Glandular hairs of Salvia officinalis: New data on morphology, localization and histochemistry in relation to function

Abstract

The structure, site and histochemistry of glandular hairs on the vegetative and reproductive parts of Salvia officinalis were investigated by UV and conventional light microscopy and by scanning electron microscopy. Five distinct types of glandular hair (one peltate and four capitate) with different sites, secretory modes and secretions, were identified, and a functional role postulated for each type. All the hair types show mixed secretions, i.e., hydrophilic and lipophilic, except type I capitate hairs, which have hydrophilic secretions only. In peltate hairs and in type II capitate hairs hydrophilic secretion prevails; in the remaining types, lipophilic secretion dominates. The manner, time and role of erection of peltate hairs on the reproductive organs and the role of non-glandular hairs are also considered.