TEORES DE FENÓLICOS EM RAIZ DE MILHO SOB TOXIDEZ DE ALUMÍNIO

Aluminum (Al) tolerance mechanisms proposed in the literature can be classified as exclusion and internal tolerance mechanisms. Exclusion mechanisms prevent the Al from crossing the plasma membrane and penetrating the simplast. Internal tolerance mechanisms immobilize, compartmentalize or detoxify Al that penetrates the simplast. It has been suggested that phenolic compounds act in both mechanisms, due to its capacity to chelate metals as Al and to act as a strong antioxidant in response to abiotic stresses. The objective of this work was to identify differences in the content of total soluble phenolics and phenolic acids (ferulic acid, 5-5'diferulic and para-cumaric), bounded to the cell wall of maize roots between inbred lines contrasting in their tolerance to Al, Cateto 237 (tolerant) and L53 (sensitive), when exposed to Al toxicity. Seedlings were