2017 Update: Barto’s REU project

Ashely Barto, an REU student in summer 2017, developed an independent project looking at how pollination influences reproductive success in Echinacea angustifolia. She was interested in how heads that get pollinated each day differ from heads that only get visited infrequently, but receive a lot of pollen on those sporadic visits.

Over 19 days in July 2017, 1980 styles from 21 capitula were pollinated following a randomly assigned pollination schedule: pulse or steady. Capitula assigned to the pulse pollination treatment received pollen on all emergent styles at the same time, so there was a range of style ages. Steady pollination capitula received pollen daily, so all styles were pollinated on the day they emerged. Style shriveling, a proxy for pollination, was used as the response variable.

Using a generalized linear model, interactions between style age, floret position, and pollination treatment were considered to create a pollination rate model. Style age and pollination treatment did not interact or have an additive effect on pollination rates. Instead, floret position within the capitulum was the only factor essential to modeling pollination rates in Echinacea. The results suggest resource allocation plays a major role in Echinacea reproduction. Ashley will investigate seed set from the same capitula later this year to further elucidate the role of style age, floret position, and pollination treatments in Echinacea reproduction.

Echinacea on its third day flowering. Within the disc florets, there are persisting styles in Row 1 (A), fresh styles in Row 2 (B), and new anthers in Row 3 (C).

Ashley presented her work at the 2017 Arkansas INBRE Conference on October 28. Arkansas INBRE is the Arkansas Institutional Development Award’s network of biomedical research conference, and this year, it was hosted at the University of Arkansas. While this conference attracted undergraduates from many states to present on biomedical research in biology, chemistry, and physics, there were many posters like Ashley’s sharing summer research outside of the medical scope central to the conference’s theme. Ashley was able to talk about the Echinacea Project’s big picture work and how her independent REU Project fit into that larger image.