Abstract

PUNTIERI, Javier G; DAMASCOS, María A  and  SOUZA, María S. Ontogenetic tendencies in the size and form of leaves in Nothofagus pumilio (Poepp. et Endl.) Krasser (Fagaceae). Ecol. austral [online]. 2001, vol.11, n.2, pp.105-114. ISSN 1667-782X.

Variations in the area, length and length/width ratio of Nothofagus pumilio leaves along shoots and among shoots of different size were studied. For three populations of trees, similar tendencies in leaf size and form were found for shoots of similar size. In short shoots, those with three green leaves, the size of the lamina tended to increase from the proximal to the distal leaf. In shoots with more leaves, the size of the lamina increased from the most proximal leaf to the fourth or fifth leaf and decreased from these leaves to the most distal ones. Short shoots, which were found close to the centre of the crown (in presumably more shaded conditions) tended to have smaller leaves than longer shoots, which developed in more peripheral (and less shaded) placements. Since distal leaves of shoots of intermediate and large length tend to be relatively small, the capacity of these shoots to take photosynthetic advantage of their size would be limited in the short term.

Keywords : Leaf area; Leaf length; Nothofagus pumilio; Ontogenetic gradients; Shoot size.

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