Reticulate leaf venation, characterized by the presence of loops, is a distinguishing feature of many flowering plants. However, our understanding of both the geometry and the morphogenesis of reticulate vein patterns is far from complete. We show that in the Chinese money plant (Pilea peperomioides), major veins form an approximate Voronoi diagram surrounding secretory pores known as hydathodes. We also propose a mechanistic model based on polar transport of the plant hormone auxin to produce Voronoi patterns, and we support this model with experimental evidence. In contrast to classical models where veins directly connect auxin sources to sinks, our model generates veins that bisect the space between adjacent auxin sources, collectively forming loops. The paradigm change offered by this model may open the door to study reticulate vein formation in other species.
Download the paper and all supplementary materials from the publisher's site.
OR
Download the paper from here.
Download the supplementary information from here.
Download the movies from here:
Movie 2
Simulation of auxin propagation in the presence of a cap on auxin concentration with 2 auxin sources on a rectangluar grid
(corresponds to Supplmentary Figure 9).
Movie 3
Simulation of auxin propagation in the presence of caps on auxin concentration and the rate of endocytosis with 2 auxin sources on a rectangular grid
(corresponds to Fig. 4d and Supplementary Figure 10).
Movie 4
Simulation of auxin propagation in the presence of caps on auxin concentration and the rate of endocytosis with 5 auxin sources on a square grid
(corresponds to Fig. 4e).
Movie 5
Movie 6
Movie 7
Movie 8
Movie 9
Simulation of auxin driven patterning on Pilea leaves assuming auxin sources at hydathode positions.
Movie 5 corresponds to the leaf sample shown in Fig. 5a. Movies 6-9 correspond to the leaf samples shown in Supplementary Figure 11a-d.
Movie 10
Movie 11
Movie 12
Movie 13
Simulation of model progression in Supplementary Figure 14b, d-f.
Movie 14
Movie 15
Movie 16
Movie 17
Movie 18
Movie 19
Movie 20
Simulation of improved model in Fig. 7b-e. Movies 16, 18, and 20 are zoomed-out versions of Movies 15, 17, and 19.