Effect of nitrogen concentration of nutrient solution on the growth and nutrient constituents of hydroponically grown spinach [Spinacia oleracea L.].
1990
Zhang C.L. | Watanabe Y. | Shimada N.
Effect of nitrogen concentration of nutrient solution on the growth and the nutritional quality of spinach was investigated. Ascorbic acid, sugars, nitrate and oxalate contents were analyzed for quality evaluation of spinach. The fresh weight of the plants grown in the 1/5 fold nitrate concentration of nutrient solution decreased about 10% as compared with that of the 1/3 fold or higher concentration, and the leaf color of their plants was slightly pale. Ascorbic acid and sugar contents increased with the decrease of the nitrogen concentration of nutrient solution. In plants grown in the 1/5 fold nitrate concentration, the total sugar content was abut 1.7 times higher than that of plants in standard nutrient solution. The contents of nitrate and oxalate showed a completely opposite tendency to that of the contents of ascorbic acid and sugar. Especially, nitrate content of plants in the 1/5 fold nitrate concentration was only 7.8 mg per 100 g fresh weight.
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