Acta Botanica Brasilica
Print version ISSN 0102-3306
CARMO, Flávia Maria da Silva; BORGES, Eduardo Euclydes de Lima e and TAKAKI, Massanori. Allelopathy of Brazilian sassafras (Ocotea odorifera (Vell.) Rohwer) aqueous extracts. Acta Bot. Bras. [online]. 2007, vol.21, n.3, pp. 697-705. ISSN 0102-3306. http://dx.doi.org/10.1590/S0102-33062007000300016.
Allelopathic studies investigate the positive and negative effects of secondary metabolites of plants, microorganisms and fungi on the development of neighboring individuals. In this work, the allelopathic effects of aqueous extracts of leaves, bark and root bark of Brazilian sassafras (Ocotea odorifera (Vell.) Rowher) on seed germination, root and shoot growth, chlorophyll content and respiratory activity of the root cells of sorghum seedlings (Sorghum bicolor (L) Moench cv. Embrapa BR 303) were analyzed. The extracts were prepared by adding dried, powdered plant material to distilled non-ionized water at 1:10 (w/v). After continuous agitation for 24 h, these solutions were decanted and vacuum-filtered through filter paper, thus constituting the tested extracts. Bark and root bark aqueous extracts caused root growth inhibition in sorghum seedlings while shoot growth was stimulated by the root bark extract. Leaf and bark extracts induced an increase in wet root biomass and a decrease in chlorophyll content. All extracts caused negative effects on sorghum seedling root cell respiration. We concluded that secondary metabolites from Brazilian sassafras caused metabolic and morphological alterations in the sorghum seedlings and the presence of these plants in the environment can cause similar effects on other neighboring plant species.
Keywords : chlorophyll; phenolic compounds; Lauraceae; root cell respiration; terpenoids.