Flower colour variation in the montane plant Gentiana lutea L. (Gentianaceae) is unrelated to abiotic factors

Abstract

Background: Flower colour variation among populations may result from the spatial variation of selective agents. The structure of phenotypic variation informs on the ecological processes related to this variation. Variation in floral traits is mainly attributed to variation in the pollinator fauna, while variation in vegetative traits is usually linked to abiotic factors or herbivores.

Aims: We investigated the geographical variation of flower colour (and correlated traits) in Gentiana lutea and the relationship with the variation in abiotic factors.

Methods: Phenotypic variation (flower colour, petal length, petal width, stalk length, leaf length, flower number, petal number and number of basal leaves) was assessed in 429 plants of 12 populations located at north-west Iberia. Additionally, we obtained data on the geographical coordinates, elevation, temperature, rainfall and radiation for each population.

Results: Populations mostly differed in flower colour, from orange to yellow from west to the east. Abiotic factors were unrelated to variation in either floral or vegetative traits.

Conclusions: Phenotypic variation among G. lutea populations does not result from adaptation to environmental factors. Other factors, such as historical events or selective pressure exerted by biotic interactions, might explain the flower colour variation in G. lutea along the Cantabrian Range.

Keywords:

• flower colour variation
• Gentiana lutea
• G. lutea var. aurantiaca
• geographical variation
• radiation
• rainfall
• temperature

Acknowledgements

The authors thank M. Melgosa and F.M. Martínez for chromaticity advising; P. Domínguez, and M. Losada, for field assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Plan Nacional de I + D + I (2008–2011), CGL2009-08959 Ministerio de Ciencia e Innovación. T. Veiga was supported by a Ph.D. grant from the Plan Galego de Investigación e Crecemento 2011/2015 (Plan I2C), Consellería de Educación e Ordenación Universitaria. I.M. was supported by a Parga Pondal (European Social Fund) grant.

Notes on contributors

Tania Veiga

Tania Veiga, PhD, is interested in the evolutionary ecology of plant–animal interactions. Recent publications include: Sobral et al. (2015) “Selective pressures explain differences in flower color among Gentiana lutea populations”. PLoS ONE. Veiga et al. (2014) “Are pollinators and seed predators selective agents on flower color in Gentiana lutea?” Evolutionary Ecology.

Javier Guitián

Javier Guitián is a Professor of Botany at USC. He studies the evolutionary ecology of plant–animal interactions. His recent publications include: Sobral et al. (2015) “Selective pressures explain differences in flower color among Gentiana lutea populations”. PLoS ONE. Veiga et al. (2014) “Are pollinators and seed predators selective agents on flower color in Gentiana lutea?” Evolutionary Ecology.

Pablo Guitián

Pablo Guitián is a professor of Botany at USC. He is interested in the evolutionary ecology of plant–animal interactions. His recent publications include: Sobral et al. (2015) “Selective pressures explain differences in flower color among Gentiana lutea populations”. PLoS ONE. Veiga et al. (2014) “Are pollinators and seed predators selective agents on flower color in Gentiana lutea?” Evolutionary Ecology.

José Guitián

José Guitián is a professor of Ecology at USC. He studies the evolutionary ecology of plant–animal interactions. His recent publications include: Sobral et al. (2015) “Selective pressures explain differences in flower color among Gentiana lutea populations”. PLoS ONE. Veiga et al. (2014) “Are pollinators and seed predators selective agents on flower color in Gentiana lutea?” Evolutionary Ecology.

Ignacio Munilla

Ignacio Munilla, PhD, is an ecological consultant. He studies the ecology and conservation of seabirds and plant–animal interactions. His recent publications include: Munilla, Velando (2015) “The Iberian guillemot population crash: A plea for action at margins”. Biological Conservation. Munilla, Guitián (2014) “Long-term individual-level variation of reproductive features in Sorbus aucuparia, a fleshy fruited tree”. Trees: Structure and Function.

Mar Sobral

Mar Sobral, PhD, studies the evolutionary ecology of plant–animal interactions and biodiversity ecosystem services. Recent publications include: Sobral et al. (2015) “Selective pressures explain differences in flower color among Gentiana lutea populations”. PLoS ONE. Veiga et al. (2014) “Are pollinators and seed predators selective agents on flower color in Gentiana lutea?” Evolutionary Ecology.