Anatomical studies of shoot bud-forming roots of Brazilian tree species

Abstract

The present study is the first confirmation of the presence of shoot sprouts on roots in tree species of the Brazilian tropical forest, as these underground systems are usually only analysed by external gross morphological observations. The shoot-bearing roots of seven species, collected in a forest block frequently affected by fire, were sectioned and analysed for the number of primary xylem ridges, stele type and reserve compounds. Starch was the predominant reserve compound and occurred in different quantities among the species. The epicormic shoot buds, which arise spontaneously on root cuttings or plants subjected to fire, were analysed in two of the studied species. These buds showed different sites of origin but were considered epicormic (reparative) since they did not carry bud traces along the secondary xylem during their early development. Shoot bud formation on root systems is generally associated with disturbed environments, and confirmation that sprouting from roots does occur may modify many aspects of our appreciation of the community dynamics of forest species and models that define how we manage and rehabilitate Brazilian forest fragments.