info:eu-repo/semantics/article
Sucrose-Enzyme Relationships in Immature Sugarcane as Affected by Varying Levels of Nitrate and Potassium Supplied in Sand Culture
Título en español.
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Resumen
Immature sugarcane plants grown in sand culture were subjected to conditions of potassium and nitrate stress in order that abnormal carbohydrate levels would be induced. The objective was to learn what areas of sugar metabolism were involved in the degradation of sucrose. The methods centered upon leaf enzymes, of which the following were identified and measured: Amylase, invertase, hexokinase, acid phosphatases, phosphorylase, phosphohexose isomerase, aldolase, triose phosphate dehydrogenase, phosphoglyceryl kinase, pyruvic carboxylase, condensing enzyme, α-ketoglutaric carboxylase, isocitric dehydrogenase, cytochrome-C reductase, fumarase, transaminase, oxalacetic carboxylase, peroxidase, catalase, and polyphenol oxidase. The enzyme preparations consisted of dialyzed water-soluble protein extracted from freeze-dried leaf tissue and precipitated with ammonium sulfate between 32- and 95-percent saturation. Sugar determinations for leaf and sheath tissue included total ketoses, sucrose, fructose, total reducing sugars, and glucose. Sheath-percent-moisture, total dry weight, and leaf protein were also measured. Treatments were applied from 9 weeks to 27 weeks of age and a total of seven harvests were made at 21-day intervals. Plantas inmaduras de caña de azúcar sembradas en arena se sometieron a un tratamiento excesivo de potasio y nitrato, con el propósito de inducir niveles anormales de hidratos de carbono. El objetivo era descubrir qué fases del metabolismo del azúcar estaban relacionadas con la reducción de la sacarosa. Los métodos se centraron sobre las enzimas foliares, de los cuales los siguientes se identificaron y midieron: amilasa, invertasa, hexoquinasa, fosfatasas ácidas, fosforilasa, fosfohexosa, isomerasa, aldolasa, dehidrogenasa trio-fosfatada, quinasa fosfoglicerada, carboxilasa pirúvica, enzima para condensar, carboxilasa alfaquetoglutárica, dehidrogenasa isocítrica, reductasa, citocroma C, fumarasa, transaminasa, carboxilasa oxalacética, peroxidasa, catalasa y oxidasa polifenólica. Las preparaciones enzimáticas consistieron de proteína dializada, soluble en agua, extraída de tejido foliar seco-congelado y precipitado con sulfato amónico a una saturación entre 32 y 95 por ciento. Los ensayos para las determinaciones de azúcares en el tejido de la hoja y la yagua incluyeron las quetosas totales, sacarosa, fructosa, azúcares reductores totales y glucosa. También se midió el porcentaje de humedad en la yagua, su peso total cuando seca, y el contenido de proteína en la hoja. Se aplicaron tratamientos a cañas de 9 hasta 27 semanas de edad y se hicieron siete cosechas a intervalos de 21 días.