Effects of selenium application on nutrient uptake and nutritional quality of Codonopsis lanceolata

Abstract

Codonopsis lanceolata is widely cultivated and consumed in China, Korea, and Japan because of its beneficial effects on health; it is an effective antioxidant and reduces the risks of diabetes, obesity, and cancer. The effects of C. lanceolata on human health are similar to that of selenium (Se). Hence, the aim of this study was to determine whether Se application could increase Se content in C. lanceolata and enhance its beneficial effects on human health. Pot experiments were conducted, and sodium selenite was applied to evaluate the effects of Se application (0, 0.5, 1.0, 1.5, and 2.0mgSekg−1 soil) on C. lanceolata. The biomass of C. lanceolata increased and was the highest when treated with 1.0mgSekg−1 soil, but after this level, there was a decrease in C. lanceolata biomass. Compared with the corresponding organs of the control group, Selenium accumulation in stems, leaves and fruits significantly increased with Se levels increasing, the highest values appeared at 1.0mgSekg−1 soil level for roots and fruits, and at 1.5mgSekg−1 soil level for stems and leaves, respectively. Selenium application increased N, P, and K accumulation, and altered the distribution of N and K, but not of P. Compared to the control, at 1.0mgSekg−1 soil level, the contents of polysaccharide, total flavonoid, total saponin increased significantly, thereby enhancing the health benefit of C. lanceolata; the contents of protein, total amino acid and essential amino acid increased significantly, thereby enhancing the nutritional quality of C. lanceolata; the contents of Se and Zn increased concurrently, suggesting the suitability of simultaneous biofortification with Zn and Se. Furthermore, the highest concentration of Se in C. lanceolata root (5.93μgg−1 dry weight) was considered to be safe for human consumption. Approximately 12g (dry weight) of C. lanceolata root treated with 1.0mgSekg−1 soil is sufficient to fulfill the daily human requirement of Se. In conclusion, C. lanceolata is a good candidate for Se biofortification, and 1.0mgSekg−1 soil is the optimum.