Feeling the force: how pollen tubes deal with obstacles

Area of Science:

• Plant Biology
• Biophysics
• Cellular Mechanics

Background:

• Physical forces regulate plant development and morphogenesis by translating mechanical stress into physiological changes.
• Pollen tubes are excellent single-cell models for studying mechanical stimuli due to their rapid response to external cues.

Purpose of the Study:

• To investigate how pollen tubes perceive and respond to mechanical stress from obstacles.
• To quantify the forces involved in pollen tube navigation and obstacle avoidance.
• To develop a method for calculating turgor pressure using force and optical data.

Main Methods:

• Utilized a lab-on-a-chip device integrated with a microelectromechanical systems (MEMS)-based capacitive force sensor.
• Exposed pollen tubes to mechanical stress and monitored real-time growth reconfiguration and force generation.
• Experimentally determined the perceptive force threshold for *Lilium longiflorum* and *Arabidopsis thaliana*.

Main Results:

• Identified distinct stages of obstacle avoidance: force perception, growth adjustment, and penetration.
• Quantified the forces experienced by pollen tubes when encountering mechanical barriers.
• Established a method to calculate turgor pressure from force and optical measurements.

Conclusions:

• Pollen tubes actively sense physical barriers and modify their growth to overcome them.
• The developed system provides a platform for studying intracellular activities during force perception and growth adaptation in tip-growing cells.
• This research enhances understanding of mechanosensing in plant cells and offers insights into pollen tube guidance mechanisms.