Preformation, neoformation and bud structure in species of Proteaceae from northern Patagonia

MAGNIN N.A.* ; GROSFELD J.AND BARTHÉLÉMY D.

Congreso; VI Southern Connection Congress; 2010

Southern Connection

Preformation and neformation in woody species are processes associated with the vigour of shoots which respond to endogenous and environmental factors. For four species of the family Proteaceae over several ontogenetic stages (seedling, juvenile and adult), the content of leaf primordia of winter buds were studied and compared with the number of leaves of shoots developed from buds in equivalent positions. Two of the species, Embothrium coccineum and Lomatia hirsuta, have scaly buds in which green leaf primordia are covered by leaves devoid of lamina and with a broad base (cataphylls). For both species shoot growth included neoformation, and the juvenile ontogenetic stage was the most vigorous one in terms of shoot growth. The other two species, Lomatia ferruginea and Gevuina avellana, had naked buds and entirely preformed shoots along their whole ontogenetic gradient; in these two species shoot vigor was relatively constant throughout ontogeny. Both species with naked buds are present exclusively in the phytogeographical Valdivian district, while both species with scaly buds are distributed throughout the gradient of the Andean-Patagonian forests. A detailed description of bud structure, preformation and neoformation through ontogeny may contribute in our understanding of the growth, functioning and distribution of Protaceae species.