Fresh "Pollen Adhesive" Weakens Humidity-Dependent Pollen Adhesion.

Area of Science:

• Plant Biology
• Biophysics
• Surface Science

Background:

• Pollenkitt is crucial for pollen adhesion and pollination.
• Factors influencing pollen adhesion, such as humidity and pollenkitt integrity, require further quantitative investigation.

Purpose of the Study:

• To quantitatively investigate how relative humidity (RH), pollenkitt loss, and exposure time affect pollen adhesion.
• To clarify the role of pollenkitt in pollen adhesion under varying environmental conditions.

Main Methods:

• Atomic force microscopy was used to measure pollen adhesion.
• Pollen grains of *Hypochaeris radicata* were tested in different states: fresh, aged, and without pollenkitt.
• Capillary models were employed to explain observed adhesion phenomena.

Main Results:

• Higher RH significantly increased pollen adhesion on hydrophilic surfaces, but had minimal effect on hydrophobic surfaces.
• On hydrophilic surfaces, fresh pollen showed less RH-dependent adhesion compared to aged or pollenkitt-less pollen.
• On hydrophobic surfaces, fresh pollen exhibited significantly lower adhesion than aged pollen.

Conclusions:

• Pollenkitt's adhesive role is complex; abundant fresh pollenkitt can reduce adhesion under specific conditions.
• Relative humidity significantly impacts pollen adhesion, with effects varying based on surface hydrophobicity and pollen condition.
• This study provides novel insights into pollen adhesion mechanisms and pollination dynamics.