Glandular trichomes and secreted material in Salvia wagneriana Polak.

Salvia wagneriana is a shrub of the subgenus Calosphace, growing in Central America, particularly in Mexico and Costa Rica, frequently cultivated in the gardens of the warm-temperate regions for his beautiful, red inflorescences. The subject of this work is a study of the glandular trichomes present on the plant and of their type of secretion. The leaves of Salvia wagneriana bear numerous glandular trichomes both on abaxial and adaxial sides. They occur as peltate and capitate. The peltate trichomes consist of one basal epidermal cell, a stalk cell and a broad head of 4 secretory cells. Three types of capitate trichomes are present: capitate type I, consisting of one basal epidermal cell, one stalk cell and a round head of one single broad cell; capitate type II, consisting of one basal epidermal cell, one stalk cell and an elongated head of one cell; capitate type III, consisting of a basal epidermal cell, 1-6 stalk cells and a single rounded head cell. All these types of trichomes are present on the leaf, although type III is rare; however it is frequent on the flowers, particularly on the calix. The histochemical and ultrastructural observations evidence in peltate hairs a lipophylic secretion constituted mostly of essential oil and in capitate type I hairs a mainly hydrophilic secretion. The other two types of capitate hairs show a lipophylic secretion constituted mainly of essential oil. Flavonoids have been evidenced in all the hair types. In the essential oil, obtained by hydrodistillation of the leaves, twenty nine components, have been identified by GC-MS: monoterpene hydrocarbons account for 0.3%, oxigenated monoterpenes 6.3%, sesquiterpene hydrocarbons 47.1%, oxygenated sesquiterpenes 2.9%, non-terpenoidic compounds 13.2%.