Microrganismos como potenciais agentes promotores do crescimento em plantas de jambu (Acmella Oleracea (L.) R. K. Jansen).

Abstract

Jambu, Acmella oleracea (L.) R.K. Jansen is a vegetable of great economic importance in the northern region of Brazil. However, for its growth and productivity, various chemical applications are used, such as fertilizers, and insecticides, among others, which can currently be replaced by various biologically-based products, such as microorganisms that stimulate plant production. The aim was to evaluate entomopathogenic fungi and plant disease biocontrol agents in promoting the growth of jambu plants, using biometric, physiological, and biochemical parameters. The bioassays were conducted in a commercial area of peri-urban agriculture, in protected and unprotected hanging beds, during the rainy and dry periods. Three biological inoculants were used: the fungi: Metarhizium anisopliae, Beauveria bassiana and the Trichoderma asperellum mix (Isolates UFRA T06, UFRA T09, UFRA T12, UFRA T52), and the control with the application of water only. The experimental design was randomized blocks, with xxx replications. Biomass, gas exchange, chlorophyll, carbohydrates, and characterization of the isolates in terms of phosphate solubilization and AIA production were assessed. In the rainy season, according to the interaction, the growth parameters were significant, with the protected system showing an increase in most of the variables evaluated compared to the unprotected system. The best results were shown by M. anisopliae and T. asperellum, compared to the control treatment. In the dry period, there was a significant difference for all the variables (p< 0.05). The fungal isolates were able to increase the levels of chlorophyll a and b, sucrose in the plants, solubilize phosphate and produce AIA. It can be concluded that, under the conditions evaluated, the best planting system for jambu is protected cultivation, both during the dry and rainy seasons. The fungi M. anisopliae and B. bassiana promote growth in jambu plants, through increases in biomass, gas exchange, chlorophyll a and b, and sucrose, especially in the rainy season. As for the characterization of the fungal isolates, they are phosphate solubilizers and AIA producers.