A coupled phloem/xylem transport model

Transport of carbohydrates and water are essential aspects of plant functioning. This paper presents a novel approach for modelling these processes combining mathematical and computational methods.

Phases of the simulation, each performed by an L-system derivation step. Arrows in the phase bo
Phases of the simulation, each performed by an L-system derivation step. Arrows in the phase boxes indicate the direction that the L-system string is scanned. In the Develop phase the plant structure and the multi-module for each organ is updated. This includes the information exchange between the water and carbohydrate transport modules for calculation of the Münch counter-flow and the xylem pull terms. Due to the simple boundary conditions for water transport in this model, only two derivation steps were required to calculate water flux and water potential in the system. The carbohydrate transport computation required several phases to complete, because the source/sink fluxes are represented by non-linear functions of the carbon potential.

Seleznyova and Hanan have produced the first mechanistic transport model that is capable of simulating continuous distributions of the system variables in a complex developing structure. The model simulations emphasize sensitivity of the phloem and xylem fluxes to the presence of distributed sinks and sources. The methods will be useful for modelling carbohydrate transport and distribution at different scales of plant organization.

This paper is part of the Annals of Botany Special Issue on Functional-Structural Plant Growth Modelling. It will be free access until June 2018, then available only to subscribers until April 2019 when it will be free access again.

Further reading

Seleznyova, A. N., & Hanan, J. (2018). Mechanistic modelling of coupled phloem/xylem transport for L-systems: combining analytical and computational methods. Annals of Botany, 121(5), 991–1003. https://doi.org/10.1093/aob/mcx204