A ballistic pollen dispersal strategy hidden in stylar oscillation

Abstract

Asteraceae, the most successful flowering plant family, is adapted to the vast range of ecological niches. Their adaptability is partially based on their strong ability of reproduction. The initial, yet challenging, step for plant reproduction is to transport pollen to flower-visiting pollinators. Using quantitative experiments and numerical simulations, here we show that the common floral feature of Asteraceae, a pollen-bearing style, serves as a ballistic lever for catapulting pollen grains to pollinators. This is likely to be a pollination strategy to propel pollen to blind spots of pollinators bodies, which are beyond the physical reach of the styles. Our results suggest that the specific morphology and length of the floret, as well as the pollen adhesion, avoid pollen waste by catapulting pollen within a certain range equal to the size of a flowerhead. The insights into the functional floral oscillation may shed light on the superficially unremarkable, but ubiquitous functional floral design of Asteraceae.