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Highlights: [•] Bioethanol production from shedding bark of Melaleuca leucadendron (Paper bark tree). [•] Sub-critical water pretreated biomass yielded glucan solubilization of 85%. [•] Complete glucan solublization achieved at optimum dilute acid condition. [•] Glucose to ethanol conversion rate of 0.475gg−1 (91% ethanol yield). [ABSTRACT FROM AUTHOR]

The genus Melaleuca consists of around 260 species covering over eight million hectares (including native and introduced species) and distributed mostly in Australia, but also occurring in South-East Asia, the Southern United States and the Caribbean. Melaleuca populations predominantly occur in wetland or/and coastal ecosystems where they have been significantly affected by climate change. This paper assesses the potential responses of the Melaleuca genus to climate change, based on the synthesis of worldwide published data. The main findings include: (i) that the Melaleuca genus has a rich species diversity, and significant phenotypic diversity in a variety of ecosystems; (ii) they demonstrate significant local adaptation to harsh conditions; and (iii) the fossil records and taxon biology indicate the evolution of the Melaleuca genus began around 38 million years ago and they have survived several significant climatic alterations, particularly a shift towards cooler and drier climates that has occurred over this period. These findings show that the Melaleuca genus is highly resilient and adaptable and based on this, this paper argues that Melaleuca can adapt to climate change through Wright's 'migrational adaptation', and can be managed to achieve sustainable benefits. [ABSTRACT FROM AUTHOR]

Highlights: [•] SCW pretreatment primarily extracted amorphous parts of the PBT biomass. [•] SCW pretreatment at 180°C exposed crystalline cellulose nanofibers of PBT. [•] Dilute acid pretreatment at 160°C exhibited a large decrease in CrI. [•] Dilute acid pretreated biomass had a disrupted intermolecular hydrogen bonds. [•] Pretreatment of PBT with SCW and dilute acid resulted in high glucose release. [ABSTRACT FROM AUTHOR]

Introduction: Essential oil of Melaleuca leucadendron used as antimycotic and antimicrobial. The oil also used as antiinflammation and antifungal. Methods: The present study will assist in standardization for quality, purity and sample identification. Various standardization parameters like morphological characters, microscopic evaluation, physicochemical evaluations) preliminary phytochemical screening and TLC chromatographic profile of the extract were carried out and the qualitative parameters were reported. Result: In the pharmacognostical studies, in an attempt to standardize the leaves of M. leucadendron have been shown which will be definitely useful to the future scientist for the identification of the plants. Conclusion: These studies provide referential information for correct identification and standardization of this plant material. [ABSTRACT FROM AUTHOR]

Water availability is a key determinant of the zonation patterns in estuarine vegetation, but water availability and the use of different water sources over space and time are not well understood. We have determined the seasonal water use patterns of riparian vegetation over an estuarine ecotone. Our aim was to investigate how the water use patterns of estuarine vegetation respond to variations in the availability of tidal creek water and rain-derived freshwater. The levels of natural stable isotopes of oxygen and hydrogen were assessed in the stem of the mangrove Avicennia marina (tall and scrub growth forms), Casuarina glauca and Melaleuca quinquenervia that were distributed along transects from river/creek-front towards inland habitats. The isotopic composition of plant tissues and the potential water sources were assessed in both the wet season, when freshwater from rainfall is present, and the dry season, when mangrove trees are expected to be more dependent on tidal water, and when Casuarina and Melaleuca are expected to be dependent on groundwater. Our results indicate that rainwater during the wet season contributes significantly to estuarine vegetation, even to creek-side mangroves which are inundated by tidal creek water daily, and that estuarine vegetation depends primarily on freshwater throughout the year. In contrast, high intertidal scrub mangroves were found to use the greatest proportion of tidal creek water, supplemented by groundwater in the dry season. Contrary to prediction, inland trees C. glauca and M. quinquenervia were found also to rely predominantly on rainwater-even in the dry season. The results of this study reveal a high level of complexity in vegetation water use in estuarine settings. [ABSTRACT FROM AUTHOR]

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Highlights: [•] Paper bark tree shedding bark has higher glucan component. [•] SCW at mild temperature is efficient for pretreatment of shedding bark. [•] High ethanol production (63.2 g/L) was achieved at 0.25 g/mL solid loading. [•] High ethanol (43.7 g/L) and yield (91.25%) were obtained at 0.15 g/mL solid loading. [Copyright &y& Elsevier]

Aim Geographical and climatic barriers to organismal dispersal and distribution play a major role in speciation. We use a sister-pair of widespread savanna trees ( Melaleuca argentea and M. fluviatilis) to test the influence of putative barriers on divergence within and between species across an otherwise continuous landscape. Location The Australian monsoon tropics ( AMT). Methods Chloroplast and nuclear DNA sequences were used to estimate variation between and within species. Hypotheses invoking vicariance and ecological speciation as the mechanisms of divergence between species were explicitly tested using ecological niche modelling. Results We found little evidence for divergence across the Carpentaria Basin, although some chloroplast DNA haplotypes were restricted to regions to the east or west. Pilbara populations were distinct from those to the east across the Great Sandy Desert, including those from the Kimberley. There was a complex pattern of genetic divergence and niche differentiation among M. argentea and M. fluviatilis within a region of secondary range overlap coincident with currently recognized species boundaries across the Great Dividing Range. Main conclusions The two morphospecies are ecologically and genetically distinct, and maintain those differences in sympatry. Speciation might have occurred in allopatry in separate drainage basins that later came into contact. The Pilbara population appears to be distinct but requires further investigation. [ABSTRACT FROM AUTHOR]

Melaleuca lophocoracorum A.J. Ford, Craven & Brophy is described, illustrated and diagnosed against the allied species M. styphelioides and M. squamophloia. Notes on habitat, distribution, conservation status and leaf essential oil content are provided. [ABSTRACT FROM AUTHOR]

