Abstract:

To explore the enrichment of strontium (Sr) in lettuce, this study adopted a laboratory cultivation method and established three cultivation approaches for lettuce: soil culture with solid strontium chloride, soil culture with liquid strontium chloride, and hydroponics. Using these methods, the enrichment of strontium in lettuce was investigated during its seedling, growth, maturity, and senescence stages. The experimental results showed that all three strontium addition methods successfully achieved strontium enrichment in lettuce. Under soil cultivation, when the solid strontium addition in the soil increased from 0 mg/kg to 200 mg/kg, the strontium content in lettuce at all growth stages significantly increased. For instance, the strontium content during the seedling stage rose from 2.98 mg/kg to 169.07 mg/kg; in the mode of soil culture with liquid strontium chloride, the concentration of liquid strontium in the soil increased from 0 mmol/L to 10 mmol/L, and the strontium content increased most significantly during the seedling stage, from 0.25 mg/kg to 510.24 mg/kg. For hydroponics, increasing the strontium concentration in water from 0 mmol/L to 5 mmol/L significantly increased the strontium content in lettuce. The maturity period was most obvious. When the strontium concentration in water was 5 mmol/L, the strontium content in lettuce could reach 1008.25 mg/kg. In addition, in the strontium concentration set in this experiment, the content of strontium in lettuce grown in soil increased with the increase of strontium concentration, and no significant inhibitory effect was observed; for hydroponic experiments, 3 mmol/L was the optimal culture concentration. The study validated the method for strontium enrichment in lettuce and the optimal concentration, providing a reference for strontium enrichment in crops.

Key words: strontium enrichment, lettuce, growth period, soil cultivation, hydroponics