Vegetative anatomy in Iochroma australe (Solanaceae)

MACHADO, A. S.; COSA M. T. ; BARBOZA G. E.

Joao Pessoa

Simposio; XXI Simpósio de Plantas Medicinais do Brasil.; 2010

Universidade Federale do Paraíba

Iochroma australe Griseb., known as "pera del cerro", “ciruelo” or “serminuela” is a shrub that grows in western South America, from the north of Colombia to northwestern of Argentina in high and humid valleys from Jujuy to Catamarca (Hunziker, 2001). It possesses yellow fruits with an agreeable flavor similar to apple or melon, for what they are consumed locally. Due to its tubular blue flowers, this species is very showy and is cultivated as ornamental in other countries. Phytochemically, I. australe contains many peculiar steroidal compounds named withanolide glycosides (Burton, 2000) in leaves and stems, with selective herbicidal activity against weed species. Besides, these compounds have citotoxic activity against cancer cells (Mamone, 2008). In this work we analyze the anatomy of the vegetative organs of I. australe to provide diagnostic data of interest for the identification of this species when quality control is required due to its medicinal properties. Transverse sections of stems and leaves were made and stained with astral blue and basic fuchsine. For the study of the leaf epidermis, the peeling technique was used. The obtained information was evaluated by statistical methods. The leaves are amphistomatic; the anisocytic and anomocytic stomata are scanty in the epiphyll; the stomatal index varies from 1.19 ± 6.79 to 12.52 ± 17.54 in the adaxial and abaxial surface respectively. Eglandular and glandular trichomes are abundant in leaves and stems, like in other species of this genus, with a frequency of 15.12 ± 13.15 mm2 in the adaxial surface and 27.31 ± 16.17 mm2 in the abaxial side. The dorsiventral mesophyll contains druses whereas the petiole and stem present crystal sands. In the stem, the periderm is originated in a subepidermic layer; the cortex has conspicuous groups of fibers associated with the external phloem which also appear in connection with the internal phloem. Types and position of the stoma, types of trichomes, and types of crystals are the most relevant diagnostic characters in leaves while the origin of the periderm and the position of the fibers in the stem.Griseb., known as "pera del cerro", “ciruelo” or “serminuela” is a shrub that grows in western South America, from the north of Colombia to northwestern of Argentina in high and humid valleys from Jujuy to Catamarca (Hunziker, 2001). It possesses yellow fruits with an agreeable flavor similar to apple or melon, for what they are consumed locally. Due to its tubular blue flowers, this species is very showy and is cultivated as ornamental in other countries. Phytochemically, I. australe contains many peculiar steroidal compounds named withanolide glycosides (Burton, 2000) in leaves and stems, with selective herbicidal activity against weed species. Besides, these compounds have citotoxic activity against cancer cells (Mamone, 2008). In this work we analyze the anatomy of the vegetative organs of I. australe to provide diagnostic data of interest for the identification of this species when quality control is required due to its medicinal properties. Transverse sections of stems and leaves were made and stained with astral blue and basic fuchsine. For the study of the leaf epidermis, the peeling technique was used. The obtained information was evaluated by statistical methods. The leaves are amphistomatic; the anisocytic and anomocytic stomata are scanty in the epiphyll; the stomatal index varies from 1.19 ± 6.79 to 12.52 ± 17.54 in the adaxial and abaxial surface respectively. Eglandular and glandular trichomes are abundant in leaves and stems, like in other species of this genus, with a frequency of 15.12 ± 13.15 mm2 in the adaxial surface and 27.31 ± 16.17 mm2 in the abaxial side. The dorsiventral mesophyll contains druses whereas the petiole and stem present crystal sands. In the stem, the periderm is originated in a subepidermic layer; the cortex has conspicuous groups of fibers associated with the external phloem which also appear in connection with the internal phloem. Types and position of the stoma, types of trichomes, and types of crystals are the most relevant diagnostic characters in leaves while the origin of the periderm and the position of the fibers in the stem.