Density-dependent pollen limitation and reproductive assurance in a wind-pollinated herb with contrasting sexual systems

Details

Serval ID
serval:BIB_1986BE3D9500
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Density-dependent pollen limitation and reproductive assurance in a wind-pollinated herb with contrasting sexual systems
Journal
Journal of Ecology
Author(s)
Hesse E., Pannell J.R.
ISSN
0022-0477
Publication state
Published
Issued date
2011
Peer-reviewed
Oui
Volume
99
Number
6
Pages
1531-1539
Language
english
Abstract
1. Wind pollination is thought to have evolved in response to selection for mechanisms to promote pollination success, when animal pollinators become scarce or unreliable. We might thus expect wind-pollinated plants to be less prone to pollen limitation than their insect-pollinated counterparts. Yet, if pollen loads on stigmas of wind-pollinated species decline with distance from pollen donors, seed set might nevertheless be pollen-limited in populations of plants that cannot self-fertilize their progeny, but not in self-compatible hermaphroditic populations.2. Here, we test this hypothesis by comparing pollen limitation between dioecious and hermaphroditic (monoecious) populations of the wind-pollinated herb Mercurialis annua.3. In natural populations, seed set was pollen-limited in low-density patches of dioecious, but not hermaphroditic, M. annua, a finding consistent with patterns of distance-dependent seed set by females in an experimental array. Nevertheless, seed set was incomplete in both dioecious and hermaphroditic populations, even at high local densities. Further, both factors limited the seed set of females and hermaphrodites, after we manipulated pollen and resource availability in a common garden experiment.4. Synthesis. Our results are consistent with the idea that pollen limitation plays a role in the evolution of combined vs. separate sexes in M. annua. Taken together, they point to the potential importance of pollen transfer between flowers on the same plant (geitonogamy) by wind as a mechanism of reproductive assurance and to the dual roles played by pollen and resource availability in limiting seed set. Thus, seed set can be pollen-limited in sparse populations of a wind-pollinated species, where mates are rare or absent, having potentially important demographic and evolutionary implications.
Keywords
dioecy, local mating environment, Mercurialis annua, monoecy, reproductive ecology, resource availability, seed set
Web of science
Open Access
Yes
Create date
23/02/2012 13:13
Last modification date
20/08/2019 12:50
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