Biofortification of Raphanus sativus through irrigation with Ca²⁺ solutions does not increase calcium content

Micronutrient deficiencies, which affect more than two billion people globally, occur when an individual does not receive adequate amounts of essential vitamins or minerals. Biofortification aims to increase the nutritional content of food crops, and it is an important tool in decreasing the effects of micronutrient deficiencies. Specifically, hypocalcemia, or calcium deficiency, causes a wide range of symptoms that affect many different body systems. In this study, we tested the hypothesis that increasing the amount of calcium available to the food crop during growth would increase the amount of calcium present in the food crop. A total of 180 radish (Raphanus sativus) plants were grown in a controlled environment and irrigated with water of varying Ca²⁺ concentrations. The height of each plant was measured every five days beginning at day 0 to track the growth. At maturity, a random sample of four plants from each group were tested for calcium and magnesium content using an atomic absorption spectrophotometer. The group that received the highest concentration of Ca²⁺ grew significantly smaller than most other groups. The Ca²⁺ contents of leaf samples had no significant difference in Ca²⁺ or Mg²⁺ content; however, the Ca²⁺ content of root samples showed a significant decrease from the control in both Ca²⁺ and Mg²⁺ content across several experimental groups. These results provide preliminary evidence that irrigation with Ca²⁺ solutions does not increase the calcium content of mature plants, but further testing is needed to confirm these results. If increased calcium in irrigation water significantly increases the calcium content of mature radish plants, this technique could be used to increase the calcium content of other crops in areas with high rates of hypocalcemia.