Interação entre alumínio e manganês no crescimento e nutrição de mudas de cana-energia e cana-de-açúcar
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Data
2021-10-18
Autores
Sodré, Diego Correia
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Universidade Estadual Paulista (Unesp)
Resumo
A cana-de-açúcar é a principal matéria-prima utilizada para a produção de açúcar e etanol no Brasil, o maior produtor mundial desta cultura. As toxicidades por alumínio (Al3+) e manganês (Mn2+) são duas das principais restrições à produção de culturas em solos ácidos. Embora se conheça relativamente bem o efeito tóxico desses elementos isoladamente, pouco se sabe sobre o efeito interativo deles. Além disso, a maioria dos estudos de toxicidade de Al e Mn são realizados com genótipos de cana-de-açúcar tradicionais, sendo escassos estudos sobre toxicidade de Al e Mn em genótipos de cana-energia. Portanto, na presente tese foram desenvolvidos experimentos com mudas de cana-de-açúcar (IACSP95-5000) e cana-energia (Vertix 9 e Vertix 2), nas condições de hidroponia alternativa adaptado em casa de vegetação com o objetivo verificar se a toxicidade de Al e Mn agem de forma independente ou de forma interativa sobre aspectos da nutrição nitrogenada e sobre o crescimento das plantas. Para isso foram desenvolvidos dois experimentos. No primeiro avaliou-se a interação fitotóxica do Al3+ e Mn2+ em mudas de cana-de-açúcar (IACSP95-5000), e constou de um esquema fatorial 2x5, sendo 2 níveis de Al (presença e ausência), combinados com 5 níveis de Mn2+ (0, 200, 400, 600, 800 mg L-1). O segundo experimento constou de um esquema fatorial 3x2, no qual as mudas dos 3 genótipos (IACSP95-5000, Vertix 9 e Vertix 2) foram submetidas a 2 níveis de Al (ausência e presença de 60 mg L-1). Ambos os experimentos foram instalados e conduzidos no delineamento inteiramente casualizado, com 4 repetições. Transcorrido 50 dias da aplicação dos tratamentos, foram avaliados os efeitos dos mesmos sobre as variáveis biométricas das plantas, o teor, o acúmulo e as eficiências nutricionais (absorção, translocação e utilização) de nitrogênio para ambos os experimentos. No primeiro experimento ainda foi avaliado o efeito dos tratamentos sobre os teores de fosforo, potássio, enxofre, cálcio e magnésio. Observou-se efeito significativo (p>0,01) para interação Al3+ x Mn2+ na maioria das variáveis avaliadas, sendo que o efeito fitotóxicos da interação é maior que a soma individual dos efeitos. Os efeitos fitotóxicos causados pela interação dos metais foram prejudiciais ao desenvolvimento das mudas de cana-de-açúcar, com destaque para teor, acúmulo e eficiência de utilização de nitrogênio que foram drasticamente reduzidos. A cana-energia apresentou maior tolerância que a cana-de-açúcar quando submetidas ao mesmo nível de alumínio do sistema. somente a variável eficiência de utilização de N a cana-de-açúcar foi mais eficaz que os de cana-energia quando submetidas a ausência de alumínio (Al0).
