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

The structure, site and histochemistry of glandular hairs on the vegetative and reproductive parts of Salvia officinalis were investigated by UV and c onventional light microscopy and by scanning electron microscopy. Five dist inct types of glandular hair (one peltate and four capitate) with different sites, secretory modes and secretions, were identified, and a functional r ole postulated for each type. All the hair types show mixed secretions, i.e ., hydrophilic and lipophilic, except type I capitate hairs, which have hyd rophilic secretions only. In peltate hairs and in type II capitate hairs hy drophilic secretion prevails; in the remaining types, lipophilic secretion dominates. The manner, time and role of erection of peltate hairs on the re productive organs and the role of non-glandular hairs are also considered. (C) 1999 Annals of Botany Company.