Abstract— In the preset investigation, the effect of presence of phorate in the growth medium on the chemical composition of root exudates of Pisum sativum collected by two different methods was studied. Results indicated significant increase in the total protein, free thiol gruops, riboflavin, ascorbic acid, total glutathione content in the root exudates the plants exposed to phorate. Among some antioxidative and hydrolytic enzyme activities estimated, significant increase was observed in acid phosphatase, phosphodiestearse, glutathione S transferase and catalase activities in plants grown in presence of phorate with respect to controls. On the contrary, no significant changes were observed in the total carbohydrate content, organophosphate hydrolase, ascorbate peroxidase; amino acids, sugars, and phenolic acid composition. hence, results of the present investigation provide some limited by preliminary evidence on the fact that the exudation behavior of roots is altered on sensing the presence of contaminants (phorate) in the rhizosphere, which can be one of the reasons for the rhizosphere effect i.e enhance degradation of toxic pollutants in the rhizosphere. Keywords— Root exudates; Pisum sativum; Phorate; Contaminants; Rhizodegradation I. INTRODUCTION ITTLE attention has been given to the study of exudation behaviour of plant roots in stress conditions like the presence of toxic pollutants in the soil. Root exudates are responsible for a wide array of interactions going in the rhizosphere like plant-microbe and plant-plant. Response of plants with respect to exudation on the presence of contaminants is not yet studied. Therefore, in this study an initial attempt has been made to investigate the effect of presence of phorate, on organophosphate insecticide on the composition of root exudates of B. juncea. Pesticides are widely used in agriculture and insect vector control programs, as around 4 million tons of pesticides are applied to crops annually round the world (Miller, 2004). Organophosphorus compounds account for around 38% of total pesticides used globally (Post, 1998) and phorate {O, O-diethyl S-[(ethylthio) 1 Department of Biotechnology, Motilal Nehru National Institute of Technology (MNNIT), Teliyarganj, Allahabad 211004, India E-mail: radharani@mnnit.ac.in; raadharaani1982@gmail.com 2 Ecorestoration Division, National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440020, India * corresponding author methyl] phosphorodithioate} is one of the high toxicity organophosphate compound extensively used to control insects (Gallo and Lawryk, 1991) on various field crops. document is a template for Word (doc) versions. If you are reading a paper version of this document, so you can use it to prepare your manuscript. II. MATERIALS AND METHODS A. Collection of root exudates Technical grade phorate, purity >95% was provided by Meerut agrochemicals limited, India. All other chemicals were of analytical reagent grade or of a higher purity (Merck, India). Root exudates from Pisum sativum (L) (Sweet Pea) were collected by sand culture method (method 1) according to Gaidamak, (1971) and by extracting roots in calcium chloride (method 2) according to Steingrobe et al. (2002). Root exudates were concentrated 100 folds by lyophilization, purified by dialysis and stored at -4 ºC until further analysis (Dundek et al., 2011). B. Analysis of the root exudates Root exudates were analyzed for total carbohydrate content using Anthrone’s method, proteins by Bradford’s test, and total free thiol groups by Ellman’s test (Kuwata et al., 1982). Free amino acids, sugars and organic acids were determined by thin layer chromatography (TLC) using silica gel plates. Butanol: glacial acetic acid: water (4:1:1) was the mobile phase for amino acids and 2% ninhydrin in acetone was used as developer. For sugars, chloroform: methanol: 0.25% potassium chloride (KCl) (5: 4: 1) was the solvent and orcinol (1%) in 5% H2SO4 was the indicator solution used. Analytical grade rhamnose, xylose, maltose, sucrose, raffinose, glucose, mannose, fructose, ribose, lactose, galactose were used as standards. Organic acids were detected on silica gel 60-F245 (Merck) plates using analytical grade acetic acid, butyric acid, salicyclic acid, dihydroxy benzoic acid, lactic acid, 2- ketoglutaric acid, malonic acid, oxalic acid, tartaric acid, citric acid, sulphanic acid, maleic acid as standards. The solvent system used as mobile phase for monocarboxylic acid was composed of propanol: ammonium hydroxide (7: 3) and that for dicarboxylic acids was propanol: ammonium hydroxide: Radha Rani* 1 , Asha Juwarkar 2 Effect of Presence of Pesticides in Growth Medium on the Exudation Behaviour of Plants: A Study with Phorate (An Organophosphate Insecticide) and Pisum Sativum (L.) L International Conference on Biological, Environment and Food Engineering (BEFE-2015) May 15-16, 2015 Singapore http://dx.doi.org/10.15242/IICBE.C0515009 38