants interact with each other which could be extremely useful to model whole fields or orchards.

Some of the highlighted recent studies discussed by Louarn and Song are about lamp placement for tomatoes in greenhouses (left), different training systems of vine plants (middle) and multi-scale carbon allocation model (MuSCA) for apple trees (right).

“The interest of FSPMs in ecology goes beyond the dynamics of plant communities, and also addresses the questions of plant interactions with organisms at different trophic levels in ecosystems, including host–pathogen systems, plant–insect relationships and plant community responses to herbivory. Although less developed, such models could contribute in future to deepening our understanding of integrated plant responses to combined biotic and abiotic stresses”, Louarn and Song wrote. 

“As a relatively young, multidisciplinary community, the FSPM community still has to figure out how to avoid the trap of being too complex in its approaches while providing limited generality”, conclude the authors.