Effects of Sucrose and Raffinose Combination on the Rapid Propagation of Curcuma kwangsiensis S. G. Lee & C. F. Liang through Tissue Culture

Objective This study aimed to systematically investigate the effects of sucrose and raffinose combinations on the induction of primary shoot clusters and the proliferation of subcultured buds during the in vitro culture of Curcuma kwangsiensis S. K. Lee & C. F. Liang. The goal was to optimize its rapid propagation system and provide a theoretical basis for the efficient propagation of germplasm resources.

Method Rhizome buds of C. kwangsiensis were used as explants. MS medium supplemented with agar (6 g/L) served as the basal medium. The primary induction medium contained 6-BA (2 mg/L) and NAA (0.1 mg/L), while the proliferation medium contained 6-BA (5 mg/L) and NAA (0.2 mg/L). Seven sugar concentration combinations, with sucrose and raffinose ranging from 0% to 3%, were designed. Their effects on the induction rate of shoot clusters, proliferation coefficient, and root development at different culture stages were systematically analyzed.

Result In the primary induction experiment, the sucrose-raffinose combinations significantly enhanced the shoot cluster induction rate. The treatment with 2% raffinose + 1% sucrose performed optimally, achieving an induction rate of 81.82% and producing the highest number of shoot clusters. In contrast, treatments with 3% sucrose or 3% raffinose alone yielded induction rates of only 36.36% and 20 %, respectively. During subculture proliferation, the combination of 2% raffinose + 3% sucrose achieved the highest proliferation coefficient of 3.80, with vigorous shoots. The sugar combinations also influenced the rhizogenesis of C. kwangsiensis. The combination of 0.5% raffinose + 3% sucrose significantly promoted root growth, resulting in an average root number exceeding 11, an average root length over 35 mm, and an average root diameter above 2 mm.

Conclusion Sucrose-raffinose combinations effectively optimize the in vitro propagation efficiency of C. kwangsiensis. The optimal formulation for primary shoot clusters induction is 2% raffinose + 1% sucrose, while 2% raffinose + 3% sucrose achieves highly efficient bud proliferation. Furthermore, 0.5% raffinose + 3% sucrose significantly enhances root development. This study provides a valuable reference for establishing a standardized rapid propagation protocol for this species.