| Abstract: In order to study the effect of different concentrations of nitrogen, phosphorus and potassium on the growth and chlorophyll content of celery, and select the optimum concentration of nitrogen, phosphorus and potassium fertilizers suitable for the production of hydroponic celery, two celery cultivars 'Jinnan Shiqing' and 'Jinhuang Qincai' were used as the material to carry out hydroponic cultivation under the conditions of different concentrations of nitrogen, phosphorus and potassium fertilizers. The differences of plant phenotype and chlorophyll content among the treatments were compared and analyzed. The results showed that nitrogen, phosphorus and potassium fertilizers were the necessary nutrient elements in celery hydroponics culture, and the appropriate fertilizer concentration and ratio could promote the chlorophyll content and growth of celery. The content of chlorophyll in 'Jinnan Shiqin' was relatively higher. The optimum concentration of different fertilizer was different among different cultivars and different parts of celery. Among them, the demand for various types fertilizers of 'Jinnan Shiqin' was slightly greater than that of 'Jinhuang Qincai', which was more sensitive to nutrient deficiency conditions. The effect of nitrogen fertilizer on increasing chlorophyll content in different parts of celery was more balanced and obvious, and its optimum concentration was different in two cultivars of celery. Phosphorus fertilizer had the most significant effect on increasing the total chlorophyll content of celery. Potassium fertilizer mainly promoted the increase of chlorophyll content in celery petioles. In the hydroponic production of celery, the concentration ranges of nitrogen, phosphorus and potassium fertilizers in the nutrient solution could be set at 5-8 mmol/L, 0.3-0.6 mmol/L and 5-7 mmol/L, respectively, and the proportion of nitrogen, phosphorus and potassium fertilizers should be adjusted appropriately according to the fertilizer demand of cultivars. |