Composición química y revisión de las propiedades acaricidas de los aceites esenciales de Melinis minutiflora y Lantana camara / Chemical composition and review of the acaricidal properties of the essential oils of Melinis minutiflora and Lantana camara

The present study determined the volatile chemical components of the essential oils (EA) of the Melinis minutiflora and Lantana camara species, by means of gas chromatography coupled to a mass spectrometer, the species were collected in the cantons of Quilanga and Loja, the extraction was carried out by steam distillation. In the essential oil (EA) of M. minutiflora, 20 compounds were identified, representing 93.21%, the compounds in the highest concentration: 1-tetradecanol (16.30%), (E) -cariophylene (12.44%), germacrene D (10.99%), (E) -nerolidol (8.28%), δ-cadinene (5.61%), α-humulene (5.36%), viridiflorol (4.78%) and (Z) -ß-farnesene (4.76%). In the AE of L. camara, 68 compounds were identified, representing 96.54%, the compounds with the highest concentration (E) -caryophyllene (15.46%), germacrene D (12.21%), α-humulene (9.92%), bicyclogermacrene (7.06 %), γ-terpinene (5.97%) and germacrene B (4.66%). The species M. minutifloraand L. Camarahave repellent, acaricidal properties in adult larvae of Amblyomma cajennense and Rhipicephalus (Boophylus) microplus.

El presente estudio determinó los componentes químicos volátiles de los aceites esenciales (AEs) de las especies Melinis minutiflora y Lantana camara, mediante cromatografía de gases acoplado a espectrómetro de masas, las especies se recolectaron en los cantones de Quilanga y Loja, la extracción se hizo mediante destilación por arrastre de vapor. En el aceite esencial (AE) de M. minutiflora se identificaron 20 compuestos, representan el93,21%, los compuestos en mayor concentración: 1-tetradecanol (16,30%), (E)-cariofileno (12,44 %), germacreno D (10,99%), (E)-nerolidol (8,28 %), δ-cadineno (5,61 %), α-humuleno (5,36 %), viridiflorol (4,78 %) y (Z)-ß-farneseno (4,76 %). En el AE de L. camara se identificaron 68 compuestos, representan el 96,54%, los compuestos en mayor concentración (E)-cariofileno (15,46%), germacreno D (12,21%), α-humuleno (9,92%), bicyclogermacreno (7,06%), γ-terpineno (5,97%) y germacreno B (4,66%); las especies M. minutiflora y L. cámara, presentan propiedades repelentes, acaricidas en larvas, adultas de Amblyomma cajennense y Rhipicephalus (Boophylus) microplus.

Gamma radiation on seeds of natal grass [Melinis repens (Willd.) Zizka] induced plant's morphological and nutritional variability.

Induced mutagenesis through gamma radiation generates structural and chemical changes in plants. This study evaluated the morphological and nutritional variability of natal grass [Melinis repens (Willd.) Zizka] plants produced from seed irradiated with gamma radiation. Natal grass seed was collected from wild populations in the state of Chihuahua, Mexico. The seed was exposed to a source of Co60. The radiation doses were: 0, 10, 50, 100, 150, 200, 250, 300 and 350 Gray (Gy). Sixty-six first generation mutant genotypes (M1), produced from irradiated seed, and nine non-mutant genotypes (M0), developed from non-irradiated seed (0 Gy), were evaluated. For the morphological characterization, 18 variables were measured on the plants when they were at the reproductive stage. The nutritional analysis was performed on the M0, as well as on a group of plants from the M1, which resulted morphologically different (p <0.005) from the rest. The differenced M1 plants were classified as promising mutant genotypes (M1p). Results showed that variability was induced in the M1p. These individuals presented morphological differences in leaf weight-tillering weight ratio and foliage height, compared to the rest of the plants (p <0.001). The M1p 250-10 genotype presented the highest (p <0.001) crude protein and the lowest (p <0.001) lignin contents. Gamma radiation in the seed of natal grass induced morphological and nutritional variability. With that, promising mutant genotypes, with desirable morphological and nutritional attributes, were identified.