Abstract：Deficiency symptoms of nitrogen，phosphorus and potassium in Solanum torvum seedlings
cultured in nutrient solution were induced and observed，along with the determination of growth parameters and
physiological characteristics. Results indicated that each specific nutrient deficiency induced exclusive symptoms.
The emergence time and severity of 3 different nutrient deficiencies were different. The symptom of nitrogen
deficiency emerged the earliest. The nitrogen and potassium deficiency had the most obvious effect on aboveground
plant parts. The number of leaves，whole-plant dry weight and root total volume under nutrient deficiency
treatments were all lower than those of the contrast，whereas the root to shoot ratio was higher than that of the
contrast. The chlorophyll contents in both old and tender leaves were significant lower than that of the contrast
under N deficiency treatment，but the chlorophyll content of tender leaves was significantly higher than that of the
contrast under P deficiency treatment. There were extreme obvious differences in the root system activities. N and
P deficiency weakened the activity of plant root system. While K deficiency significantly increased root activity by
44.34% as compared with the contrast.