Abstract
The comparative morphology of the seeds of three Australian Citrus species, C. australasica C. inodora and C. garrawayi, was studied. Their seed characteristics were broadly similar to those of the cultivated species of the genus, when observed under light and scanning electron microscopy. Citrus garrawayi differed in seed shape (rounded to triangular) and seed coat morphology (i.e., thicker with longer epidermal protrusions) from C. australasica and C. inodora (rounded surface with flat underside in shape). The well-developed minute epidermal protrusions on the seed coat of C. garrawayi were more similar to those in the cultivated species, C. × sinensis and C. × aurantium. In contrast, the surface topography of C. australasica and C. inodora seeds was more like that of the cultivated species, C. × aurantifolia and C. × limon. Seed morphology, especially surface topography, was found to be a useful tool for taxonomic identification in Australian wild citrus.
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Acknowledgements
We gratefully thank Malcolm Smith (QDPI), Roger Goebel (QPDI) and Phil Boyle (BBG) for kindly donating fruits and Dr Deb Stenzel (AEMF) for training in Scanning Electron Microscopy. Kim Hamilton received part funding from the Millennium Seed Bank Project, Royal Botanic Gardens, Kew and the Bioversity-ACIAR project, ‘Development of Advanced Technologies for the Conservation of Tropical Fruits’.
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Hamilton, K.N., Ashmore, S.E. & Drew, R.A. Morphological characterization of seeds of three Australian wild Citrus species (Rutaceae): Citrus australasica F. Muell., C. inodora F.M. Bailey and C. garrawayi F.M. Bailey. Genet Resour Crop Evol 55, 683–693 (2008). https://doi.org/10.1007/s10722-007-9274-x
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DOI: https://doi.org/10.1007/s10722-007-9274-x