© 1991 Heron Publishing—Victoria, Canada
Temporal variations in cold sensitivity of root growth in cold-stored white spruce seedlings
Edith L. Camm (1, 2) and George J. Harper (1)
1. Department of Forest Sciences, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4 / 2. Department of Botany, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4 / Received March 14, 1990
Summary
We examined effects of soil temperature on the number of roots produced by white spruce (Picea glauca (Moench.) Voss) seedlings during the first month of growth following 0–30 weeks of storage in darkness at –2 °C. After storage,
seedlings were planted in pots and placed in a controlled-environment chamber with a constant air temperature of 11 °C and
a 16-h photoperiod. Water baths were used to keep soil temperature at 3, 7 or 11 °C. The number of long roots (> 10 mm) produced
was strongly dependent on soil temperature. At soil temperatures of 3 or 7 °C, the number of long roots produced was only
11 to 30% that at 11 °C. Seedlings that had been stored for 14 weeks and then planted in soil at 11 °C produced the greatest
number of long roots. For seedlings planted in soil at 11 °C, the number of long roots increased with time of storage up to
14–18 weeks and then declined progressively with length of storage. No increase in number of long roots with length of storage
up to 18 weeks was evident in seedlings planted in soil at 3 or 7 °C. The maximum number of short roots (5–10 mm) was observed
in seedlings that had been stored for 17 weeks and then planted in soil at 7 or 11 °C.
