Phenotypic Differences Between Natural and Selected Populations of Picea Abies. II. Apical Mitotic Activity and Growth Related Parameters
Abstract:Apical mitotic index (MI) and growth of non-juvenile Norway spruce [Picea abies (L.) Karst.] populations growing in northern Sweden (63°54′ N) were monitored in 1996. Annual leader shoot lengths and shoot growth components for the period 1990-1997 were measured in 1997. In 1997 populations transferred more than approximately 3° in latitude were found to be shorter than local populations. MI levels were initially high in all populations in mid-April. In spring, populations originating north of 63°30′ N showed higher MI levels, and started shoot growth earlier, than populations originating further south. In autumn, MI levels were higher in populations originating south of 63°30′ N than in populations originating further north and higher in seed orchard populations than in natural populations of similar latitudinal origin. The number of stem-units (NSU) was correlated with tree height and leader shoot length. NSU and elongation of stem-units appeared to be primarily influenced by summer temperature. Prolonged MI activity in autumn did not result in high NSU but appeared to be associated with a higher risk of frost damage to buds. The results are discussed in relation to climatic factors, seed transfer, selection and inherent growth rhythms.
Document Type: Research Article
Affiliations: 1: The Forestry Research Institute of Sweden, P.O. Box 3, SE-918 21 Sävar, Sweden 2: Swedish University of Agricultural Sciences, Faculty of Forestry, Department of Forest Genetics and Plant Physiology, SE-901 83 Umea˚, Sweden
Publication date: 2000-11-25