Propagation of Ornamental Plants
9(3): 143-150, 2009
SEED STORAGE POTENTIAL FOR DWARF BIRCH (BETULA GLANDULOSA MICHX.)
Kathleen Forbes and Tannis Beardmore*
Natural Resources Canada, Canadian Forest Service-Atlantic Region, Hugh John Fleming Forestry Complex, PO 4000, Fredericton, New Brunswick, Canada, E3A 5P9,
*Fax: + 1 506 452 3525, *E-mail: firstname.lastname@example.org
Seed from 27 Dwarf birch (Betula glandulosa Michx.) shrubs were collected from the one remaining B. glandulosa population in New Brunswick. Average initial germination was 69% for the 27 shrubs, ranging between 38 to 96%, and the mean germination time (MGT) in days was 5.8. Stratification (seed imbibed with water 5°C in the dark for 3 weeks) did not improve germination or decrease the MGT, suggesting that the seed was not initially dormant. Seed from a selection of 7 shrubs tolerated 2-week low temperature treatments to -20, -80 and -196°C and a 1-year -196°C treatment. The -196?C treated seed appeared to develop dormancy. Non-stratified -196°C treated seed germination averaged 30% for the 7 shrubs, and germination increased to 67% with stratification and was not significantly different from the germination of the control seed. The MGT decreased in the stratified -196°C treated seeds as compared to the non-stratified -196°C seed. In the -20 and -80°C 2-week treated seed stratification decreased germination and increased MGT. Seed from the 27 shrubs tolerated storage for up to 6 years at 5°C, with only 2 shrubs (shrub 1 and 19) exhibited a significant decrease in germination ion after 6 years. The MGT significantly increased in all seed 6 years after storage, suggesting that seed deterioration was occurring and the seed was reaching their maximum storage potential.
Key words: Betula glandulosa, ex situ conservation, mean germination time, percent germination, storage