Melaleuca alternifolia Cheel is an economically important medicinal plant. Its chemical constitution is well known, being rich in terpinen-4-ol, which is the main responsible for its medicinal properties. However, in this species is difficult to obtain good seedlings from seed germination, what makes the vegetative propagation benefic to its commercialization, maintaining the productive characteristics and quality of extracted oil. This study aimed to evaluate the rooting of tea tree cuttings, collected in the apical, middle and basal portions of the stock plant branches, and treated with different concentrations of indolebutyric acid (IBA). Cuttings with a length of 6 cm, with one third of the apex leaves and a bevel cutting on the base, were treated with hydroalcoholic solutions of IBA (0, 1500 and 3000 mg L-1) immersing the base for 10 seconds. In the sequence cuttings were planted in tubes containing vermiculite and placed in a greenhouse. After 91 days, the rooting percentage, number of roots, average length of roots, callus percentage, survival and mortality were evaluated. Percentage of rooting cuttings was less than 43.8%, and it was not influenced by the branch type or by tested IBA concentrations. [ABSTRACT FROM AUTHOR]

Broth microdilution assays were used to determine minimum inhibitory concentrations (MICs) and fractional inhibitory concentration indices (FICIs) of tea tree oil (TTO), tobramycin, colistin and aztreonam (ATM) against clinical cystic fibrosis-associated Pseudomonas aeruginosa (CFPA) isolates (n = 20). The minimum biofilm eradication concentration (MBEC) and fractional biofilm eradication concentration index (FBECI) were also determined using a similar microbroth dilution checkerboard assay, with biofilms formed using the MBEC device ® . TTO was effective at lower concentrations against multidrug-resistant (MDR) CFPA isolates (n = 3) in a biofilm compared to in a planktonic state (MBEC 18·7-fold lower than MIC). CFPA within biofilm was less susceptible to ATM, colistin and tobramycin compared to planktonic cells (MBEC 6·3-fold, 9·3-fold, and 2·1-fold higher than MIC respectively). All combinations of essential oil and antibiotic showed indifferent relationships (FICI 0·52-1·72) when tested against planktonic MDR CFPA isolates (n = 5). Against CFPA isolates (n = 3) in biofilm, combinations of TTO/aztreonam and TTO/colistin showed indifferent relationships (mean FBECI 0·85 and 0·60 respectively), whereas TTO/tobramycin showed a synergistic relationship (mean FBECI 0·42). The antibiofilm properties of TTO and the synergistic relationship seen between TTO and tobramycin against CFPA in vitro make inhaled TTO a promising candidate as a potential therapeutic agent., (© 2021 The Society for Applied Microbiology.)

Objective: Evaluate the effect of essential oil in odor reduction for intestinal ostomy bags., Method: Primary study, semi-experimental, prospective clinical trial with quantitative approach. A product prepared with Melaleuca armillaris leaves was tested in ostomy pouches, with and without effluents, for adhesion and odor control. Instrument: Labeled Magnitude Scale., Results: Colostomized participants, with a mean age of 73 ± 14.94, predominantly males; and informal caregivers, with a mean age of 44 ± 8.98, predominantly females. In the visual evaluation of the oil, 100% of the participants perceived its adherence. Regarding the evaluation of effluent odor by the colostomized, five reported "strong odor" before oil use and, six reported "weak" odor after use (p = 0.005). Five informal caregivers reported "very strong" effluent odor before oil use; and one reported "weak" and nine reported "moderate" after use (p = 0.0025)., Conclusion: There was a reduction in the odor of effluents in the ostomy pouches with the essential oil of Melaleuca armillaris at 10%. Application for patent registration in the Brazilian National Institute of Industrial Property (INPI) under no. BR 10 2020 026987 9.

The chemical composition of the essential oils of Melaleuca armillaris Sm., Melaleuca styphelioides Sm. and Melaleuca acuminata F. Muell., collected in Tunisia, was studied by means of GC and GC-MS analysis. In all, 46 compounds were identified, 38 for M. armillaris, 20 for M. acuminata and eight for M. styphelioides, respectively. The presence of a sesquiterpenic fraction (52.2%) characterized the oil from M. armillaris; M. sthypheliodes oil was rich in methyl eugenol, a phenolic compound (91.1%), while M. acuminata oil is mainly constituted by oxygenated monoterpenoids (95.6%). The essential oils were evaluated for their in vitro potentially phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Lepidium sativum L., Sinapis arvensis L., Triticum durum L. and Phalaris canariensis L. seeds. The radicle elongation of five seeds was inhibited at the highest doses tested, while germination of all seeds was not affected. Moreover, the essential oils showed low antimicrobial activity against eight selected microorganisms. [ABSTRACT FROM AUTHOR]

Our previous studies demonstrated that precoating of filter fibers with biologically active tea tree oil (TTO) enhances physical collection efficiency of conventional heating, ventilation, and air conditioning (HVAC) filters, and provides cost effective and rapid inactivation of captured bacterial and fungal particles on the filter surface. The main aim of this study was to investigate the antiviral activity of two natural disinfectants, i.e., TTO and eucalyptus oil (EUO), against the influenza virus captured onto the filter surface. It was found that both tested oils possess strong antiviral properties when used as fiber coating materials, capable of inactivating captured microorganisms within 5–10 min of contact on the fiber surface. The antiviral activity of TTO was also successfully challenged in aerosol form by mixing viable airborne viral particles with oil droplets in the rotational aerosol chamber. The results look very promising for further development of virus inactivating procedures and technologies for air quality applications. Copyright 2012 American Association for Aerosol Research [ABSTRACT FROM PUBLISHER]

