Morphoelastic modelling of pattern development in the petal epidermal cell cuticle

Area of Science:

• Plant biology
• Biophysics
• Materials science

Background:

• Plant petal epidermal cells develop intricate surface patterns, specifically nano-ridges.
• The cuticle, a protective layer on plant surfaces, comprises distinct sub-layers influencing cell morphology.

Purpose of the Study:

• To investigate the origin and propagation of surface nano-ridges in plant petal epidermal cells.
• To develop and validate a mechanical model for cuticle development and pattern formation.

Main Methods:

• Utilized *Hibiscus trionum* as a model system to track cell shape and cuticle development.
• Quantified pattern formation and geometrical changes in the cuticle's distinct sub-layers.
• Developed and numerically investigated a quasi-static morphoelastic model of a growing bi-layer cuticle.

Main Results:

• The cuticle consists of an expanding uppermost layer and a substrate layer.
• The mechanical model successfully recreated observed developmental patterns in petals.
• Identified key factors influencing pattern features: stiffness mismatch, cell-wall curvature, cell expansion, and layer growth rates.

Conclusions:

• The cuticle functions as a growing bi-layer, driving nano-ridge formation.
• Understanding these mechanical principles explains the development of surface patterns in plants.
• Provides insights into why some plant systems exhibit surface patterns while others do not.