Pulverização foliar de boro e silício é viável agronomicamente para planta de couve-flor
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Data
2020-07-27
Autores
Silva, José Lucas Farias da
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Universidade Estadual Paulista (Unesp)
Resumo
A aplicação via foliar de boro (B) tem sido amplamente utilizada no cultivo de brássicas, mas falta pesquisa sobre sua relação com Si. Objetivou-se verificar se os efeitos da aplicação via foliar de B, na nutrição e no crescimento da couve-flor, podem ser potencializados com a adição de silício (Si) na calda de aplicação. O experimento foi realizado em casa de vegetação, sendo os tratamentos constituídos em esquema fatorial 4 x 2, sendo quatro concentrações de B via foliar (0,0; 0,11; 0,25 e 0,42 g L-1), na ausência e presença (12 mmol L-1) de Si, dispostos em blocos casualizados, com quatro repetições. Foi utilizado o ácido bórico como fonte de B e o silicato de potássio como fonte de Si, sendo as concentrações de potássio equilibradas nos tratamentos sem Si. As plantas foram cultivadas em vasos preenchidos com areia lavada, que receberam a solução nutritiva com baixa concentração de B, e os tratamentos via foliar, que foram cultivadas por cento e cinquenta dias, totalizando nove aplicações. A aplicação via foliar de B com adição de Si na calda, em relação a sua ausência, aumenta a absorção de B. Além disso, o Si aliviou o estresse oxidativo ao diminuir a produção de malondialdeído e de peróxido de hidrogênio por aumentar a produção de compostos fenólicos e de ácido ascórbico, refletindo na firmeza dos tecidos foliares, bem como incrementou a produção de pigmentos fotossintetizantes, a eficiência quântica do fotossistema II e as variáveis de crescimento das plantas de couve-flor. A adição de Si na calda, para aplicação via foliar de B em couve-flor, é viável agronomicamente.
The foliar application of boron (B) has been widely used in the cultivation of brassica, but research on its relationship with silicon (Si) is lacking. The objective was to verify if the effects of B foliar spray on cauliflower nutrition and growth can be enhanced with the addition of Si in the spraying liquid. The experiment was carried out in a greenhouse, with the treatments constituted of a 4 x 2 factorial scheme, with four concentrations of B via leaf (0.0; 0.11; 0.25 and 0.42 g L-1) in the absence and presence (12 mmol L-1) of Si, arranged in randomized blocks, with four replicates. Boric acid was used as a source of B and potassium silicate as a source of Si, with potassium concentrations balanced in treatments without Si. The plants were grown in pots filled with washed sand that received the nutrient solution with low concentration of B, and the treatments via leaf, that were grown for one hundred and fifty days, totaling nine applications. The foliar spraying of B with the addition of Si in the spraying liquid, in relation to its absence, increases the absorption of B. In addition, Si relieved oxidative stress by decreasing the production of malondialdehyde and hydrogen peroxide by increasing the production of phenolic compounds and ascorbic acid, reflecting on the firmness of the leaf tissues, as well as increasing the production of photosynthetic pigments, quantum efficiency of photosystem II, and the growth variables of cauliflower plants. The addition of Si in the spray solution for foliar spraying of B is agronomically viable for cauliflower plants.
The foliar application of boron (B) has been widely used in the cultivation of brassica, but research on its relationship with silicon (Si) is lacking. The objective was to verify if the effects of B foliar spray on cauliflower nutrition and growth can be enhanced with the addition of Si in the spraying liquid. The experiment was carried out in a greenhouse, with the treatments constituted of a 4 x 2 factorial scheme, with four concentrations of B via leaf (0.0; 0.11; 0.25 and 0.42 g L-1) in the absence and presence (12 mmol L-1) of Si, arranged in randomized blocks, with four replicates. Boric acid was used as a source of B and potassium silicate as a source of Si, with potassium concentrations balanced in treatments without Si. The plants were grown in pots filled with washed sand that received the nutrient solution with low concentration of B, and the treatments via leaf, that were grown for one hundred and fifty days, totaling nine applications. The foliar spraying of B with the addition of Si in the spraying liquid, in relation to its absence, increases the absorption of B. In addition, Si relieved oxidative stress by decreasing the production of malondialdehyde and hydrogen peroxide by increasing the production of phenolic compounds and ascorbic acid, reflecting on the firmness of the leaf tissues, as well as increasing the production of photosynthetic pigments, quantum efficiency of photosystem II, and the growth variables of cauliflower plants. The addition of Si in the spray solution for foliar spraying of B is agronomically viable for cauliflower plants.
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Elemento benéfico, Estresse nutricional, Micronutriente, Brassica oleracea var. botrytis