IN-VITRO PROPAGATION OF WESTERN-AUSTRALIAN RUSHES (RESTIONACEAE AND RELATED FAMILIES) BY EMBRYO CULTURE .1. IN-VITRO EMBRYO GROWTH

This study outlines the first method for initiating micropropagation of a wide range of wild and commercially significant species of various Southern Hemisphere rushes (Restionaceae) by embryo culture. Most species showed best embryo growth on half-strength Murashige and Skoog basal medium, with the addition of gibberellic acid (1-5 mu M) and/or zeatin (1-5 mu M). Results showed there was a high level of variability in seed germinability as indicated by in vitro embryo growth (6-96%), with no apparent link to growth form, generic status or habitat preference. Embryo growth was achieved for several rare and/or restricted taxa (Loxocarya 'magna' ined Lepidobolus contorta Meney & Dixon Hopkinsia anoectocolea (F Muell.) Cutler, Lepidobolus contorta Meney & Dixon ined). The low germination of whole seeds of most species (average of 10%) indicates that whole seed germination under controlled conditions considerably understates the potential germinability of species of Restionaceae. In this context, embryo culture is useful for assessment of germinability and for initiating stock cultures for micropropagation.