A study of the reproductive biology of blue-flowered Conospermum species (Proteaceae)
Lynley M. Stone A C D , Kevin A. Seaton B , Margaret Byrne A and Jen A. McComb CA Science Division, Department of Environment and Conservation, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia.
B Department of Agriculture and Food Western Australia, Plant Industries, Horticulture, Locked Bag 4, Bentley Delivery Centre, WA 6983, Australia.
C Biological Sciences, Murdoch University, Murdoch, WA 6150, Australia.
D Corresponding author. Email: lynleys@calm.wa.gov.au
Australian Journal of Botany 54(6) 543-551 https://doi.org/10.1071/BT05125
Submitted: 14 July 2005 Accepted: 9 March 2006 Published: 15 September 2006
Abstract
Blue-flowered Conospermum species are endemic to Western Australia, and are highly sought after in the horticulture industry. Aspects of the reproductive biology of several species were investigated. The paniculate inflorescences of Conospermum eatoniae E.Pritz. contain 6–10 florets; however, the uppermost two or three florets never open and only the basal one or two florets in an inflorescence set seed. When insect pollinators are excluded, flowers do not self-pollinate and set seed. Stigma receptivity occurred for up to 6 days following triggering of the style and was variable between C. eatoniae, C. amoenum Meisn. subsp. amoenum, C. caeruleum R.Br. and C. brownii Meisn. Hand-pollination with 10 pollen genotypes and two maternal C. eatoniae parents showed that although pollen tubes were observed in the style, no seed was set. Genetic analysis of open-set seed progeny showed that C. eatoniae outcrossed infrequently when grown in clonal rows in a plantation, but outcrossing was common in wild plants. This study demonstrates that the reproductive biology of blue-flowered Conospermum is complex and requires further investigation if the species are to be widely cultivated for horticulture.
Acknowledgments
This study was funded by a postgraduate ARC–SPIRT grant between Murdoch University, Department of Conservation and Land Management and the Western Australian Department of Agriculture.
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