Phenotypic Differences Between Natural and Selected Populations of Picea Abies. II. Apical Mitotic Activity and Growth Related Parameters

• Published in: Scandinavian journal of forest research Vol. 15; no. 5; pp. 500 - 509
• Main Authors: Westin, Johan, Sundblad, Lars-Göran, Strand, Martin, Hällgren, Jan-Erik
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.01.2000
• Subjects: Buds; Climate; Mitotic Activity; Rhythm; Selection; Shoot Growth; Stem Units; Transfer
• ISSN: 0282-7581; 1651-1891
• DOI: 10.1080/028275800750173410

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.