Journal Article

Environmental regulation of dormancy loss in seeds of <i>Lomatium dissectum</i> (Apiaceae)

Melissa Scholten, Jacklyn Donahue, Nancy L. Shaw and Marcelo D. Serpe

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 103, issue 7, pages 1091-1101
Published in print May 2009 | ISSN: 0305-7364
Published online February 2009 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcp038
Environmental regulation of dormancy loss in seeds of Lomatium dissectum (Apiaceae)

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  • Ecology and Conservation
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Background and Aims Lomatium dissectum

(Apiaceae) is a perennial, herbaceous plant of wide distribution in Western North America. At the time of dispersal, L. dissectum seeds are dormant and have under-developed embryos. The aims of this work were to determine the requirements for dormancy break and germination, to characterize the type of seed dormancy, and to determine the effect of dehydration after embryo growth on seed viability and secondary dormancy.

Methods

The temperature requirements for embryo growth and germination were investigated under growth chamber and field conditions. The effect of GA3 on embryo growth was also analysed to determine the specific type of seed dormancy. The effect of dehydration on seed viability and induction of secondary dormancy were tested in seeds where embryos had elongated about 4-fold their initial length. Most experiments examining the nature of seed dormancy were conducted with seeds collected at one site in two different years. To characterize the degree of variation in dormancy-breaking requirements among seed populations, the stratification requirements of seeds collected at eight different sites were compared.

Key Results

Embryo growth prior to and during germination occurred at temperatures between 3 and 6 °C and was negligible at stratification temperatures of 0·5 and 9·1 °C. Seeds buried in the field and exposed to natural winter conditions showed similar trends. Interruption of the cold stratification period by 8 weeks of dehydration decreased seed viability by about 30 % and induced secondary dormancy in the remaining viable seeds. Comparison of the cold stratification requirements of different seed populations indicates that seeds collected from moist habitats have longer cold stratification requirements that those from semiarid environments.

Conclusions

Seeds of L. dissectum have deep complex morphophysiological dormancy. The requirements for dormancy break and germination reflect an adaptation to trigger germination in late winter.

Keywords: Apiaceae; cold stratification; Lomatium dissectum; morphophysiological dormancy; secondary dormancy; seed germination

Journal Article.  7152 words.  Illustrated.

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

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