Abstract Detail

Recent Topics Posters

Altrichter, Kristine M. [1], Aeilts, Luke [2], Taylor, Mackenzie L. [1].

Reproductive Development in Ruppia maritima .

The genus Ruppia, the sole genus in the family Ruppiaceae (Alismatales), consists of aquatic plants found in estuaries, salt-marshes and both saline and alkaline inland lakes on every continent except Antarctica. The most widely distributed species, R. maritima, can be found from subarctic to tropical regions of both hemispheres. R. maritima exhibits water pollination (hydrophily), in which pollen is transported via the water surface. The transition to hydrophily is known to be accompanied by modifications in pollen structure, but the consequences of this evolutionary transition for reproductive development are not well-understood. In this study, we characterized pollen structure and development across the entire pollen lifecycle, focusing on development during the progamic phase, the life history stage from pollen germination to fertilization. The structure of mature pollen was documented using light, scanning, and transmission electron microscopy. Field collections and hand-pollinations were conducted to determine reproductive timing, the pollen tube pathway, and rates of pollen germination and pollen tube growth. We confirmed that mature grains exhibit a reticulate proximal surface and a smooth distal surface. The entire mature exine is also covered by a thick layer of tapetally-derived material. Immature inflorescences with developing pollen are enclosed in a sheath, but over time, the inflorescences are pushed out of the sheath by the elongating peduncle. The onset of stigma receptivity, and therefore pollen germination, occurs before anther dehiscence. Pollen grains germinated within five minutes after pollination and pollen tubes reached the ovule within one hour after pollination. Rapid pollen germination is likely favored in an aquatic system in which pollen may be washed away. The short time to fertilization is a consequence of a short pollen tube pathway.  Investigating the reproductive biology of water pollinated plants, such as R. maritima, provides data regarding the evolutionary consequences of the transition to hydrophily for pollen development and the pollen tube pathway.

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

Keywords:
none specified

Presentation Type: Recent Topics Poster
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PRT034
Abstract ID:1819
Candidate for Awards:None