Male sterility in triploid dandelions: asexual females vs asexual hermaphrodites

Male reproductive output, pollen in plants and sperm in animals has been shown to constitute a substantial cost for many organisms. In parthenogenetic hermaphrodites, selection is therefore expected to reduce the allocation of resources to male reproductive output. However, sustained production of p...

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Bibliographic Details
Published in:Heredity 2006-01, Vol.96 (1), p.45-52
Main Authors: Meirmans, P.G, Nijs, H.C.M. den, Tienderen, P.H. van
Format: Article
Language:English
Subjects:
apomixis
Biomedical and Life Sciences
Biomedicine
Cytogenetics
Ecology
Evolutionary Biology
females
Flowers
gametogenesis
genes
Genetic Markers
Human Genetics
Male sterility
nuclear genome
original-article
Parthenogenesis
plant fertility
Plant Genetics and Genomics
Plasticity
Pollen
Reproduction
Resource allocation
seed set
Seeds
Sex Ratio
Taraxacum
Taraxacum - genetics
Taraxacum - physiology
triploidy
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Summary:Male reproductive output, pollen in plants and sperm in animals has been shown to constitute a substantial cost for many organisms. In parthenogenetic hermaphrodites, selection is therefore expected to reduce the allocation of resources to male reproductive output. However, sustained production of pollen or sperm has been observed in numerous asexual hermaphrodites. We studied the widespread production of pollen by triploid asexual dandelions, Taraxacum sect. Ruderalia, comparing rare male sterile individuals with pollen producing asexuals. We found that individuals can show plasticity in the production of pollen, but that it is nevertheless possible to distinguish between (facultatively) male sterile asexuals and male fertile asexuals. Based on evidence from genetic markers and crosses, we conclude that the male sterility in asexual dandelions is caused by nuclear genes, in contrast to the cytoplasmically inherited male sterility previously found in sexual dandelions. Male sterile lineages did not produce more seeds per flower head, heavier seeds or seeds that were more viable. However, male sterile plants did produce more seed heads and hence more seeds than pollen producing ones, indicating that they were able to reallocate resources toward seed production. Considering the difference in seed production, it remains puzzling that not more asexual dandelions are male sterile.
ISSN:0018-067X
1365-2540
DOI:10.1038/sj.hdy.6800750