Foliar-Applied Lithium And Its Effect On Morpho-Physiological Behavior And The Elemental Composition Of Lettuce

Lithium (Li) intake is insufficient in many countries of the world. Low dietary intake of Li is associated with many psycho-behavioral disorders (e.g., increased suicide and homicide rates, aggressive behaviors, unipolar/bipolar disorders, and acute mania). Agronomic biofortification is a good strategy to increase Li intake in the human diet. This study aims to evaluate the effect of Li foliar application on the biofortification of two lettuce cultivars, as well as its influence on morpho-physiological characteristics and elemental composition. The experiment was carried out in a randomized complete block design in a 2 x 5 factorial scheme with four replicates. Two curly lettuce cultivars (SVR 2005 and Solaris) were treated with five levels of Li (0, 16, 32, 48, and 64 g ha-1) applied via foliar under semi-controlled conditions. Both cultivars showed higher Li content and accumulation with the application of 64 g ha-1of Li. For the Solaris cultivar, the supply of 37 g ha-1of Li guarantees the consumption of approximately 30% of the daily Li recommendation. The morpho-physiological characteristics of the Solaris and SVR 2005 cultivars presented positive results with the application of between 20 and 41 g ha-1of Li. The content of potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) was altered by the foliar application of Li. The results obtained in this study show that the application of Li via leaves, under semi-controlled conditions, is an efficient strategy to biofortify lettuce and provide Li in the human diet. However, attention must be paid to the contents of macro and micronutrients in lettuce.