Types of stem cuttings and treatment with indolebutyric acid for propagation of Lippia alba (linalool chemotype)

Resumen

Introduction: Lippia alba (Mill.) NE Br. Ex P. Wilson, commonly known as bushy lippia, is a plant native to Brazil used to treat respiratory conditions as well as gastrointestinal and hepatic disorders.
Objective: Evaluate the survival, rooting and budding of different types of cuttings of L. alba (linalool chemotype) using indolebutyric acid (IBA).
Method: L. alba branches with leaves were collected in September 2016 in the city of Pinhais, Paraná, Brazil. Four types of cuttings were evaluated: apical herbaceous and thin, medium-thickness and thick semi-woody (0.25±0.06; 0.60±0.1; 1.2±0.2 cm in diameter, respectively) taken from the central section of the branch and without leaves. The bases of the different types of cuttings were submerged in three treatment substances: IBA (2 000 mg/l^-1), hydroalcoholic solution (50 % v/v) and distilled water. The cuttings were planted in 120 cm³ plastic tubes filled with commercial substrate Tropstrato HT^® and were kept under intermittent mist. At 30 days an evaluation was performed of the rates of survival, rooting and budding, the average number and length of roots, and the dry mass of roots and buds.
Results: No interaction was observed between the types of cuttings and the treatments applied. The four types of cuttings exhibited high survival and rooting percentages (averages above 86.7 %) and did not differ between themselves. Treatment with IBA fostered rooting with the highest percentages (98.1 %). Dry root mass was greater in apical herbaceous and thick semi-woody cuttings.
Conclusions: For propagation of L. alba (linalool chemotype), use may be made of apical herbaceous and thin, medium-thickness or thick semi-woody cuttings, which exhibit rooting percentages above 85 %. Treatment of the cuttings with IBA at 2 000 mg/l^-1 improves the rooting percentage.

Key words: auxin, bushy lippia, ethanol, medicinal plant, rooting.