Reciclagem de resíduo siderúrgico para a produção de mudas de Corymbia associada à bioestimulação com Bacillus sp. CCMD862.

Abstract

This thesis is the result of experimental research focusing on the recycling of electric arc furnace slag (EAE), a by-product of steel refining, combined with plant growth-promoting rhizobacteria (PGPR) for use as a bioimput in agriculture. In this study, I am working to understand the synergistic effects of this combination on the plant development of clones of Corymbia torelliana x Corymbia citriodora, a hybrid used to produce charcoal, among other things. In order to achieve this objective, structured stages were defined, which guided the obtaining of bacterial isolates with the capacity to promote plant growth and simultaneous tolerance to the steel by-product, as well as the investigation of the physiological, biochemical, morpho-anatomical, nutritional and growth responses presented by the selected plant species. The thesis is divided into four chapters. Chapter 1 provides background on the origin, characterization, management, challenges and potential for using EAE steel waste in agriculture, the potential of the plant-PGPR interaction, including examples of interaction with the Corymbia genus. Chapter 2 presents the prospecting of PGPR in a steel waste deposit area, the characterization of the Bacillus sp. CCMD862 isolate and the results of its inoculation on the growth of hybrid Corymbia clonal seedlings. Chapter 3 presents the effects of the combination of EAE and Bacillus sp. CCMD862 on the photosynthetic, biochemical, nutritional and growth parameters of Corymbia sp. Chapter 4 presents the morpho-anatomical changes in Corymbia sp. roots caused by the combination of the rhizobacterium Bacillus sp. CCMD862 with EAE, related to the plant's growth gains. The last section presents the main conclusions of this study and the implications for future research.