Eucalyptus Paniculata Research Articles

Chemistry and Bioactivities of Six Tunisian Eucalyptus Species.

The complex taxonomy of Eucalyptus genus, the renewed interest in natural compounds able to combat microbial strains, the overuse of synthetic pesticides, the consequent request for alternative control methods were the reasons for this research. The essential oils (Eos) of Eucalyptus bosistoana, Eucalyptus melliodora, Eucalyptus odorata, Eucalyptus paniculata, Eucalyptus salmonopholia, and Eucalyptus transcontinentalis were analyzed by GC/MS and their potential phytotoxic activity was evaluated against the germination and radicle elongation of Sinapis arvensis, Raphanus sativus and Lolium multiflorum. The antibiofilm activity was assayed against both Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii) bacteria. Monoterpenoids were the most representative constituents in all EOs and eucalyptol was the dominant component except in E. melliodora EO, in which p-cymene was the most abundant. In phytotoxic assays, the EOs from E. odorata and E. paniculata were the most active against germination and radical elongation of the tested seeds. Finally, the Eucalyptus EOs proved their capacity to effectively inhibit the adhesion process of all five pathogen strains, with percentages often reaching and exceeding 90%. These Eucalytpus EOs could have possible employments in the food, health and agricultural fields.

Secretion of IL-6 by fibroblasts exposed to Australian honeys involves lipopolysaccharide and is independent of floral source

Honey stimulates cellular secretion of cytokines, which has been attributed to activation of lipopolysaccharide (LPS)-dependent and LPS-independent pathways. The objective of this study was to identify whether LPS is present in Australian honey samples at levels that can stimulate interleukin-6 (IL-6) secretion by fibroblasts and whether it can transduce cell signalling by activating toll-like receptor 4 (TLR4). IL-6 was measured in culture media of fibroblasts exposed to honey for 24 h. LPS was detected in a 0.125 mg/mL solution of grey ironbark honey (0.61 ± 0.05 ng/g honey). TLR4 signalling was observed in RAW264.7 macrophages that were exposed to honey and this was prevented by preincubating the honey with the LPS-neutralising agent, polymyxin B. Australian Eucalyptus, Leptospermum and Cyathode honeys stimulated IL-6 secretion in cultured human dermal fibroblasts. To examine whether the response was dependent on floral source, fibroblasts were exposed to four different samples of grey ironbark honey obtained from Queensland and New South Wales, Australia. The magnitude of the cytokine response to these honeys was highly varied. We conclude that Australian honeys contain endotoxin at levels that can stimulate IL-6 secretion by fibroblasts and that signalling in macrophages involves TLR4 activation. The IL-6 secretory response was independent of floral source.

Use of kinetic data to model potential antioxidant activity: Radical scavenging capacity of Australian Eucalyptus honeys

Antioxidant activity of honeys may be beneficial in wound healing processes by protecting cells against lipid oxidation. The DPPH assay assesses the efficacy of antioxidant molecules to reduce DPPH• to DPPHH. Studies determining EC50 are limited by single time-point determinations of antioxidant effect and can miss vital information about the rate of antioxidant response. Acquisition of kinetic data allows determination of the radical scavenging capacity (RSC) of honeys. The purpose of this study was to determine the RSC of 53 honeys from 16 species of Australian Eucalyptus trees and four samples of New Zealand manuka (Leptospermum scoparium) honey. Whereas honeys could not be differentiated based on EC50 values, significant differences were observed for RSC, supporting collection of kinetic data for honey analysis. The greatest RSC was observed for New Zealand manuka (4.6 ± 0.3 × 10−5 mg.mL−1.min−1), grey ironbark (E. paniculate; 3.4 ± 0.2 × 10−5 mg.mL−1.min−1) and river red gum honeys (E. camaldulensis; 3.2 ± 0.2 × 10−5 mg.mL−1.min−1).

