CAMBIOS MORFOLÓGICOS Y FISIOLÓGICOS INDUCIDOS EN Rhizopus stolonifer (Ehrenb.:Fr.) Vuill. POR EFECTO DEL QUITOSANO, OLIGOQUITOSANO Y ACEITES ESENCIALES

Abstract

The current agricultural demand efficient fungicides need to counter the post-harvest diseases without causing pollution problems affecting the environment and human health. Among some compounds compatible with the environment that have been studied include chitosan, oligochitosan and essential oils which are known to possess antifungal effect, however, there is little knowledge about the mode of action of these compounds in fungal cells Rhizopus stolonifer causal agent of soft rot in fruits and vegetables this paper therefore seeks to deepen involvement in how the morphology and physiology of this fungus. The aim of this study was to determine the cellular and physiological changes induced on R. stolonifer by chitosan, oligochitosan and essential oils of clove and cinnamon. R. stolonifer spores were inoculated in liquid medium MM containing chitosan, oligochitosan or essential oils of clove or cinnamon. The following determinations were evaluated: changes on cell morphology, variations on pH of the medium, release of cellular proteins, changes in membrane integrity, ultraestructural and effects on oxygen consumption. In general, the compounds tested caused growth inhibition and morphological changes on the hyphae of R. stolonifer. The presence of oligochitosan caused that R. stolonifer was unable to acidify the pH of the culture medium and chitosan even induced that the fungus increased the pH. Not demonstrated that the compounds tested induced liberation of cellular proteins or affecting the integrity of the plasma membrane. Chitosan, oligochitosan and essential oil of clove induced significant increases in cell wall thickness. The oligochitosan caused an increased vacuolation. Low and intermediate concentrations of oligochitosan, clove and cinnamon oils caused acceleration in respiration. Cinnamon essential oil caused a marked increase in oxygen consumption. Significant changes in cellular and physiology of R. stolonifer by the effect of chitosan, oligochitosan and essential oils of clove and cinnamon were demonstrated.