K:Mg combination in rubisco activity, photosynthetic metabolism, antioxidant, and their relationship with coffee plant productivity

Author(s)

Nandhara Angélica Carvalho Mendes

• Document type: Master's Dissertation
• Press: Jaboticabal. 2023-09-05.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2023-07-18
• Advisor: André Rodrigues dos Reis

Abstract

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. (AU)

• FAPESP's process: 20/16177-0 - K:Mg combination in Rubisco's activity, photosynthetic metabolism, antioxidant and relationships with coffee productivity
• Grantee: Nandhara Angélica Carvalho Mendes
• Support Opportunities: Scholarships in Brazil - Master