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Melaleuca quinquenervia is widely grown in tropical areas worldwide. Studies have demonstrated that extracts of its buds, leaves, and branches obtained through hydrodistillation, steam distillation, or solvent extraction exhibit physiological activities, including anti-melanogenic, antibacterial, and antioxidant properties; nevertheless, such extracts are mostly not effectively collected or adequately utilized. Accordingly, this study applied a rapid, effective, and easy-to-operate microwave-assisted water extraction (MAWE) technique for the first time to prepare M. quinquenervia leaf extract (MLE) with improved physiological activities. The results indicated that the optimal irradiation time and liquid/solid ratio for the production of the MLE were 180 s and 20 mL/g, respectively. Under optimal conditions, the freeze-dried MLE achieved a high yield (6.28% ± 0.08%) and highly effective broad-spectrum physiological activities. The MLE exhibited strong antioxidant, antiaging, and anti-inflammatory activities and excellent antityrosinase and antimicrobial activities. Additionally, the MLE was noncytotoxic at concentrations of ≤300 mg/L, at which it exhibited pharmacological activity. The results also indicated that the MLE comprised a total of 24 chemical compounds and 17 phenolic compounds. Among these compounds, luteolin contributed to antityrosinase activity. The extract's antiaging activity was attributed to ellagic acid and quercetin, its anti-inflammatory activity resulted from ellagic acid and kaempferol, and its antimicrobial activity resulted from quercetin and 3-O-methylellagic acid. In conclusion, the MAWE-derived MLE may be useful as a functional ingredient in cosmetic products, health foods, and botanical drugs. [ABSTRACT FROM AUTHOR]

To predict the potential success of an invading non-native species, it is important to understand its dynamics and interactions with native species in the early stages of its invasion. In spatially implicit models, mathematical stability criteria are commonly used to predict whether an invading population grows in number in an early time period. But spatial context is important for real invasions as an invading population may first occur as a small number of individuals scatter spatially. The invasion dynamics are therefore not describable in terms of population level state variables. A better approach is spatially explicit individual-based modeling (IBM). We use an established spatially explicit IBM to predict the invasion of the non-native tree, Melaleuca quinquenervia (Cav.) Blake, to a native community in southern Florida. We show that the initial spatial distribution, both the spatial density of individuals and the area they cover, affects its success in growing numerically and spreading. The formation of a cluster of a sufficient number and density of individuals may be needed for the invader to locally outcompete the native species and become established. Different initial densities, identical in number and density but differing in random positions of individuals, can produce very different trajectories of the invading population through time, even affecting invasion success and failure. [ABSTRACT FROM AUTHOR]

The southern tip of North America coalesces into one of the world's largest freshwater wetlands, the Everglades, Florida, USA. Though this region is much like an island, home to high biodiversity and endemism, it is also the site of a century of development and associated landscape-scale species invasions. Melaleuca quinquenervia (hereafter melaleuca), a tree native to tropical Australia, was planted extensively throughout south Florida as street trees, levee stabilizers, and later to reduce standing water in marshy areas. Through extensive cooperation with the United States Department of Agriculture's Australian Biological Control Laboratory, several biological control agents were released, three of which later successfully established. Herein we examine evidence that plant community shifts determined from vegetation surveys and remotely sensed images reflect changes from melaleuca-dominated wetlands (before management) to native communities (after management). Melaleuca-dominated community types decreased from 1990 to 2020 by more than 99%. Vegetation surveys also reflect an increase in cypress wetlands, pinelands, and open water wetlands, all of which were dominated by melaleuca in previous decades. We also found the normalized difference vegetation index (NDVI) increased in melaleuca-invaded wetlands during peak infestations but decreased again after communities recovered to sawgrass-dominated wetlands. These responses are concomitant with the development of integrative management techniques for melaleuca that include mechanical, chemical, and biological control. Our results confirm previous findings that biological control likely augments conventional management methods by limiting recovery of invasive species. [ABSTRACT FROM AUTHOR]

