A Dynamical Phyllotaxis Model to Determine Floral Organ Number
Fig 4
Reconstructing pentamerous floral development.
A. Flower of Silene coeli-rosa (Caryophyllaceae). B. Reproduction of the S. coeli-rosa floral meristem traced from an SEM image by Lyndon [34]; the colors were modified. Numbers indicate the initiation order. K (sepals), C (petals), St (stamens), AB (axillary bud). C. Average position of the S. coeli-rosa floral primordia reconstructed from the divergence angle and plastochron ratio (E) measured by Lyndon (Table 1 in [34]). The number of measured apices is 9 for sepals, 5 for petals, 7 for stamens, and 2 for carpels. The positions of sepals and petals are depicted in large squares, and those of stamens and carpels are depicted in small squares. D. Spatial pattern of the model simulation. The first ten primordia are shown by large circles, and the subsequent ten primordia are shown by small circles. τ = 600, R0 = 30.0, α = 3.0, σr = 0.05, σθ = 5.0, λini = λg = 20.0, PMP = 0. E. Divergence angle (top panel) and plastochron ratio (middle) between two succeeding primordia, and the distance from the center of the apex (bottom panel) in S. coeli-rosa (blue squares) and in the model simulation (red circles). The order of petal initiation was estimated from that of the adjacent stamens (St6-St10 in B) following the experimental report [34]. The measurements agree with the model until the ninth primordium (open arrowhead). Error bars for the divergence angle and plastochron ratio of S. coeli-rosa denote the standard errors. Because the absolute values of the S. coeli-rosa primordia radii were not published, the distance from the center is normalized by the radius of the first sepal. The values of the parameters are the same as those in D. The green line (D and E bottom panel) indicates the meristem boundary in the simulation.