Stimulation of germination of Acacia pulchella: laboratory basis for forest management options.
The shrub A. pulchella is a valued understorey species of jarrah (Eucalyptus marginata) forests in south-western Australia. It regenerates from buried seeds mainly after fire, which breaks seed dormancy. Tests examined the effects of five heating durations on germination of A. pulchella seeds buried at five depths in two soil types (sand or gravel) kept dry or at field capacity. Results showed that mean germination of unheated seeds was only 4%, but germination was >60% after temperatures reached 55-60°C, with some seeds germinating after exposure to temperatures >200°C. While duration of heating, depth of seed burial, and soil moisture content all affected germination response to soil heating, both soil types gave the same response.