Efeito alelopático de nanoemulsões produzidas com óleo essencial de alecrim e óleo-resina de copaíba

• Autor(a) principal: Chamoun, Luciana Barbosa Soares
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/11202
• topic: Oxidative stress; Enzymes; Rosmarinus officinalis; Copaifera spp; Agronomia; Stress oxidativo; Enzimas; Alecrim; Copaíba; Alelopatia; 57

Allelopathy is defined as the ability of plants to produce chemical compounds that, when released into the environment, can influence, positively or negatively, other plants. Essential oils are secondary metabolites obtained from different parts of the plant, containing volatile compounds that may be associated with biological effects. The objective of this study was to evaluate the allelopathic potential of the essential oil of Rosmarinus officinalis L. (Rosemary) and oil-resin of Copaifera spp. (Copaiba), in the form of nanoemulsions, since the efficiency of the compounds can be improved. The nanoemulsions were produced with a concentration of 5% of the oils of Rosemary and Copaíba and, later, diluted with distilled water to 5, 7 and 10 mg / mL. Germination, initial growth, and enzymatic activity of the seeds of the species Lactuca sativa (Lettuce) were evaluated. The experimental design was completely randomized and for each treatment, 5 replications were made. The germination and growth data were compared by analysis of variance (ANOVA), followed by the Tukey test at 5% probability. The results showed that the rosemary essential oil nanoemulsions had a negative allelopathic influence on the germination percentage (% G), germination speed index (GSI), mean germination time (MGT), leaf length, root length and decrease in the activity of the enzyme peroxidase. The increase in concentration led to more pronounced results in the analyzed variables. Such effects are due to the specific action of their main chemical constituents or, possibly, by the interaction between them. The monoterpene 1,8-cineole is reported as a potent inhibitor and appears as the major constituent of the rosemary essential oil. The nanoemulsions of Copaiba oil-resin showed a positive influence on some evaluated attributes. There was no influence on %G, shoot length and enzyme activity. The lowest concentrations of the copaiba oil nanoemulsions used in this study (5 and 7 mg / mL) showed stimulatory allelopathic effect on root growth. The non-allelopathic influence on the %G can be attributed to the chemical structure of the sesquiterpene caryophyllene, a compound found in greater quantity in the copaiba oil. These results indicate that the allelopathic influence is related to the constitution and structure of the chemical components, as well as their concentration