< Back to Article
Geometric and mechanical guidance: Role of stigmatic epidermis in early pollen tube pathfinding in arabidopsis
Fig 4
Effect of longitudinal growth guidance on pollen tube trajectories.
(A) Two-dimensional representation of the papilla, indicating where the alignment forces act (yellow region). (B) Example of pollen tube trajectories on WT papilla surfaces under various initial conditions, the initial pollen grain position z0 and initial pollen tube direction 
(indicated by black arrows), simulated without growth guidance (upper panel) and with growth guidance (adimensional guidance strength 
, lower panel). The numbers in brackets denote the normalized initial position (
) and the initial directions (
) for each trajectory. T represents the number of turns the pollen tube makes to reach the papilla base. Each configuration is labelled from a to f. (C) Morphological phase diagram of the pollen tube turn number T depending on the initial pollen grain position z0 (normalised to the papilla head length 
) and the initial pollen tube direction (
) on WT papillae. 
denotes the papilla pole, 
the frontier between the head and cylindrical shaft, and 
the pollen grain landing limit. The colour code indicates the number of turns the trajectories undergoes before it reaches the papilla base. The letters d, e, f correspond to the example configurations depicted in (B). Trajectories of pollen tubes on ktn1-5 papilla with identical initial conditions and the corresponding morphological phase diagram are shown in S3 Fig. (D) Comparison of simulated (solid lines) and experimental (squares) cumulative distributions of pollen tube turn numbers. Simulated cumulative distributions for turn numbers on WT papillae are calculated with a growth guidance of 
(dashed orange curve). Simulated cumulative distributions for turn numbers on ktn1-5 papillae are calculated without guidance (blue curve, reproduced from Fig 3E). To calculate the cumulative fraction for experimental data, we utilized data from Ref [6], where we examined 251 WT and 327 ktn1-5 pollinated papillae; error bars represent the standard error of the mean. The label ktn1 refers to the ktn1-5 mutant.
doi: https://doi.org/10.1371/journal.pcbi.1013077.g004