Potencial alelopático de folhas, caule e raiz de melia azedarach em espécies de ocorrência na caatinga

Abstract

The Caatinga is subject to several forms of environmental aggression of anthropic nature, such as the introduction of invasive exotic species, which may have allelopathic activity in the native species, interfering with the germination of the seeds and their initial development. The present work aimed to evaluate the allelopathic potential of the exotic species Melia azedarach Linnaeus on the target species of the Caatinga: Bauhinia cheilantha (Bong.) Steud., Mimosa tenuiflora (Willd.) Poir. and Piptadenia stipulacea (Benth.) Ducke, belonging to the Fabaceae family. The effects were evaluated by seed germination, germination velocity index and primary root size, bioassay results with aqueous solution, sandwich and plant-box methods. For each target species, root, stem and leaves M. azedarach were used, totaling nine bioassays. In the aqueous solution method, five treatments with four replicates were used; in the sandwich method four treatments and five replications were used and in the plant-box method there were 36 treatments with four replicates. The results were submitted to analysis of variance (Test F) and the means were compared by the Tukey test at 5% of probability. By the bioassay response with the three applied methods, it was verified that the increase in the concentration of the aqueous solutions and dry material of M. azedarach, caused inhibition in seed germination, decrease in IVG and root length of the target species, more pronounced by compounds of the donor root than by the stem and leaf compounds.