Can Foliage Water Content Measurements Replace Freezer Tests in Determining a Safe Lifting Time For Frozen Storage of Conifer Seedlings?
Several researchers have reported a strong relationship between the frost hardiness of planting stock and its shoot water content (Pellet and White 1969, Rosvall-A*hnebrink 1977, Jonsson et. al. 1981, Colombo 1990, Calme' et. al. 1992). The last cited work was done in Quebec. Calme' et. al (1992) examined the relationship between shoot water content and injury sustained in a -10oC freezer test by containerized seedlings of three species (Jack pine, white, and black spruce). They reported that frost hardy seedlings had shoot dry to fresh weight ratio of less than 0.3. Consequently, they suggested that measuring shoot water may rapidly predict seedling frost tolerance. In fact, the dry weight to fresh weight ratio of excised shoot tips (terminal 2 cm) has been used operationally in Sweden to determine safe lifting time for storage of conifer seedlings. Seedlings are lifted when the ratio is 0.31 or less (Hulte'n and Lindell 1980).
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Author(s): Marek J. Krasowski, A. Caputa, Christopher D.B. Hawkins
Publication: National Nursery Proceedings - 1994
Event:
Combined Western Forest Nursery Association and the Forest Nursery Association of British Columbia
1994 - Moscow, ID