Temporary Immersion Bioreactor System (SETIS™): Technology for Large Scale In Vitro Production of Boesenbergia rotunda

Boesenbergia rotunda is a well-known Southeast Asian herbal that has been used as a condiment, traditional medicine, and more recently in certain modern pharmaceutical goods. At Forest Research Institute Malaysia (FRIM), mass production of B. rotunda was obtained using tissue culture technique known as temporary immersion bioreactor system (TIBs), SETIS™, an efficient plant production system. However, it was observed that the young leaves were unable to open or unfurl due to lack of space in the vessel. This created unhealthy plant development and caused high mortality during acclimatisation period, as the unfurled leaves might have insufficient cuticular layer on their surface. A technique to manipulate the plant height was needed to facilitate leaf development and enhance high survival rates. Therefore, this study aimed to investigate the effect of paclobutrazol (PBZ) in the manipulation of medium culture formulations towards B. rotunda plant height. Young shoots of B. rotunda were treated in MS medium supplemented with 2 mg/L BAP and different concentrations of PBZ using SETIS™. Results indicated a reduction in plant height, where samples treated with 0.1 mg/L and 1.0 mg/L gave a plant height of 16.93 ± 2.00 cm and 20.17 ± 3.20 cm, respectively, compared to 34.27 ± 2.73 cm in control. The photosynthetic rates showed an increment in samples treated with 0.1 mg/L and 1.0 mg/L PBZ (0.56 ± 0.09 and 0.56 ± 0.07 μmol/m2/s), respectively, compared to the control (0.18 ± 0.04 μmol/m2/s). The PBZ treatments successfully inhibited B. rotunda plant heights to facilitate the development in vitro and increase survival rates during acclimatisation process.