Chemical composition of some plantation wood species (Eucalyptus saligna, Cupressus lusitanica and Eucalyptus paniculata) and assessment of compatibility with plaster

The aim of this work was to evaluate the chemical composition of some plantation wood and the assessment of their compatibility with plaster. A quantitative analysis of the chemical composition each of the species (Eucalyptus saligna, Cupressus lusitanica and Eucalyptus paniculata) was carried out, followed by chemical compatibility evaluation using different types of wood particles. The quantitative analyses were carried out on wood powder of size between 0.27 and 0.30 mm. The results obtained were 2.4, 3.4 and 1.6% for ethanol–benzene extract (EAB); 2.6, 3.2 and 2.4% for hot water extract (EE); 12.4, 21.6 and 12.1% for 1% sodium hydroxide extract (ES); 48.6, 48.4 and 40.4% for cellulose content (C); 34.8, 34.3 and 36.3% for lignin content (L); then 0.1, 0.6, 0.3% for ash content (CE) respectively of E. saligna, C. lusitanica and E. paniculata. Chemical compatibility CA was measured from hydration temperature curves as a function of time using the area method. The results showed that compatibility CA decreased from 100 to 68% as the wood content in the composite increased up to 15% for all species and types of particles used. At this minimum value, the species was still considered as highly compatible in accordance with literature. Although compatibility is good, it decreased in the order E. paniculata followed by E. saligna and then C. lusitanica, the least compatible due to the inhibiting action of extractives.

Flow cytometry and cytogenetic tools in eucalypts: genome size variation × karyotype stability

The eucalypts comprise a group of woody plants used in commercial forest plantations owing to their high growth rates, adaptability to various ecological conditions and multiple applications. Despite the enormous amount of molecular data available for eucalypts, a basic understanding of the nature of its genome still requires information regarding the DNA amount in the genus. In this work, we estimated the genome size and base composition of 25 eucalypt species. With a comparative karyotype approach, we aimed to identify possible chromosomal alterations correlated with the genome size variation. Classical cytogenetic and genomic in situ hybridization experiments were conducted for this purpose. The studied species showed genome size ranging from 2C = 0.91 (Corymbia intermedia) to 2C = 1.37 pg (Eucalyptus paniculata) and AT/CG ratios varying from AT = 61.3 (Eucalyptus urophylla) to AT = 62.85% (C. intermedia). Comparative karyotype analysis revealed no remarkable differences in chromosome number (2n = 22) or morphology among eucalypt species despite considerable differences in nuclear DNA content. The genome in situ hybridization method did not distinguish non-homologous chromosomal regions of Eucalyptus baileyana and Corymbia citriodora, despite the difference of 0.45 pg between their genome sizes. The results found in the present work corroborate the consideration of small and dispersed DNA changes as the main cause of genome size variation in eucalypts.

<b>Flexural properties of four fast-growing eucalypts woods deteriorated by three different field tests

Durability is a wood characteristic determined by several factors, making it difficult to investigate the service life of pieces designated for outdoor use. In this study, the decaying of juvenile and adult woods of four fast-growing eucalypts from southern Brazil subjected to three different exposure environments was monitored through mechanical properties (flexural test). The study material was obtained from adult trees of Eucalyptus botryoides, Corymbia citriodora, Eucalyptus paniculata and Eucalyptus tereticornis. Field tests were conducted in the city of Piratini, southern Brazil, and samplings were carried out during 540 days of experiment. Comparing the four eucalypts, the decreasing order of biological resistance was: Eucalyptus tereticornis, Corymbia citriodora, Eucalyptus paniculata and Eucalyptus botryoides. The mature wood showed greater and more stable physical-mechanical properties than juvenile wood.

Decay resistance of four fast-growing Eucalypts wood exposed to three types of fields

The evaluation of wood durability enables the definition of reliable parameters to predict the servicelife of wood-based products. This study aimed to evaluate the wood deterioration of four fast-growing eucalypts species (Eucalyptus botryoides, Corymbia citriodora, Eucalyptus paniculata e Eucalyptustereticornis) exposed to three field tests (outdoor, flooded site and forest canopy) during 540 days. The physical properties measured were: mass loss, density and moisture content. Furthermore, we determined changes in wood color by CIEL*a*b* method and performed a visual analysis by CENgrades. Among the four wood eucalypts, Eucalyptus tereticornis presented the highest decay resistance. The flooded site presented the best conditions for the proliferation of xylophagous agents. Mature wood was least susceptible to deterioration than juvenile wood.