Sugarcane is the main raw material used to produce sugar and ethanol in Brazil, the world's largest producer of this crop. Aluminum (Al3+) and manganese (Mn2+) toxicities are two of the main constraints to crop production in acidic soils. Although the toxic effect of these elements in isolation is relatively well known, little is known about their interactive effect. In addition, most studies of Al and Mn toxicity are carried out with traditional sugarcane genotypes, with few studies on Al and Mn toxicity in energy cane genotypes. Therefore, two experiments were carried out with sugarcane seedlings (IACSP95-5000) and energy cane (Vertix 9 and Vertix 2), under alternative hydroponics conditions adapted in a greenhouse, to verify if Al and Mn toxicity act independently or interactively on aspects of nitrogen nutrition and plant growth. The first experiment evaluated the phytotoxic interaction of Al3+ and Mn2+ in sugarcane seedlings (IACSP95-5000), using a completely randomized 2x5 factorial scheme design, with 2 levels of Al3+ (presence and absence), combined with 5 levels of Mn2+ (0, 200, 400, 600, 800 mg L-1 ). The second experiment consisted of a 3x2 factorial scheme, in which the seedlings of the 3 genotypes (IACSP95-5000, Vertix 9 and Vertix 2) were submitted to 2 levels of Al3+ (absence and presence, 60 mg L-1 ). Both experiments were installed and conducted in a completely randomized design, with 4 replications. After 50 days, treatment effects on biometric variables such as content, accumulation, and nutritional efficiencies (absorption, translocation, and utilization) of nitrogen were evaluated for both experiments. In the first experiment, was also evaluated the effect on phosphorus, potassium, sulfur, calcium, and magnesium was also evaluated. A significant effect (p>0.01) was observed for Al3+ x Mn2+ interaction in most of the variables evaluated, and the phytotoxic effect of the interaction is greater than the individual sum of the effects. The phytotoxic effects caused by the interaction of metals were harmful to the development of sugarcane seedlings, with emphasis on nitrogen content, accumulation, and efficiency of use, which were drastically reduced. The energy cane showed greater tolerance than the sugar cane when submitted to the same level of aluminum in the system. only the variable N utilization efficiency in sugarcane was more effective than energy cane when subjected to the absence of aluminum (Al0)
Sugarcane is the main raw material used to produce sugar and ethanol in Brazil, the world's largest producer of this crop. Aluminum (Al3+) and manganese (Mn2+) toxicities are two of the main constraints to crop production in acidic soils. Although the toxic effect of these elements in isolation is relatively well known, little is known about their interactive effect. In addition, most studies of Al and Mn toxicity are carried out with traditional sugarcane genotypes, with few studies on Al and Mn toxicity in energy cane genotypes. Therefore, two experiments were carried out with sugarcane seedlings (IACSP95-5000) and energy cane (Vertix 9 and Vertix 2), under alternative hydroponics conditions adapted in a greenhouse, to verify if Al and Mn toxicity act independently or interactively on aspects of nitrogen nutrition and plant growth. The first experiment evaluated the phytotoxic interaction of Al3+ and Mn2+ in sugarcane seedlings (IACSP95-5000), using a completely randomized 2x5 factorial scheme design, with 2 levels of Al3+ (presence and absence), combined with 5 levels of Mn2+ (0, 200, 400, 600, 800 mg L-1 ). The second experiment consisted of a 3x2 factorial scheme, in which the seedlings of the 3 genotypes (IACSP95-5000, Vertix 9 and Vertix 2) were submitted to 2 levels of Al3+ (absence and presence, 60 mg L-1 ). Both experiments were installed and conducted in a completely randomized design, with 4 replications. After 50 days, treatment effects on biometric variables such as content, accumulation, and nutritional efficiencies (absorption, translocation, and utilization) of nitrogen were evaluated for both experiments. In the first experiment, was also evaluated the effect on phosphorus, potassium, sulfur, calcium, and magnesium was also evaluated. A significant effect (p>0.01) was observed for Al3+ x Mn2+ interaction in most of the variables evaluated, and the phytotoxic effect of the interaction is greater than the individual sum of the effects. The phytotoxic effects caused by the interaction of metals were harmful to the development of sugarcane seedlings, with emphasis on nitrogen content, accumulation, and efficiency of use, which were drastically reduced. The energy cane showed greater tolerance than the sugar cane when submitted to the same level of aluminum in the system. only the variable N utilization efficiency in sugarcane was more effective than energy cane when subjected to the absence of aluminum (Al0)
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Saccharum officinarum, Agrocombustíveis, Plantas efeito do alumínio, Plantas efeito do manganês, Interação genótipo-ambiente.