Inoculação de rizobactérias em sistema hidropônico na nutrição, produção e qualidade da alface americana
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Data
2023-02-17
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Universidade Estadual Paulista (Unesp)
Resumo
O uso de bactérias promotoras de crescimento de plantas tem aumentado a cada dia em busca de uma agricultura sustentável. A inoculação com Azospirillum brasilense, Bacillus subtilis e Pseudomonas fluorescens tem sido promissora para aumentar a produtividade, acúmulo de nutrientes, crescimento de raízes e na fisiologia das plantas cultivadas, porém pouco se sabe do efeito deste microrganismo em cultivo hidropônico. O objetivo deste estudo foi estimar a dose de inoculante com a bactéria A. brasilense, B. subtilis e P. fluorescens como combinar as doses indicadas para aumenta a produtividade, os componentes produtivos, as trocas gasosas, nutrição de plantas e a análise econômica, assim como a redução do nitrato foliar de alface hidropônica. Houve menor acúmulo de NO3- e aumento da atividade da enzima nitrato redutase nas folhas de alface com o aumento das doses de A. brasilense. A dose de 44 mL 100 L-1 do inoculante de A. brasilense proporcionou maior produtividade de folhas frescas de alface americana (cultivar Angelina), sendo a dose indicada para conseguir proporcionar a maior eficiência produtiva. A inoculação com doses entre 34 e 39 mL 100 L-1 aumentou a eficiência fotossintética, a assimilação de CO2 e a eficiência do uso da água pelas plantas de alface. A inoculação de B. subtilis na dose de 33 mL 100 L-1 via solução nutritiva no cultivo hidropônico de alface proporcionou maior eficiência fotossintética, acúmulo de N e produtividade de folhas das plantas, além de a redução do acúmulo de NO3- e aumento da atividade da enzima nitrato redutase na parte aérea das plantas. A inoculação de P. fluorescens na dose de 29 mL 100 L-1 via solução nutritiva no cultivo hidropônico de alface proporcionou maior eficiência fotossintética, acúmulo de N e produtividade de folhas das plantas, além de a redução do acúmulo de NO3- e aumento da atividade da enzima nitrato redutase na parte aérea das plantas de alface. Houve redução do acúmulo de NO3- foliar na alface em 69, 83, 82 e 75% sob as inoculações com A. brasilense, B. subtilis, A. brasilense + B. subtilis e A. brasilense + B. subtilis + P. fluorescens, respectivamente. A inoculação isolada de P. fluorescens e a coinoculação de B. subtilis + P. fluorescens são as mais indicadas para cultivo de alface hidropônico, por proporcionar a maior produtividade, lucratividade e acúmulos de N, K, Ca, Mg, Cu e Mn.
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.
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.
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Lactuca sativa, Assimilação de carbono, Absorção de nutrientes, Bactérias promotoras do crescimento de plantas, Nitrato redutase, Hidroponia, Carbon assimilation, Nutrient uptake, Plant growth-promoting bacteria, Nitrate reductase, Hydroponics