Journal Article

Natural variation in germination responses of Arabidopsis to seasonal cues and their associated physiological mechanisms

Deepak Barua, Colleen Butler, Tracy E. Tisdale and Kathleen Donohue

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 109, issue 1, pages 209-226
Published in print January 2012 | ISSN: 0305-7364
Published online October 2011 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcr264
Natural variation in germination responses of Arabidopsis to seasonal cues and their associated physiological mechanisms

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  • Ecology and Conservation
  • Evolutionary Biology
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Background and Aims

Despite the intense interest in phenological adaptation to environmental change, the fundamental character of natural variation in germination is almost entirely unknown. Specifically, it is not known whether different genotypes within a species are germination specialists to particular conditions, nor is it known what physiological mechanisms of germination regulation vary in natural populations and how they are associated with responses to particular environmental factors.

Methods

We used a set of recombinant inbred genotypes of Arabidopsis thaliana, in which linkage disequilibrium has been disrupted over seven generations, to test for genetic variation and covariation in germination responses to distinct environmental factors. We then examined physiological mechanisms associated with those responses, including seed-coat permeability and sensitivity to the phytohormones gibberellic acid (GA) and abscisic acid (ABA).

Key Results

Genetic variation for germination was environment-dependent, but no evidence for specialization of germination to different conditions was found. Hormonal sensitivities also exhibited significant genetic variation, but seed-coat properties did not. GA sensitivity was associated with germination responses to multiple environmental factors, but seed-coat permeability and ABA sensitivity were associated with specific germination responses, suggesting that an evolutionary change in GA sensitivity could affect germination in multiple environments, but that of ABA sensitivity may affect germination under more restricted conditions.

Conclusions

The physiological mechanisms of germination responses to specific environmental factors therefore can influence the ability to adapt to diverse seasonal environments encountered during colonization of new habitats or with future predicted climate change.

Keywords: Abscisic acid; dormancy; germination; gibberellic acid; hormonal sensitivity; natural variation; pleiotropy; Arabidopsis thaliana

Journal Article.  12139 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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