Abstract:Phenolic compounds are toxic allelochemicals widely distributed in agriculture and natural ecosystems. They accumulate largely in plant soils, inhibit plant growth and pollute environments. Oxidative degradation of phenolic allelochemicals by Fenton’s reagent was studied under natural conditions. In a 1.0 ml reaction solution containing 8×10-3 mol/L (0.028%) of hydrogen peroxide (H2O2), 5.4×10-4 mol/L (0.075%) of FeSO4, and 10-3 mol/L of phenolics or 160 μg ml-1 of soil extracts, p-coumaric acid was oxidized by 55% and 74% in 10 and 30 minutes, respectively; p-hydroxybenzoic acid was oxidized by 90% within 10 minutes; juglone was completely oxidized within 10 minutes. p-Coumaric acid, the main allelochemical in extracts of soil beneath forest of bamboo (Bambusa chungii), was oxidized by 75% in 2 h. Direct application of 0.1% or 1% of H2O2 of Fenton’s reagent to the soil from bamboo forest resulted in a 32% or 37% degradation of p-coumaric acid in the soil. Activities of antioxidant enzymes of catalase and peroxidase, but no superoxide dismutase, were detected in the bamboo soil. These enzymes may decompose H2O2 employed to soil and reduced its function in soil. Meanwhile, they are responsible for decomposition of surplus H2O2 in the soil. Results indicated that Fenton’s reagent might be a potential reagent for degradation of toxic allelochemcials in plant soils and cultural solutions.
