Establishment and clonal propagation of Lippia dulcis Trevir. through in vitro single node cultures
Lippia dulcis Trevir. (Verbenaceae) is a species with medicinal potential that is used as a tranquilizer and to control diabetes in the western region of Pará, Brazil. The objective of this study was to determine the establishment and clonal propagation of Lippia dulcis through single nodal segments grown in different concentrations of salts in a MS (Murashige and Skoog) medium (MS, MS/2, MS/4) and determine the best period for subculturing the species. Nodal segments cultivated in the MS medium showed a higher survival percentage and better development than those grown in more dilute media (MS/2, MS/4). The concentration of the salts affected the dry weight gain of some plant parts. Plantlets cultivated in the MS medium obtained better leaf dry weight and total leaf area than plantlets cultivated in half-strength MS. The half-strength MS medium proved to be most effective for root length growth and root dry weight gainin vitro. The growth curve showed that day 30 was the time for subculturing the species. Starting with only one nodal segment, 3125 plantlets were obtained after sixth months of cultivation at a multiplication rate of five. The plantlets of Lippia dulcis were removed from the flasks and acclimatized with success in a greenhouse.
Index terms: Growth analysis; micropropagation; shoot proliferation; nodal segment.