MuSCA: a multi-scale source-sink carbon allocation model to explore carbon allocation in plants. An application to...

Area of Science:

• Plant physiology
• Computational modeling
• Ecological modeling

Background:

• Carbon allocation models often use fixed topological scales, hindering cross-model comparisons.
• Understanding the impact of scale on plant carbon allocation is crucial for accurate modeling.

Purpose of the Study:

• Develop a multi-scale carbon allocation model (MuSCA) to assess the influence of topological scale on simulated plant carbon dynamics.
• Evaluate the trade-off between computational efficiency and predictive accuracy across different scales.

Main Methods:

• Tested MuSCA on three apple tree structures across five topological scales, from metamer to first-order branches.
• Simulated carbon allocation with varying sap friction coefficients and compared fruit dry mass increments to field data.

Main Results:

• MuSCA accurately represented carbon competition effects on fruit growth.
• Finer scales (metamer, growth unit) showed minimal divergence (~1%) from reference, while coarser scales (first-order branches) diverged up to 60%.
• Reduced topological resolution decreased computation time by up to four orders of magnitude.

Conclusions:

• Topological scale is a critical factor influencing carbon allocation simulations.
• MuSCA enables evaluation of scale-dependent accuracy and computational cost in plant modeling.
• Careful consideration of scale is essential when developing or comparing carbon allocation models.