Melaleuca quinquenervia is widely grown in tropical areas worldwide. Studies have demonstrated that extracts of its buds, leaves, and branches obtained through hydrodistillation, steam distillation, or solvent extraction exhibit physiological activities, including anti-melanogenic, antibacterial, and antioxidant properties; nevertheless, such extracts are mostly not effectively collected or adequately utilized. Accordingly, this study applied a rapid, effective, and easy-to-operate microwave-assisted water extraction (MAWE) technique for the first time to prepare M. quinquenervia leaf extract (MLE) with improved physiological activities. The results indicated that the optimal irradiation time and liquid/solid ratio for the production of the MLE were 180 s and 20 mL/g, respectively. Under optimal conditions, the freeze-dried MLE achieved a high yield (6.28% ± 0.08%) and highly effective broad-spectrum physiological activities. The MLE exhibited strong antioxidant, antiaging, and anti-inflammatory activities and excellent antityrosinase and antimicrobial activities. Additionally, the MLE was noncytotoxic at concentrations of ≤300 mg/L, at which it exhibited pharmacological activity. The results also indicated that the MLE comprised a total of 24 chemical compounds and 17 phenolic compounds. Among these compounds, luteolin contributed to antityrosinase activity. The extract’s antiaging activity was attributed to ellagic acid and quercetin, its anti-inflammatory activity resulted from ellagic acid and kaempferol, and its antimicrobial activity resulted from quercetin and 3-O-methylellagic acid. In conclusion, the MAWE-derived MLE may be useful as a functional ingredient in cosmetic products, health foods, and botanical drugs.

Our understanding of tree stem methane (CH4) emissions is evolving rapidly. Few studies have combined seasonal measurements of soil, water and tree stem CH4 emissions from forested wetlands, inhibiting our capacity to constrain the tree stem CH4 flux contribution to the total wetland CH4 flux. Here we present annual data from a subtropical freshwater Melaleuca quinquenervia wetland forest, spanning an elevational topo‐gradient (Lower, Transitional and Upper zones). Eight field campaigns captured an annual hydrological flood‐dry‐flood cycle, measuring stem fluxes on 30 trees, from four stem heights, and up to 30 adjacent soil or water CH4 fluxes per campaign. Tree stem CH4 fluxes ranged several orders of magnitude between hydrological seasons and topo‐gradient zones, spanning from small CH4 uptake to an emission of ∼203 mmol m−2 d−1. Soil CH4 fluxes were similarly dynamic and shifted from CH4 emission (saturated soil) to uptake (dry soil). In Lower and Transitional zones respectively, tree stem CH4 contribution to the net CH4 ecosystem flux was greatest during flooded conditions (49.9% and 70.2%) but less important during dry periods (3.1% and 28.2%). Minor tree stem emissions from the Upper elevation zone still offset the Upper zone CH4 soil sink capacity by ∼51% during dry conditions. Water table height was the strongest driver of tree stem CH4 fluxes, however tree emissions peaked once the soil was inundated and did not increase with further water depth. This study highlights the importance of quantifying the wetland tree stem CH4 emissions pathway as an important and seasonally oscillating component of wetland CH4 budgets. Plain Language Summary: Wetland tree stems were recently shown to emit the potent greenhouse gas—methane (CH4), which is ∼45 times more powerful than carbon dioxide at warming the Earth's atmosphere. With very few studies published on this "treethane" phenomenon, it is still largely unknown as to why, when and how much methane wetland trees may contribute to the natural emissions from wetland ecosystems. This is important to understand in the context of global methane budgets, climate change and atmospheric models. Our study measured some of the first‐ever wetland tree stem methane emissions spanning an annual cycle, accounting for the seasonal changes in water level of an ephemeral forested wetland ‐ dominated by Melaleuca quinquenervia trees. Under the wettest conditions, we found that tree stems emitted the most methane, and accounted for the majority of the total wetland flux (compared to methane emissions from the wetland water surface). We hypothesize that the methane is largely coming from the low‐oxygen wetland soils, and is being transported upwards through the tree roots, transpiration stream and bark layers. The tree stem methane emissions were much lower during dry periods, when soil methane emissions were dominant. Overall, tree stems contributed 28%–68% of the annual methane emissions from the wetland forest, highlighting the importance of accounting for tree stem methane emissions within wetland methane budgets. Key Points: Bi‐monthly tree stem methane emissions were quantified in a subtropical wetland Melaleuca quinquenervia forest over an annual cycleDynamic tree stem methane emissions spanned six orders of magnitude and were largely driven by changes in the water table heightTree stems contributed 28%–68% of the annual wetland methane flux, therefore are an important component of forested‐wetland methane budgets [ABSTRACT FROM AUTHOR]

