Silício via fertirrigação mitiga os efeitos da toxicidade de cobre aplicado via semente em plantas de soja
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Data
2022-07-27
Autores
Ferreira, Patrícia Messias
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Universidade Estadual Paulista (Unesp)
Resumo
A aplicação de doses inadequadas de cobre (Cu) na forma de óxido cúprico (CuO) pode diminuir o crescimento vegetal, isso porque os limites entre a deficiência e a toxicidade são muito próximos. Em plantas de soja, os micronutrientes podem ser fornecidos via tratamento de sementes, sendo um método muito vantajoso para atenuar deficiências na fase inicial de crescimento, mas pode ser tóxico se altas doses de fertilizantes forem aplicadas. O silício (Si) pode atenuar os danos causados pela toxicidade de Cu aplicado no tratamento de sementes de soja, mas não existem relatos. Objetivou-se avaliar os efeitos do Cu na forma de óxido na toxicidade do metal em plantas de soja que recebeu o Cu via tratamento de sementes e se a posterior aplicação de Si via fertirrigação na cultura pode mitigar esse estresse e os mecanismos envolvidos. Foram realizados dois experimentos sob condição controlada, sendo utilizado o delineamento de blocos casualizados em ambos. No primeiro experimento, os tratamentos consistiram em esquema fatorial de 6 x 2, sendo o primeiro fator constituído de doses de Cu: 0, 1, 4, 7, 15 e 29 g kg-1 de semente via tratamento de sementes combinadas com dois tempos de duração dos tratamentos: por 48 e 96 h, com 3 repetições. No segundo experimento, os tratamentos também consistiram em esquema fatorial de 6 x 2, sendo o primeiro fator constituído das mesmas doses utilizadas para o primeiro experimento, combinadas com a ausência e presença (2 mmol L-1) de aplicação de Si via fertirrigação, com 5 repetições. As análises foram realizadas 10 e 38 dias após a emergência, no primeiro e segundo experimento, respectivamente. A aplicação de Si proporcionou aumento do acúmulo de N, da eficiência de utilização de Cu, do número de nódulos, do teor de proteína, diminuiu o índice de extravasamento de eletrólitos, incrementando o acúmulo de massa seca. Altas doses de CuO fornecidos via tratamento de sementes induz toxicidade a partir de 1 g kg-1 de semente em plantas jovens de soja, observados pela diminuição da massa seca das plantas conforme aumento das doses. O fornecimento de Si via fertirrigação no solo foi favorável para o tratamento de sementes com Cu usando óxidos ao modular a eficiência de uso do cobre favorecendo o acúmulo de N e consequentemente a produção de massa seca.
The application of inadequate doses of copper (Cu) in the form of cupric oxide (CuO) can reduce plant growth, because the limits between deficiency and toxicity are very close. In soybean plants, micronutrients can be supplied via seed treatment, being a very advantageous method to alleviate deficiencies in the initial phase of growth, but it can be toxic if high doses of fertilizer are applied. Silicon (Si) can attenuate the damage caused by the toxicity of Cu applied in the treatment of soybean seeds, but there are no reports. The objective was to evaluate the effects of Cu in the oxide form on the metal toxicity in soybean plants that received Cu via seed treatment and whether the subsequent application of Si via fertigation in the crop can mitigate this stress and the mechanisms involved. Two experiments were carried out under controlled conditions, using a randomized block design in both. In the first experiment, the treatments consisted of a 6 x 2 factorial scheme, with the first factor consisting of Cu doses: 0, 1, 4, 7, 15 and 29 g kg-1 of seed via seed treatment combined with two times. duration of treatments: for 48 and 96 h, with 3 repetitions. In the second experiment, the treatments also consisted of a 6 x 2 factorial scheme, with the first factor consisting of the same doses used for the first experiment, combined with the absence and presence (2 mmol L-1) of Si application via fertigation, with 5 repetitions. Analyzes were performed 10 and 38 days after emergence, in the first and second experiments, respectively. The application of Si provided an increase in the accumulation of N, in the efficiency of use of Cu, in the number of nodules, in the protein content, decreased the rate of electrolyte leakage, increasing the accumulation of dry mass. High doses of CuO supplied via seed treatment induce toxicity from 1 g kg-1 of seed in young soybean plants, observed by the decrease in the dry mass of the plants as the doses increase. The supply of Si via soil fertigation was favorable for the treatment of seeds with Cu using oxides by modulating the efficiency of copper use, favoring the accumulation of N and consequently the production of dry mass.
The application of inadequate doses of copper (Cu) in the form of cupric oxide (CuO) can reduce plant growth, because the limits between deficiency and toxicity are very close. In soybean plants, micronutrients can be supplied via seed treatment, being a very advantageous method to alleviate deficiencies in the initial phase of growth, but it can be toxic if high doses of fertilizer are applied. Silicon (Si) can attenuate the damage caused by the toxicity of Cu applied in the treatment of soybean seeds, but there are no reports. The objective was to evaluate the effects of Cu in the oxide form on the metal toxicity in soybean plants that received Cu via seed treatment and whether the subsequent application of Si via fertigation in the crop can mitigate this stress and the mechanisms involved. Two experiments were carried out under controlled conditions, using a randomized block design in both. In the first experiment, the treatments consisted of a 6 x 2 factorial scheme, with the first factor consisting of Cu doses: 0, 1, 4, 7, 15 and 29 g kg-1 of seed via seed treatment combined with two times. duration of treatments: for 48 and 96 h, with 3 repetitions. In the second experiment, the treatments also consisted of a 6 x 2 factorial scheme, with the first factor consisting of the same doses used for the first experiment, combined with the absence and presence (2 mmol L-1) of Si application via fertigation, with 5 repetitions. Analyzes were performed 10 and 38 days after emergence, in the first and second experiments, respectively. The application of Si provided an increase in the accumulation of N, in the efficiency of use of Cu, in the number of nodules, in the protein content, decreased the rate of electrolyte leakage, increasing the accumulation of dry mass. High doses of CuO supplied via seed treatment induce toxicity from 1 g kg-1 of seed in young soybean plants, observed by the decrease in the dry mass of the plants as the doses increase. The supply of Si via soil fertigation was favorable for the treatment of seeds with Cu using oxides by modulating the efficiency of copper use, favoring the accumulation of N and consequently the production of dry mass.
Descrição
Palavras-chave
Estresse abiótico, Estresse oxidativo, Micronutriente, Metal pesado, Soja