In-vitro plant regeneration of mature adlai (Coix lacryma-jobi L.) embryos using coconut water as a natural alternative growth promoter

In-vitro culture has paved the way for the development of plant cultivars with enhanced morphophysiological characteristics. Adlai (Coix lacryma-jobi L.), a grain-producing crop with promising economic potential, has benefited from pioneering studies using synthetic hormones to induce regeneration. Although proven to be effective, the use of these hormones makes tissue culture an expensive technique. This study aimed to provide a cost-effective alternative by evaluating the efficiency and determining the optimal concentrations of coconut water as a natural alternative for 6-BAP (6-benzylaminopurine), while still producing plantlets of comparable quality. After 18 days of incubation, the morphological and physiological characteristics of the plantlets were recorded. Among the treatments, 7.5% matured coconut water consistently supported balanced growth, including optimal root elongation, shoot height, high biomass accumulation, and favorable stomatal dimensions, indicating enhanced water-use efficiency and gas exchange. Meanwhile, 15% matured coconut promoted leaf proliferation and the highest chlorophyll content, induced smaller stomatal apertures and reduced structural biomass. Overall, this study supports the potential of coconut water as a natural and cheaper alternative to synthetic hormones, thereby reducing the overall costs associated with tissue culture technology.