Hiệu lực phòng trừ của một số chế phẩm bột từ cây tinh dầu đối với mọt thóc đỏ (Tribolium castaneum Herbst) và mọt ngô (Sitophilus zeamais Motschsky) gây hại nông sản bảo quản trong kho

In this study, the effects of herbal products processed from attar trees on the control of Tribolium castaneum Herbst and Sitophilus zeamais Motschsky which damage stored agricultural products were investigated under laboratory conditions. The results showed that the powders made from Chenopodium ambrosioides Linn., bark of Cinnamomum cassia Blume and Eucalyptus paniculata Sm. were able to exterminate T. castaneum with the effectiveness dose of 4.5 g powder. The mortality ratio of T. castaneum increased with treatment time, reached 100%, 71,28% and 100% at 30 days after treatment, respectively. For effectiveness on S. zeamais, the powder products of C. ambrosioides had the highest efficiency with 100% S. zeamais killed after 3 days at a dose of 2.5 g; the product from the bark of C. cassia and Melia azedarach Linn. had highest ability to kill S. zeamais after treatment at a dose of 4.5 g with 78.09% and 97.81% mortalities, respectively, and increased with treatment time.

Caracterização da lignina obtida da madeira de diferentes espécies por meio do processo organosolv

Lignin is a biopolymer extremely abundant with phenolic characteristics that have great potential for use in various applications. However, their three-dimensional structure of complex formation varies depending on various aspects including the specie and the way of obtaining. In this context, this study aimed to characterize the lignin obtained from four species (Eucalyptus paniculata Sm, Eucalyptus botryoides Sm, Eucalyptus tereticornis Smith, Corymbia citriodora Hook) through Organosolv process (ethanol/water). Lignins were determined as its composition, structure and functional groups. The reactivity of lignins was analyzed by total phenol content and the oxidant power. The physic-chemical properties of the lignins were determined by alternative techniques such as GPC (gel permeation chromatography) and ATR-IR (infrared attenuated total reflectance). The results showed that the lignin obtained from different species by the Organosolv process has high purity, because they have low levels of sugars and inorganic contaminants. In addition, all lignins presented high polydispersity and a higher average molecular weight was verified in E. paniculata lignin.

Observed relationships between leaf H218O Péclet effective length and leaf hydraulic conductance reflect assumptions in Craig-Gordon model calculations.

Stable oxygen isotope techniques may be a useful tool to investigate the pathways of water movement within leaves. However, implementation of such methods is limited due to uncertainty in the effective path length (L) for the Péclet effect in leaf water enrichment models. Previous studies have found relationships between L and physiological parameters such as transpiration rate (E) and leaf hydraulic conductance (k(leaf)) both within and between species. However, these studies relied on assumptions in their calculation of L, which were not directly tested. Eucalyptus paniculata Smith was used to evaluate the relationships between L, k(leaf) and E under differing water availability and a range of leaf temperatures. Coupled gas exchange and transpiration isotope measurements allowed previous assumptions to be directly tested. L was significantly and negatively related to both k(leaf) and E when the isotopic signature of water vapour was assumed to be in equilibrium with source water, was equivalent to the room vapour or equal to source water. However, the relationship between L and k(leaf) was non-significant when measured δ( 18)O of transpired vapour was used and disappeared entirely when non-steady-state leaves were excluded, and when evaporation site water was calculated from coupled gas exchange and transpiration isotope values. These results suggest that great care must be taken when calculating L, particularly regarding assumptions of isotopic steady state and δ( 18)O of vapour. Previous suggestions of changes in pathways for water movement as transpiration rate varied need to be reassessed in light of these observations.

