Determination of the extent of primary dormancy in seed of eucalypt species of HEMS forest in East Gippsland.  M. T. Lutze, P. W. Geary and M. J. Bowler.  November 1998.  17pp. (unpubl.)

SUMMARY

This study determined whether primary dormancy is present in seed of four eucalypt species of the High Elevation Mixed Species (HEMS) forest in East Gippsland.

Up to 11 seedlots of each of E. obliqua, E. fastigata, E. denticulata and E. cypellocarpa were collected from different sites across East Gippsland for testing, and seven seedlots of E. delegatensis from operational seed collections were selected as a control. Each seedlot was split into 24 sub-samples (4 stratification periods x 6 replicates) and weighed into petri dishes for stratification at 3-5°C followed by germination at optimal temperature. Increasing percentage germination at the end of the germination period with increasing period of stratification was used as the indicator of primary dormancy.

All seedlots of E. delegatensis showed clear evidence of primary dormancy, but out of the 41 HEMS seedlots tested, only two seedlots of E. denticulata showed slight evidence of primary dormancy. The E. denticulata seedlot with greatest evidence of primary dormancy had a difference in % germination between 0 and 6 weeks stratification of 9%. There was no clear relationship between elevation or aspect and the occurrence of this dormancy.

Rate of germination at optimal germination temperatures of all HEMS species generally increased with increasing stratification period. The implications of the results for HEMS forest regeneration and seed testing are discussed.