© 1993 Heron Publishing—Victoria, Canada
Influence of photoperiod and temperature on frost hardiness and free amino acid concentrations in black spruce seedlings
K. D. Odlum (1), T. J. Blake (2), Y. T. Kim (1) and C. Glerum (1, 3)
1. Ontario Ministry of Natural Resources, Ontario Forest Research Institute, P.O. Box 969, 1235 Queen Street East, Sault Ste.
Marie, Ontario, P6A 5N5, Canada / 2. Faculty of Forestry, University of Toronto, Earth Sciences Centre, 33 Willcocks Street, Toronto, Ontario, M5S 3B3, Canada / 3. Glenfore Consulting, R.R. 1, King City, Ontario, L0G 1K0, Canada / Received June 26, 1992
Summary
We investigated the effects of a 4-week exposure to an 8-h or 18-h photoperiod at 5 or 25 °C on the development of hardiness
to –20 °C and the accumulation of proline (Pro), arginine (Arg) and tryptophan (Trp) in shoots of black spruce (Picea mariana (Mill.) B.S.P.) seedlings. The greatest degree of hardening to –20 °C occurred in seedlings exposed to an 8-h photoperiod
at 25 °C, and some hardening occurred in seedlings exposed to 5 °C in either an 8-h or 18-h photoperiod. Proline accumulated
in shoots in response to 5 °C and either an 8-h or 18-h photoperiod, whereas Trp accumulated in response to an 8-h photoperiod
at either temperature, and Arg only accumulated in shoots in the 5 °C + 8-h photoperiod treatment. Only the accumulation of
Trp was significantly related to the degree of hardiness to –20 °C.
