Header

UZH-Logo

Maintenance Infos

Heterostyly promotes disassortative pollination and reduces sexual interference in Darwin's primroses: evidence from experimental studies


Keller, Barbara; Thomson, James D; Conti, Elena (2014). Heterostyly promotes disassortative pollination and reduces sexual interference in Darwin's primroses: evidence from experimental studies. Functional Ecology, 28(6):1413-1425.

Abstract

Different strategies to reduce selfing and promote outcrossing have evolved in hermaphroditic flowers. Heterostyly, a complex floral polymorphism that occurs in at least 27 families of angiosperms, is hypothesized to achieve both goals by optimizing cross-pollination (via disassortative pollen transfer) and restricting gamete wastage to autogamy (via the reduction in sexual interference between male and female organs).
In heterostylous flowers, the reciprocal positioning of sexual organs in different morphs and the pollen incompatibility system within flower or between flowers of the same morph are thought to optimize both male and female functions, reducing the conflicts inherent to the occurrence of both sexual organs in the same reproductive unit. Specific elements of the disassortative-pollination and sexual-interference hypotheses have been tested individually before. However, despite the long-standing interest in heterostyly – ever since Darwin's seminal work on primroses – the predictions derived from these two hypotheses have never been experimentally and systematically examined in the same system.
Using distylous primroses (Primula elatior, P. vulgaris), we compare pollen transfer (i) between reciprocal and non-reciprocal flowers; (ii) from anthers onto different parts of the pollinator's body; and (iii) within flower and between flowers of the same morph. We further test whether (iv) anther–stigma distance correlates with self-pollen transfer and whether (v) seed set differs after pollinations with compatible, incompatible and both pollen types.
Reciprocal herkogamy promotes differential placement of pollen onto different parts of the pollinator's body, thus effecting transfer of more pollen to reciprocal than to non-reciprocal stigmas and realizing the key predictions of the disassortative-pollination hypothesis. However, short-styled flowers transfer pollen more disassortatively than long-styled flowers in both species, whereas long-styled flowers export more pollen to non-reciprocal than to reciprocal stigmas in P. vulgaris, thus compromising male function in this species. Furthermore, larger distance between sexual organs lowers self- and intra-morph pollination and the pollen incompatibility system decreases seed production after self-pollination, thus diminishing sexual interference.
Our results help us understand how the morphological and physiological components of heterostyly contribute to optimizing pollen transfer and minimizing self- and intra-morph pollination, thus promoting more efficient outcrossing in species with this floral polymorphism.

Abstract

Different strategies to reduce selfing and promote outcrossing have evolved in hermaphroditic flowers. Heterostyly, a complex floral polymorphism that occurs in at least 27 families of angiosperms, is hypothesized to achieve both goals by optimizing cross-pollination (via disassortative pollen transfer) and restricting gamete wastage to autogamy (via the reduction in sexual interference between male and female organs).
In heterostylous flowers, the reciprocal positioning of sexual organs in different morphs and the pollen incompatibility system within flower or between flowers of the same morph are thought to optimize both male and female functions, reducing the conflicts inherent to the occurrence of both sexual organs in the same reproductive unit. Specific elements of the disassortative-pollination and sexual-interference hypotheses have been tested individually before. However, despite the long-standing interest in heterostyly – ever since Darwin's seminal work on primroses – the predictions derived from these two hypotheses have never been experimentally and systematically examined in the same system.
Using distylous primroses (Primula elatior, P. vulgaris), we compare pollen transfer (i) between reciprocal and non-reciprocal flowers; (ii) from anthers onto different parts of the pollinator's body; and (iii) within flower and between flowers of the same morph. We further test whether (iv) anther–stigma distance correlates with self-pollen transfer and whether (v) seed set differs after pollinations with compatible, incompatible and both pollen types.
Reciprocal herkogamy promotes differential placement of pollen onto different parts of the pollinator's body, thus effecting transfer of more pollen to reciprocal than to non-reciprocal stigmas and realizing the key predictions of the disassortative-pollination hypothesis. However, short-styled flowers transfer pollen more disassortatively than long-styled flowers in both species, whereas long-styled flowers export more pollen to non-reciprocal than to reciprocal stigmas in P. vulgaris, thus compromising male function in this species. Furthermore, larger distance between sexual organs lowers self- and intra-morph pollination and the pollen incompatibility system decreases seed production after self-pollination, thus diminishing sexual interference.
Our results help us understand how the morphological and physiological components of heterostyly contribute to optimizing pollen transfer and minimizing self- and intra-morph pollination, thus promoting more efficient outcrossing in species with this floral polymorphism.

Statistics

Citations

18 citations in Web of Science®
18 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

3 downloads since deposited on 22 May 2014
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Systematic and Evolutionary Botany
Dewey Decimal Classification:580 Plants (Botany)
Language:English
Date:2014
Deposited On:22 May 2014 14:14
Last Modified:05 Apr 2016 17:53
Publisher:Wiley-Blackwell
ISSN:0269-8463
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1111/1365-2435.12274

Download

Preview Icon on Download
Content: Published Version
Filetype: PDF - Registered users only
Size: 651kB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations