Leaf oils and waxes of 29 native Tasmanian Eucalyptus species were studied from primarily a taxonomic aspect and their effects on insect-plant selection were evaluated. E. nitens, an important introduced pulpwood species that is not indigenous to Tasmania was also investigated in detail. The chemical compositions of leaf oils and waxes of both juvenile and adult leaf samples of each species were examined by GC-MS. Results indicated that the distribution of both oil and wax components within Tasmanian eucalypts and their relative proportions between subgenera and species have taxonomic importance. A chemotaxonomic classification based on these data was constructed and this classification more functionally describes insect-host-tree relationships as opposed to the classification based on morphological differences. The results of this study indicated that differences in leaf oils of eucalypt species are correlated to genetic divergence in the biosynthesis of terpenoid compounds and that biochemically related terpenoid compounds provide sensitive taxonomic characteristics for the identification of eucalypt species. A study, using material from species/provenance trials, indicated that seasonal variation in leaf oil chemicals was influenced by time, ontogenetic and physiological aging effects. The variation pattern of leaf oils between different species was found to be under strong genetic control and environmental factors tended to affect leaf oils quantitatively but not qualitatively. For the first time the chemical composition of eucalypt leaf waxes of trees from a large number of species localities has been determined by the direct analysis of crude wax. In a representative number of species localities, wax morphology was examined by scanning electron microscopy (SEM). Two general wax categories, amorphous and structured were found, the latter including three types. The results indicated that wax structure was correlated with chemical composition and that the distribution and variation ,- in both wax chemicals and wax types has relevance at all levels of the taxonomic hierarchy. The chemical composition of leaf oils and waxes among most provenances and localities of E. nitens were examined. The differences in leaf oil characteristics of two forms of E. nitens has supported the separation of the two morphological forms into separate species, E. nitens and E. denticulata. Results indicated that the chemical composition of leaf oils and waxes of E. nitens was similar to most Symphyomyrtus species but that oil yields from all E. nitens populations were significantly lower. Commercially important eucalypt species are attacked by two paropsine defoliating beetles: Chrysophtharta bimaculata and C. agricola (Coleoptera: Chrysomelidae, Paropsini). The feeding and oviposition preferences of these beetles and the feeding response of their larvae to eucalypt leaves were examined in laboratory bioassay in which the effects of leaf oils and waxes were evaluated. The results indicated that leaf acceptance or rejection by C. bimaculata and C. agricola was correlated to differences in leaf oils and waxes which were chemotaxonomically correlated among Tasmanian eucalypt species. The toxic effects of 1,8-cineole and related chemicals on C. bimuculata beetles were confirmed by leaf extract and chemical bioassay. It was found that the leaves of E. nitens were successfully attacked by C. bimuculata through the lack of chemical defence, notably low levels of 1,8-cineole. The wax bloom on juvenile foliage acts also as a physical defence against adult C. bimaculata beetles. Results also indicated that leaf preference of C. agricola was related more to variation in the triterpenoid class of wax chemicals. The inheritance of leaf oils and waxes in interspecific F1 hybrids of Eucalyptus was analysed. Results indicated that both oil and wax chemicals were strongly inherited in F1 hybrids and were valuable for identification of tree hybrids. Bioassay results indicated that feeding resistance was related to the inheritance of leaf oils in interspecific F1 hybrids. Hybrids between high and low cineole species had intermediate cineole levels and were therefore more resistant to C. bimaculata attack than the low cineole parent.

There has been a massive expansion of Eucalyptus plantations in Australia in the last decade. As most eucalypt species are native to Australia, this has raised concerns about genetic pollution of native species gene pools. To assess the risk of genetic pollution, five key aspects of gene flow from E. nitens plantations in Tasmania were studied. Firstly, the pattern of pollen dispersal from plantations into native E. ovata forests was examined at three sites. The frequency of F1 hybrids among 119 000 progeny, grown from open-pollinated seed collected from E. ovata trees at varying distances from E. nitens plantations, was determined. A leptokurtic pattern of pollen flow was evident, with the mean level of hybridisation at the plantation boundaries (0-100 m) being 14%, dropping to 1% by 200-300 m and continuing at this level to the extent of the studied areas (max. 1600 m). Secondly, the first exotic E. ovata x nitens F1 hybrids actually established in the wild were discovered and verified using morphological and allozyme analyses. Thirdly, field trials were established to assess the fitness of the exotic E. ovata x nitens F1 hybrids in the wild. The hybrids displayed poorer early-age performance relative to their pure E. ovata half-sibs. However, many were still alive and growing successfully two years after planting. Fourthly, surveys of flowering time were conducted on native Symphyomyrtus species, which were potentially at risk of gene flow from plantations. This was combined with a spatial analysis of the proximity of eucalypt plantations to each native species, and used to produce an overall assessment of the potential for exotic hybridisation and gene flow. These results indicated that at least eight of the 16 Symphyomyrtus species in Tasmania appear to have significant potential for pollination by E. nitens, and will need further study. Finally, the crossability of E. nitens pollen on native female Symphyomyrtus species was assessed using artificial pollination techniques. A number of species did not produce hybrids with E. nitens, indicating that post-mating barriers may be acting to prevent hybridisation. Overall results suggest that the main risk of genetic pollution in Tasmania is limited to a few species. Of those species, the ability of first and later generation hybrids to survive to reproductive maturity and backcross with native populations, allowing the introgression of exotic genes, is yet to be assessed.

