Preformation and neoformation in Nothofagus antarctica (G. Forster) Oersted (Nothofagaceae) shrubs.

PUNTIERI JAVIER; STECCONI MARINA; BARTHÉLÉMY DANIEL

ANNALS OF BOTANY

Academic Press

Lugar: Londres; Año: 2002 vol. 89 p. 665 - 673

0305-7364

For Nothofagus antarctica (G. Forster) Oerst. shrubs, the size (length and diameter) and the number of leaf primordia of winter buds was compared with the size and number of leaves of shoots derived from buds in equivalent positions. Buds developed in two successive years were compared in terms of size and number of leaf primordia. Both bud size and the number of leaf primordia per bud were higher for distal than for proximally-positioned buds. Shoots developed in the five positions closest to the distal end of their parent shoots had a number of leaves significantly higher than more proximally-positioned shoots of the same parent shoots. The positive relationship between the size of a shoot and that of its parent shoot was stronger for proximal than for distal positions on the parent shoots. For each bud position on the parent shoots, there were differences in the number of leaf primordia per bud between consecutive years. The correlations between the number of leaf primordia per bud and bud size, bud position and parent shoot size varied between years. Only shoots produced close to the distal end of a parent shoot developed neoformed leaves; more proximal sibling shoots consisted entirely of preformed leaves. Leaf neoformation, a process usually linked with high shoot vigour in woody plants, seems to be widespread among the relatively small shoots developed in N. antarctica shrubs, which may relate to the species’ opportunistic response to disturbance.