H. Li et al., VARIATION IN VOLATILE LEAF OILS OF THE TASMANIAN EUCALYPTUS SPECIES .1. SUBGENUS MONOCALYPTUS, Biochemical systematics and ecology, 23(3), 1995, pp. 299-318
Volatile oils were analysed from juvenile and adult leaves collected f
rom natural populations of five species from the series Obliquae (Euca
lyptus obliqua, E. delegatensis, E regnans, E. sieberi and E pauciflor
a) and seven species from the series Piperitae (E. risdonii, E. tenuir
amis, E. pulchella, E amygdalina, E. nitida, E. radiata and E. coccife
ra) of the informal subgenus Monocalyptus (genus Eucalyptus). Oil yiel
ds (1.3-4.9% dry wt.) from adult leaves of all species were markedly h
igher than from corresponding juvenile leaves (0.1-3.1% dry wt.). Vola
tile leaf oils of most species are rich in alpha- and beta-phellandren
e, cis- and trans menth-2-en-1-ol, while some were rich in 1,8-cineole
or alpha, beta and gamma-eudesmol. Multivariate analyses indicated th
at the Tasmanian eucalypt species from series Obliquae are well differ
entiated and exhibit little intraspecific variation in percentage oil
composition. In contrast, species from the series Piperitae show great
intraspecific variation and are poorly differentiated which is consis
tent with morphological studies. The chemical composition of Volatile
oils of juvenile and adult leaves were qualitatively similar but were
quantitatively different in some oil components for some species. Resu
lts indicated that volatile leaf oils are useful for chemotaxonomic st
udies in Eucalyptus.