1Grupo de Química Ecológica, Departamento de Química, Universidad de Los Andes, Mérida 5101, Venezuela.
2Laboratorio de Productos Naturales, Instituto de Investigaciones, Facultad de Farmacia, Universidad de Los Andes, Mérida 5101, Venezuela.
*Correspondence author. E-mail: alonsome123@yahoo.com
The extraction and chemical composition of essential oil of Minthostachys mollis (Kunth) Griseb (Lamiaceae) and its inhibitory effects on germination and shoot/root elongation of lettuce, tomato, cucumber and Bidens pilosa (L.) var pilosa are described. Hydrodistillation gave 2.9% (v/w) of essential oil (97.8% of terpenoids). Pulegone (83.6%), menthone (7.6%), limonene (2.0%) linalool (1.2%), and isomenthone (0.8%) were the major components of essential oil. This oil was applied at 1.0, 2.5 and 5.0 μl on filter paper disks for bioassay. The seed germination of all test spp was completely inhibited even with the lowest dose. Five days-old transplants of seedlings (7 days for B. pilosa) exposed to 5, 10 and 20 ppm of oil in the vapour phase inhibited the elongation of shoot more than root and its inhibition was concentration dependent. B. pilosa was most resistant and tomato the most sensitive plants. Shoot growth of B. pilosa was inhibited at 20 ppm with necrosis of hypocotyls.
Allelopathy, Bidens pilosa, cucumber, essential oil, growth inhibition, lettuce, menthone, Minthostachys mollis, pulegone, tomato, Venezuela
