Real-time conversion of tissue-scale mechanical forces into an interdigitated growth pattern.

Area of Science:

• Plant biology
• Biophysics
• Developmental biology

Background:

• Leaf epidermis morphology is key to plant development.
• Pavement cells are the fundamental units driving leaf expansion through irreversible morphing.
• Cell lobing influences leaf expansion and is evolutionarily conserved.

Purpose of the Study:

• To define how tissue-scale cell wall tensile forces and microtubule-cellulose synthase systems control interdigitated growth patterns in real time.
• To investigate the mechanical coupling between adjacent cells driving lobe formation.
• To establish a mechanistic model for cell lobing in leaves.

Main Methods:

• Utilized finite element pavement cell models to analyze cell wall tensile stress.
• Observed the role of cortical microtubules in patterning cellulose fibers.
• Investigated mechanical coupling via the pectin-rich middle lamella.

Main Results:

• Cortical microtubules pattern cellulose fibers, creating anisotropic walls.
• Localized polarized growth is mechanically coupled between adjacent cells, driving lobe formation.
• Cell wall tensile stress acts as an upstream patterning element linking cell and tissue biomechanics.

Conclusions:

• Mechanistic models of lobe formation provide insights into leaf morphology and function.
• Understanding cell lobing is foundational for analyzing leaf development and agronomic traits.
• The interplay of mechanical forces and cytoskeletal elements governs pavement cell morphogenesis.