Abstract Detail

Pollination Biology

Hendrix, Melisa [1], Krakos, Kyra [2].

The pollination systems of Ruellia strepens and Ruellia humilis.

A self-compatible breeding system reduces the reliance on pollinators, but can result in a loss of genetic variation and lowered reproductive success. Flowering species that are self-incompatible rely entirely on pollinators for full seed set, and multiple environmental factors can impact that plant-pollinator interaction. The common species of Ruellia found throughout Missouri are Ruellia strepens and Ruellia humilis. This study looked at reproductive behavior and what factors influence reproductive success in R. strepens and R. humilis. Individual plants (n = 10) of each species were evaluated and measured for growth and development, flowering, fruiting and pollinator species. To determine the main pollinators, plants were observed in 20 minute intervals (n = 130). Visitation duration, foraging patterns, and stigma contact were recorded. Pollen loads from a sample of visitors were collected and analyzed for amount and type. The main pollinators were determined by combining visitation rate and pollen load average. Breeding system was determined with hand pollination experiments (n = 56) Treatments included: 1. open (no manipulation), 2. control (anthers removed), 3. self-pollinated, 4. cross-pollinated. Stigmas were collected for each treatment and the presence of pollen tubes were determined using fluorescent microscopy. Insects were collected to determine primary pollinators and gauge the movement of pollen. Our results indicated both species of Ruellia require specific habitats to survive. R. strepens prefers indirect sunlight and moist soil along the edges of open woods, borders of streams and ponds. R. humilis prefers direct sunlight and dry or well drained soils in glades, prairies and fields. R. strepens’ flowers open during the early morning dark hours, allowing pollination by moth species while R. humilis’ flowers open after sunrise, allowing pollination by bees and other generalists such as Long-tongued bees, including Anthophorid bees and Leaf-Cutting bees. Both Ruellia species are self compatible, but most seed set is due to outcross pollen. Self-pollination produced small fruit and low seed set in R. strepens and R. humilis, while cross-pollination in both species produced larger fruit and a higher yield of seed. If a decline in bees or other generalists persist, some species of Ruellia could be at risk.

Broader Impacts:

1 - Maryville University, 650 Maryville University Dr, St. Louis, Mo, 63141, USA
2 - Maryville University, Biology, 650 Maryville University, St Louis, MO, 63141, USA

Keywords:
pollination
breeding system
Ruellia.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:30 PM
Number: PPL007
Abstract ID:499
Candidate for Awards:None