Composition and structure of organosolv lignins from four eucalypt species

Lignins were extracted from different species using organosolv process (ethanol/water). Obtained organosolv lignins were characterised by various methods to determine their composition, structure and functional groups with the purpose of evaluating their potential use for obtaining value-added compounds. The purity of organosolv lignins was determined. The total phenols content and the antioxidant power were analysed in order to know the reactivity of lignins. The ratio S/G was determined by nitrobenzene oxidation. In addition, molecular weight distribution, infrared spectroscopy and thermo gravimetrical analysis were carried out in order to determine the physical and chemical properties of organosolv lignins. Obtained organosolv lignins have very high purity and low sugar and inorganic contamination. All organosolv lignins samples have high polydispersity, and lignin from grey ironbark wood had the highest molecular weight average. Among the organosolv lignins, lemon-scented gum showed the highest average value of S/G ratio and the lowest average value of total phenols.

Propriedades Físicas da Madeira Termorretificada de Quatro Folhosas

In this study, we aimed to analyze the physical properties of four thermally treated eucalyptuses. To this end, 20 trees (~60 years old) of Eucalyptus botryoides, Corymbia citriodora, Eucalyptus paniculata, and Eucalyptus tereticornis were randomly selected in the municipality of Charqueadas, Rio Grande do Sul state, Brazil. We prepared samples near the pith and bark of trees in order to characterize the selection of juvenile and mature wood, respectively. The samples were kept in a climatic chamber to obtain the equilibrium moisture content (~12%), which was the initial condition for the thermal treatments at 200 °C for 1 hour. Changes due to thermal treatment resulted in an increase in the dimensional stability of wood. Among the eucalyptuses, the lowest hygroscopicity was found for the mature wood of Eucalyptus paniculata, while the highest and the lowest increases of dimensional stability were observed for Eucalyptus tereticornis and Corymbia citriodora wood, respectively.

Fitossociologia em sub-bosque de Eucalyptus paniculata Smith da Lagoa do Piauzinho, Ipaba, Minas Gerais, Brasil

Eucalyptus is a common element in the landscapes of southeastern Brazil, with economic and forestry value, and is also the target of several controversies. In this study, floristic and phytosociologic parameters are described for the understory of an Eucalyptus paniculata wood located at Lagoa do Piauzinho, municipality of Ipaba, in the Brazilian state of Minas Gerais. Sampling was done between April and May 2006, for the analysis of floristic composition, species aggregation, and horizontal, diametric and vertical structure. One hundred and one individuals belonging to 22 species of 16 families were sampled in two parcels. The most abundant species were Apuleia leiocarpa, Lecythis lurida and Casearia sp. 2. The floristic diversity of the area was low compared to those found in other similar studies. The E. paniculata wood offered adequate conditions for the development of the different successional stages, with some latesuccession species starting to appear and to colonize the understory.

Ranking and mapping koala habitat quality for conservation planning on the basis of indirect evidence of tree-species use: a case study of Noosa Shire, south-eastern Queensland

