Figure 1.
Schematic sketch of metabolite supply in leaves. (a) Vasculature of a leaf displaying the primary vein horizontally at the centre and secondary veins as next biggest veins departing from the primary vein, down to the highly inter-webbed higher order veins. (b) The secondary vein (thick blue) supplies the tubular higher order vein network with metabolites and fluid. (c) Xylem vessel network modelled as network of tubes of varying radius R and length ℓ. Inflow of fluid flow rate Q and metabolite flux J from upstream tubes (left). Fluid evaporation through stomata at the leaf surface modelled by constant outflow Qout at every network node. Metabolites are advected and diffuse within the fluid. In addition, metabolites get absorbed ϕ along the tube wall into cells at a constant rate ν. (Online version in colour.)