The Impact of 6-Benzylaminopurine (BAP) on Plant Growth, Micro-rhizome Induction and Phytochemical Content of Black Ginger (Kaempferia parviflora) Using Two In-vitro Culture System

Abstract

This study investigates the impact of 6-Benzylaminopurine (BAP) on shoot multiplication, micro-rhizome induction, and 5,7,4-trimethoxyflavone content in Kaempferia parviflora, commonly known as kunyit hitam or black ginger. Explants were cultivated using two culture systems, conventional semi-solid medium and the temporary immersion system (RITA®) with varying BAP concentrations (0 to 7.5 mg/L). Results revealed that BAP concentration significantly influenced shoot and root development. Optimal shoot proliferation was achieved at 2.5 mg/L BAP, while root growth decreased at higher concentrations. The semi-solid culture system outperformed RITA® in overall plantlet development and micro-rhizome fresh weight. Phytochemical analysis indicated that antioxidant activity, total phenolic content, and total flavonoid content were enhanced under higher BAP concentrations and were further increased through drying. Additionally, the semi-solid system yielded higher levels of 5,7,4-trimethoxyflavone compared to RITA®. These findings demonstrate that BAP optimization is critical for efficient propagation and secondary metabolite enhancement in K. parviflora, offering insights for improved cultivation and phytochemical enrichment strategies.