Combinação K:Mg na atividade da rubisco, metabolismo fotossintético, antioxidante e relações com a produtividade do cafeeiro
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Data
2023-07-18
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Universidade Estadual Paulista (Unesp)
Resumo
O café é a segunda bebida mais consumida em todo o mundo, ficando atrás apenas da água, e sua demanda está constantemente aumentando no mercado. No entanto, para suprir essa exigência, as técnicas de cultivo precisam superar as adversidades que afetam o desenvolvimento das plantas, sendo o café (Coffea arabica) particularmente afetado pela deficiência de magnésio. A carência de magnésio nas plantas de café pode ser resultado de atividades antropogênicas, como o fornecimento inadequado de fertilizantes potássicos, o que leva a um antagonismo na absorção de magnésio que prejudica a produtividade. Este estudo teve como objetivo avaliar os efeitos de diferentes combinações de doses de potássio e magnésio em diversos aspectos, incluindo produtividade, concentração de pigmentos fotossintéticos, atividade da enzima rubisco, metabolismo antioxidante, a translocação de açúcares e o metabolismo nitrogenado. O experimento foi conduzido em campo. Foi utilizado o delineamento experimental em blocos casualizados, com tratamentos dispostos em um esquema fatorial 4 x 4, consistindo em 4 doses de potássio (0, 150, 300 e 450 kg ha-1 de K2O) e 4 doses de magnésio (0, 25, 50 e 150 kg ha-1 de MgO), em dois anos. Neste estudo, foram avaliados os seguintes parâmetros: produtividade, concentração de pigmentos fotossintéticos, atividade da enzima rubisco, concentração de malonaldeído e peróxido de hidrogênio, atividade da superóxido dismutase, ascorbato peroxidase e catalase, concentração de açúcar total em folhas e grãos, concentração de nitrato, amônia e de aminoácidos. A aplicação de 150 kg ha-1 de K2O e 25 kg ha-1 de MgO resultou em aumento da produtividade, concentração dos pigmentos fotossintéticos, atividade da enzima rubisco, metabolismo antioxidante e translocação de açúcares, em ambos os anos. Este estudo apresenta novos insights fundamentais sobre o efeito de K e Mg na produtividade e no metabolismo fotossintético e antioxidante do cafeeiro.
Coffee is the second most consumed beverage worldwide, second only to water, and its demand is steadily increasing in the market. However, to meet this demand, cultivation techniques must overcome the adversities that affect plant development, with coffee (Coffea arabica) being particularly affected by magnesium deficiency. The lack of magnesium in coffee plants may result from anthropogenic activities, such as inadequate supply of potassium fertilizers, leading to an antagonism in magnesium absorption that impairs yield. This study aimed to assess the effects of different combinations of potassium and magnesium doses on various aspects, including yield, concentration of photosynthetic pigments, rubisco enzyme activity, antioxidant metabolism, sugar translocation, and nitrogen metabolism. The experiment was conducted in the field. The experimental design was randomized complete blocks, with treatments arranged in a 4 x 4 factorial scheme, consisting of 4 potassium doses (0, 150, 300, and 450 kg ha-1 of K2O) and 4 magnesium doses (0, 25, 50, and 150 kg ha-1 of MgO), over two years. The following parameters were evaluated in the study: yield, concentration of photosynthetic pigments, rubisco activity, malondialdehyde and hydrogen peroxide concentration, superoxide dismutase, ascorbate peroxidase and catalase activity, total sugar concentration in leaves and grains, nitrate, ammonia, and amino acids concentration. The application of 150 kg ha-1 of K2O and 25 kg ha-1 of MgO resulted in increased productivity, concentration of photosynthetic pigments, rubisco enzyme activity, antioxidant metabolism, and sugar translocation in both years. This study provides fundamental new insights into the effect of K and Mg on coffee yield and photosynthetic metabolism.
Coffee is the second most consumed beverage worldwide, second only to water, and its demand is steadily increasing in the market. However, to meet this demand, cultivation techniques must overcome the adversities that affect plant development, with coffee (Coffea arabica) being particularly affected by magnesium deficiency. The lack of magnesium in coffee plants may result from anthropogenic activities, such as inadequate supply of potassium fertilizers, leading to an antagonism in magnesium absorption that impairs yield. This study aimed to assess the effects of different combinations of potassium and magnesium doses on various aspects, including yield, concentration of photosynthetic pigments, rubisco enzyme activity, antioxidant metabolism, sugar translocation, and nitrogen metabolism. The experiment was conducted in the field. The experimental design was randomized complete blocks, with treatments arranged in a 4 x 4 factorial scheme, consisting of 4 potassium doses (0, 150, 300, and 450 kg ha-1 of K2O) and 4 magnesium doses (0, 25, 50, and 150 kg ha-1 of MgO), over two years. The following parameters were evaluated in the study: yield, concentration of photosynthetic pigments, rubisco activity, malondialdehyde and hydrogen peroxide concentration, superoxide dismutase, ascorbate peroxidase and catalase activity, total sugar concentration in leaves and grains, nitrate, ammonia, and amino acids concentration. The application of 150 kg ha-1 of K2O and 25 kg ha-1 of MgO resulted in increased productivity, concentration of photosynthetic pigments, rubisco enzyme activity, antioxidant metabolism, and sugar translocation in both years. This study provides fundamental new insights into the effect of K and Mg on coffee yield and photosynthetic metabolism.
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Palavras-chave
Fisiologia vegetal, Antagonismo mineral, Cafeeiro, Sustentabilidade, Fotossintese