EPICUTICULAR WAX STRUCTURE AND REGENERATION ON DEVELOPING JUVENILE EUCALYPTUS LEAVES

Eighteen species of Eucalyptus L'Her. were studied for changes in wax morphology of juvenile foliage with leaf age using environmental scann ing electron microscopy. Three species were studied for wax regenerati on following removal from the adaxial surface of day 16 and day 30 lea ves (16 and 30 days following lamina separation, respectively) while s till attached to the tree. For each leaf age, four leaves per species were sampled at 0, 1, 3, 9 and 15 days after wax removal. All species had tube wax on juvenile leaves but there were differences between the species, in the length and conformation of tubes and percentage surfa ce area covered by wax. Tube length was greatest in day 30 leaves, but tube diameter was narrower than day O leaves (unfolding leaves). Ther e were significant differences in wax structure between the proximal a nd distal ends of day 0 leaves of 10 species, and tubes were observed crystallising from amorphous wax deposits in the proximal area only. S ignificant wax regeneration occurred more rapidly on day 16 leaves tha n day 30 leaves. Wax morphology was consistent across six species of t he series Viminales. Thirteen species of Eucalyptus are recommended fo r the cut foliage industry.