Respostas de cana-de-açúcar e de cana-energia à aplicação de manganês com silício via radicular e foliar
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Data
2022-04-13
Autores
Oliveira, Kamilla Silva [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O cultivo de cana-de-açúcar e de cana-energia tem ampliado para áreas com deficiência de manganês (Mn) no Brasil, além de ser um dos micronutrientes mais requeridos pela cultura, o que pode limitar o crescimento destas espécies, os estudos são muito restritos. Em caso deficiência identificada durante o ciclo das plantas, a correção de deficiência é feita em sua maioria pela aplicação foliar, contudo, é incerta a responsividade destas espécies a esta prática, e não se conhece as concentrações ideais. Faz-se necessário, portanto, avaliar os fatores bioquímicos e fisiológicos da nutrição de Mn nestas espécies e formas de amenizar os danos da deficiência, bem como formas de melhorar a eficiência da adubação. O fornecimento de silício (Si) pode favorecer a nutrição com Mn via raiz e atenuar os danos bioquímicos e fisiológicos. Além disso, o uso de Si em associação com o Mn via foliar poderia melhorar a nutrição com Mn e reduzir a dose necessária. A pesquisa teve como objetivo avaliar os efeitos do fornecimento de Mn com e sem associação com Si via radicular e foliar em plantas de cana-de-açúcar e de cana-energia, os mecanismos bioquímicos, fisiológicos e nutricionais do Si de melhorar a nutrição com Mn e atenuar o estresse da deficiência do micronutriente. Para isso realizou-se cinco experimentos em casa de vegetação. Inicialmente foram realizados experimentos em arranjo fatorial 2 x 2 em solução nutritiva avaliando o efeito do fornecimento de Si (2,0 mmol L-1), e sua ausência, na nutrição com Mn e mecanismos de atenuação da deficiência (peroxidação lipídica, sistema de defesa antioxidante e componentes fisiológicos) via solução nutritiva em plantas de cana-de-açúcar (experimento I), cana-energia tipo I (experimento II) e cana-energia tipo II (experimento III) sob suficiência e deficiência de Mn. Posteriormente, foi investigado o fornecimento via foliar de 4 concentrações de Mn (0,0; 0,32; 0,68 e 0,96 g L-1) em arranjo fatorial 4 x 2, com Si (0,476 g L-1) e sem associação com Si na calda em plantas de cana-de-açúcar (experimento IV) e cana-energia tipo I (experimento V) sob deficiência de Mn. A deficiência de Mn reduziu o crescimento das plantas de cana-de-açúcar e de cana-energia por aumentar o estresse oxidativo, reduzir compostos antioxidantes e prejudicar o metabolismo fisiológico, principalmente nos genótipos de cana-energia. O fornecimento de Si via solução nutritiva melhorou a nutrição de Mn e as respostas bioquímicas e fisiológicas em plantas sob suficiência e deficiência de Mn, mas, plantas de cana-de-açúcar e cana-energia tipo I apresentaram melhor resposta na suficiência, enquanto na deficiência, os genótipos de cana-energia tiveram maiores benefícios bioquímicos e fisiológicos pelo Si. O fornecimento foliar de concentrações de Mn que induziu melhor resultado em crescimento e melhorou a nutrição das plantas de cana-de-açúcar e de cana-energia corrigindo a deficiência. Quando o Si esteve presente na calda de aplicação foliar houve maior acúmulo de Mn, redução do estresse oxidativo e modulação de enzimas antioxidantes, melhorando o crescimento. O uso de Si pode ser ferramenta para melhorar a nutrição de cana-de-açúcar e de cana-energia, e forma eficiente de atenuar os danos da deficiência de Mn, principalmente em cana-energia. A aplicação foliar é viável para corrigir a deficiência de Mn em ambas as espécies.
