Revestimento ativo com incorporação de nanoemulsão de óleo essencial de tomilho com potencial aplicação em sementes de tomate
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Data
2020-02-14
Autores
Guedes, Natália Assis
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Universidade Federal do Espírito Santo
Resumo
Tomato has limited production due to the high susceptibility to attack by pests and diseases. Treatment of tomato seeds helps to minimize the incidence of Fusarium oxysporum f. sp. lycopersici (FOL), the causative agent of fusariosis. The treatment with essential oils (EO) and coatings based on biodegradable polymers has been studied to ensure the use of healthy and good quality seeds during storage and planting. The aim of this work was evaluate the antifungal activity on FOL and phytotoxicity of thyme EO nanoemulsion incorporated or not in coatings on tomato seeds. The major compounds of thyme EO were p-cymene (29.99%), thymol (18.17%) and carvacrol (21.18%). Thyme EO nanoemulsion kept an average droplet diameter of less than 216 nm for 23 days after its formulation. The nanoemulsion showed an IC50 of 108.43 ppm. Its effect incorporated or not in cassava starch coating was evaluated at 0; 2,500; 5,000; 7,500 and 10,000 ppm on germination, length of hypocotyl and primary root, fresh and dry mass of tomato seedlings. All parameters that were evaluated has showed the same results or greater than controls. These results demonstrated that thyme EO nanoemulsion incorporated or not in coatings at concentrations lower than 10,000 ppm do not cause damage to tomato seeds. The influence of cassava starch (0.5-5% (m m-1 )) and glycerol (5-50% (m m-1 in relation to the starch mass)) used in the coating formulation was evaluated according to some texture parameters: hardness, adhesiveness, fracture, cohesiveness, elasticity and gumminess. Formulations with 5% starch (m m-1 ) and 27.5% glycerol (m m-1 ) content has showed more adhesive coatings than the other ones. The number of coating layers on the seeds was also evaluated. Seeds covered with two applications of the coating showed germination, fresh and dry mass of seedlings and length of hypocotyl and primary root, greater than or equal to the controls. This research aims to contribute to the development of products for efficient seed coating and protect the health of the farmer and the environment
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Palavras-chave
Thymus vulgaris , Nanoemulsão , Fitotoxicidade , filme biodegradável , Nanoemulsion , Phytotoxicity , Edible film