AOBPreview originally published online on September 18, 2007
Annals of Botany 2007 100(6):1155-1164; doi:10.1093/aob/mcm209
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Wind-Dragged Corolla Enhances Self-Pollination: A New Mechanism of Delayed Self-Pollination
1 State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, P.R. China
2 Key Laboratory of Quantitative Vegetation Ecology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, P.R. China
3 Department of Entomology, China Agricultural University, Beijing 100094, P.R. China
4 Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China
5 Laboratory of Pollination Ecology, Institute of Evolution, University of Haifa, Israel
* For correspondence. E-mail luoyb{at}ibcas.ac.cn
Received: 17 April 2007 Returned for revision: 19 June 2007 Accepted: 16 July 2007 Published electronically: 18 September 2007
Background and Aims: Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis.
Methods: Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field.
Key Results: Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited.
Conclusions: This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect participation by wind, is also a new addition to ambophily.
Key words: Ambophily, anther movement, Bignoniaceae, corolla abscission, delayed self-pollination, Incarvillea sinensis var. sinensis, reproductive assurance, stigma closure
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  Compiled by, F. Tooke, T. Chiurugwi, and N. Battey Flowering Newsletter bibliography for 2007 J. Exp. Bot., July 18, 2008; (2008) ern109v1. [Full Text] [PDF]
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