Avaliação do potencial alelopático dos caules e folhas de capim-gordura (Melinis minutiflora P. Beauv.,Poaceae) sobre a germinação de sementes de alface (Lactuva sativa L., Asteracaceae)

Abstract

Over time, the plants develop a chemical substancial synthesis as responses to suffered pressures in the nature. These chemical susbtantials are called secondary metabolites. The secondary metabolites exercises a series of functions in the plants organism, an example of it, is the allelopathy compounds production. The allelopathy is the result of this chemical products synthesis and as a result it can affect in a positive or negative germination and in the development of others organisms. The changes that occurred in the Cerrado in the last 30 years brought a series of consequences to original flora, the introduction of exotic species for fodder purposes has disposed several gramineous species through the direct competition. Despite the threat increasing to this area, there are a few studies that deal with the backlash allelopathy compounds through the exotic gramineous. This way, the purpose of this work was evaluate the allelopathy potencial from Melinis minutiflora steams and leaves about the germination of Lactuva Sativa seeds. Biossays germination were done with aqueous extracts concentration to 5%, 3%, 1% and still a treatment control. After ten germination days, the result points to a lack of intervention to the total number of germinated seeds, as well as to the average time of germination. There are no significant differences among the treatment done. However, the M. Minutilfora allelopathy potencial can be observed at the beginning of the plantules development, extracts with higher concentrations show reduction in the root size when compared to the control treatment. Besides, there is the appearance of necrotic roots.