Mecanismos bioquímicos e fisiológicos na cultura da mandioca (Manihot esculenta Crantz) submetida a diferentes indutores de resistência

Abstract

Cassava (Manihot esculenta Crantz) is a cultivated dicotyledonous plant with perennial growth and belongs to the family Euphorbiaceae. It has a characteristic of family consumption and its national production is concentrated around 37% in the Northeast, where it is focused on artisanal production of flour Among the main fungi causing deteriotation in cassava plants, stands out Scytalidium lignicola, which can be controlled by the induction of resistance by the use of biotic or abiotic products. The enzymes involved in plant defense mechanisms against phytopathogens involve metabolic alterations that are correlated with changes in their activities, such as in primary and secondary metabolisms. The objective of the present study was to evaluate the development of root rot of cassava caused by Scytalidium lignicola after the application of abiotic resistance inducers in plants, verifying the influence of enzymatic and physiological activities. The experiment was conducted in a greenhouse at the Federal Rural University of Pernambuco, Garanhuns Academic Unit. A completely randomized design (CRD) was used, distributed in a factorial scheme (5x4), with five treatments: Salicylic Acid; Chitosan; Amino butyric acid (BABA); Acibenzolar-S- methyl (Bion®) and distilled water as a control treatment, with four collection periods and three replicates. The severity of root rot of cassava in the aerial part and root was evaluated in a percentage scale of 0-100% of symptoms, as well as the biochemical parameters with the main catalase oxidative enzymes; polyphenoloxidase; peroxidase; β-1,3 glucanase; protease; phenylalanine ammonia lyase and total protein and the physiological parameters, such as: stomatal conductance; chlorophyll a, b and total; fresh mass of aerial parte; fresh root mass; dry mass of aerial parte; root dry mass; stem diameter; plant height; number of leaves per plant; leaf area; number of roots per plant and root length. The results were submitted to analysis of variance (ANOVA) compared to the Tukey test at the 5% probability level (p <0.05), using statistical software Sisvar. The results were submitted to analysis of variance (ANOVA) compared to the Tukey test at the 5% probability level (p<0.05), using statistical software Sisvar. The pathogenic stress time influenced the biochemical and physiological mechanisms for plants at ninety days affected by the severity of root rot through the pathogenic fungus Scytalidium lignicola. A reduction in the severity of root rot symptoms of cassava evaluated in root and aerial parts of plants when treated with acibenzolar-S-methyl (BION) abiotic resistance inducers was observed.