AOBPreview originally published online on April 19, 2005
Annals of Botany 2005 96(1):159-163; doi:10.1093/aob/mci151
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Successful Seed Germination of the Nickel Hyperaccumulator Stackhousia tryonii
1 Primary Industries Research Centre, School of Biological and Environmental Sciences, Central Queensland University, Rockhampton, Queensland 4702, Australia, 2 Department of Botany, University of Calabar, Calabar, Nigeria and 3 School of Botany, The University of Melbourne, Victoria 3010, Australia
* For correspondence. E-mail naveen.bhatia{at}ansto.gov.au
Received: 22 November 2004 Returned for revision: 19 January 2005 Accepted: 28 February 2005 Published electronically: 19 April 2005
Background and Aims Stackhousia tryonii, a rare nickel hyperaccumulating herb, is endemic to ultramafic (serpentine) soils of central Queensland, Australia. The effects of eight dormancy-relieving treatments on germination of stored seeds of Stackhousia tryonii were investigated under controlled light and temperature conditions.
Methods The treatments were: untreated (control i), leached and dehydrated (primed control ii), treating with gibberellic acid (150 and 300 µM), smoke extract (5 and 10 %, v/v) and potassium cyanide (40 and 80 mM).
Key Results Freshly harvested seeds did not germinate. Germination percentage increased with time of storage for up to 18 months (38·3 %). Gibberellin, smoke extract and cyanide treatments did not significantly improve germination. Light did not affect seed germination and there was no interaction between dormancy-relieving treatments and light. A significant inhibition of germination occurred in seeds treated with 5 % (but not 10 %) aqueous smoke extract. Saturated fatty acids, predominantly tridecanoic (C13:0), constituted about 90 % of the total fatty acids in the oil of freshly harvested seeds. In contrast, there was increased accumulation (>75 %) of mono-unsaturated (oleic, C18:1) and poly-unsaturated (linoleic, C18:2; linolenic, C18:3) fatty acids in the oil of stored seeds.
Conclusions Seeds of S. tryonii require an after-ripening period for germination.
Key words: After-ripening period, central Queensland, fatty acid, metal hyperaccumulation, nickel (Ni), seed dormancy, seed germination, serpentine soil, Stackhousia tryonii, ultramafic soil