Evaluation of new protocols to Curcuma longa micropropagation: A medicinal and ornamental specie

Turmeric (Curcuma longa) is an Asian native species used for ornamental, medicinal and food purposes. However, its conventional propagation method is costly and inefficient. Therefore, this study aimed to verify appropriate asepsis methods for shoots from rhizomes, evaluate concentrations of activated charcoal and sucrose, and determine appropriate salt concentrations in Murashige and Skoog (MS) medium for turmeric growth. Three independent assays were performed. First, asepsis methods were verified for explants; second was for concentrations of sucrose and activated charcoal and in the final assay salt concentrations was evaluated. In all assays, MS medium supplemented with 30 g/L of sucrose, 6.5 g/L of agar and pH adjusted to 5.8 was used. Two growth regulators were added to the culture medium: 4.44 µM of 6-benzyl-amino-purine (BAP) and 1.08 µM of α-naphthalene acetic acid (NAA). Data obtained were subjected to analysis of variance (ANOVA) at p ≤ 0.05 probability. The averages were compared by Tukey’s test and polynomial regression at p ≤ 0.05. All the asepsis methods evaluated showed similar effects. The highest concentration was obtained by utilizing 60 mg/L sucrose for the most part of the evaluated characteristics; however, it is recommended that activated charcoal be used at a concentration of 4.5 g/L. For salt concentrations, averages were compared by polynomial regression at (p ≤ 0.05) probability in 50 to 60% MS medium, and resulted in longer root systems, greater numbers of shoots and more leaves. The usual dose of 3% sucrose resulted in lower development of in vitro seedlings. Salt concentrations higher than 60% were toxic to turmeric tissues and consequently compromised the root system and the aerial part of developing seedlings.