Production, postharvest treatment and epicuticular wax structure of cut stems of Eucalyptus L'her foliage

Abstract

Species of Eucalyptus L' Hér. were subjected to trials to investigate their suitability for floriculture and the effect of pruning for cut foliageproduction. After pruning at 19 months the interaction of species x pruning height was significant for tree height, increase in height after pruning, trunk diameter and lignotuber diameter. There were significant differences between species, in the lengths of stems, total number of stems and total weight of stems at 12 months after pruning, with E. globulus producing the highest number and weight of stems. For E. gunnii pruning to 1.0 m at 25 months produced most stems at 6 months after pruning. Postharvest trials were conducted to assess the vase life of cut stems, and the effect of pulsing and simulated transportation on vase life. Holding solutions containing 1% or 2% sucrose significantly increased vase life of E. globulus and E. cinerea over the control, but pulsing E. cinerea in 1%, 5%, or 10% sucrose for 2 hours at 24°C or 24 hours at 3°C had no effect. In simulated transport trials, a 5% sucrose pulse significantly increased the vase life of E. spathulata x E. platypus. Eighteen species of Eucalyptus L'Hér. were studied for changes in wax morphology of juvenile foliage with leaf age using Environmental Scanning Electron Microscopy. All species had tube wax on juvenile leaves but there were differences between the species, in the length and conformation of tubes and percentage surface area covered by wax. Tube length was greatest in day 30 leaves, but tube diameter was narrower than day 0 leaves. There were significant differences in wax structure between the proximal and distal ends of day 0 leaves of ten species, and tubes were observed crystallising from amorphous wax deposits in the proximal area only.