A new species of gall midge, Ophelmodiplosis clavata Kolesik gen. et sp. nov., induces club-like galls on branchlet tips of she-oaks Casuarina glauca, C. equisetifolia and C. cunninghamiana in Australia. The presence of galls may possibly retard development of the male flower-bearing branchlets and thus restrict sexual reproduction of the host plant. A new genus is erected to contain the new species. Ophelmodiplosis belongs to the supertribe Cecidomyiidi and its closest relative is Lophodiplosis Gagné, an Australian genus containing species that cause galls on leaves, stems and buds of Melaleuca trees. The new species is considered for biological control of C. glauca, C. equisetifolia and C. cunninghamiana, which are serious weeds in the coastal USA, including Florida, Hawaii and the Caribbean. [ABSTRACT FROM AUTHOR]

In 2010 and 2011, a disease exhibiting characteristics of white mold was found on Sedum sarmentosum, a crassulaceous weed under canopies of tea trees, in Zhushan County, Hubei Province, China. Based on the cultural and morphological characteristics, the pathogen was identified as Sclerotinia nivalis Saito. In the phylogenetic tree inferred from the internal transcribed spacer (ITS)-rDNA sequences, the pathogen was clustered with five previously characterized isolates of S. nivalis, forming a unique clade, thus confirming the morpho-cultural identification. Koch's postulates were fulfilled by pathogenicity tests using the isolate SsSn-24 and Let-19 of S. nivalis on plants of S. sarmentosum. To our knowledge, this is the first report of S. nivalis on S. sarmentosum in the family Crassulaceae. [ABSTRACT FROM AUTHOR]

This study demonstrates unequivocally the presence of crassulacean acid metabolism (CAM) in a species of the Rubiaceae, the fourth largest angiosperm plant family. The tropical Australian endemic epiphytic ant-plant, Myrmecodia beccarii Hook.f., exhibits net CO uptake in the dark and a concomitant accumulation of titratable acidity in plants in the field and in cultivation. Plants growing near Cardwell, in a north Queensland coastal seasonally dry forest of Melaleuca viridiflora Sol. ex Gaertn., accumulated ~50 % of their 24 h carbon gain in the dark during the warm wet season. During the transition from the wet season to the dry season, 24 h carbon gain was reduced whilst the proportion of carbon accumulated during the dark increased. By mid dry season many plants exhibited zero net carbon uptake over 24 h, but CO uptake in the dark was observed in some plants following localised rainfall. In a shade-house experiment, droughted plants in which CO uptake in the light was absent and dark CO uptake was reduced, were able to return to relatively high rates of CO uptake in the light and dark within 12 h of rewatering. [ABSTRACT FROM AUTHOR]

Many hemipteran insects are important agricultural pests because they cause direct feeding damage to their host plants and/or transmit plant disease agents including viruses and bacteria. Microscopic and behavioral studies on five hemipteran species from four families (Psyllidae, Aphididae, Cicadellidae, and Aleyrodidae) showed that their exuviae (molted skins) normally had either fully or partially extended stylets in a feeding-like position. In most cases these stylets were still partially embedded in their host plants after ecdysis, which indicated that plant-feeding hemipteran nymphs use their stylets to anchor themselves to host plants during molting. This phenomenon was used here to study the stylet length and ultrastructure in exuviae of various instars, which is normally more difficult in nymphs than in adults because of the fragility and smaller size of nymphs. Additionally, autofluorescence was used for studying the hemipteran salivary sheaths of nymphs and adults in their host plants. This method is based on fixation of free hand sections of plant parts on which hemipteran insects have been feeding, then mounting and examination of these sections with epifluorescence or confocal microscopy. No embedding, microtomy, or staining is necessary for this method that makes it much faster and simpler than other methods. Autofiuorescence was also used to study the location and size of bacteriomes/mycetomes (organs containing symbionts) in hemipteran eggs and nymphs. The above methods were applied successfully with the Asian citrus psyllid (Diaphorina citri Kuwayama), melaleuca psyllid (Boreioglycaspis melaleucae Moore), oleander aphid (Aphis nerii Boyer de Fonscolomb), the whitefly Bemisia tabaci (Gennadius), and/or the glassy-winged sharpshooter leafhopper (Homalodisca vitripennis Germar). [ABSTRACT FROM AUTHOR]

Six essential oils (EOs), Juniperus phoenicea (leaves and berries), Thymus capitatus, Lauris nobilis, Melaleuca armillaris, and Eucalyptus gracilis, were screened for their antioxidant and antihypertensive activity as well as their chemical compositions. We identified and quantified 24 compounds (representing 99.8% of total oil) for J. phoenicea leaves, 14 compounds (representing 98.8% of total oil) for J. phoenicea berries, 11 compounds (representing 99.6% of total oil) for T. capitatus, 32 compounds (representing 98.9% of total oil) for L. nobilis, 32 compounds (representing 98.7% of total oil) for M. armillaris, and 26 compounds (representing 99.3% of total oil) for E. gracilis. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the antioxidant activity was in the range of 0.59 to 2183.6 mg/L, whereas T. capitatus (1.24 ± 0.05 mg/L) gave the best activity in the 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonate assay. Antihypertensive activity was evaluated by testing the vasorelaxing capacity of EOs on rat aorta precontracted by phenylephrine (10−6 M). T. capitatus and L. nobilis were most active for an antihypertensive activity (29 ± 3 and 59 ± 2 mg/L, respectively). Correlations between chemical composition or antioxidant activity and/or antihypertensive activity were studied. Significant correlation has been found for antihypertensive activity and p-cymene ( R2= 0.86), β-elemene ( R2= 0.90), and β-myrcene ( R2= 0.76). A good correlation has been found between antihypertensive activity and antioxidant activity by DPPH assay ( R2= 0.98). Antioxidant activity can contribute to the prevention of the increase of the blood pressure. According to the literature, no study has been reported until now of correlation between antihypertensive activity and antioxidant activity. Natural EOs can find its interest and application in a medicinal area. [ABSTRACT FROM AUTHOR]