Context Mapping the habitat and distribution of a species is critical for developing effective conservation plans. Koala (Phascolarctos cinereus, Phascolarctidae) distribution is constrained by the nutritional and shelter requirements provided by a relatively small number of key tree species in any given area. Identifying these key species provides a practical foundation for mapping koala habitat and prioritising areas for conservation. Aims To determine key tree species for koalas in Noosa Shire (south-eastern Queensland, Australia) as a basis for mapping koala habitat quality. Methods We applied a faecal-pellet survey methodology in 1996/97 to assess evidence of use by koalas of 4031 trees from 96 randomly stratified survey sites across different eucalypt-forest and woodland communities. Results were compared with those from a later survey undertaken in 2001/02 involving 5535 trees from 195 sites that were distributed across broadly similar areas with the aim to investigate aspects of koala landscape ecology. Key results A total of 66.7% of the 1996/97 survey sites contained koala faecal pellets, recorded under 953 eucalypt trees (14 species) and 1670 non-eucalypt trees (27 species). The proportion of trees at a given survey site that had koala faecal pellets at the base ranged from 2.2% to 94.7% (mean = 31.13 ± 2.59% s.e.). For the 2001/02 dataset, koala pellets were found at 55.4% of sites, from 794 eucalypt and 2240 non-eucalypt trees. The proportion of trees with pellets ranged from 3% to 80% (mean = 21.07 ± 1.77% s.e.). Both the 1996/97 and 2001/02 surveys identified the same three tree species (forest red gum, Eucalyptus tereticornis, swamp mahogany, E. robusta, and tallowwood, E. microcorys) as the highest-ranked for koala use in the study area. Three additional species (red mahogany, E. resinifera, small-fruited grey gum, E. propinqua, and grey ironbark, E. siderophloia) were identified in the 1996/97 surveys as key eucalypt species. Of the non-eucalypts in the 1996/97 dataset, coast cypress pine (Callitris columellaris) and broad-leaved paperbark (Melaleuca quinquenervia) ranked highest for use by koalas, followed by pink bloodwood (Corymbia intermedia) and brush box (Lophostemon confertus). White bottlebrush (Callistemon salignus), hard corkwood (Endiandra sieberi), M. quinquenervia and C. intermedia ranked highest in the 2001/02 dataset. The findings showed significantly greater use of larger eucalypts (i.e. 300-mm to >600-mm diameter at breast height). Conclusions The identified key eucalypt species, being the critical limiting resource for koalas, were used to assign koala habitat-quality classes to mapped regional ecosystem types to create a Koala Habitat Atlas (KHA) for Noosa Shire. The combined two highest quality classes based on abundance of the key eucalypt species comprised only 15.7% of the total land area of the Shire. Implications The KHA approach provides a practical and repeatable method for developing koala habitat-suitability mapping for national-, regional- and local-scale conservation and recovery planning purposes.

Testing optimised hardwood drying schedules that allow for biological variability

AbstractThe development of optimised drying schedules for addressing problems caused by the amount of biological variability in timber is desirable to produce timber of adequate and reproducible quality. It has been shown that an optimised drying schedule can be developed that allows for the biological variability of timber. Experimental testing of the schedules for hardwood timber, Eucalyptus paniculata (grey ironbark) from New South Wales in Australia has shown that the experimental results for 50% and 70% quality levels are within the bounds of the predictions, but the results for a 90% level are difficult to explain. Both experimental results and simulation predictions agree that greater variability in timber properties both decreases the profit and results in the maximum profit being given at lower values of the quality level.

Canopy nectar production and the impact of logging and climate in Grey Ironbark Eucalyptus paniculata (Smith) forests

Nectar in tall forest canopies is a significant, but poorly quantified, resource for Australian fauna, as well as the European Honeybee Apis mellifera. We investigated the impact of logging on nectar production in the canopy of Grey Ironbark Eucalyptus paniculata (Smith) forests in southern Australia. Using cherry-pickers and cranes we measured nectar production in large and small trees in replicate sites in each of recently logged, young regrowth and old regrowth forest over three consecutive years (2004?2006). We focused on over-night nectar production, although nectar was produced during both the day and night. Logging history and tree size, when considered individually, had no significant effect on nectar production per flower, although the two factors showed a significant interaction. However, these differences were relatively minor in comparison to the negative relationship with drought. Little nectar was produced per flower under any logging history in drought. During good conditions nectar production varied depending on logging history. When scaled up to the forest stand, logging history had a marked effect on nectar production with old regrowth forest producing seven times as much sugar per ha as recently logged forest. Young regrowth forest 15?20 years old produced nectar quantities intermediate between that of recently logged forest and regrowth forest. At the compartment scale, current practices require the retention of old forest and the typical extent of this retention reduced the difference between old regrowth forest and recently logged forest to a factor of two times. Nectar production per flower was low and a limited resource in autumn 2004 and late-winter 2005, but was copious and in surplus in early summer 2006. Nectar standing crops at the flower scale appeared to be determined by an interaction between environmental conditions (drought) that negatively influenced nectar production and the feeding activity of flower visitors at the time, which itself is affected by prevailing temperatures and nectar attributes, such as sugar concentration and regional nectar availability. We suggest that management actions should focus on minimising nectar depletion in poor flowering years when the nectar resource is limiting.

