Author(s) |
Vaughton, Glenda V
Ramsey, Michael W
Johnson, Steven D
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Publication Date |
2010
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Abstract |
• Background and Aims: Animal pollination is typically an uncertain process that interacts with self-incompatibility status to determine reproductive success. Seed set is often pollen-limited, but species with late-acting self-incompatibility (SI) may be particularly vulnerable, if self-pollen deposition results in ovule discounting. Pollination is examined and the occurrence of late-acting SI and ovule discounting assessed in 'Cyrtanthus breviflorus'. • Methods: The pollination system was characterized by observing floral visitors and assessing nectar production and spectral reflectance of flowers. To assess late-acting SI and ovule discounting, growth of self- and cross-pollen tubes, and seed set following open pollination or hand pollination with varying proportions of self- and cross-pollen, were examined. • Key Results: Native honeybees 'Apis mellifera scutellata' pollinated flowers as they actively collected pollen. Most flowers (≥70 %) did not contain nectar, while the rest produced minute volumes of dilute nectar. The flowers which are yellow to humans are visually conspicuous to bees with a strong contrast between UV-reflecting tepals and UV-absorbing anthers and pollen. Plants were self-incompatible, but self-rejection was late-acting and both self- and cross-pollen tubes penetrated ovules. Seed set of open-pollinated flowers was pollen-limited, despite pollen deposition exceeding ovule number by 6-fold. Open-pollinated seed set was similar to that of the cross + self-pollen treatment, but was less than that of the cross-pollen-only treatment. • Conclusions: Flowers of 'C. breviflorus' are pollinated primarily by pollen-collecting bees and possess a late-acting SI system, previously unknown in this clade of the Amaryllidaceae. Pollinators of 'C. breviflorus' deposit mixtures of cross- and self-pollen and, because SI is late-acting, self-pollen disables ovules, reducing female fertility. This study thus contributes to growing evidence that seed production in plants with late-acting SI systems is frequently limited by pollen quality, even when pollinators are abundant.
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Citation |
Annals of Botany, 106(4), p. 547-555
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ISSN |
1095-8290
0305-7364
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Link | |
Publisher |
Oxford University Press
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Title |
Pollination and late-acting self-incompatibility in 'Cyrtanthus breviflorus' (Amaryllidaceae): implications for seed production
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Type of document |
Journal Article
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Entity Type |
Publication
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