Shallow freshwater wetlands that are permanently inundated are prone to developing dense mats of highly-competitive clonal species. We examine vegetation pattern and change in a tropical impoundment (Fogg Dam) in northern Australia in the context of succession towards vegetation closure with adverse implications for biodiversity and tourism. The area of open water declined 44 % between 1993 and 2005. Closed vegetation comprised a floating mat complex featuring a stoloniferous grass, ferns and young trees, and a sedgeland rooted in the soft sediment layer comprising monodominant circular patches of the rhizomatous Eleocharis sphacelata. Depth to the underlying firm substrate varied little between the closed vegetation types and between them and the remaining open water, but the soft sediment layer was markedly deeper under sedgeland and it contained much coarse plant matter consisting mainly of dead Eleocharis. This suggests that E. sphacelata may be creating its environment in order to invade areas of deeper water. Although other wetland plants create more favourable environments for themselves by accreting sediment and/or modifying soil chemistry, this may be the first report of an invasive species modifying depth using its own plant matter. At Fogg Dam, encroachment of closed vegetation into open water areas is not limited by depth and will likely result in the entire wetland being closed over within a decade. To restore diversity, an adaptive disturbance regime is required, some options for which are briefly discussed. [ABSTRACT FROM AUTHOR]

The leaf essential oils of the seven endemic New Caledonian species of the genus Melaleuca have been examined. Melaleuca sphaerodendra var. microphylla and Melaleuca brevisepala produced oils in which β-caryophyllene (28.8% and 26.8% respectively) was the principal component. α-Pinene (24.8%) and β-caryophyllene (14.1%) were the principal compounds detected in the leaf oil of Melaleuca pancheri. Melaleuca brongniartii produced an oil in which the principal monoterpenes were γ-pinene (23.3%), β-pinene (10.3%) and limonene (19.8%). γ-Terpinene (15.2%), p-cymene (12.8%) and terpinolene (17.5%) were the major components in the leaf essential oil of Melaleuca buseana, whereas the leaf oil of Melaleuca dawsonii contained a-pinene (12.8%) and α-phellandrene (10.3%) as principal components. In Melaleuca gnidioides α-pinene (23.6%), β-pinene (13.6%) and spathulenol (14.7%) were the major components. All of these oils differed from the leaf oil of Melaleuca quinquenervia, an indigenous New Caledonian species also found in Australia and New Guinea. [ABSTRACT FROM AUTHOR]

Riparian vegetation typically provides substantial allochthonous material to aquatic ecosystems where micro-organisms can play an important role in organic matter degradation which can support consumer biomass. We examined the effects of leaf litter quality (e.g., leaf nutrients, lignin and cellulose content), leaf species mixing, and microbial community diversity on in-stream breakdown rates of litter from dominant riparian trees ( Melaleuca argentea, M. leucadendra, and Nauclea orientalis) in both a perennial and intermittent river in Australia's wet-dry tropics. Leaf mass remaining after 82 days of in-stream incubation was negatively correlated ( P < 0.05) with initial leaf N and P content while initial lignin and cellulose content had no statistically significant effect. Breakdown rates of incubated leaves of both Melaleuca and Nauclea were significantly higher in mixed litter bags compared with single species litter bags. Although it was expected that leaf N content would decrease from initial levels during decomposition, we found either similar or slightly higher N content following in-stream incubation suggesting microbial colonisation increased overall N content. Stable isotopes of δC and δN for the major sources and consumers in both rivers provide evidence that leaf litter was an important macroinvertebrate food source in the perennial river where heavy shading may limit algal production. However, in the intermittent river where riparian cover was low, benthic algae were the major organic carbon source for consumers. Our findings suggest that riparian tree species influence rates of in-stream organic matter processing, microbial community composition, and aquatic food web dynamics in tropical wet-dry streams. [ABSTRACT FROM AUTHOR]

The capacity of many plant species to resprout in fire-prone shrublands is thought to engender persistence, yet management concerns exist for the long-term persistence of some resprouting species given anthropogenic impacts including shortened fire intervals, long periods of fire exclusion, and/or fires of increasingly high severity. We explored the potential demographic effects of different fire interval regimes on lignotuberous resprouter species using the last fire interval for 36 sites (33 experimental fires, 3 wildfires) in biodiverse SW Australian shrublands, spanning an interval range of 3-42 years. Mortality and regrowth 1 year following the last fire was assessed for >7,000 tagged individuals from 20 shrub and sub-shrub species. Using generalized linear mixed effect models, we estimated the influence of fire interval (and selected fire and environmental covariates) on mortality and regrowth rates across all species, and individually for the four most common species. The overall model, as well as the models for three of the four most common species ( Banksia attenuata, Melaleuca leuropoma, and M. systena, but not Hibbertia hypericoides) supported the hypothesis of increased mortality at short and long fire intervals, most likely due to total non-structural carbohydrate (TNC) and bud-bank limitation, respectively. However, no relationship between regrowth rate and fire interval was detected, suggesting that increased mortality at short (3-5 year) fire intervals may not be due solely to resource (TNC) limitation. Results show that lignotuberous resprouters are potentially vulnerable to population decline through attrition of mature plants under both shortened and lengthened fire interval regimes. [ABSTRACT FROM AUTHOR]

