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Structural, physiological and molecular aspects of heterogeneity in seeds: a review

Published online by Cambridge University Press:  22 February 2007

Angel Matilla*
Affiliation:
Departamento de Biología Vegetal, Laboratorio de Fisiología Vegetal, Facultad de Farmacia, Universidad de Santiago de Compostela, 15 782-Santiago de Compostela, A Coruña, Spain
Mercedes Gallardo
Affiliation:
Departamento de Biología Vegetal y Ciencias del Suelo, Laboratorio de Fisiología Vegetal, Facultad de Ciencias, Universidad de Vigo, E-36200-Vigo, Pontevedra, Spain
María Isabel Puga-Hermida
Affiliation:
Departamento de Biología Vegetal y Ciencias del Suelo, Laboratorio de Fisiología Vegetal, Facultad de Ciencias, Universidad de Vigo, E-36200-Vigo, Pontevedra, Spain
*
*Correspondence: Fax: +34 981 593 054 Email: bvmatilla@usc.es

Abstract

Higher plants have several strategies to perpetuate themselves under adequate ecophysiological conditions. The production of heterogeneous seeds is one such strategy. That is, to ensure the survival of the next generation, an individual plant might produce seeds that are heterogeneous with respect to the extent of dormancy, dispersion and persistence within the seed bank. Heterogeneity can affect not only certain physiological and molecular properties related to seed germination, but also such characteristics as colour, size and shape, parameters commonly used to differentiate morphs within a heterogeneous seed population. In heterogeneous seeds, the above features determine seed behaviour and alter their mechanism of germination. In this work, emphasis is placed on the existence of seed mutants having major alterations in characteristics of the testa and hormonal response. These mutants constitute a valuable tool for elucidating the mechanism of dormancy, germination and perpetuation of seeds. Finally, ontogeny and heterogeneity are reviewed, providing the first data related to the possible hormonal control of heterogeneity in seeds. These results raise the hypothesis that one of the factors triggering differences in germination among heterogeneous seeds may be an alteration in the signalling and action mechanism of ethylene and abscisic acid (ABA).

Type
Research Review
Copyright
Copyright © Cambridge University Press 2005

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