Cellular Heterogeneity in Pressure and Growth Emerges from Tissue Topology and Geometry

Area of Science:

• Plant biology
• Biophysics
• Developmental biology

Background:

• Cell-to-cell heterogeneity is common in biological systems, impacting processes like cell growth.
• In plants, cell growth is regulated by cell wall mechanics and turgor pressure.
• While cell wall properties have been studied, spatial variations in turgor pressure remain less understood.

Purpose of the Study:

• To investigate the spatial variation of turgor pressure in the Arabidopsis shoot apical meristem.
• To understand the relationship between turgor pressure, cell size, local topology, and tissue expansion.
• To explore the role of turgor pressure heterogeneity in plant growth control and tissue homeostasis.

Main Methods:

• Utilized atomic force microscopy to measure turgor pressure.
• Developed and applied a physical model of pressurized cells to analyze tissue expansion.
• Integrated cell wall mechanics and tissue hydraulics in the model.

Main Results:

• Demonstrated that turgor pressure is heterogeneous within the Arabidopsis shoot apical meristem.
• Showed that turgor pressure negatively correlates with cell size and the number of neighboring cells (local topology).
• Model predictions align with experimental findings, linking tissue hydraulics and cell wall mechanics to growth.

Conclusions:

• Turgor pressure is a significant source of patterned cell heterogeneity in plant tissues.
• Local topology and cell mechanical state are linked to cell growth through turgor pressure.
• Water conductivity may play a role in regulating growth in the shoot apical meristem, contributing to tissue homeostasis.