Population connectivity for most marine species is dictated by dispersal during the pelagic larval stage. Although reef fish larvae are known to display behavioral adaptations that influence settlement site selection, little is known about the development of behavioral preferences throughout the larval phase. Whether larvae are attracted to the same sensory cues throughout their larval phase, or exhibit distinct ontogenetic shifts in sensory preference is unknown. Here, we demonstrate an ontogenetic shift in olfactory cue preferences for two species of anemonefish, a process that could aid in understanding both patterns of dispersal and settlement. Aquarium-bred naïve Amphiprion percula and A. melanopus larvae were tested for olfactory preference of relevant reef-associated chemical cues throughout the 11-day pelagic larval stage. Age posthatching had a significant effect on the preference for olfactory cues from host anemones and live corals for both species. Preferences of olfactory cues from tropical plants of A. percula, increased by approximately ninefold between hatching and settlement, with A. percula larvae showing a fivefold increase in preference for the olfactory cue produced by the grass species. Larval age had no effect on the olfactory preference for untreated seawater over the swamp-based tree Melaleuca nervosa, which was always avoided compared with blank seawater. These results indicate that reef fish larvae are capable of utilizing olfactory cues early in the larval stage and may be predisposed to disperse away from reefs, with innate olfactory preferences drawing newly hatched larvae into the pelagic environment. Toward the end of the larval phase, larvae become attracted to the olfactory cues of appropriate habitats, which may assist them in identification of and navigation toward suitable settlement sites. [ABSTRACT FROM AUTHOR]

Summary [ABSTRACT FROM AUTHOR]

Melaleuca alternifolia (tea tree) and Thymus vulgaris (thyme) essential oils were tested for their antifungal activity to investigate the possibility of their use for seed treatment. The ability of the two oils to inhibit mycelial growth was studied by in vitro assay on agar medium containing different concentrations of the essential oils (0%, 0.05%, 0.1%, 0.25%, 0.5%, 1% v/v). Seven seed-borne pathogen fungi of large interest Ascochyta rabiei, Colletotrichum lindemuthianum, Fusarium graminearum, F. culmorum, Drechslera avenae, Alternaria radicina and A. dauci were transferred on the modified medium in order to test the oils antifungal activity, by calculating the Percentage of Mycelial Growth Inhibition (%MGI) and the Minimum Inhibitory Concentration (MIC). Results showed that both the oils had a clear reducing effect on fungal growth, that was dose-dependent and it differed depending on the fungal species, confirming what is already reported in literature, with T. vulgaris oil to be one of the most potent agent against fungi. M. alternifolia and T. vulgaris oils can be considered potential alternative natural fungicides to the synthetic chemicals that are currently used to prevent and control seed-borne diseases, and could be used in agriculture for safe and eco-friendly seed-treatments. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the relationship between hummock height and depth of inundation in a permanently inundated wetland in south-eastern Australia. Our survey of 318 hummocks, in water ranging from 0 to 70cm depth, revealed a significant positive linear relationship and strong correlation between hummock height and water depth (r 2 =0.53 and 0.79 for Melaleuca ericifolia and Phragmites australis hummocks respectively). We also investigated whether water regime affects the decomposition rate of litter on hummocks; specifically, whether constant inundation slows decomposition to an extent that would promote accumulation of litter and hummock-building. On the contrary, we found that constantly submerged M. ericifolia litter decomposed faster than dry litter, but at a similar rate to litter that experienced intermittent inundation (decay rates (k) 0.0015d−1, 0.0010d−1 and 0.0008d−1 for submerged, intermittent and dry treatments respectively). Submerged P. australis litter also decomposed faster (k =0.0024d−1) than dry litter (k =0.0011d−1). We discuss the interaction of water regime and decomposition of organic material and implications for the maintenance of hummock and hollow topography. [Copyright &y& Elsevier]

In this paper, the spatial-temporal dynamics of soil moisture content was investigated in an evergreen broad-leaved forest and a tea tree plantation in Ailao Mountains, which was dominated by Fagaceae (Castanopsis wattii and Lithocarpus xylocarpus). Soil moisture content was studied between January 2005 and December 2006 at different depths (from 0-150 cm) with a neutron probe. The results showed that mean soil moisture content in the evergreen broad-leaved forest was usually higher than in the tea tree plantation in the dry season, whereas it was lower than the tea tree plantation in the rainy season. In addition, mean soil moisture content was depth dependent, and in the 10-50 cm layer the spatial variability was due to the active root zone within this depth area in two types of land use. From 50-150 cm, the spatial variability was slightly increasing in the evergreen broad-leaved forest or relatively stable in the tea tree plantation. Our study also showed that soil moisture content was higher and more stable under the evergreen broad-leaved forest than the tea tree plantation, hence we stress that evergreen broad-leaved forest plays an important role in holding soil moisture. It is suggested that the protection of evergreen broad-leaved forest should be strengthened. [ABSTRACT FROM AUTHOR]

Population bottlenecks may result in the loss of genetic diversity, with potentially negative consequences for species of interest in conservation biology, including rare species, invasive species and biological control agents. We examined mtDNA sequence data and four variable microsatellite loci (SSRs) in the melaleuca psyllid Boreioglycaspis melaleucae, which was introduced from Australia to Florida as a biological control agent of the invasive plant Melaleuca quinquenervia. We sampled psyllids in the native and introduced ranges as well as individuals stored from the original founding population. There was a clear loss of mtDNA haplotype diversity, as well as a loss of rare microsatellite alleles, in the introduced range. However, there was little genetic differentiation between the home and introduced ranges, and no evidence for a genetic bottleneck based on an analysis of heterozygosity with the microsatellite markers. Overall, the data showed that the demographic bottleneck had a limited effect on the genetics of populations in the new range. [ABSTRACT FROM AUTHOR]

