AOBPreview published online on January 31, 2008
Annals of Botany, doi:10.1093/aob/mcn009
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Mimicking a Semi-arid Tropical Environment Achieves Dormancy Alleviation for Seeds of Australian Native Goodeniaceae and Asteraceae
1 Integrated Seed Research Unit, School of Land, Crop and Food Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
2 Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex, RH17 6TN, UK
3 School of Pharmacy, The University of Queensland, St. Lucia, QLD 4072, Australia
* For correspondence. E-mail. g.hoyle1{at}uq.edu.au
Received: 31 October 2007 Returned for revision: 18 December 2007 Accepted: 9 January 2008
Background and Aims: Seed physiological dormancy (PD) limits the use and conservation of some of Queensland's (Qld) native forb species. It was hypothesised that optimum dormancy-alleviating treatments would reflect environmental conditions that seeds experience in situ, and this premise was tested for PD seeds of four species native to south-west Qld.
Methods: High temperatures and increased rainfall during summer are characteristic of this semi-arid tropical environment. Ex situ treatments were designed to mimic conditions that seeds dispersed in spring experience during the summer months before germinating in cooler autumn temperatures. Seeds received between 4 and 20 weeks of a dry after-ripening (DAR), warm stratification or dry/wet cycling treatment (DAR interspersed with short periods of warm stratification), in darkness, before being transferred to germination test conditions. In addition, natural dormancy alleviation of one of the Goodeniaceae species was investigated in situ.
Key Results: Dry/wet cycling resulted in higher levels of germination of Actinobole uliginosum (Asteraceae), Goodenia cycloptera and Velleia glabrata (Goodeniaceae) when compared with constant DAR or stratification, while Goodenia fascicularis (Goodeniaceae) responded better to short durations of warm stratification. Long durations of DAR partially alleviated PD of A. uliginosum; however, stratification induced and maintained dormancy of this species. Modifications to the dry/wet cycling treatment and germination test conditions based on data collected in situ enabled germination of G. cycloptera and V. glabrata to be further improved.
Conclusions: Treatments designed using temperature, relative humidity and rainfall data for the period between natural seed dispersal and germination can successfully alleviate PD. Differences between the four species in conditions that resulted in maximum germination indicate that, in addition to responding to broad-scale climate patterns, species may be adapted to particular microsites and/or seasonal conditions.
Key words: Seed dormancy, germination, dry after-ripening, dry/wet cycling, south-west Queensland, Australia, semi-arid tropical, Actinobole uliginosum, Asteraceae, Goodenia fascicularis, Goodenia cycloptera, Velleia glabrata, Goodeniaceae
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  G. L. Hoyle, K. J. Steadman, M. I. Daws, and S. W. Adkins Pre- and Post-harvest Influences on Seed Dormancy Status of an Australian Goodeniaceae species, Goodenia fascicularis Ann. Bot., July 1, 2008; 102(1): 93 - 101. [Abstract] [Full Text] [PDF]
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