A proposta do presente trabalho foi investigar como os ácidos p-cumárico (p-CA) e p-hidroxibenzóico (p-HD) afetam a atividade da peroxidase (POD, EC 1.11.1.7), a peroxidação lipídica (LP) e o crescimento de raízes de soja (Glycine max (L.) Merr.). Plântulas de três dias foram cultivadas em solução nutritiva com p-CA ou p-HD (0,1 a 1 mM) por 48 horas. Após absorção, ambos os compostos (a 0,5 e 1 mM) reduziram o comprimento das raízes (RL), a biomassa fresca (FW) e a biomassa seca (DW) enquanto aumentaram a atividade da POD solúvel, a atividade da POD ligada à parede celular (com p-CA 1 mM e p-HD 0,5 mM), e a LP.

The scope of the present study was to investigate how the p-coumaric (p-CA) and p-hydroxybenzoic (p-HD) acids affect the peroxidase (POD, EC 1.11.1.7) activity, the lipid peroxidation (LP) and the root growth of soybean (Glycine max (L.) Merr.). Three-day-old seedlings were cultivated in nutrient solution containing p-CA or p-HD (0.1 to 1 mM) for 48 h. After uptake, both compounds (at 0.5 and 1 mM) decreased root length (RL), fresh weight (FW) and dry weight (DW) while increased soluble POD activity, cell wall (CW)-bound POD activity (with 1 mM p-CA and 0.5 mM p-HD) and LP.

The influence of the allelochemicals ferulic (FA) and vanillic (VA) acids on peroxidase (POD, EC 1.11.1.7) and phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activities and their relationships with phenolic acid (PhAs) contents and root growth of soybean (Glycine max (L.) Merr.) were examined. Three-day-old seedlings were cultivated in nutrient solution containing FA or VA (0.1 to 1 mM) for 48 h. Both compounds (at 0.5 and 1 mM) decreased root length (RL), fresh weight (FW) and dry weight (DW) and increased PhAs contents. At 0.5 and 1 mM, FA increased soluble POD activity (18% and 47%, respectively) and cell wall (CW)-bound POD activity (61% and 34%), while VA increased soluble POD activity (33% and 17%) but did not affect CW-bound POD activity. At 1 mM, FA increased (82%) while VA reduced (32%) PAL activities. The results are discussed on the basis of the role of these compounds on phenylpropanoid metabolism and root growth and suggest that the effects caused on POD and PAL activities are some of the many mechanisms by which allelochemicals influence plant growth

A técnica de depleção foi usada para determinar como raízes de soja consomem os ácidos ferúlico e p-hidroxibenzóico em solução nutritiva. Os resultados mostraram que extremidades excisadas de raízes de soja consumiram rapidamente estes aleloquímicos. Entre concentrações de 0,1 e 1,0 mM, 50% ou mais de ácido ferúlico foi consumido após 6 h de depleção. Embora o consumo tenha iniciado somente após 3 h, comportamento idêntico foi encontrado com ácido p-hidroxibenzóico.

Depletion method was used to describe how soybean root consumed ferulic and p-hydroxybenzoic acids in nutrient culture. The results showed that excised cultured soybean roots consumed these allelochemicals very rapidly. At concentrations between 0.1 and 1.0 mM, roots consumed 50% or more of ferulic acid after 6-h depletion. Although consumption started only after 3 h, similar behavior was verified with p-hydroxybenzoic acid.