Effects of sucrose concentration and membrane filter number on the growth and volatile compounds of micropropagated Lippia rotundifolia Cham. plantlets

Abstract

Lippia rotundifolia Cham. is a medicinal species, native to Brazilian mountainous regions, with leaves rich in monoterpenes. The objective of this study was to evaluate the effect of different concentrations of sucrose in MS medium with a natural ventilation system using porous membranes on the growth and contents of volatile compounds in L. rotundifolia plantlets. The experimental design was completely randomized, with 12 treatments, consisting of a factorial system of four ventilation systems and three sucrose concentrations. The treatments were a system with no porous membrane (NMS) and three natural ventilation systems (AMS) containing one, two, and four porous membranes. The sucrose concentrations were 0, 15, and 30 g L−1. The natural ventilation systems were superior to NMS. The natural ventilation system with two and four porous membranes and 15 g L−1 sucrose in MS medium led to higher in vitro growth rates in L. rotundifolia. AMS using manufactured porous membranes was found to be a more efficient in vitro cultivation method than NMS. The ventilation system with four porous membranes and a sucrose concentration of 15 g L−1 was the most efficient, since an increase in the photosynthetic rate and less evaporative water loss were observed in this ventilation system. Volatile organic content was influenced by ventilation systems and sucrose concentrations. Major compounds myrcene, limonene, myrcenone and ocimenone were identified. AMS4 and presence of sucrose (15 and 30 g L−1) increased the myrcene and ocimenone content. The myrcenone content was favored by NMS without sucrose. Overall, the alternative membrane system with 15 g L−1 of sacarose can be recommended in the in vitro culture method of L. rotundifolia.