THE ALLELOPATHIC EFFECT OF MAIZE AND SORGHUM ON SOME PHYSIOLOGICAL TERISTICS OF WHEAT AND BROAD BEAN USING HYDROPONICS

Abstract

Two experiments were conducted to test the allelopathic potential of aqueous extracts concentrations of maize (Zea mays L.) and sorghum (Sorghum bicolor L.) on some physiological characteristics of wheat (Triticum aestivum L.) and broad bean (Vicia faba L.) plants in two cultures. The effective allelochemicals available in extracts of maize and sorghum have been isolated and identified. The experiments included two factors, the Main plots were the growing culture (Sand culture and Soil culture) and the Sub-plots were five concentrations of (0,25,50,75 and 100%) the aqueous extracts of the whole plants (root and shoot for maize (in first experiment) and sorghum (in the second one), Results indicated that: Most of the studied characteristics in wheat and broad bean decreased in sand culture when treated with the aqueous extracts of maize and sorghum.Increasing the aqueous extracts of maize to 100% decreased the plant content of soluble carbohydrate, chlorophyll a, chlorophyll b, protein to 0.29 ,0.39, 0.39 and 0.28 % in wheat, and to 0.28 , 0.46 , 0.53 and 0.46 % in broad bean. While Increasing the aqueous extracts of sorghum to 100% decreased the plant content of soluble carbohydrate, chlorophyll a, chlorophyll b, protein to 0.34 and 0.56 and 0.64 and 0.39 % in wheat, and to 0.41 and 0.47 and 0.44 and 0.20 % in broad bean, respectively compared to control treatment (0%).Chromatographic analysis revealed the presence of 8 compounds in aqueous extracts of maize. The isolated compounds are phenolic in nature and known to have potential phytotoxicity as syringic, gallic, caffeic, vanillic, ferulic, coumaric, catechol and hydroxybenzoic. While Chromatographic analysis revealed the existence of 10 compounds in aqueous extracts of sorghum, 8 of them similar to what found in maize in addition to quinon, benzaquinon .