A palaeoecological record has been constructed for Myora Springs, North Stradbroke Island that provides a detailed picture of environmental change for this site over the last millennium. From ~800 to 500 years ago the site is dominated by paperbark (Melaleuca) swamp surrounded by open eucalypt woodland and only a small amount of rainforest. This period may reflect the drier conditions of a persistent 'warm' El Niño Southern Oscillation event possibly associated with the Little Ice Age phenomenon. From ~500 to 200 years ago the vegetation composition of the swamp and surrounding dryland communities changes, with a greater representation of she-oak (Casuarinaceae), rainforest and pteridophytes at the expense of the Melaleuca and eucalypts, suggesting wetter conditions. From ~200 years ago to the middle/late 20th century there is clear evidence of European settlement with increased representation of paperbark swamp and open eucalypt woodland at the expense of the Casuarinaceae reflecting a shift in fire regimes, most likely associated with European arrival. In addition, the cessation of sedimentation and the dominance of the site by the modern rainforest community reflects the construction of the East Coast Road and channeling of swamp waters through a single channel from the mid to late 20th century. [ABSTRACT FROM AUTHOR]

Melaleuca swamp forests form a fringe around seasonally inundated freshwater flood plains of Kakadu National Park (KNP). Previous studies based on the analysis of aerial photography reported an increase in woody plant cover on these flood plains, apparently associated with changed fire regimes, increased rainfall and possibly increased atmospheric CO. In opposition to this woody vegetation encroachment past high densities of feral buffalo in the 1960 to mid 1980s changed the hydrology of the KNP flood plains, allowing increased penetration of saltwater causing extensive death of Melaleuca forests. Climate change has increased sea levels and there is concern that this will threaten the freshwater ecosystems of KNP. We hypothesized that Melaleuca forests that were previously impacted by high densities of feral buffalo have continued to decline because of salinization driven by sea level rise. We examined this hypothesis by overlaying georeferenced aerial photography taken in 1964, 1984 and 2004 in a geographic information environment, and then constructing generalized linear fixed effects and mixed effects models to rank the statistical strength of different drivers of Melaleuca forest contraction. We found that there has been a 5% overall contraction of Melaleuca forests over the last 50 years on our study sites, although the amount of contraction varied both geographically and temporally. The amount of Melaleuca forest contraction was greatest during the 1984-2004 interval, when buffalo densities were low. Contraction was greatest on the Melaleuca forest edges, at low-lying sites, and where high densities of buffalo were apparent in 1964. These results suggest the enduring legacy effect of past buffalo damage will amplify the effects of sea level rise on the flood plains of KNP. [ABSTRACT FROM AUTHOR]

Islands of monsoon rainforest and Melaleuca swamp punctuate vast tracts of savanna in monsoonal northern Australia. Seedlings of species from each of these habitat associations were grown in a common garden. Monsoon forest species had higher specific leaf area, lower photosynthetic capacity and lower photosynthetic light compensation points, and required lower irradiance to achieve 50% of light-saturated photosynthesis compared with savanna or swamp species. These traits probably contribute towards greater shade tolerance beneath dense monsoon-forest canopies, whereas savanna and swamp canopies are relatively open. Swamp species, especially two Melaleuca species, had high stomatal conductance and small CO2 drawdown during photosynthesis, and more negative leaf δ13C, compared with monsoon forest and savanna species. Higher stomatal conductance increases carbon uptake during photosynthesis and a high transpiration rate would increase transport of nutrients to absorbing surfaces in the root by mass flow. Thus, a strategy of high transpiration and low water-use efficiency appears to be favoured in swamp species compared with monsoon-forest and savanna species. Instantaneous measurements of the ratio of intercellular to ambient CO2 concentrations (ci/ca) explained 81% of variation in leaf δ13C across 44 species sampled in this and other studies, suggesting that leaf δ13C generally provides a robust proxy for comparisons of ci/ca, even when applied across species. [ABSTRACT FROM AUTHOR]

Abstract: This study examined the polyphenols of tea leaves as chemotaxonomic markers to investigate the phenetic relationship between 89 wild (the small-leaved C. sinensis var. sinensis and large-leaved C. sinensis var. assamica), hybrid, and cultivated tea trees from China and Japan. (−)-Epigallocatechin 3-O-gallate, EGCG (1); (−)-epigallocatechin, EGC (2); (−)-epicatechin 3-O-gallate, ECG (3); (−)-epicatechin, EC (4); (+)-catechin, CA (5); strictinin, STR (6); and gallic acid, GA (7) were used as polyphenolic markers. Of the 13 polyphenol patterns observed, Principal Component Analysis (PCA) indicated that the structure-types of the flavonoid B-rings, such as the pyrogallol-(EGCG (1) and EGC (2)) and catechol-(ECG (3) and EC (4)) types, greatly influenced the classification. Ward’s minimum-variance cluster analysis was used to produce a dendrogram that consisted of three sub-clusters. One sub-cluster (A) was composed of old tea trees ‘Gushu’ cha (C. sinensis var. assamica) and cv ‘Taidi’ cha, suggesting that relatively primitive tea trees contain greater amounts of compounds 3 and 4 and lower amounts of compounds 1 and 2. The other two sub-clusters B and C, made up of Chinese hybrids (sub-cluster B) and Japanese and Taiwanese tea trees (sub-cluster C), had lower contents of 3 and 4 than sub-cluster A. Therefore, PCA and cluster analysis indicated that the greater the amounts of 1 and 2 (and the lower of 3 and 4), the more recent the origin of the tea line. Based on morphological characteristics, geographical information, and the historical information on tea trees, these results show good agreement with the current theory of tea tree origins, and this suggests that the Xishuangbanna district and Puer City are among the original sites of the tea tree species. [Copyright &y& Elsevier]

