Effect Of Low-potassium Nutrition On The Quality And Potassium Content Of Leafy Vegetables

Study on low-potassium food was not only the urgent needs of patients with hyperkalemia but also been a focus in relative fields. This study used hydroponics on the basis of SCAU leafy nutrient solution B and discussed on changes in quality and potassium content of mustard, lettuce, spinach and other leafy vegetables under low-potassium nutrition by three methods which included to the reduction of potassium concentration in nutrient solution, discontinue nutrient solution supplying at late period and sodium instead of potassium. In order to find the optimum cultivation methods for leafy vegetables, providing theoretical guidance and technical support for the study of low-potassium food. The results of the research were show as follows:1. Low-potassium nutrition would be reduced the yield of leafy vegetables on the different level. The yield appeared to reduce when mustard, spinach, milk cabbage in potassium supply were lower than 2.37mmol/L. The yield appeared to reduce when Shanghai cabbage and lettuce in potassium supply were lower than 1.19mmol/L, 0.79mmol/L respectively. Discontinued nutrient solution 2 days and 4 days after harvest would be reduced in the yield of mustard, spinach, lettuce.2. Low-potassium nutrition had different effects on the quality of leafy vegetables. Soluble sugar contents in potassium supply which less than 1.19mmol/L and discontinued nutrient solution 4 days had significantly increased in six kinds of vegetables. The vitamin C content in spinach and mosaic lettuce would be decreased when potassium supply less than 2.37mmol/L. Vitamin C content decreased when Shanghai cabbage and milk cabbage in potassium supply were lower than 1.19mmol/L, 0.59mmol/L respectively. Discontinued nutrient solution 2 days could reduce the nitrite content in mustard, lettuce, spinach. Vitamin C would reduce in mustard and lettuce when nutrient solution discontinued over 4 days and 6 days.3. These ways would reduce the potassium content of vegetables significantly and their yield and quality had a smaller effect:Lettuce grew at 1.19mmol/L potassium supply, mustard, spinach, mosaic lettuce, milk cabbage and Shanghai cabbage grew at 0.79mmol/L potassium supply, discontinued nutrient solution 6-8 days for lettuce, mustard, spinach. This cultivation method caused potassium content fall 54%-61% compare with the control.4. The sodium content of vegetables was raised with potassium content decreased within the scope of security. Sodium could significantly inhibit the growth of spinach. Mustard and lettuce grew at 0.79mmol/L potassium supply added sodium not only could ensure the yield, but also decreased 64% potassium content.In summary, this study suggested that reducing potassium supply to 1.19mmol/L-0.79mmol/L, and discontinued nutrient solution 6-8 days were the optimal solution for low-potassium vegetable production.