Acid neutralising capacity of two different bauxite residues (red mud) and their potential applications for treating acid sulfate water and soils

The acid neutralising capacity (ANC) and potential beneficial uses of 2 different bauxite residues (red mud) were investigated. The results show that the ANC is much higher in the red mud disposed of using a dry stacking method at the Pingguo Alumina Refinery (China) than in the red mud disposed of by a wet method using seawater at the Queensland Alumina Ltd Refinery (Australia). The higher ANC in the Pingguo red mud is attributable to its high CaO and low SiO2. An incubation experiment showed that leaching of alkaline materials from the lime-treated sample was much greater than that from the red mud-treated sample. This suggests that red mud may be superior to lime for treating potential acid sulfate soils, which contain sulfide minerals that could take a long time to oxidise and release soluble acid. The effects of 2 acid-filtering systems were tested, both of which used red mud as the main material for removal of acid from passing acidic water. The results showed that the red mud–CaCO3 filter performed better than the red mud–Mg(OH)2 filter. Results from pot trials in Australia further demonstrated that the application of combined red mud and sewage sludge significantly improved the soil conditions for the growth of 5 Australian native tree species, in addition to Eucalyptus paniculata, which successfully grew in the same mine soil amended with the red mud and sewage sludge in previous work of G. Maddocks et al. The results from the pot experiment in China showed that the application of combined neutralising agents (red mud/lime blends) and sewage sludge to the extremely acidic mine soil was insufficient for creating appropriate ecological conditions for the growth of vetiver grass. In this experiment, additional application of zeolitic rock powder significantly improved the growth performance of the plant.

OPTIMISATION OF HARDWOOD DRYING SCHEDULES ALLOWING FOR BIOLOGICAL VARIABILITY

ABSTRACT The amount of biological variability in timber creates considerable problems in producing timber of adequate and reproducible quality with a predictable amount of variability in final moisture contents. The development of optimised drying schedules for addressing these problems is therefore desirable. Previous methods (largely of a stochastic type) are reviewed in this work and their limitations assessed. The physical parameters which have the greatest impact on the stress levels (and hence quality) of the timber have been assessed using a diffusion model for the drying of Australian hardwood timber. This deterministic model is then used, together with statistical methods for quantifying the confidence regions for the variability in the physical parameters with the greatest impact, in a systematic technique to develop a new optimised schedule for grey ironbark timber (Eucalyptus paniculaia). This new schedule is then compared with a previous optimised schedule, which did not take this variability into account. The productivity (amount of good quality timber divided by drying time) appears to be maximised when the schedule is such that 90% of the timber produced is good quality.

Debarking of fibrous-barked hardwoods by ultra-high pressure water jets

Ultra-high pressure water jets, operating at 48 300 kPa through a ring-type No. 6 nozzle with 15° fan and 1.57 mm diameter opening, were used in practical trials for debarking several hardwood species. Eucalyptus paniculata, E. agglomerata, E. acmenioides, E. pilularis and Syncarpia glomulifera were tested, as they are known to be difficult to debark. The effects of these jets on the configuration of the detached bark, were also assessed. Except for E. pilularis, all species were effectively debarked, and a classification was made of the relative difficulty with which various barks were removed. In E. pilularis the bark adhered strongly to the timber, the surface of which was extensively damaged by the water jets. The high pressure water often broke and shattered the bark, which sometimes underwent pronounced defibration. In particular, the bark of E. acmenioides and E. paniculata was broken down into a material, which should be readily utilisable without further processing. Finally, these trials have shown that the design of a small-size hydraulic debarker is feasible and should eventually be a commercially viable proposition.

The Types of Eucalyptus paniculata Sm. and E. siderophloia Benth. and Their Probable Relationships

The Types of Eucalyptus paniculata Sm. and E. siderophloia Benth. and Their Probable Relationships