The performance of a cineole-rich essential oil as an extraction solvent for vegetable oil was studied. This essential oil was obtained from Melaleuca quinquenervia (Cav.) St Blake Myrtaceae, commonly called niaouli, an invasive plant on the eastern coast of Madagascar. The whole essential oil was used without preliminary isolation of terpenes. Experimentation was carried out with Cucurbita maxima Duchesne Cucurbitaceae seeds. The Soxhlet method was used for the oil extraction, and solvent recovery was performed by hydrodistillation. Niaouli essential oil allowed a better extraction yield of 39% compared to hexane, with 36%. The linoleic acid content of the oil was also higher: 37.19% against 7.25% for hexane. After 30 weeks of storage, the seed powder linoleic acid content increased to 44.99% for niaouli oil against 25.00% for hexane oil. With the screw press extraction method, the best yield of 13.00% was obtained with roasting pretreatment while heating at 60°C. However, the best oleic acid content of 45.36% was obtained at 50°C. It was demonstrated that the seed powder underwent biochemical changes during storage which were similar to intracellular catabolic reactions of fatty acids. The high expenses induced by the deterpenation process in terms of cost and energy limit the diffusion and the development of the use of terpenes as alternative solvents. The results of this research support the idea that it is possible to avoid this costly step by directly using the entire essential oil since this can provide a vegetable oil of good quality. [ABSTRACT FROM AUTHOR]

Antioxidant and antifungal activities of three essential oils (EOs): Melaleuca ericifolia Smith (rosalina; REO), Melaleuca quinquenervia (niaouli; NEO) and Abies alba (fir; FEO) were determined. The antioxidant capacity was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the disc diffusion method was applied to evaluate their antifungal efficacy (in four concentrations 62.5 μL/L, 125 μL/L, 250 μL/L, 500 μL/L used) against Penicillium (P.) expansum microscopic filamentous fungus isolated from bread samples. From the findings it can be clearly evident that antioxidant activities of the EOs were very weak with values ranging from 25.81 ± 7.8 TEAC (6.2 ± 1.4%; FEO) to 162.0 ± 2.1 TEAC (15.9 ± 0.4%; NEO). Regarding antifungal properties, our results revealed that the effects of the EOs on P. expansum growth inhibition were dose-dependent, and they were proportionally increased with increasing EOs concentrations. Detected inhibition zones ranged from 0.00 ± 0.00 mm (for all EOs at 62.5 μL/L) to 11.67 ± 1.15 mm (for REO at 500 μL/L). In conclusion, all analyzed EOs possess promising in vitro antifungal activity (despite their weak antioxidant capacity) suggesting their use as a promising natural preservative in the food industry.

Antioxidant and antifungal activities of three essential oils (EOs): Melaleuca ericifolia Smith (rosalina; REO), Melaleuca quinquenervia (niaouli; NEO) and Abies alba (fir; FEO) were determined. The antioxidant capacity was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the disc diffusion method was applied to evaluate their antifungal efficacy (in four concentrations 62.5 µL/L, 125 µL/L, 250 µL/L, 500 µL/L used) against Penicillium (P.) expansum microscopic filamentous fungus isolated from bread samples. From the findings it can be clearly evident that antioxidant activities of the EOs were very weak with values ranging from 25.81 ± 7.8 TEAC (6.2 ± 1.4%; FEO) to 162.0 ± 2.1 TEAC (15.9 ± 0.4%; NEO). Regarding antifungal properties, our results revealed that the effects of the EOs on P. expansum growth inhibition were dose-dependent, and they were proportionally increased with increasing EOs concentrations. Detected inhibition zones ranged from 0.00 ± 0.00 mm (for all EOs at 62.5 µL/L) to 11.67 ± 1.15 mm (for REO at 500 µL/L). In conclusion, all analyzed EOs possess promising in vitro antifungal activity (despite their weak antioxidant capacity) suggesting their use as a promising natural preservative in the food industry. [ABSTRACT FROM AUTHOR]

