Pavement cells and the topology puzzle

Area of Science:

• Plant biology
• Developmental biology
• Biophysics

Background:

• D'Arcy Thompson highlighted surface tension's role in cell shape and tissue topology.
• Leaf epidermal pavement cells display complex, jigsaw-like shapes, deviating from classical models.

Purpose of the Study:

• Investigate the topology of developing Arabidopsis leaves composed of pavement cells.
• Determine the driving forces behind the observed cell topology and its establishment during development.

Main Methods:

• Image analysis of approximately 50,000 pavement cells from Arabidopsis leaves.
• Development and simulation of graph models to identify cellular division rules.
• In vivo tracking of 800 mitotic events to verify predicted dynamics.

Main Results:

• A unique topological signature was identified in Arabidopsis leaf pavement cells, differing from other epidermal tissues.
• This topological distribution is established early in development, before characteristic cell shapes emerge.
• Topological homeostasis is maintained throughout growth, unaffected by cell division or maturation zones.

Conclusions:

• The distinct topology of Arabidopsis leaf pavement cells is primarily driven by life history processes.
• Cell surface mechanics and the final jigsaw-like cell shape are not the main determinants of this topology.
• A parsimonious model predicting cellular division planes relative to neighbors successfully reproduces the observed topology.