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A series of experiments was conducted with the view of obtaining baseline information on the use of polyethylene glycol (PEG) on Tasmanian Oak for the purpose of improving the quality of the seasoned structural timber product. Tasmanian Oak is the marketing name for a triad of Tasmanian-grown eucalypt species (E. delegatensis, E. obliqua, and E. regnans). Incubation of freshly-milled timber in aqueous PEG solutions prior to seasoning follows on from investigations in northern hemispheric timber species such as hoop pine and spruce in the middle of the 20th Century. PEG penetrates freshly sawn Tasmanian Oak in a manner which is considerate of incubation time, temperature, PEG molecular weight/size and timber density. Histological examination indicated that PEG penetrated completely throughout the structure of the wood substance in three orientations (transverse, radial and tangential). During air-drying of PEG soaked timber, further migration of PEG into Tasmanian Oak is negligible. The rate of moisture content loss in Tasmanian Oak was shown to be retarded by PEG pre-treatment although the ability to prevent moisture loss was not concomitant with dimensional stability. An investigation to explain the change in rate of moisture loss examined effects on the thermodynamic property, water activity. Results indicated that a change in solution water activity could partly expain changes in the rate of moisture content loss, but more research is required to better divine this relationship. Shrinkage in Tasmanian Oak was reduced after treatment with aqueous PEG 400 solutions at or above 30% (v/v), with a greater percentage reduction in tangential shrinkage compared to reduction in radial shrinkage. This is significant as backsawn (a.k.a. flatsawn) timber, with its broader tangential face, was in particular focus. The reduction in shrinkage was consistent with PEG concentration in the incubating medium. A decrease in the formation of drying defect, such as surface and internal checking accompanied the improvement in keeping sawn dimensions. Backsawn Tasmanian Oak obtained from young trees (less than 20 years) from plantation resource presents a challenging profile for commercial timber drying and will become more prevalent as the logging of old-growth forests is phased out. Timber seasoners may be faced with options of longer drying times or lower yields due to drying defect unless a method can be developed to provide added protection to the sawn timber product during drying. At this stage, pre-treatment of Tasmanian Oak with PEG shows the hallmarks of providing a solution to this emerging dilemma.

This thesis examines the quantitative genetics of intra- and inter-specific hybrids of E. globzllus ssp. globl~lus and E. nitens. The trials established to make this study are unique in forestry, due to the fact that the same parents have been used in open-pollination, intra- and inter-provenance (or intra-species) crosses and inter-species F1 hybrids. This has allowed direct comparison of genetic parameters derived from different cross types. The traits examined include frost resistance using an electrical conductivity method, growth (diameter at breast height over bark DBHOB, at ages 2, 3, 4, 6 and 10 years) and Pilodyn penetration at age 6 years as an indirect measure of wood density. The results demonstrate that the measured performance of frost, growth and Pilodyn traits in the inter-specific Fi hybrid E. nitens x globulus is always intermediate or comparable with one or other of the parent species. In the frost trait, the inter-specific hybrid was no better than the frost sensitive E. globulus, so there is no overall advantage in producing the hybrid for this trait. Negative mid-parent heterosis was observed for early age growth traits in inter-specific E. nitens x globulus FI hybrids involving Taranna E. globulus male parents. The inter-specific FI hybrids demonstrated generally poor survival and a high proportion of abnormal and slow growing phenotypes, which eventually died. This latter phenomenon was not evident in pure species crosses, either within or between provenances. It is shown that in E. globulus open-pollinated progeny estimates of additive genetic parameters are inflated and that breeding values for growth in E. globulus are poorly estimated, possibly due to the confounding effects of variation in inbreeding. This was not the case for traits of high heritability such as Pilodyn. Within the E. nitens population studied, open-pollinated estimates compared well with control-pollinated estimates for all traits. Genetic parameter estimates from control-pollinated progeny indicate low heritability for growth in E. globulus which diminish over time. Dominance effects were low and comparable with additive genetic effects but were site specific. In E. nitens heritability for growth is moderate to high, tending to increase over time with significantly low levels of dominance, which diminish over time. Pilodyn has low to moderate heritabilities with low levels of dominance in both species. Moderate levels of heritability were demonstrated for frost resistance in both species, but dominance effects could not be accurately estimated. The correlation of performance of parents in intia-specific crosses through their General Combining Ability (GCA) is compared with performance in inter-specific hybrids through General Hybridising Ability (GHA). It is shown that there is little or no correlation between GCA and GHA in inter-specific F1 hybrids for growth or frost resistance, but there was a good correlation for Pilodyn. This indicates that, for growth and frost resistance, there may be different genes, which contribute to expression between species and these may not combine according to classical quantitative genetic theory. In contrast, within E. globulus there was very high correlation of within-provenance GCA with between-provenance GHA for growth and Pilodyn, indicating the same genes are acting within the species, regardless of provenance. It is demonstrated that standard quantitative genetic models do not cope adequately with inter-specific F1 hybrid populations for growth traits in this case. In addition, the implication for breeding and deployment of interspecific Fi hybrids is compromised by the lack of ability to predict performance of potential hybrid combinations from pure species performance of parents.