Plants use a wide array of secondary metabolites including terpenes as defense against herbivore and pathogen attack, which can be constitutively expressed or induced. Here, we investigated aspects of the chemical and molecular basis of resistance against the exotic rust fungus Austropuccinia psidii in Melaleuca quinquenervia, with a focus on terpenes. Foliar terpenes of resistant and susceptible plants were quantified, and we assessed whether chemotypic variation contributed to resistance to infection by A. psidii. We found that chemotypes did not contribute to the resistance and susceptibility of M. quinquenervia. However, in one of the chemotypes (Chemotype 2), susceptible plants showed higher concentrations of several terpenes including α‐pinene, limonene, 1,8‐cineole, and viridiflorol compared with resistant plants. Transcriptome profiling of these plants showed that several TPS genes were strongly induced in response to infection by A. psidii. Functional characterization of these TPS showed them to be mono‐ and sesquiterpene synthases producing compounds including 1,8‐cineole, β‐caryophyllene, viridiflorol and nerolidol. The expression of these TPS genes correlated with metabolite data in a susceptible plant. These results suggest the complexity of resistance mechanism regulated by M. quinquenervia and that modulation of terpenes may be one of the components that contribute to resistance against A. psidii. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of M. quinquenervia extract on ethanol-induced peptic ulcer in rats. Methods: The following three groups of (n = 6) Sprague Dawley rats were included in this study: vehicle (C), ethanol-administered (E) and ethanol + M. quinquenervia-treated (MQ). MQ group rats received 100 μg/mL M. quinquenervia essential oil just before 96 % ethanol induction (1 ml/kg). One hour after ulcer induction, the animals were euthanized, and gastric and duodenal tissues were removed. Tissue samples were analysed for myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, and histopathological examinations were performed by light microscopy. Results: Gastric and duodenal GSH levels that decreased in the ethanol-administered ulcer groups (p < 0.001), rose following MQ treatment (p < 0.5). Moreover, elevated MPO and MDA levels (p < 0.5) in gastric tissues decreased after MQ-treatment. Similarly, the MQ-treated group showed recovery and control-like morphology compared to the ethanol group in both gastric and duodenal tissues when examined by microscopy. Conclusion: The results indicate that M. quinquenervia extract has a positive impact on gastric injury in rats due to its antioxidant activity. Thus, the plant has a potential for the clinical management of gastric ulcer. [ABSTRACT FROM AUTHOR]

Introduction: Melaleuca is a Myrtaceous genus of flowering plants of about 290 species, distributed throughout Indonesia, Papua New Guinea, Australia, and New Caledonia. Objective: To identify the chemical composition of the essential oils from leaves, twigs and fruits of M. quinquenervia cultivated as ornamental in Costa Rica. Methods: The essential oils were obtained through the steam distillation process in a Clevenger type apparatus. The chemical composition of the oils was done by GC-FID and GC-MS, using the retention indices on a DB-5 type capillary column in addition to mass spectral fragmentation patterns. Results: The essential oils consisted mainly of terpenoids (88,2-96,6%). A total of 88 compounds were identified, accounting for 93.1-97.0% of the total amount of the oils. The major constituents from the leaf oil were 1,8-cineole (31,5%), viridiflorol (21,7%), and α-pinene (17,9%). The fruit essential oil consisted mainly of viridiflorol (42,1%), α-pinene (15,0%), limonene (6,4%), α-humulene (4,7%), β-caryophyllene (3,9%), and 1,8-cineole (3,4%). The major components of twigs oil were viridiflorol (66,0%), and 1,10-di-epi-cubenol (4,0%). Conclusion: The plants introduced in Costa Rica belong to chemotype II whose oils contain as major constituents 1,8-cineole and viridiflorol, and it suggest that the original plants were brought from southern Queensland or northern New South Wales (Australia) or from New Caledonia.

Austropuccinia psidii is a fungal plant pathogen that infects species within the Myrtaceae, causing the disease myrtle rust. Myrtle rust is causing declines in populations within natural and managed ecosystems and is expected to result in species extinctions. Despite this, variation in response to A. psidii exist within some species, from complete susceptibility to resistance that prevents or limits infection by the pathogen. Untargeted metabolomics using Ultra Performance Liquid Chromatography with Ion Mobility followed by analysis using MetaboAnalyst 3.0, was used to explore the chemical defence profiles of resistant, hypersensitive and susceptible phenotypes within Melaleuca quinquenervia during the early stages of A. psidii infection. We were able to identify three separate pools of secondary metabolites: (i) metabolites classified structurally as flavonoids that were naturally higher in the leaves of resistant individuals prior to infection, (ii) organoheterocyclic and carbohydrate-related metabolites that varied with the level of host resistance post-infection, and (iii) metabolites from the terpenoid pathways that were responsive to disease progression regardless of resistance phenotype suggesting that these play a minimal role in disease resistance during the early stages of colonization of this species. Based on the classes of these secondary metabolites, our results provide an improved understanding of key pathways that could be linked more generally to rust resistance with particular application within Melaleuca.

