POTENTIAL USE OF SPENT TEA LEAVES EXTRACT (Camellia sinensis L.) TO PROMOTE EARLY GROWTH OF SALT-STRESSED SEEDLINGS OF BLACK CHERRY TOMATOES (Solanum lycopersicum L. var. cerasiforme)

Salinity stress is a major abiotic factor limiting the productivity of tomato (Solanum lycopersicum L. var. cerasiforme) by impairing seed germination and seedling growth. Spent tea leaf (STL) extract, derived from tea processing residues, contains bioactive compounds such as polyphenols, alkaloids, essential amino acids, fatty acids, and minerals, known to enhance plant stress tolerance. This study investigated the potential of STL extracts from black, green, and oolong teas as seed priming agents to alleviate the adverse effects of salinity stress in black cherry tomato. The seeds were germinated on filter papers containing NaCl solution at different concentrations of 0, 2.5, 5.0, and 7.0 g/L. At 7 g/L NaCl, significant reductions were observed in germination rate, root length, shoot length, and the seed vigor index. To counteract salinity stress effects, seeds were treated with STL extracts derived from black, green, and oolong teas at concentrations of 1%, 2%, and 4%. Among the treatments, seeds primed with 1% oolong STL extract exhibited the most notable improvements across all measured parameters. Under 7.0 g/L NaCl conditions, this treatment produced the highest final germination percentage, average daily germination rate, and Timson index. Additionally, significant enhancements in shoot length, root length, and fresh biomass were observed in seeds treated with oolong STL compared to those subjected to saline conditions without priming.