Detrimental Effects of Lithium on in vitro Seedlings of Pea (Vigna radiata)

The global demand for lithium-ion batteries has raised concerns about environmental consequences stemming from lithium leaching. In this study, we investigated the effects of lithium, sourced from Li2SO4, on in vitro seed germination and seedling growth of green moong (Vigna radiata). Our experiments used woody plant medium supplemented with 1 mg/l naphthalene acetic acid (NAA) and 2 mg/l benzyl adenine (BA). We observed that in vitro seed germination remained unaffected by lithium concentration. However, at concentrations of 3-5 mg/l of lithium, significant changes were observed in stem parameters including growth reduction, shoot tip damage and stem discolouration. Root growth was inhibited at lithium concentrations of 4 and 5 mg/l. Additionally, we noted leaf abscission, dark colouration and reduced leaf area in a dose-dependent manner. Necrotic lesions were not observed in the seedlings. Chlorophyll accumulation, phenolic content and peroxidase (POD) activity showed enhancement with increasing lithium concentration. Our data analysis strongly suggests dose-dependent toxicity in young seedlings under in vitro conditions. These findings shed light on the potential ecological implications of lithium leaching from retired batteries.