Germination and storage studies of selected Australian tropical native grasses in relation to their ecology and use in land rehabilitation

"A study was financed by the Victoria River District Conservation Association (VRDCA) and Greening Australia Northern Territory (GANT) to examine the germination and storage requirements of a range of grasses indigenous to the northern part of the Northern Territory. The aim was to increase understanding of the germination requirements and dormancy cycles of species that could be utilised for restoration and rehabilitation purposes, and be commercially grown and harvested for seed supply to pastoralists (initially through a co-operative), mining companies and contractors involved in the construction of railway lines and raised banks, roads and bridges. In 2000 and 2001, seeds of twenty-five grass species were collected from across the Northern Territory and were placed into long-term storage trials. Results showed that some tropical seeds retained their viability when frozen (Astrebla squarrosa), while others achieved their germination potential after storage in a garden shed (Brachyachne convergens). A trial was undertaken to test for the suitability of three indigenous grass species in batter stabilisation, using an exotic pasture grass as a control. The species were monitored for their ability to germinate rapidly, produce stolons and to mature and seed quickly. The study found that while two of the species (Brachyachne convergens and Chloris pectinata) showed great potential, they were infringed upon by the invasive Chloris gayana (Rhodes grass) during the second season. 2 Studies were also conducted using Scanning Electron Microscopy to examine the surface of the seeds in their storage treatments. This study provided a database of the morphological features of all of the seed species in storage, the information thaof which could be utilised by other researchers.One dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to extract and analyse the molecular mass of proteins in the seed of Triodia bitextura at various stages of imbibition prior to germination. The results demonstrated that storage condition affects the seed viability of this species possibly due to the structural break-down of stored macro-proteins prior to imbibition. Field observations were also conducted on ten sites across the top of the North Territory. GANT has been monitoring sites at which they had planted selected species of grasses to test their suitability for rehabilitation work across a range of environmental conditions. These observations, in combination with separate GANT observations led to the selection of four indigenous species, three of which (Chrysopogon elongatus, Alloteropsis semialata and Dichanthium fecundum) are now under commercial cultivation. The fourth species, Brachyachne convergens, is undergoing further experimentation. The end result of this study is an increased understanding of the dormancy cycles of some species of seed, their optimum storage requirements and testing their suitability for use in rehabilitation and restoration of disturbed lands." -- abstract