Auckland, the largest city in New Zealand, with a population of approx. 700,000, is notorius for its high incidence of respiratory allergies, particularly asthma. At a conservative estimate, one in every ten persons in the region suffers from allergic asthma and/or rhinitis (hay fever). In the Auckland Hospital Board area alone, there were 58 deaths from asthma in 1979 and 57 in 1980 (an average of 5 per month). Asthma and rhinitis affect people of all ages. To investigate the reason for the high incidence of these respiratory allergies, an aerobiological study of the qualitative and quantitative composition of the air spora was thus undertaken. To include a reasonably representative cross section of the region for air sampling three localities from near the centre of the city to the western suburban fringe were chosen along a 20km axis encompassing commercial, residential, agricultural, horticultural and forested environments. A Burkard 7-day recording volumetric spore trap was operated continuously at each locality, from 1 September 1979 to 31 August 1980. Counting and identification of spores and pollen grains were undertaken within 5 random microscope fields along each of 12 traverses across the spore trap tapes representing alternate hours of the day on Mondays and Tuesdays. Data were converted to concentrations (numbers m-3 of air). Of a total of 38 spore or pollen categories recorded, 24 displayed seasonal and circadian periodicities. The survey revealed that there was considerable contamination of the atmosphere by spores of various fungi, particularly in summer and autumn with peaks at all sites in autumn. It is of interest that the admission rate of patients with "status asthmaticus" in the two year period January 1979 ��� December 1980, was also high in summer and autumn with peaks in both years in April (autumn). Fungal spores >3��m constituted c. 99% of the Auckland air spora in all seasons, even spring, the chief pollen season. Basidiospores were the most abundant type of the region. Amongst indentified basidiospores, Ganoderma and Coprinus predominated. Basidiospores ascribable to Hypholoma, "Calvatia-Bovista" Tilletiopsis, Entoloma and Thelephora were also recorded. Ascospores of various genera were also abundant at all sites. Among them, those ascribable to the genus Leptosphaeria were most common, followed by "Hypoxylon-Xylaria", Pleospora and Venturia. Conidia of Cladosporium were one of the principal components. Other conidia recorded, although in small numbers, belonged to the genera Polythrincium (trifolii), Epicoccum, Pithomyces (chartarum), Stemphylium, Alternaria, Periconia, Torula, Helicomyces, Helminthosporium (Drechslera), Pestalotia, Cryptostroma, Tetraploa, Arthrinium and Monilia. Conidia of "Aspergillus-Penicillium" type were the most prevalent at the city site. A comparison of the air spora at the three localities revealed major quantitative but not qualitative differences. The suburban locality emerged with higher spore concentrations than the urban and forested sites. The relationships between some meteorological factors and the 14 most prevalent categories of the air spora were analysed. Cladosporium and Polythrincium showed a significant correlation with temperature; unidentifiable ascospores were correlated with midnight temperature, humidity and, strongly, with rainfall; Leptosphaeria correlated with rainfall and midnight temperature. Unidentifiable coloured and hyaline basidiospores as well as Ganoderma and Coprinus were positively correlated with temperature. Coloured basidiospores and Ganoderma also showed a significant "negative" correlation with wind speed. On the basis of the aerobiological findings and a potential link with asthma admissions to hospital a total of 67 aqueous and lyophilized extracts from basidiomycetous fungi collected in the Auckland region were prepared in buffered saline, with W/V standardized concentration, for immunological studies. 'Total protein' content of the extracts were estimated. A total of 129 allergic patients both "heterogeneous group" and diagnosed, attending hospital allergy clinic, were tested by the skin prick method. Over 10% of the patients reacted positively to the crude extracts of the following fungi: Ganoderma mastoporum*, Ganoderma applanatum**, Scleroderma albidum*, Coprinus micaceus*, Lycoperdon compactum*, Hydnum crocidens var. badius**, Xeromphalina podocarpi***, Auricularia polytricha***, Agaricus bisporus*,Bovista brunnea*, Panaeolina foenisecii**, Hypholoma acutum**, Calvatia* sp. Pseudohydnum gelatinosum***, Trametes versicolor***, Favolaschia calocera***, Cortinarius*, Tyromyces*** sp. and Hydnum crocidens**. Allergenicity to many of these genera has rarely been investigated or reported. The findings of the investigation suggest that fungal spores in general, and basidiospores in particular, may play an important role in the high incidence of allergic asthma and rhinitis in the Auckland region. * spores alone extracted ** hymenial tissue extracted *** whole sporophores extracted / Whole document restricted, but available by request, use the feedback form to request access.