Germination response under elevated salinities of six semi-arid bluebush species (Western Australia)

The Western Australian semi-arid regions are characterized by extreme and often unpredictable climatic conditions, low soil fertility and often poor soil structure. Revegetation of disturbed surfaces and saline sites is by direct seeding. This paper summarizes the germination responses of six local bluebush species applications to direct sowing programmes in the arid and semi-arid regions of Western Australia. Replicate seed germination trials completed in the 15-30° C range established preferred temperatures for Eriochiton sclerolaenoides, Maireana georgei, M. pentatropis, M. pyramidata, M. trichoptera and M. triplera. Pre-sowing treatments included pre-soaking of fruits and removal of the perianth. For two species, Maireana pyramidata and M. trichoptera, presoaking improved germination. Removing the perianth resulted in an increase in germination numbers, a faster germination rate, and increased seed vigour. Seeds were exposed to elevated salinity levels, simulating direct seeding onto Eriochiton sclerolaenoides. Good germination results were also obtained for Maireana pyramidata, M. trichoptera and M. triptera. Depth of sowing trials established maximum seedling emergence from a 5 mm sowing depth. Sowing seeds deeper than 10 mm severely reduced emergence.