Abstract Detail

Celebrating More Than Three Decades of Research in Nymphaeales: A Colloquium Honoring Ed Schneider

Taylor, Mackenzie L. [1], McGlynn, Mary C. [1], Manke, Erik [1], Cooley, Diane [1].

Post-pollination Development in Nymphaeaceae: Consequences of Flower Evolution.

An important function of the flower is to facilitate the growth of a pollen tube from the stigma to the ovule, where it delivers the sperm to the egg. Evolution in flower size and morphology, therefore, has consequences for the developmental events that are critical for successful fertilization. Nymphaeaceae exhibits considerable diversity in flower size, with flowers ranging from a few mm in diameter in Barclaya to over 25 cm in diameter in Victoria. Evolution in flower size and the associated changes in floral morphology have undoubtedly had consequences for development during the progamic phase, the period between pollination and fertilization, in these genera. Investigating post-pollination development in this family, in a comparative context, will yield valuable data as to how pollen development and flower morphology evolve in concert. In order to understand the consequences of flower evolution for the progamic phase in Nymphaeaceae, reproductive characters, including stigmatic surface area, pollen germination and pollen tube growth rates, pollen tube path lengths, and time to ovule entry, as well as the ultrastructural characteristics of the pollen tube pathway, were documented in Victoria amazonica, V. cruziana, Nymphaea odorata, and Nuphar polysepala. Flower ultrastructural characters were also documented in Barclaya longifolia. Flower size does affect post-pollination development in Nymphaeaceae. In Victoria, the distance to the apical ovules is significantly longer than in Nymphaea, which contributes to a longer progamic phase (10 hours) relative to Nymphaea (2.5 hours). However, Victoria also exhibits slow pollen germination and pollen tube growth rates, relative to both Nymphaea and Nuphar, and this contributes to a longer time to ovule entry, as well. Although the distances to the apical ovules in Victoria and Nuphar are not significantly different, pollen tubes must travel much farther to reach basal ovules in Victoria due to vertical elongation of the ovary locule. Other floral characters, such as the size and orientation of the receptive stigmatic surface, affect programic phase development in Nymphaeaceae, as well. Data addressing the interplay among flower morphology, carpel ultrastructure, and pollen development during the progamic phase, particularly in an early-divergent lineage such as Nymphaeales, will contribute to a more comprehensive understanding of this critical life history stage and provide insight into reproductive developmental evolution in flowering plants.

1 - Creighton University, Department Of Biology, 2500 California Plaza, Omaha, NE, 68178, USA

Keywords:
Nymphaeaceae
progamic phase
pollen tube growth
pollen
post-pollination development
pollen germination
reproductive timing
Victoria
Nuphar
Nymphaea.

Presentation Type: Colloquium Presentations
Session: C3
Location: Salon 12/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 10:45 AM
Number: C3008
Abstract ID:1207
Candidate for Awards:None