Melaleuca quinquenervia (hereafter melaleuca) was until recently one of the worst ecological invaders in Florida. Introduced for horticulture and levee stabilisation during the early twentieth century, melaleuca spread to cover vast areas of the largest freshwater wetlands ecosystem in North America, The Everglades. From 1997 until 2008, four insects and an associated nematode were approved and released for control of melaleuca, three of which are known to have established. Biological control is frequently a slow and incremental process, but with the integration of complimentary control methods (e.g. chemical and mechanical removal), melaleuca infestations are a fraction of their former range. These few persistent infestations are facilitated by conditions that prevent one species, Oxyops vitiosa, the melaleuca snout weevil, from completing its life cycle, which prompted the testing of and application to release Lophodiplosis indentata (Diptera: Cecidomyiidae). This leaf gall forming midge feeds within pea-shaped growths distributed throughout the canopy. No-choice host range tests suggest that L. indentata will occasionally oviposit on unsuitable host plants, but gall induction and formation is only accomplished on M. quinquenervia. A petition for the release of L. indentata was recommended by TAG in May 2020. [word count: 181] [ABSTRACT FROM AUTHOR]

We develop a suitable delivery system for niaouli essential oil (NEO) using a nanoemulsification method for acne vulgaris. Prepared nanoemulsions (NEs) were characterized for droplet dimension, rheology, surface charge, and stability. The ability of NEO formulations against Propionibacterium acnes and Staphylococcus epidermidis was investigated and all formulations showed antiacne potential in vitro. Ex vivo permeation studies indicated significant improvement in drug permeations and steady state flux of all NEO-NEs compared to the neat NEO (p < 0.05). On the basis of the studied pharmaceutical parameters, enhanced ex vivo skin permeation, and marked effect on acne pathogens, formulation NEO-NE4 was found to be the best (oil (NEO; 10% v/v); Kolliphor EL (9.25% v/v), Carbitol (27.75% v/v), and water (53% v/v)). Concisely, the in vitro and ex vivo results revealed that nanoemulsification improved the delivery as well as bioactivities of NEO significantly.

• Herbivore exclusion reveals direct and indirect impacts of biological agents. • Melaleuca quinquenervia was directly impacted via biomass consumption. • Exotic trees were indirectly impacted via disruption of plant-nutrient feedbacks. • Melaleuca quinquenervia is now less invasive during the early stages of invasion. • Knowledge gained is vital to the development of effective management programs. Herein we present the results of a 5-year herbivore exclusion experiment in which the suppression of two successful biological control agents revealed a nutrient feedback cycle that promoted the growth and dominance of the exotic tree Melaleuca quinquenervia. When herbivory was restricted, plants produced greater quantities of aboveground biomass, which transferred a greater volume of litterfall and a larger load of nutrients to the soil surface. The resulting organic layer on the surface of the soil decomposed more quickly releasing nutrients and resulting in a larger pool of total phosphorus in the surficial soil layer. These mineralized-soil-nutrients were available for uptake by the exotic plant, which produced a greater quantity of surficial roots in the restricted-herbivory plots creating a positive nutrient-feedback cycle to biomass production. Our data suggest that, in addition to the direct suppression of exotic plants through biomass consumption, biological control agents may provide indirect suppression of weeds by preventing the establishment or altering the magnitude and/or direction of an invasion-promoting feedback cycle. [ABSTRACT FROM AUTHOR]

