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| Author(s): |
Carlos Eduardo da Silva Oliveira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ilha Solteira. 2023-04-13. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Ilha Solteira |
| Defense date: | 2023-02-17 |
| Advisor: | Marcelo Carvalho Minhoto Teixeira Filho |
| Abstract | |
The use of plant growth-promoting bacteria has been increasing every day in search of sustainable agriculture. Inoculation with Azospirillum brasilense, Bacillus subtilis and Pseudomonas fluorescens has been promising to increase productivity, nutrient accumulation, root growth and the physiology of cultivated plants, but little is known about the effect of this microorganism in hydroponic cultivation. The objective of this study was to estimate the inoculant dose with the bacteria A. brasilense, B. subtilis and P. fluorescens, how to combine the indicated doses to increase productivity, productive components, gas exchange, plant nutrition and economic analysis, as well as the reduction of foliar nitrate in hydroponic lettuce. There was less accumulation of NO3- and an increase in the activity of the enzyme nitrate reductase in lettuce leaves with increasing doses of A. brasilense. The dose of 44 mL 100 L-1 of the inoculant of A. brasilense provided greater yield of fresh iceberg lettuce leaves (cultivar Angelina), being the indicated dose to achieve greater productive efficiency. Inoculation with doses between 34 and 39 mL 100 L-1 increased photosynthetic efficiency, CO2 assimilation and water use efficiency by lettuce plants. Inoculation of B. subtilis at a dose of 33 mL 100 L-1 via nutrient solution in hydroponic lettuce cultivation provided greater photosynthetic efficiency, N accumulation and plant leaf yield, as well as reduced NO3- accumulation and increased activity of the enzyme nitrate reductase in the shoot of plants. Inoculation of P. fluorescens at a dose of 29 mL 100 L-1 via nutrient solution in hydroponic lettuce cultivation provided greater photosynthetic efficiency, N accumulation and plant leaf yield, in addition to reducing NO3- accumulation and increasing activity of the enzyme nitrate reductase in the aerial part of lettuce plants. There was a reduction in leaf NO3- accumulation in lettuce by 69, 83, 82 and 75% under inoculations with A. brasilense, B. subtilis, A. brasilense + B. subtilis and A. brasilense + B. subtilis + P. fluorescens, respectively. Isolated inoculation of P. fluorescens and co-inoculation of B. subtilis + P. fluorescens are the most suitable for hydroponic lettuce cultivation, as they provide greater yield, profitability and accumulation of N, K, Ca, Mg, Cu and Mn. (AU) | |
| FAPESP's process: | 20/11621-0 - Inoculation of rizobacteria in a hydroponic system in nutrition, production and quality of American lettuce |
| Grantee: | Carlos Eduardo da Silva Oliveira |
| Support Opportunities: | Scholarships in Brazil - Doctorate |