Lithium: An Element with Potential for Biostimulation and Biofortification Approaches in Plants

Lithium (Li) is the lightest metal in existence. Its effects on higher plants are still under discussion because both positive and toxic results have been reported in different species. In the last decade, the use of Li has increased considerably, and it is projected that Li waste will be an environmental problem in the near future, such that various organisms, including plants, may be altered by its presence. Interestingly, Li can trigger hormesis, with beneficial effects at low doses and inhibitory or harmful effects at high doses. Currently, numerous research groups are focusing their studies on agriculture to obtain crops fortified with Li, which represents a nutritional advantage in food if adequate concentrations are used. However, more studies are still needed in order to understand the biochemical mechanisms of the effects of Li on plants. This review describes the natural and anthropogenic sources of Li, as well as the concentrations of this element in different environments. Regarding the uses of Li in different areas, topics related to doses that cause toxicity and lethality in humans are addressed. Given its impact on crop production, mechanisms of Li uptake and transport in higher plants are reviewed, as well as the effects on plant metabolism and physiology. Likewise, the perspective on the controlled use of Li in biostimulation and biofortification of crops is addressed.