Root-mediated allelopathic interference of bhringraj (Eclipta alba L.) Hassk. on peanut (Arachis hypogaea) and mung bean (Vigna radiata)

The root mediated allelopathic interference of Eclipta alba infested soil on growth, physiological parameters and antioxidant enzyme activity was conducted on Arachis hypogaea L. and vigna radiata L. It was found that rhizosphere soil significantly reduced the germination percentage, seedling growth and dry biomass depending upon the species sensitivity. The germination inhibition was correlated with membrane deterioration as proved by a strong electrolyte leakage, increase in malondialdehyde (MDA) and H2O2 content. The physiological parameters like chlorophyll content, photosynthetic rate (P-n), intercellular CO2 concentration (C-i), stomatal conductance (G(s)), and transpiration (E) also showed significant reduction in E. alba infested soil and non-significant increase in leaf temperature (L-t) of two test species. The test seedlings have circumvented the allelochemicals stress, by both significant decrease and non-significant increase in the antioxidant activities in E. alba infested soil in contrast to control soil. Rhizosphere soil contained significantly higher amount of water-soluble phenolics as the putative allelochemicals, which were vanillic acid, benzoic acid, ferulic acid, and p-coumaric acid. The study concluded that rhizosphere soil exerts an allelopathic influence on peanut and mung bean by releasing water soluble phenolic acids as putative allelochemicals in soil. (C) 2014 Elsevier B.V. All rights reserved.