Resumo

TEJEDA-SARTORIUS, Olga et al. Inhibidores de la germinación en el residuo seco del tallo del amaranto (Amaranthus hypochondriacus). Rev. Soc. Quím. Méx [online]. 2004, vol.48, n.2, pp.118-123. ISSN 0583-7693.

We evaluated the effect of the aqueous extract of amaranth (Amaranthus hypochondriacus L. var. Azteca) stem dry residue on germination and radicle and shoot length of Amaranthus hybridus L., at different concentrations. The aqueous extract at concentrations of 108 and 54 ppm inhibited the germination of this species (100% and 68.42%, respectively) and also significantly decreased radicle and shoot length, when the inhibition was not total. Ferulic (FEA) and p-coumaric (PCA) acids were identified as the main phenolic acids in amaranth dry stems. The present study represents the first report on the presence of both phenolic acids in this plant material. The isolation, separation and identification of these compounds were performed by alkaline hydrolysis, thin layer chromatography, high performance liquid chromatography and hydrogen nuclear magnetic resonance. The toxicity of aqueous extract was compared with standards of AFE and APC. Combination of both acids at 10^-3 M caused more delay in the germination of A. hybridus compared with the individual acids. Concentration of 10^-3 M of individual and combined acids significantly decreased seedlings growth.

Palavras-chave : Amaranthus hypochondriacus; A. hybridus; allelopathy; ferulic acid; p-coumaric acid; weed.

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