Pollen clumping and wind dispersal in an invasive angiosperm

Area of Science:

• Ecology
• Plant reproductive biology
• Bio-physics

Background:

• Pollen dispersal is crucial for plant population connectivity.
• Pollen clumping is typical in insect-pollinated plants and often considered detrimental for wind pollination due to shorter dispersal distances.
• However, pollen clumps are observed in wind-pollinated species, prompting further investigation.

Purpose of the Study:

• To investigate the effect of pollen clumping on wind dispersal under natural conditions.
• To determine if pollen clumping is detrimental or advantageous for wind pollination in Ambrosia artemisiifolia (common ragweed).

Main Methods:

• Simultaneous measurements of pollen clump size during pollen shedding from male flowers and in the atmosphere.
• Utilizing a transport model combined with empirical data on clump size.

Main Results:

• Pollen clumps were observed in airborne pollen of common ragweed.
• Results indicated that pollen clumps are advantageous for wind pollination, not detrimental.
• Initial clumps facilitate pollination of the parent population.

Conclusions:

• Pollen clumping can enhance wind pollination success.
• Breakup of larger clumps into smaller ones allows for cross-pollination of distant populations.
• This finding challenges the traditional view of pollen clumping in wind-pollinated species.