The variation of foliar monoterpenes in the Australian Tea Tree ( Melaleuca alternifolia) has been of significant interest both to the essential oil industry as well as to ecologists. The majority of studies on leaf chemistry have been aimed directly towards obtaining oil of higher quality or quantity. In the current study, we aimed to understand how molecular mechanisms contribute to the chemical variability of this species, based on chemical analysis of the leaf oils from a biochemical perspective. Correlations between monoterpenes across the species as well as within chemotypes show strong, persistent patterns, which enable us to establish groups based on possible common biosynthetic origins. We found that three distinct enzymes corresponding to these groups: a sabinene-hydrate synthase, a 1,8-cineole synthase, and a terpinolene synthase may be sufficient to explain all six chemotypes in M. alternifolia. [ABSTRACT FROM AUTHOR]

Abstract: Myrtaceae is one of the chemically most variable and most significant essential oil yielding plant families. Despite an abundance of chemical information, very little work has focussed on the biochemistry of terpene production in these plants. We describe 70 unique partial terpene synthase transcripts and eight full-length cDNA clones from 21 myrtaceous species, and compare phylogenetic relationships and leaf oil composition to reveal clades defined by common function. We provide further support for the correlation between function and phylogenetic relationships by the first functional characterisation of terpene synthases from Myrtaceae: a 1,8-cineole synthase from Eucalyptus sideroxylon and a caryophyllene synthase from Eucalyptus dives. [Copyright &y& Elsevier]

With about 335 species, the tribe Melaleuceae comprises a major lineage within the Australian Myrtaceae. Here we investigate relationships within Melaleuceae using cpDNA sequences (ndhF) and 27 morphological characters. We find strong evidence for the non-monophyly of Melaleuca, with all other currently recognized genera of Melaleuceae (Beaufortia, Calothamnus, Conothamnus, Eremaea, Lamarchea, Petraeomyrtus, Phymatocarpus, Regelia) falling within that genus. Our findings are broadly consistent with previous studies using nuclear ITS DNA sequence data; however, the cpDNA phylogeny estimate is more resolved and has higher support for major nodes. Melaleuceae is found to comprise three major clades, each containing species of Melaleuca and each with good support. The M. leucadendra (broad-leaf paper-barks), M. uncinata, M. pungens and M. acacioides groups, New Caledonian callistemons, and all other currently recognized genera of Melaleuceae form one clade. Australian Callistemon species, which have been synonymised recently with Melaleuca, cluster within a second clade of Melaleuca that includes the M. fulgens, M. laxiflora and M. ordinifolia groups, and some members of the M. lanceolata and M. cuticularis groups. A third clade includes other members of the M. lanceolata and M. cuticularis groups, M. foliolosa and the M. huegelii group. No morphological support or diagnostic synapomorphies are identified for any of these clades. Together with previous studies, our findings indicate that the circumscription of Melaleuca, and the generic status of other genera within Melaleuceae, is poorly supported, and we propose that all genera within the Melaleuceae are synonymised with Melaleuca. [ABSTRACT FROM AUTHOR]

Melaleuca alternifolia is cultivated for the production of an essential oil useful in the cosmetic and pharmaceutical industries. Despite the economic importance of this species, there is little knowledge about its in vitro propagation. The aim of this study was to establish an efficient protocol for micropropagation of M. alternifolia. With the goal of in vitro multiplication by axillary shoot proliferation, both solid and liquid MS and WPM media were tested with supplementation with BA at 0, 0.55, 1.11, 2.22, 3.33, and 4.44 μM. The best result for shoot multiplication was obtained when either 0.55 μM BA was added into solid MS medium or 1.11 μM BA was added into liquid MS medium, with 5.6 and 11.8 shoots per explant generated, respectively. On solid or liquid WPM medium supplemented with 0.55 μM BA, the proliferation rates were 5.5 and 4.7, respectively. Three auxins (NAA, IAA, and IBA) were tested at 0.53 and 2.64 μM during the rooting stage. Several sucrose concentrations (15, 30, and 45 g L−1) were compared to a sucrose-free medium. Rooting performances on four culture media were then compared: MS, half-strength MS (MS/2), MS + activated charcoal (AC), and MS/2 + AC. The results showed that auxin addition to culture medium is not necessary for in vitro rooting . Rooted microcuttings from different culture media were acclimatized in a greenhouse, and the survival percentage was evaluated. All shoots cultured in an auxin-free MS medium supplemented with sucrose (30 g L−1) produced roots, and all plants survived during acclimatization. Activated charcoal added in rooting medium reduced rooting rates. [ABSTRACT FROM AUTHOR]

Abstract: Although many emergent wetland plants may readily tolerate rapid changes in flooding and drying under freshwater conditions, their tolerance to dynamic water regimes may be compromised by salinity. Melaleuca-dominated woodlands occur naturally in Australia, south-east Asia and New Caledonia. Coastal wetlands dominated by Swamp paperbark (Melaleuca ericifolia) (Myrtaceae), native to south-east Australia, are commonly degraded as a consequence of altered water regime and salinity. This study simulates the release of M. ericifolia seeds from the aerial canopy under a range of water regime and salinity scenarios to determine conditions limiting sexual recruitment. Plant growth and survival were examined following seed release under two static water regimes (moist and flooded sediment) and two dynamic water regimes (simulated drawdown—“flooded-moist” and simulated re-flooding—“moist-flooded”). All water regimes, excluding the continuously flooded regime, were examined at three salinities: 0.1dSm−1 (fresh), 8dSm−1 and 16dSm−1, over a 50-day period commencing 44 days after the seeds were sown. The flooded treatment was examined at 0.1dSm−1 only, to confirm that flooding prohibits establishment of M. ericifolia. Seed and seedlings were positively buoyant and establishment was limited to moist soil. Flotation of seedlings in the flooded-moist treatment, however, did not inhibit subsequent establishment upon moist soil, even at the highest salinity of 16dSm−1. Growth, but not survival, was reduced by salinities of 8dSm−1 and 16dSm−1 in the moist treatment. Flotation of seedlings in saline water in the flooded-moist treatment did not reduce growth or survival compared with fresh water. Survival of seedlings in the moist-flooded treatment was lower in the freshwater and 16dSm−1 treatment compared with the moist treatment, but not at 8dSm−1. These findings suggest that water regime influences establishment of young M. ericifolia plants more strongly than does salinity, at least up to ∼1/3 seawater and in the short term (<2 months). Seedlings are likely to establish during a drawdown where the soil is exposed at salinities of ≤16dSm−1. In contrast, premature re-flooding of seedlings, even with fresh water, will compromise survival. [Copyright &y& Elsevier]

