Gelation of Culture Medium with K-Carrageenan Improves and Reduces the Cost of in vitro Propagation of Comanthera mucugensis (Giul.) L. R. Parra & Giul

Abstract

In vitro multiplication is the main method for seedling production of Comanthera mucugensis, an endangered ornamental plant. The technique consists of cultivating plant tissues under aseptic conditions, controlled environment, and using appropriate culture medium. The physical characteristics of the medium are mainly determined by the presence of a gelling agent. Agar is the most used substance on the in vitro cultivation of C. mucugensis, however, it is one of the most costly components to manufacture the medium. The objective of the present study was to evaluate the effect of κ-carrageenan as an alternative gelling agent in the propagation of C. mucugensis. The seeds and stem explants were cultured on medium gelled with agar or κ-carrageenan, both at 7 g L-1 concentration. The results indicated that the plants established in medium with κ-carrageenan presented an increase in length and induced formation of shoots. Direct organogenesis was also improved with the use of this gelling agent. In comparison, agar culture presented the lowest rate of direct regeneration and the lowest number of shoots. In addition, gelation with κ-carrageenan was efficient in increasing the frequency of callogenesis, as well as, the highest callus regeneration and number of shoots per callus. Rooting was not affected by the type of gelling agent. The substitution of agar for κ-carrageenan can represent a reduction of 23.2% in the cost of manufacturing the culture medium for in vitro propagation of C. mucugensis.