Highlights • n -Alkanes were characterised across both temporal and spatial variations in climate. • Characteristics show little correlation with climate through time at a site. • Characteristics correlate significantly with climate across a large spatial transect. • Correlations are consistent with the functional role of n -alkanes. • Sub-fossil leaf wax records are likely to reflect large climatological shifts. Abstract In higher plants, leaf waxes provide a barrier to non-stomatal water loss, and their composition varies both between and within species. Characteristics of n -alkanes, a suite of ubiquitous compounds in these waxes, are thought to be influenced by the availability of water and the temperature in a plant's growing environment. Longer n -alkane distributions with less variability in chain length are hypothesised to confer greater resistance to non-stomatal water loss and thus are expected in higher abundance in desiccating environments. Relationships between the distribution of n -alkanes and both precipitation and temperature have previously been observed. Despite this, it is unclear whether n -alkane chain length distributions vary plastically in response to climate, or whether they are fixed within populations in different climate settings. To better understand this, we examine the relationship between n -alkane characteristics of Melaleuca quinquenervia and both spatial and temporal climate variation. Across eastern Australia, we find that n -alkane homolog concentrations and distributions in leaves of M. quinquenervia do not vary with climate where samples are proximate, even when climate shows significant variability. However, the concentration and distribution of n -alkane homologs do differ considerably between geographically separated populations in very different climate regimes. These results suggest n -alkane characteristics are not a plastic response to climate variability, and instead are likely fixed and could be driven by genetic differences between populations. This has important implications for the use of n -alkane characteristics as palaeoenvironmental proxies. [ABSTRACT FROM AUTHOR]

The exotic tree Melaleuca quinquenervia (melaleuca) has invaded and formed monotypic forest stands in ecologically sensitive wetlands of Florida. We hypothesized that natural-enemy impact would influence melaleuca's litter and seed fall dynamics via chronic attacks, and enhance native species diversity, which will be reflected in leaf litter composition. This hypothesis was tested during 1997-2013 by studying melaleuca stands in occasionally inundated habitats infested by its natural enemies. Results from our study showed: (1) an initial increase in the leaf and seed fall during the first-half of the study period, followed by about 70% decline during remainder of the study period, (2) a positive correlation between the amount of leaf and seed fall, (3) a negative correlation between the proportion of natural-enemy damaged melaleuca leaf litter and the quantity of fallen seeds, and (4) a slow but steady increase of the non-melaleuca leaf litter amount by 81% and with a corresponding decrease in melaleuca leaf litter by 15%. Of the 17 non-melaleuca species recovered, we recorded two perennials at the onset of the study, which increased to seven during the second half of the study period, one of which was non-native. Cladium and Myrsine species produced significantly more leaf-litter by the end of the study period. Over 80% of the melaleuca leaf litter manifested natural-enemy damage during the last 7-year of the study period. These results provide evidence of a negative influence of natural enemy attack on melaleuca leaf and seed fall dynamics and a positive influence on native species diversity in the fallen leaf litter. [ABSTRACT FROM AUTHOR]

A new species of gall midge, Contarinia melaleucae Kolesik sp. nov., is described that feeds on Melaleuca quinquenervia (Myrtaceae) in Northern Australia. Pale yellow larvae live gregariously within vegetative buds, causing growth retardation or death of the buds. The new species has potential for biological control of M. quinquenervia in southern Florida, USA. [ABSTRACT FROM AUTHOR]

Biochar has been heralded for improving soil quality, sequestering C, and converting organic residues into valueadded amendments. Biochar research in agricultural settings has been primarily conducted on acidic soils, with few studies evaluating biochar effects on alkaline soils. Given the rise of small-scale, sustainable farmers experimenting with biochar in South Florida's alkaline, carbonaceous soil, this study sought to assess biochar use in South Florida using an invasive plant species as a feedstock. Melaleuca quinquenervia (Cav.) S.T. Blake biomass was converted into biochar to measure how application at two rates, 2 and 5% (w/w), affects plant growth, soil macro- and micronutrients, and microbial gas flux (CO2) in a potted greenhouse experiment using Phaseolus vulgaris L. Plant growth was inhibited with biochar addition at the 2 and 5% rates. Dry shoot, pod weight, and pod length decreased significantly between treatments (P < 0.001). Significant reductions in plant-available P, Ca, Mg, Cu, and Zn were observed in the 5% biochar soil postharvest (P < 0.05). Compared with the control, addition of biochar at 2 and 5% rates significantly reduced CO2 flux during the growing season, but not at harvest (P < 0.01). Our results indicate that those considering biochar application in South Florida's alkaline soil should be cautious in selecting feedstock and temperature for biochar production. Biochar can be produced at lower temperatures to decrease pH, but the concomitant increase in volatile matter (VM) is of concern. Although CO2 flux may have decreased, the deleterious impacts of M. quinquenervia biochar (pH = 8.12, VM = 26.5%) on P. vulgaris production should not be dismissed. [ABSTRACT FROM AUTHOR]

