Nitrate utilization and carbohydrate distribution as affected by nitrogen and potassium nutrition in sugar cane plants

• Autor(a) principal: Silveira, Joaquim Albenísio Gomes da
• Data de Publicação: 1991
• Outros Autores: Crocomo, Otto Jesu
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/3335
• topic: plant nutrition; N and K metabolism; N assimilation; sugars; Saccharum; nutrição de plantas; metabolismo de N e K; assimilação de N; açúcares; Saccharum

The experiment was carried out in a greenhouse and in nutrient solutions with three combination of with three K levels each combination. The N and K levels, alone, affected the dry matter distribution between roots, stalks and leaves, more than N-K interactions. N and K-deficient plants presented the lowest growth of leaves and stalks, respectively. The N2K3 combination promoted the largest dry matter accumulation in the stalks. These plants showed lower nitrate and soluble N-amino concentrations and lower nitrate reductase activity than N2K1 and N2K2. The protein concentration was altered only by N deficiency. The N conversion index (kg of stalk/kg of N) was reduced by increasing N levels and in K-deficient plants. The highest N levels caused decreases in the concentrations of sucrose and reducing sugars in leaves and stalks. The N2K3 combination showed the highest levels of sucrose in leaves and stalks. The highest yield in N2K3 combination may be related with higher photosynthetic efficiency, higher sucrose translocation to the stalk and lower energetic costs of nitrogen utilization.