Effect of foliar application of lithium on biofortification, physiological components, and production of irrigated rice

Context Lithium (Li) is an essential trace element for human health. Although the biofortification of rice (Oryza sativa) with Li is a promising strategy to overcome its deficiency, little is known about its biological activity in plants. Aims We determined the effect of sources and doses of Li applied via the leaves on the biofortification, physiological components, and production of irrigated rice. Methods The experimental design consisted of randomised blocks in a 5 × 3 factorial arrangement, with four replicates. The factors consisted of five doses of Li (0, 50, 100 150, and 200 g ha−1) and three sources (lithium sulfate, Li2SO4·H2O; lithium hydroxide, LiOH·H2O; and lithium chloride, LiCl). Key results Regardless of the source used, foliar application of Li allowed bioaccumulation in rice grains without influencing the development and grain yield of the crop. Supplying Li to rice plants in the form of Li2SO4·H2O increased the photosynthetic rate and water use efficiency. Moreover, regardless of the source used, the consumption of rice grains biofortified with Li at a dose of 200 g ha−1 can supply more than 50% of the minimum recommended daily intake of the element. Conclusions Foliar spraying of Li is effective for agronomic biofortification of rice. Implications Biofortification of rice with Li can contribute to reducing its deficiency in naturally poor regions.