Mechanisms related to the stimulation of germination in hardcoatedseeds: implications for the management of fire-proneshrublands

摘要

Fuel-control techniques such as clearing and prescribed burning modify the shrublandrnstructure by changing the environmental conditions. The object of this study is to analysernsome of the mechanisms involved in the loss of dormancy in hard-coated seeds during or after thernapplication of fuel-control techniques. Different methods of scarification were applied to the seedrncoat, thus simulating processes that occur during fuel-control applications, e.g. temperature increasernin prescribed fires or mechanical scarification in clearing. We planted 4 lots of 25 seedsrneach, based on the scarification method used and the colour of the seeds. The experiment lasted forrn60 days, and germination data were collected every 2 days. The different scarification methodsrnapplied to the seeds produced a significant increase in their germination in comparison with untreatedrnseeds. The highest germination rates (with values superior to 90 %) were observed in thernseeds that had been scarified by mechanical means; in contrast, germination in seeds scarified byrnheat was never greater than 50 %. These results seem to indicate that fuel-control treatments mayrnfavour posterior vegetation regeneration.