Nitrate is one of the nitrogen - containing substances absorbed by plants. Nitrate is reduced in roots , branches
or leaves, depending on plant type and environmental conditions. Detecting nitrate nitrogen content in plants
is significant to understand the nitrogen metabolism mechanism.
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NO3 can react with salicylic acid to form nitrosalicylic acid under the condition of concentrated acid, which
shows yellow under the condition of pH>12. Within a certain range, the color depth is proportional to the
content.
Reagents and Equipments Required but Not Provided:
Spectrophotometer/microplate reader, micro glass cuvette/96 well flat-bottom plate, water bath, desk
centrifuge, mortar/homogenizer, ice and distilled water.
Sample preparation:
Add 1 mL distilled water into 0.1 g tissue, fully grinding at RT and put it in 90℃ water bath for 30 min,
shaking during the time. Or put in 90℃ shaker, centrifuge at 12000 g, 25℃ for 15 min after cooling. Take the
supernatant on ice for test.
