Sex allocation in an hermaphroditic plant: the case of gynodioecy in Thymus vulgaris L.

Authors

  • A. Atlan,

    Corresponding author
    1. Laboratoire d'évolution des systèmes génétiques, CEPE/CNRS, Route de Mende, BP 5051, 34033 Montpellier Cedex, France
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  • P. H. Gouyon,

    1. Laboratoire d'évolution des systèmes génétiques, CEPE/CNRS, Route de Mende, BP 5051, 34033 Montpellier Cedex, France
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    • 2

      Present address: Laboratoire d'Evolution et Systématique des Végétaux, Bat 362, Université Paris Sud, 91405 Orsay Cedex, France

  • T. Fournial,

    1. Laboratoire d'évolution des systèmes génétiques, CEPE/CNRS, Route de Mende, BP 5051, 34033 Montpellier Cedex, France
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  • D. Pomente,

    1. Laboratoire d'évolution des systèmes génétiques, CEPE/CNRS, Route de Mende, BP 5051, 34033 Montpellier Cedex, France
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  • D. Couvet

    1. Laboratoire d'évolution des systèmes génétiques, CEPE/CNRS, Route de Mende, BP 5051, 34033 Montpellier Cedex, France
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Abstract

Resource allocation to male and female functions was investigated in Thymus vulgaris L. (thyme), a gynodioecious species, in which females produce twice as many seeds as hermaphrodites. Negative correlations were found between male and female fertility of hermaphrodites, providing evidence of a trade-off. There was a high variability in sexual investment, some of the hermaphrodites functioning almost as males, and others almost as females. Estimation of the relative cost of male and female gametes showed that the female advantage in seed production was mainly due to reallocation of the resources not allocated to male function into female function. The determination of sex allocation was shown to have a genetic component, and there were some evidence that an interaction between nuclear and cytoplasmic genomes was involved.

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