Effects of Different Carbon Sources on In Vitro Shoot Multiplication: Solid MS Medium Optimization and Bioreactor Validation for Aquatic Plant Bucephalandra pygmaea (Becc.) P. C. Boyce & S.Y. Wong

Bucephalandra pygmaea (Becc.) P. C. Boyce & S.Y. Wong is an aquarium plant that is gaining importance in the ornamental plant sector due to its vibrant leaf colours and high adaptability to underwater conditions. This study aimed to enhance the in vitro shoot propagation efficiency of B. pygmaea ‘Bukit Kelam’ through a two-stage experimental design. In the first stage (solid MS optimisation), three carbon sources—maltose, sucrose, and glucose—were tested at 10 and 20 g L⁻¹ concentrations to determine their effects on key growth parameters, including shoot multiplication rate, plant height, leaf number, leaf area, and plant width. According to the results, 10 g L⁻¹ maltose promoted the highest shoot proliferation and leaf expansion, whereas 20 g L⁻¹ glucose caused a pronounced reduction in all morphological traits. In the second stage (bioreactor validation), the optimised 10 g L⁻¹ maltose medium was applied in both solid MS and temporary immersion (Plantform TIS) systems. Plants grown on solid MS displayed superior morphological performance (plant height, leaf area, and SPAD values), while bioreactor-cultured plants exhibited colour values, reflecting enhanced pigment intensity. Overall, 10 g L⁻¹ maltose was identified as the most effective carbon source for Bucephalandra micropropagation. The findings suggest that solid MS medium ensures compact growth and high chlorophyll content, whereas the bioreactor system favours visual colour quality—providing complementary strategies for sustainable large-scale propagation of this ornamental aquatic species.