GERMINATION OF LOMANDRA-SONDERI (DASYPOGONACEAE) PROMOTED BY PERICARPREMOVAL AND CHEMICAL-STIMULATION OF THE EMBRYO

Lomandra Labill. is a common genus in the understorey of the jarrah (E ucalyptus marginata Sm.) forest of Western Australia. Species in this genus are difficult to propagate by seed and do not readily re establi sh following mining. Limiting factors for germination success were exp lored and identified. Lomandra sonderii (F.Muell.) Ewart set very few seed (seeds per flower = 0.122). Tetrazolium tests indicated that seed viability was relatively high (50%). Germination was inhibited (0%) b y the inner pericarp tissues which surround the seed and are part of t he diaspore. Manual removal of the inner pericarp or leaching overcame this inhibition with a fifth of seeds subsequently germinating. Simil ar treatments improved germination of L. drummondii (F. Muell. ex Bent h.) Ewart from 40% to 80%. Soaking L. sonderi seeds in gibberellic aci d (GA(3), 50 mg L(-1)) further improved germination (28%). Ants (Campo notus sp. and Iridomyrmex sp.) collected and dispersed L. sonderi seed and are Likely to improve germination in the forest by removing and c onsuming the inner pericarp. Only half of the Viable excised embryos o f L. sonderi grew in vitro, indicating the presence of embryo dormancy . Embryo dormancy was overcome by GA(3) (0.5 mM) and zeatin (0.5 mM) i n the liquid culture medium. In vitro culture may be a practical means of propagating Lomandra if seed is scarce.