Characterization and inhibitory activity of chitosan on hyphae growth and morphology of Botrytis cinerea plant pathogen

Summary. Low and high molecular weight chitosan were tested in different concentrations and growth times with the aim to evaluate the inhibitory activity against Botrytis cinerea, a very important plant pathogen. Tested chitosans were characterized by vibratory spectroscopy and elementary analyzes to determine the deacetylation degree. In addiction molar mass was estimated by viscosity measuring. Scanning electron microscopy was utilized for antimicrobial activity observation. Results showed that both chitosans markedly inhibited fungal growth, which was effected by incubation time and chitosan concentration. Scanning electron microscopy observations revealed that chitosan induced changes in surface morphology. The present study show that chitosan is capable of inhibit the growth and cause serious damage to the cell structure of the B. cinerea, as well as have the ability to form an impervious layer around the cell. Therefore, chitosan could be considered as a potential alternative for synthetic fungicides. Industrial relevance. Ultrastructural analysis showed that chitosan is capable of causing serious damage to the cell structure of the B. cinerea, as well as have the ability to form an impervious layer around the cell. Chitosan could inhibit the growth of B. cinerea in vitro and consequently may be considered as a potential alternative in replacement of synthetic fungicides.info:eu-repo/semantics/publishedVersio

Laser-induced fluorescence spectrum of 3-vinyl-1H-indene.

The laser-induced fluorescence spectrum of 3-vinyl-1H-indene was recorded between 33,000 and 33,800 cm(-1). An origin band was observed at 33,455 cm(-1) along with several low-frequency modes. With the aid of density functional theory and configuration interaction calculations, the electronic transition was assigned as S1 <-- S0 and the short progression in an 80 cm(-1) mode was identified as a vinyl group torsion. Theoretical, spectroscopic, and thermochemical considerations suggest that the 3-vinyl-1H-indene spectrum results from excitation from both conformational isomers with the vinyl and indene double bonds in trans and cis arrangements. The results are discussed in the context of the identification of species arising from the discharge of benzene in argon

Eficiência de adubos fosfatados associados ao enxofre elementar na cultura do milho

A eficiência agronômica dos adubos fosfatados pode ser afetada pelas fontes de fósforo, propriedades do solo, modo de aplicação e espécie vegetal. Com o objetivo de comparar a eficiência do fosfato natural reativo (FNR) e do superfosfato triplo (SFT) associado ao enxofre elementar, aplicados no sulco de plantio na cultura do milho, instalouse um experimento em condições de campo no município de Toledo, Paraná, em um Latossolo Vermelho eutroférrico. O delineamento experimental consistiu de blocos inteiramente casualizados, em esquema fatorial 2x4x2, sendo duas fontes de fósforo (FNR e SFT), três doses de adubação (100, 200 e 300 kg ha-1 de P2O5) mais uma testemunha para cada fonte, e adição ou não de enxofre elementar (0 e 30 kg ha-1de S°), aplicados no sulco de plantio em quatro repetições. As parcelas foram constituídas por quatro linhas com 6 m de comprimento espaçadas 0,9 m, utilizando-se como área útil as duas linhas centrais desprezando-se 0,5 m das extremidades. A adubação com N e K e os tratamentos com P e S° foram realizados manualmente no sulco de plantio, sendo posteriormente semeadas com o híbrido Agroceres 8021. O SFT proporcionou maior rendimento de grãos, em comparação com o FNR, no primeiro ano de cultivo. A eficiência agronômica do FNR foi de 43% e 33% na presença e ausência de S, respectivamente. O teor de fósforo no tecido foliar foi inferior com o uso do FNR. A dose de 30 kg ha-1 de S elementar não interferiu no pH do solo, mas aumentou a eficiência da adubação fosfatada