Abstract

GARCIA, Soledad; PUNTIERI, Javier  and  VOBIS, Gernot. Morfology and anatomy of the shoot apex of Nothofagus dombeyi (Nothofagaceae) along a year. Bol. Soc. Argent. Bot. [online]. 2006, vol.41, n.1-2, pp.15-23. ISSN 1851-2372.

The present study evaluates the possible annual variation in the morphology and anatomy of the shoot apex of Nothofagus dombeyi (Nothofagaceae). From samples taken over one year, longitudinal slices of terminal buds were cut with a freezing microtome. Irrespective of the time of the year, a terminal bud consists of an apical meristem and rudiments of stem and leaves. Proximal primordia are larger and have a higher degree of differentiation than distal primordia. Around the axil of each stipule colleters are present. Each colleter is connected with the corresponding stipule through a conducting strand. The number of leaf primordia per bud is constant between April and October and diminishes later on as leaf expansion takes place, although it never reaches zero. At the end of the growth season, large and small buds may be distinguished; the latter ones dry out and fall before the next spring. In each terminal bud, distinctions in the degree of differentiation between leaf primordia in different positions and between blade and stipules of each proximal primordia are evident.

Keywords : Shoot apex; Bud; Leaf primordium; Stipule; Colleter; Nothofagus dombeyi.

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