Abstract Detail

Pollination Biology

Montgomery , Benjamin R [1], Twitty, Brittany P. [2], Phillps, Caleb W. [2].

Petal Abscission as a Mechanism of Delayed Self Pollination in Linum rigidum.

            The role of flower petals as pollinator attractants is clear. However, in some species, petals may also promote pollination upon abscission by causing anthers or dislodged pollen to directly contact the stigma. Linum rigidum (stiffstem flax) is an annual of dry prairies with large basally sympetalous petals that typically abscise within hours of anthesis. We performed several studies to test the hypothesis that petal abscission is a mechanism of delayed self pollination in this species. A breeding system study revealed that L. rigidum is self-compatible, and a phenology study indicated pollen is viable and stigmas are receptive during the afternoon on the day of anthesis, when petal abscission typically occurs. In an indoor study, we found that little or no pollen was received on stigmas of flowers with petals manually removed, while substantial pollen receipt occurred for flowers with petals left intact for natural abscission, especially when flowers were exposed to wind.  Finally, in a field study, we varied whether or not flowers were exposed to pollinators during morning and early afternoon and whether petals were manually removed after this time or allowed to abscise naturally. We found that allowing natural petal abscission increased pollen receipt and fruit set compared to treatments for which petals were manually removed around the time of natural petal abscission, especially for flowers not exposed to pollinators. Exposure to pollinators increased pollen receipt for flowers with petals removed and increased fruit set regardless of petal status. Seed set was lowest for flowers not exposed to pollinators and with petals removed. Overall, these results indicate that petal abscission leads to delayed self pollination in L. rigidum and that both pollinator visits and delayed self pollination contribute to pollination success.

1 - University Of South Carolina Upstate, Ecology And Evol. Biology, 800 University Way, Spartanburg, SC, 29303, USA
2 - University of South Carolina Upstate, Natural Sciences and Engineering, 800 University Way, Spartanburg, SC, 29303, USA

Keywords:
Delayed self pollination
Corolla abscission
Reproductive assurance
Flax.

Presentation Type: Oral Paper:Papers for Topics
Session: 32
Location: Firs South/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 11:00 AM
Number: 32012
Abstract ID:305
Candidate for Awards:None