Growth & Development

The effects of heterospecific pollen deposition on pollen-tube growth

How does the pollen of one plant species impact the reproductive success of another?

Most flowering plants rely on animal pollinators to transfer their pollen grains, but what happens if two or more plant species exploit the same pollinator? In an ideal world, pollen would be exclusively transferred from a one plant of a species to another plant of the same species (termed conspecific pollen transfer). However, with multiple species sharing pollinators it is not uncommon for the pollen from one (or more) species to be transferred to a different species (termed heterospecific pollen transfer). This has impacts on the reproductive success of both species but what determines the severity of these consequences is unclear. It has been hypothesized that it may depend on the phylogenetic relatedness of the two interactors (the pollen donor and the pollen recipient).

Fly on a flower
Syrphid fly visiting a flower of Sisyrinchium wettsteinii in the Itatiaia National Park, Brazil. Image credit: N.S. Streher.

In their new study published in AoBP, Streher et al. experimentally demonstrate that phylogenetic relatedness mediates the effect of heterospecific pollen on post-pollination success. Using three species as recipients, they showed that pollen donors of closely related species (same genus) affected pollen tube growth and had a negative impact on the post-pollination success of the recipient species. However, when pollen donors were distantly related (different family), recipient species tolerated or were even benefited by growing more pollen tubes than without the presence of heterospecific pollen. The authors conclude that their results, together with what is known from the studied community, give new insights on how plant-plant post-pollination interactions may influence plant community assembly.

Researcher highlight

Nathália Streher is a final year PhD candidate in plant biology at the University of Campinas, Brazil, under the supervision of Professor Marlies Sazima and Professor Marina Wolowski. Part of her research was developed with Dr. Tia-Lynn Ashman at the University of Pittsburgh, USA.

Nathália studies a tropical mountaintop community where she is interested in understanding how plant-pollinator and plant-plant interactions might influence plant community assembly. She is passionate about natural history and engaged with science outreach.

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