ABSTRACT
Terpenoid-containing secretory cells both in glands and in ducts fluoresce in the blue (450-460 nm) and green-yellow (500-550 nm) spectral regions (Roshchina et al., 1998a, d). The first is typical of sesquiterpenes and monoterpenes of oils. Shoulder in the red region (>600 nm) may belong to derivatives of sesquiterpene lactones such as azulenes bound with cell wall. Blue pigments azulenes are found in essential oils of glands in some Asteraceae species (Konovalov, 1995), in needles of conifer plants (Kolesnikova et al., 1980), in pollen grains (Roshchina et al., 1995) and in other secretory tissues and cells, for example in clovers leaves (Roshchina, 1999a) and in oil glands from Solidago leaves (unpublished data of Roshchina). The blue-green colour of conifer needles appears to related to blue azulenes. The compounds are found in the fractions of isolated chloroplasts (Roshchina, 1999a, b).