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For many decades effective insect repellents have relied on synthetic actives such as N,N-diethyl- meta-toluamide. Increasingly, consumers are seeking natural-based alternatives to many everyday products including insect repellents. While many studies have been published detailing the potential of essential oils to act as insect repellents, few oils have been identified as viable alternatives to synthetic actives. This study details the process involved in the selection of Australian essential oils effective as repellents and the subsequent testing of natural-based insect repellents using the selected oils. Using a combination of laboratory-based and field-based testing, oil from Melaleuca ericifolia was identified as being an effective insect repellent. When formulated into three different bases: an alcohol-based spray, an emulsion and a gel, these Melaleuca-based repellents were shown to be as effective at repelling mosquitoes Aedes vigilax (Skuse) (Diptera: Culicidae) and Verrallina carmenti (Edwards) (Diptera: Culicidae), the bush fly Musca vetustissima (Walker) (Diptera: Muscidae), and biting midges Culicoides ornatus (Taylor) (Diptera: Ceratopogonidae) and Culicoides immaculatus (Lee & Reye) (Diptera: Ceratopogonidae) as a synthetic-based commercial repellent. This study has shown that effective insect repellents based on natural active ingredients can deliver repellency on par with synthetic actives in the field. Three Melaleuca-based formulations have been registered as repellents and are now commercially available. [ABSTRACT FROM AUTHOR]

Although water regime modification and salinity are recognised as significant threats to wetland ecosystems worldwide, the effects of long-term saline flooding (decades) on woody tree persistence are poorly quantified. We compared the condition, growth, structure and reproduction (sexual and asexual) of mature individuals of the clonal tree, Melaleuca ericifolia (Myrtaceae), that experienced continual (>30 years) flooding with trees that were only intermittently (approximately every 5 years) flooded. An index developed to assess the condition of multi-stemmed trees found that continually flooded trees were in significantly poorer condition than intermittently flooded trees, having lower crown cover, foliar cover and foliar density, and a higher incidence of dead stags and dieback. Annual stem growth correlated strongly with condition scores. Evidence for a trade-off between sexual and asexual reproductions was found; flooded trees were constrained in their vegetative lateral spread (<12 m dia.) and flowered more than intermittently flooded trees, which were not restricted in lateral spread (~30 m dia.). Flooded trees used intensively by the colonially roosting Australian Sacred Ibis ( Threskiornis molucca) were in especially poor condition. These trees flowered infrequently and produced the lowest number of infructescences, but produced many new vegetative stems (ramets) within their centre. Although chronic flooding appeared to compromise the condition of M. ericifolia trees in Dowd Morass, their existence upon woody hummocks (~40 cm high) upon which they are able to produce new stems is likely to be a key mechanism in their persistence. It is unknown, however, how long this process can maintain the existing population. Production and maintenance of a large aerial seed bank by living mature trees under flooded conditions may allow M. ericifolia to regenerate sexually upon drawdown and may be important for population persistence in the longer term. [ABSTRACT FROM AUTHOR]

Lophodiplosis trifida Gagné, an Australian gall midge on paperbark, Melaleuca quinquenervia (Myrtaceae), is a recent release in southern Florida for the biological control of that host. The larval stage is described for the first time and compared to that of other Lophodiplosis species. Photos of galls and illustrations of larvae are provided. Second and third instars of L. trifida are unusual among Cecidomyiidae for the lack of setae on most papillae. [ABSTRACT FROM AUTHOR]

Periodic flooding of trees in tropical floodplains and reservoirs where water levels fluctuate is a common phenomenon. The effects of flooding and subsequent recovery on gas exchange, chlorophyll fluorescence and growth responses of Melaleuca alternifolia seedlings, a tall shrub species used in floodplain and reservoir forest restoration in southern China, were studied during a grow season (from March to December in 2007). M. alternifolia seedlings were flooded for 180 days, drained and left to recover for another 60 days. Survival rates of the seedlings were 100% during the 180-day flooding period. Chlorophyll (Chl) content, net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) of the flooded seedlings were all significantly lower than those of the control. Significant reductions of photochemical quenching coefficient (qp) and increases of nonphotochemical quenching (NPQ) in the flooded seedlings were observed. However, there were no significant differences in the maximal quantum yield of PSII photochemistry (Fv/Fm) between treatments. All seedlings survived during the two-month recovery period after the flooded treatment was drained, and the biomass and height of the recovered seedlings approached those of the control at the end of the experiment. During the first-month recovery period, Chl content, PN, gs and E in the recovered seedlings were all obviously low, then increased gradually and rose to the levels similar to the control by the end of the experiment. Quenching analysis revealed significant reductions of qp and increments of NPQ in the recovered seedlings at the beginning of draining, and a nearly complete recovery for both parameters by the end of the experiment. However, Fv/Fm of the recovered seedlings did not differ significantly from the control during the recovery period. Our study demonstrated that M. alternifolia seedlings can survive and grow through 180 days of flooding with a subsequent 60-day recovery period in drained conditions, indicating that seedlings of this species would be suitable for afforestation in areas exposed to intermittent flooding. [ABSTRACT FROM AUTHOR]