Structure and chemical content of the trichomes in two Doronicum species (Asteraceae)

Abstract

Olga V. Kostina, Lyudmila E. Muravnik

Non-glandular and three types of glandular trichomes localized on a peduncle and the phyllaries of two species (Doronicum orientale and D. macrophyllum) belonging to Senecioneae tribe of Asteraceae were studied by light and electron microscopy, as well as on histochemistry. The plant species differ on the trichome morphology, anatomy and arrangement. Three types of the glandular trichomes are formed on the vegetative and reproductive organs in D. orientale, whereas only one type exists in D. macrophyllum. It was shown by fluorescent microscopy and histochemistry that the phenolic substances, terpenoids and sesquiterpene lactones present in the glandular trichomes. The received results allow assuming that secretion of the trichomes is a chemical barrier to insects and fungi.