Aqueous extract of Crotalaria juncea on germination and initial growth of Ocimum basilicum

Abstract

This study aimed to evaluate the allelopatic potential of aqueous extracts of sunn hemp (Crotalaria juncea), prepared by infusion and maceration, under the germination and the initial growth of basil (Ocimum basilicum) plantlets, as well as identify and quantify the phenolic compounds. The concentrated aqueous express was prepared by infusion and maceration through the mixture of 100 g of dry and grinded plant material with 100 ml of distilled water, and from those the dilutions in distilled water were made, in the concentrations of 25, 50, 75 and 100% and a control. The treatments were arranged in a factorial scheme 2x5 (two preparation methods and five concentrations) with four repetitions. The tests were performed in the laboratory and green house. Were evaluated the pH, the osmotic potential, identified and quantified the phenolic compounds of the extracts. 50 seeds of basil were used for each repetition which were placed in plastic boxes with two paper leafs dampened with the concentrations of the extracts. The trial in the green house, 20 seeds of basil were seeded by each polyethylene box with the mixture of sand and soil (2:1 v/v) and dampened with the extracts with 200 ml per box. Were analyzed: percentage of germinated and emerged, germination and emergence velocity indexes, length of aerial part and root, total dry mass of plantlets. The data were submitted to an analysis of variance and the means compared by Tukey test (5%). The obtained results indicated that the sunn hemp aqueous extracts inhibited the germination and initial growth of basil in the 100 and 75% concentrations. Were identified and quantified the phenolic compounds: galic acid (20,63 µg/g), ferulic acid (10,74 µg/g) and cinnamic acid (1,36 µg/g).