Planta Med 2011; 77 - PE44
DOI: 10.1055/s-0031-1282375

Trichomes in Echium amoenum Fisch & Mey petals: A micromorphological survey

S Movafaghyan 1, H Rajaei 1
  • 1Biology Department, College of Sciences, Shiraz University, 71454, Iran

Echium amoenum Fisch & Mey (Boraginaceae) grows widely in the northern highlands of Iran. Dried petals of E. amoenum have long been used for their anxiolytic, sedative, anti-inflammatory and analgesic effects in Iranian folk medicine (1). Phytochemical studies revealed a variety of substances of which rosmarinic acid and flavonoids showed antioxidant activity in humans (2). Inhibition of humoral antibody synthesis has also been reported (3). All the published studies on E. amoenum have concentrated on the therapeutic uses and/or the phytochemical analyses. No botanical data is available and the secretory structure has not been reported so far. This study was carried out to provide elements on the morphology and localization of the secretory structure, with regard to floral development. E. amoenum flowers were collected from Ghazvin, at four developmental stages. Petals were double fixed in glutaraldehyde and osmium tetroxide, dehydrated in acetone, air dried in hexamethyldisilazan, coated with gold and viewed under the scanning electron microscope. The youngest floral buds were densely covered with protective non glandular trichomes of different length. The same trichomes covered the outer epidermis of the young petals emerging from the sepals. Short stalked capitate trichomes, with one globular secretory head were observed between the protective hairs. During development, the number of non glandular trichomes decreased, but capitate trichomes increased in number, reaching their maximum in 3.5cm long petals at full bloom. Further histochemical studies will elucidate the variable nature of the secreted material, as well as the phases of the secretion process.

References: 1. Zargari A (1996) Medicinal Plants, vol. 3. Tehran University Publications.

2. Ranjbar A et al. (2006) eCAM 3(4): 469–473.

3. Amirghofran Z et al. (2000) Iranian Journal of Medical Sciences 2(3 & 4): 119–124.