This experiment was undertaken to clarify the relationship between decreasing NO3-N concentration and substituted Cl- and SO4- in nutrient solution for the growth and NO3- content in spinach ( Spinacia oleracea L. Cultivar. Sunlight) plant. The fresh weight and the relative content of chlorophyll showed no difference among treatments when the plants were exposed to NO3 - N concentration above 2.8 mg/plant/day in the nutrient solution for 8 days before harvest. NO3- content in the leaves ranged more than 300...