Apical mitotic activity and growth in clones of Norway spruce in relation to cold hardiness

• Published in: Canadian journal of forest research Vol. 29; no. 1; pp. 40 - 46
• Main Authors: Westin, J, Sundblad, L.G, Strand, M, Hallgren, J.E
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 1999; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Air temperature; Annual variations; apical meristems; Biological and medical sciences; Cell kinetics; Cell physiology; Climate; Climatic adaptation. Acclimatization; clones; cold tolerance; diameter; Discoloration; Evergreen trees; Flowers & plants; Freezing; Frost; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Genetics; growth; growth rate; height; Low temperature; mitosis; Picea abies; Pine trees; plant characteristics; Plant physiology and development; seasonal variation; Seedlings; shoots; Spruce; Vegetation; Scandinavia; Sweden; Europe; Temperature; Growth; Mitosis; Cold resistance; Environmental factor; Bud; Mitotic index; Softwood forest tree; Gymnospermae; Coniferales; Spermatophyta; Intraspecific comparison; Apex; Picea abies; Clone
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x98-177

Seasonal development of apical mitotic activity and growth in three clones of Norway spruce (Picea abies (L.) Karst.) of the same age and origin but with differences in accumulated height growth and cold hardiness were investigated. The clones showed no consistent difference in mitotic index (MI), either in period or in general levels. The response of MI to temperature differed in spring and fall. Differences in cold hardiness between the clones was not directly coupled to differences in MI. Diameter growth ended earlier in one clone than in the other two clones, and this clone also produced lower numbers of stem units in both lateral and leader shoots. Cessation of diameter growth showed no relation to the duration and level of apical MI. The tallest clone had, as a combined effect of both size and number of stem units, significantly longer leader shoots than the other two clones. The greater leader shoot growth of the tallest clone relative to the other two clones during 1987-1996 was also most prominent after years with sudden drops in fall minimum temperatures to below ca. -12 degrees C (median; interval: -11 to -13 degrees C), following several weeks with mean temperatures above 3 degrees C.