Fig. 4.

Comparison of the final length of main stem internodes (A) and leaves (B) between observations and simulations with the calibrated model. Patterns of simulated final organ lengths are similar between the two organ types, with a gradual increase in earlier ranks, maximal lengths in middle ranks, and shorter lengths in final ranks. These values coincide with the gradual increase and decrease in overall resources, total overall sinks (e.g. seed development) and environmental conditions during development. Observed final leaf lengths follow a pattern that is similar to the simulations, though more distinct. Observed final internode lengths deviate from this pattern with a distinct depression in ranks 2–5. This depression coincides with the timing of branch development, which may interfere with main stem internode elongation in a mechanism not yet captured by the model. Upper internode ranks are also distinctly longer than simulated, which may relate to canopy closure and related shade-avoidance response.