The invasive tree Melaleuca quinquenervia (Cavanilles) Blake (Myrtaceae) is widely distributed throughout peninsular Florida, U.S.A. and poses a threat to species diversity in the wetland systems of the Florida Everglades. Biological control research targeting the weed resulted in the introduction of Oxyops vitiosa Pascoe, 1870 to Florida. Approximately three years following its release, adult weevils were collected over 12 consecutive months across six study sites, resulting in a 52:48 F:M sex ratio that did not vary among sites or over time. All female weevils were dissected and their reproductive anatomy was investigated, particularly in relation to the fluctuation of host plant suitability. The continuum of reproductive development was divided into three distinct stages: nulliparous, parous, or degenerative. The general anatomy of each stage is described. In contrast to other systems, fat body abundance provided little insight into the weevil's reproductive status, as 99.5% of all females possessed fat bodies that filled >2/3 of the abdominal cavity. Nulliparous weevils possessed the softest elytra and were lighter in color, parous weevils had the hardest and darkest elytra, while females with degenerative reproductive systems were intermediate to the other two reproductive classes. The proportion of parous O. vitiosa females in a population was strongly influenced by resource availability, as the number of actively ovipositing females increased concomitantly with increasing suitable foliage in the host's canopy. [ABSTRACT FROM AUTHOR]

A four year common garden study was initiated using once-cut Melaleuca quinquenervia trees that were subsequently subjected to a full factorial of treatments that included reduced versus unrestricted herbivory from biological control agents, a mechanical treatment (trees were not cut or were cut every 6 m), and an irrigation treatment (trees were irrigated or not). Repeated cutting reduced the total tree biomass by 76.4%, herbivory alone reduced total biomass by 58.7%, and the combination of cutting and herbivory reduced total biomass by 80.1%. Unrestricted herbivory reduced the seed biomass per tree by 93.9% in uncut trees while repeated cutting eliminated all seed production regardless of herbivory. Uncut trees subjected to unrestricted herbivory allocated an average of 8.8% of their biomass to reproductive tissue, while those exposed to restricted herbivory allocated an average of 15.8%. Unrestricted herbivory by biological control agents on uncut trees also reduced the total number of seed capsule clusters by 79.2%, the number of capsules per cluster by up to 20.8%, and the individual seed weight by up to 58.9%. Repeated cutting did reduce the amount of damage to regrowth by one biological control agent, Oxyops vitiosa (Coleoptera: Curculionidae), but did not reduce the abundance another, Boreioglycaspis melaleucae (Hemiptera: Psyllidae). Trees that were only cut once at the initiation of the study exhibited vigorous regrowth, including increased height and seed production. The mortality of trees was lower compared with other studies, highlighting the influence of localized biotic and abiotic factors on the cumulative suppressive effects of cutting and herbivory on M. quinquenervia . [ABSTRACT FROM AUTHOR]

Rationale: Purification of α‐cellulose from plant tissues is commonly conducted to facilitate the reliable measurement of stable isotope ratios. Prior research has shown that different plant species and tissues react differently to standardised cellulose extraction techniques. Thus, no single method can be applied to all materials and careful consideration must be undertaken when selecting an extraction technique. Methods: In order to evaluate their suitability for use on Melaleuca quinquenervia leaves, a suite of eight different cellulose extraction techniques were tested. Leaves of this species are preserved in perched lakes on southeast Queensland's sand islands and are a focus of ongoing palaeoclimate research. Elemental analyser/isotope ratio mass spectrometry was used to measure stable carbon and oxygen isotopic ratios and sample composition was measured using Fourier transform infrared spectroscopy. Results: We demonstrate that the standard Brendel extraction technique, particularly with a higher reagent volume and longer boiling time, produces cellulose with the lowest spread in isotopic ratios among replicates, and with the fewest impurities detected by Fourier transform infrared spectroscopy. We also show that pre‐treating the leaves to extract leaf wax lipids in order to enable paired analysis from the same sub‐fossil leaves does not significantly affect the quality of the isotopic results. Conclusions: The standard Brendel method allows the most precise stable carbon and oxygen information to be retrieved from the leaves of M. quinquenervia. This unlocks the potential to study palaeoclimate proxy records from our study site and potentially throughout the natural range of the species across eastern Australia, Papua New Guinea and New Caledonia. [ABSTRACT FROM AUTHOR]