The cultivation of sugarcane and energy cane has expanded to areas with manganese (Mn) deficiency in Brazil, in addition to being one of the micronutrients most required by the crop, and which can limit the growth of these species, but studies are very limited. In case of deficiency identified during the plant cycle the correction of deficiency is mostly made by leaf application, however it is uncertain the responsiveness of these species to this practice and the ideal concentrations. Therefore, it is necessary to evaluate the factors biochemicals and physiological of Mn nutrition in these species and ways to mitigate the damages of deficiency, as well as ways to increase fertilization efficiency. The supply of silicon (Si) can favor nutrition with Mn via root and mitigate physiological and biochemical damage. In addition, the use of Si in association with Mn via foliar could enhance nutrition with Mn and reduce the required dose. This research aimed to evaluate the effects of Mn supply with and without Si association by the root and leaves in sugarcane and energy cane plants and the biochemical, physiological, and nutritional mechanisms of Si of potentiating nutrition with Mn and attenuating the stress of micronutrient deficiency. For this, five experiments were carried out in a greenhouse. Initially, experiments were carried out in a 2 x 2 factorial arrangement in nutrient solution, evaluating the effect of Si supply (2.0 mmol L-1) and its absence in nutrition with Mn and deficiency attenuation mechanisms (lipid peroxidation, antioxidant defense system and physiological compounds) via nutrient solution in sugarcane plants (experiment I), type I energy cane (experiment II) and type II energy cane (experiment III) under sufficiency and deficiency of Mn. Subsequently, the foliar supply of 4 Mn concentrations (0.0; 0.32; 0.68 e 0.96 g L-1) in 4 x 2 factorial arrangement, with and without association with Si (0.476 g L-1) in the syrup in sugarcane plants (experiment IV) and type I energy cane (experiment V) under Mn deficiency was investigated. Mn deficiency reduced the growth of sugarcane and energy cane plants by increasing oxidative stress, reducing antioxidant compounds, and impairing physiological metabolism, especially in energy cane genotypes. The supply of Si via nutrient solution improved Mn nutrition, biochemical and physiological responses in plants under sufficiency and deficiency of Mn, but sugarcane and energy cane plants type I, showed better response in sufficiency, while in deficiency, the genotypes of energy cane had greater biochemical and physiological benefits by Si. The foliar supply of Mn concentrations that induced better results in growth and improved the nutrition of sugarcane and energy cane plants correcting the deficiency. When Si was present in the leaf application solution, there was a greater Mn accumulation, reduction of oxidative stress and modulation of antioxidant enzymes, improving growth. The use of Si can be a tool to improve the nutrition of sugarcane and energy cane and an efficient way to mitigate the damage of Mn deficiency, especially in energy cane. Leaf application is feasible to correct Mn deficiency in both species.
The cultivation of sugarcane and energy cane has expanded to areas with manganese (Mn) deficiency in Brazil, in addition to being one of the micronutrients most required by the crop, and which can limit the growth of these species, but studies are very limited. In case of deficiency identified during the plant cycle the correction of deficiency is mostly made by leaf application, however it is uncertain the responsiveness of these species to this practice and the ideal concentrations. Therefore, it is necessary to evaluate the factors biochemicals and physiological of Mn nutrition in these species and ways to mitigate the damages of deficiency, as well as ways to increase fertilization efficiency. The supply of silicon (Si) can favor nutrition with Mn via root and mitigate physiological and biochemical damage. In addition, the use of Si in association with Mn via foliar could enhance nutrition with Mn and reduce the required dose. This research aimed to evaluate the effects of Mn supply with and without Si association by the root and leaves in sugarcane and energy cane plants and the biochemical, physiological, and nutritional mechanisms of Si of potentiating nutrition with Mn and attenuating the stress of micronutrient deficiency. For this, five experiments were carried out in a greenhouse. Initially, experiments were carried out in a 2 x 2 factorial arrangement in nutrient solution, evaluating the effect of Si supply (2.0 mmol L-1) and its absence in nutrition with Mn and deficiency attenuation mechanisms (lipid peroxidation, antioxidant defense system and physiological compounds) via nutrient solution in sugarcane plants (experiment I), type I energy cane (experiment II) and type II energy cane (experiment III) under sufficiency and deficiency of Mn. Subsequently, the foliar supply of 4 Mn concentrations (0.0; 0.32; 0.68 e 0.96 g L-1) in 4 x 2 factorial arrangement, with and without association with Si (0.476 g L-1) in the syrup in sugarcane plants (experiment IV) and type I energy cane (experiment V) under Mn deficiency was investigated. Mn deficiency reduced the growth of sugarcane and energy cane plants by increasing oxidative stress, reducing antioxidant compounds, and impairing physiological metabolism, especially in energy cane genotypes. The supply of Si via nutrient solution improved Mn nutrition, biochemical and physiological responses in plants under sufficiency and deficiency of Mn, but sugarcane and energy cane plants type I, showed better response in sufficiency, while in deficiency, the genotypes of energy cane had greater biochemical and physiological benefits by Si. The foliar supply of Mn concentrations that induced better results in growth and improved the nutrition of sugarcane and energy cane plants correcting the deficiency. When Si was present in the leaf application solution, there was a greater Mn accumulation, reduction of oxidative stress and modulation of antioxidant enzymes, improving growth. The use of Si can be a tool to improve the nutrition of sugarcane and energy cane and an efficient way to mitigate the damage of Mn deficiency, especially in energy cane. Leaf application is feasible to correct Mn deficiency in both species.
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Palavras-chave
Deficiência nutricional, Fotossíntese, Metabolismo oxidativo, Saccharum officinarum L., Saccharum spontaneum L., Metabolismo, Micronutrientes