Effects of Nutritional Factors on Frost Hardening in Larix leptolepis (Sieb & Zucc.) Gord.

Hansen, J. M. (Royal Veterinary and Agricultural University, Department of Agricultural Science, Section of Horticulture, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark). Effects of nutritional factors on frost hardening in Larix leptolepis (Sieb & Zucc.) Gord. Accepted Oct. 10, 1991. Scand. J. For. Res. 7: 183-192, 1992. A method for estimating frost hardiness in seedlings of Larix leptolepis in their first stage of acclimation is demonstrated. Cuttings of the shoot tip were frozen linearly from +2 degrees C to -36 degrees C. The viability was determined by TTC-assay. Data were fitted to a logistic regression model, and hardiness was calculated from the fitting parameters. It was shown that hardiness is influenced by the duration of the fertilizer application period. No effect of the nutrient status of N, P or K in the shoots was found.