Desenvolvimento e efeito de emulsões contendo compostos bioativos sobre Fusarium oxysporum f. sp. lycopersici e qualidade fisiológica de sementes de tomate
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Data
2024-01-23
Autores
Peccini, Luan Rezende
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Universidade Federal do Espírito Santo
Resumo
Tomato is the solanaceous crop frequently affected by various pathogens, including the fungus Fusarium oxysporum f. sp. lycopersici (Fol), which causes Fusarium wilt and reduces productivity. In this study, different formulations containing thymol (Thy) or carvacrol (Car) were developed and their effects on Fol and the physiological quality of tomato seeds were evaluated. Thy emulsions (EsT) were developed considering surfactant concentration, vortex homogenization time (HVtx) and high-intensity ultrasound time (HHUs). EsT9%S1 emulsion, comprising 9.0% surfactant, 2.5 minutes of HVtx and 3.0 min of HHUs, kept kinetic stability over a 28 day storage period. EsT9%S1 showed antifungal activity against Fol at inhibitory concentrations of IC50 = 0.052 mg mL -1 and IC90 = 0.268 mg mL-1 . Seeds treated with EsT9%S1 maintained electrical conductivity (EC) and pH in the range of 240.9 to 597.7 μS cm-1 g -1 and 6.8 to 7.6, respectively over 24h. Additionally, no signs of phytotoxicity were observed in the tomato seeds. Coatings using cassava starch (CS) and glycerol (Glyc), incorporating different concentrations of carvacrol nanoemulsion (CNE) and/or red cabbage extract (RCE) were developed and characterized. Analysis of the FTIR and XRD spectra showed interactions among CS, Glyc, CNE, and/or RCE, indicated by shifts/emergence of new bands, and the appearance of amorphous peaks. The incorporation of CNE, and/or RCE made the film's surface more rough, increased thermal stability and EC, decreased pH, and modified solubility and swelling properties. Films with the addition of CNE and/or RCE exhibited antioxidant activity, an important property for protecting seeds against oxidative stress. Physiological analyses revealed the absence of phytotoxicity in the coatings applied to the tomato seeds. The results highlight the potential of EsT9%S1 and the films containing CS, Glyc, CNE, and/or RCE for evaluation as tomato seed coatings
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Tratamento de sementes , Produtos naturais , Controle alternativo , Murcha de fusário do tomateiro , Fungicidas biorracionais