Effects of Excessive Nutrient Supply and Short Day Treatment on Autumn Frost Hardiness and Time of Bud Break in Picea abies Seedlings

Contradictory results have been reported on the impact of needle nutrient concentration on frost hardiness in conifers. The aim of the present study was to test whether excessive nitrogen (N) supply would make seedlings of Picea abies (L.) Karst. more susceptible to autumn frost damage or lead to earlier bud break in the subsequent spring. Seedlings were grown in a greenhouse for one season and given a nutrient supply resulting in needle N concentrations ranging from 2.2 to 3.3%. Half of the seedlings with the lowest N fertilization were exposed to short day treatment for 3 weeks from mid August. No evidence was found in this experiment that excessive N concentrations in needles lead to increased autumn frost damage. Short day treatment resulted in less frost damage in autumn. No significant difference in time of bud break due to fertilization or day length was detected. This may have been due to a more uniform bud break caused by the storage and growth conditions.

Keywords:

• Bud Development
• Bud Flush
• Fertilization
• Frost Damage
• Nitrogen
• Norway Spruce
• Nutrition
• Seedling Quality
• Short Day Treatment