Potencial alelopático de extratos aquosos de Acacia mangium Willd na germinação de sementes de Peltophorum dubium (Sprengel) Taub

Abstract

In many countries, species of the genus Acacia, originating from Australia, are considered invasive of great allelopathic potential. The use of Acacia mangium species in experimental plantations in Brazil occurred in 1978, being recent use in commercial plantations. Many studies have confirmed the allelopathic effect of this species on the germination of other vegetables, and warn of the risk of biological invasion. The objective of this work was to evaluate the influence of Acacia mangium on the germination of a native species and its possible allelopathic effect. The species Peltophorum dubium, popularly known as Canafistula, was chosen for its occurrence in all regions of Brazil. The powder formed from the Acacia mangium bark, diluted in aqueous solution, was used to moisten Peltophorum dubium seeds. Five treatments and one control were installed, both containing 6 repetitions, each repetition formed by 25 seeds. In each treatment a solution with different concentration of Acacia mangium powder was added, in this order: 0%; 0.05%; 0.10%; 0.15%; 0.20% and 0.25% (w / v). The seeds were sown on germitest paper in a germinating chamber, with constant temperature of 25ºC and photoperiod of 24 hours. Evaluations were performed at 8, 15 and 20 days after sowing. After 20 days of sowing, all treatments presented average germination above 50%. The variables analyzed to detect if there was an allelopathic effect on seed germination were: Germination Percentage, Germination Speed Index, Average Germination Time. Through the analysis of variance it was found that there was no evidence of difference between the means of the variables, therefore, no significant allelopathic effects were obtained.