Strontium biofortification in soil and hydroponic grown tomato and lettuce

This study investigates the biofortification of tomato and lettuce plants with strontium (Sr). The Sr was applied at 0, 25, and 50 mg kg-1 in the soil experiment and 0, 2.5, and 5.0 mg L-1 in the rockwool experiment. The Sr application increased growth of plants. The Sr concentration in soil-grown tomato increased from 137 to 384 and 665 mg kg-1 with Sr treatments, respectively. Similarly, Sr concentration in tomato fruits rose from 4.53 to 10.7 and 17.5 mg kg-1. Lettuce Sr concentration increased from 64.9 to 119 and 168 mg kg-1 with Sr treatments. The Sr concentration in the vegetative parts of tomatoes grown in rockwool increased from 23 to 600 mg kg-1 with low-Sr and to 604 mg kg-1 with high-Sr application. Similarly, the Sr concentration in tomato fruits increased from 1.13 to 25.7 and 19.0 mg kg-1 with Sr treatments. The Sr concentration in lettuce grown in rockwool increased from 26.2 to 285 and 356 mg kg-1 with Sr, respectively. The fruit Ca concentrations significantly increased in response to the applied high-Sr in soil-grown tomato plants. In rockwool-grown tomato, the Ca concentrations in the vegetative parts increased from 19.3 to 27.8 g kg-1, and in the fruits, it increased from 0.66 to 1.00 g kg-1 under the low-Sr treatment compared to the control. In rockwool-grown lettuce, the Ca concentration increased with the low-Sr. In conclusion, the present research establishes that the biofortification of Sr in the edible parts of tomato and lettuce plants can be achieved successfully.