American ginseng (Panax quinquefolium L.) roots have a dormancy period which can be satisfied by exposure to low temperatures of 0° to 10°C for about 100 days. Three-year-old roots of ginseng were weighed, given variable periods (≥ 50 days) of low temperature (5°C), planted in vermiculite in pots, and grown in light or dark at 5°, 10°, 15°, or 20°. After 50 to 100 days of storage at 5°, stem growth occurred at all temperatures except 20°. At this temperature, a minimum of 75 days at 5° was required to satisfy dormancy. Stem growth rate was relatively constant at 5° and 10° but increased with storage time when grown at 15° or 20°; leaf growth rate was affected similarly, except that no leaf growth occurred at 5°. If optimum cold storage and growth requirements were not met, the plants appeared abnormal and had reduced root dry weights. After 100 days of storage, the greatest growth rate was observed at 15° and 10°. Plant growth rate was the least at 5° and 20°.
Visiting Professor. Permanent address: Agronomy Division, Korean Ginseng and Tobacco Research Institute, P.O. Box 59, Suweon, Korea.
Received for publication 9 Aug. 1984. This research was supported by Operating Grant No. A6697 of the Nat. Sci. and Eng. Res. Council of Canada held by John T.A. Proctor, and by the Korean Sci. Foundation. We are indebted to R.J. O'Hara Hines, and O.B. Allen, Dept. of Mathematics and Statistics, Univ. of Guelph, for advice and discussions on the statistical analyses, and to Dean Louttit for technical assistance. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.