Abstract Detail

Reproductive Processes

Taylor, Mackenzie [1], Wilson, Adam [2], Dang, Christie [2], Baker, Emma [2], Srail, Julie [2], Klahs, Luke [2], Williams, Caleb [2].

Pollination and postpollination development in the hydrophilous monocot Stuckenia pectinata.

Hydrophily (water-pollination) is a rare pollination mechanism in which pollen is transported to stigmas via the water surface or underwater currents. Hydrophily is associated with certain pollen and flower traits and these traits affect pollen dispersal, reception, and post-pollination processes. Despite the interconnectedness of pollination and post-pollination processes, reproductive traits have been comprehensively studied in only a few hydrophilous species. The goal of this study was to characterize reproductive development in the hydrophilous monocot, Stuckenia pectinata (Potamogetonaceae).
Stuckenia pectinata inflorescences were collected in eastern Nebraska and categorized into developmental stages based on inflorescence morphology. The number and germination status of pollen grains on carpels was documented to determine the timing of pollen reception and onset of stigma receptivity, as well as pollen load size. Pollen to ovule ratio and fruit set were also documented and additional flower buds were prepared for analysis of pollen development using combined light, scanning electron, and transmission electron microscopy. Plants with immature inflorescences were collected and maintained in individual aquaria until stigmas were receptive. Flowers were hand pollinated and collected at various time points after pollination. The germination status of pollen grains on stigmas was determined and the length of the longest pollen tube per carpel was measured to document timing of post-pollination development. The pollen tube pathway was characterized.
Stigmas are receptive prior to anther dehiscence and pollen reception and germination were high in Stuckenia, with median pollen loads of approximately 10 pollen grains per stigma and over 90% of stigmas exhibiting germinated pollen prior to anther dehiscence. Stigmas remain receptive following anther dehiscence, as inflorescences successfully self-pollinated in aquaria. All field-collected inflorescences observed for seed-set exhibited at least one maturing fruit and, on average, 63% of carpels per inflorescence had been fertilized. Pollen germination was rapid, occurring within 15 minutes after pollination and pollen tubes entered ovules within 30 minutes.
Results from this study will be compared with what is known from other water-pollinated species in an effort to better understand reproductive processes in water-pollinated plants. The potential consequences of the transition to hydrophily for post-pollination processes will be discussed.

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

pollen germination
pollen tube growth

Presentation Type: Oral Paper
Number: RP4004
Abstract ID:497
Candidate for Awards:None

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