Abstract Detail

Reproductive Processes

Humphrey, Rebecca [1], Graham, Spencer [1].

Relationship between pollen aperture number, germination rate, and pollen-tube growth in the pollen-heteromorphic Thalictrum thalictroides (Ranunculaceae).

Pollen-aperture heteromorphism, a characteristic of approximately 30% of angiosperm species, occurs when all individuals of the species produce multiple types of fertile pollen grains that differ in the number of apertures. The presence of multiple pollen-aperture types within individuals provides a controlled environment in which to study the relationship between aperture number and pollen-grain performance. Previous study has shown that fitness may differ predictably among pollen-aperture morphs and that environmental selective pressures may influence the ratio of aperture morphs within individuals and populations. To assess whether a relationship exists between pollen aperture number and germination rate, germination likelihood, and pollen-tube length in Thalictrum thalictroides (Ranunculaceae), we germinated pollen from ten individuals across three time points. We observed consistent pollen heteromorphism among individuals, greater in vitro germination rates for more-common morphs, longer pollen tubes for pollen grains with more apertures, and contrary to our expectation, a greater germination likelihood over time for grains with more apertures. These findings contradict other well-accepted results about the influence of aperture number on pollen competition in other species and suggest that further investigation into pollen-aperture evolution is warranted.

Related Links:
RP Humphrey personal webpage

1 - Aquinas College, Department of Biology and Health Science, 1700 Fulton St. E, Grand Rapids, MI, 49506, USA

pollen heteromorphism
pollen tubes
pollen germination
pollen aperture number.

Presentation Type: Oral Paper
Session: REP4, Reproductive Processes 4
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 4:00 PM
Number: REP4005
Abstract ID:621
Candidate for Awards:None

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