Shoot morphology and growth pattern in seedlings of Pinusbrutia provenances

The process of primary growth in 2-year-old seedlings of six Pinusbrutia Ten. provenances is described. At the end of the first growing season, two types of shoot morphology were observed: type 1, a terminal winter bud, and type 2, a terminal rosette of primary needles protecting the meristematic apex. During the 2nd year the seedlings exhibited a succession of shoots (varying in number from one to five), each of which was due to the elongation of a new apical bud. Morphological observations along with an anatomical examination of the winter bud led to the conclusion that the growth pattern in juvenile P. brutia is monocyclic with a variable number of summer shoots (using the terminology proposed by Lanner (Lanner, R.M. 1976. In Tree physiology and yield improvement. Editedby M.G.R. Cannell and F.T. Last. Academic Press, London, pp. 223-243)). The provenances studied differed both in growth potential and in seasonal growth pattern (differences in number of shoots, ratio of spring shoot to total growth, growth rate). Two groups could be identified: (i) the provenances of the island of Crete, which had a low growth potential and short growing season, and (ii) the high-altitude provenances of inland Turkey, with high growth potential and a growth rate that peaked in summer.