AOBPreview originally published online on January 26, 2007
Annals of Botany 2007 99(4):653-660; doi:10.1093/aob/mcl291
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Intra-plant Variation in Nectar Sugar Composition in Two Aquilegia Species (Ranunculaceae): Contrasting Patterns under Field and Glasshouse Conditions
1 Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Avenida de María Luisa s/n, E-41013, Sevilla, Spain
2 Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Consejo Superior de Investigaciones Científicas, Avenida Américo Vespucio s/n, E-41092, Sevilla, Spain
* For correspondence. E-mail azucanto{at}tunku.uady.mx
Received: 25 July 2006 Returned for revision: 21 September 2006 Accepted: 30 November 2006 Published electronically: 26 January 2007
Background and Aims: Intra-specific variation in nectar chemistry under natural conditions has been only rarely explored, yet it is an essential aspect of our understanding of how pollinator-mediated selection might act on nectar traits. This paper examines intra-specific variation in nectar sugar composition in field and glasshouse plants of the bumblebee-pollinated perennial herbs Aquilegia vulgaris subsp. vulgaris and Aquilegia pyrenaica subsp. cazorlensis (Ranunculaceae). The aims of the study are to assess the generality of extreme intra-plant variation in nectar sugar composition recently reported for other species in the field, and gaining insight on the possible mechanisms involved.
Methods: The proportions of glucose, fructose and sucrose in single-nectary nectar samples collected from field and glasshouse plants were determined using high performance liquid chromatography. A hierarchical variance partition was used to dissect total variance into components due to variation among plants, flowers within plants, and nectaries within flowers.
Key Results: Nectar of the two species was mostly sucrose-dominated, but composition varied widely in the field, ranging from sucrose-only to fructose-dominated. Most intra-specific variance was due to differences among nectaries of the same flower, and flowers of the same plant. The high intra-plant variation in sugar composition exhibited by field plants vanished in the glasshouse, where nectar composition emerged as a remarkably constant feature across plants, flowers and nectaries.
Conclusions: In addition to corroborating the results of previous studies documenting extreme intra-plant variation in nectar sugar composition in the field, this study suggests that such variation may ultimately be caused by biotic factors operating on the nectar in the field but not in the glasshouse. Pollinator visitation and pollinator-borne yeasts are suggested as likely causal agents.
Key words: Abiotic environment, Aquilegia pyrenaica subsp. cazorlensis, Aquilegia vulgaris subsp. vulgaris, biotic factors, field conditions, glasshouse, Iberian Peninsula, inter- and intra-specific variation, nectar-sugar composition, nectary, variance components
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. Canto, C. M. Herrera, M. Medrano, R. Perez, and I. M. Garcia Pollinator foraging modifies nectar sugar composition in Helleborus foetidus (Ranunculaceae):An experimental test Am. J. Botany, March 1, 2008; 95(3): 315 - 320. [Abstract] [Full Text] [PDF]
|
|