Effect of lithium on seed germination and plant growth of Amaranthus viridis

Lithium is one of the trace elements essential for the human body. The use of Li-based products has increased tremendously, leading to higher consumption patterns and the generation of lithum-based wastes. A higher concentration of lithium leads to the contamination of soil and water bodies. Lithium enters the food chain through the plant pathway. The food chain becomes contaminated with agricultural products produced on lithium-contaminated soil. Owing to this scenario, the present study is focused on studying the effect of lithium on the germination and growth of Amaranthus viridis. Germination studies were conducted in petri dishes, and the rate germination was 95% at control and 10 ppm. At higher concentrations, the rate of germination was 73% at 50 ppm, 57% at 75 ppm and 41% at 100 ppm. Pot experiments were conducted for 51 days using lithium-amended soil from 10 to 100 ppm. Pot experiments revealed that, at higher concentrations, lithium promoted the length and weight of the plant from 1.122 g/plant in the control to 2.415 g/plant at 100 ppm. The stress tolerance index was calculated for the length and dry weight of the roots and shoots, respectively. High stress tolerance at root and shoot biomass led to an increase in the biomass of the plant, which promoted the accumulation of lithium in plant parts. These results concluded that lithium stimulated plant growth at lower concentrations and increased biomass at higher concentrations, which was confirmed through the calculation of the stress tolerance index.