| Congresso Brasileiro de Microbiologia 2023 | Resumo: 8-1 | ||||
Resumo:Plant growth-promoting bacteria (PGPB) are capable of establishing symbiotic interactions of various levels with plant species and performing mechanisms that promote growth through the provision of nutrients, synthesis of phytohormones, and defenses against pathogens. In this context, the application of PGPB stands out as one of the most promising methods for eco-friendly crop-management. Besides their use in agroecosystems, inoculation of PGPB can also be an efficient strategy for ecological restoration, in combination with species as Mimosa flocculosa Burkart, a pioneer leguminous that has the potential for the recovery of degraded areas, eroded and shallow soils. The objective of the present study was to evaluate the efficiency of PGPB in the production of M. flocculosa seedlings under different doses of controlled-release fertilizer (CRF). M. flocculosa seeds were sown under conditions of 0, 1, and 2 kg m-3 of CRF Osmocote® (NPK 18-05-09 with five months of release) in commercial substrate based on composted pine bark and vermiculite. At 45 days after sowing, the seedlings were inoculated with Paraburkholderia sp. CNPSo 3281 and CNPSo 3076 strains, standardized at a concentration of 109 CFU mL-1 and commercial inoculant composed of Azospirillumm brasilense Abv-5 and Abv-6 strains at a concentration of 2 x 108 CFU mL-1. The seedlings were evaluated for stem height at 60, 90, 120, and 150 days, and also, at the end of the experiments, stem diameter, dry mass of the root and stem system, coefficient of robustness (H/DC), Dickson Quality Index (DQI) and total chlorophyll content. The results indicate a significant response to the sources of variations related to the experimental period, fertilization, and PGPB inoculation in promoting shoot growth in height (cm) of M. flocculosa seedlings. There was growth promotion in stem height in seedlings inoculated with Paraburkholderia sp. and A. brasilense compared to the control. In absence of fertilization, Paraburkholderia sp. CNPSo 3076 presented the best height increment results. The non-inoculated seedlings that received 1 kg m-3 resulted in the lowest stem growth responses in relation to the plants inoculated in these conditions. When the seedlings were cultivated with 2 kg m-3 of CRF, no difference was observed between control and inoculated plants, showing the influence of the use of chemical fertilization on the plant-growth promotion mechanisms. The use of CRF provided significant effects on the stem height, stem diameter, dry biomass, DQI, H/DC, and chlorophyll b, but no significance was attributed to these variables regarding seedling inoculation by different bacterial treatments. Palavras-chave: Nature based solutions, Paraburkholderia, Azospirillum, quality of forest seedlings, rhizobacteria Agência de fomento:CNPQ; FUNDAÇÃO ARAUCÁRIA | |||||