Plants have developed complex defense mechanisms to protect themselves against pathogens. A wide-host-range fungus, Austropuccinia psidii, which has caused severe damage to ecosystems and plantations worldwide, is a major threat to Australian ecosystems dominated by members of the family Myrtaceae. In particular, the east coast wetland foundation tree species Melaleuca quinquenervia, appears to be variably susceptible to this pathogen. Understanding the molecular basis of host resistance would enable better management of this rust disease. We identified resistant and susceptible individuals of M. quinquenervia and explored their differential gene expression in order to discover the molecular basis of resistance against A. psidii. Rust screening of germplasm showed a varying degree of response, with fully resistant to highly susceptible individuals. We used transcriptome profiling in samples collected before and at 5 days postinoculation (dpi). Differential gene expression analysis showed that numerous defense-related genes were induced in susceptible plants at 5 dpi. Mapping reads against the A. psidii genome showed that only susceptible plants contained fungal-derived transcripts. Resistant plants exhibited an overexpression of candidate A. psidii resistance-related genes such as receptor-like kinases, nucleotide-binding site leucine-rich repeat proteins, glutathione S-transferases, WRKY transcriptional regulators, and pathogenesisrelated proteins. We identified large differences in the expression of defenserelated genes among resistant individuals. [ABSTRACT FROM AUTHOR]

The environmental and economic impacts of exotic fungal species on natural and plantation forests have been historically catastrophic. Recorded surveillance and control actions are challenging because they are costly, time-consuming, and hazardous in remote areas. Prolonged periods of testing and observation of site-based tests have limitations in verifying the rapid proliferation of exotic pathogens and deterioration rates in hosts. Recent remote sensing approaches have offered fast, broad-scale, and affordable surveys as well as additional indicators that can complement on-ground tests. This paper proposes a framework that consolidates site-based insights and remote sensing capabilities to detect and segment deteriorations by fungal pathogens in natural and plantation forests. This approach is illustrated with an experimentation case of myrtle rust (Austropuccinia psidii) on paperbark tea trees (Melaleuca quinquenervia) in New SouthWales (NSW), Australia. The method integrates unmanned aerial vehicles (UAVs), hyperspectral image sensors, and data processing algorithms using machine learning. Imagery is acquired using a Headwall Nano-Hyperspec® camera, orthorectified in Headwall SpectralView®, and processed in Python programming language using eXtreme Gradient Boosting (XGBoost), Geospatial Data Abstraction Library (GDAL), and Scikit-learn third-party libraries. In total, 11,385 samples were extracted and labelled into five classes: two classes for deterioration status and three classes for background objects. Insights reveal individual detection rates of 95% for healthy trees, 97% for deteriorated trees, and a global multiclass detection rate of 97%. The methodology is versatile to be applied to additional datasets taken with different image sensors, and the processing of large datasets with freeware tools. [ABSTRACT FROM AUTHOR]

The severity of the effects of herbivory on plant fitness can be moderated by the ability of plants to compensate for biomass loss. Compensation is an important component of the ecological fitness in many plants, and has been shown to reduce the effects of pests on agricultural plant yields. It can also reduce the effectiveness of biocontrol through introduced herbivores in controlling weedy invasive plants. This study used a modeling approach to predict the effect of different levels of foliage herbivory by biological control agents introduced to control the invasive tree Melaleuca quinquennervia (melaleuca) in Florida. It is assumed in the model that melaleuca can optimally change its carbon and nitrogen allocation strategies in order to compensate for the effects of herbivory. The model includes reallocation of more resources to production and maintenance of photosynthetic tissues at the expense of roots. This compensation is shown to buffer the severity of the defoliation effect, but the model predicts a limit on the maximum herbivory that melaleuca can tolerate and survive. The model also shows that the level of available limiting nutrient (e.g., soil nitrogen) may play an important role in a melaleuca’s ability to compensate for herbivory. This study has management implications for the best ways to maximize the level of damage using biological control or other means of defoliation. [ABSTRACT FROM AUTHOR]

A field experiment evaluating herbivory from biological control agents onMelaleuca quinquenerviasaplings experienced a wildfire, which resulted in post-fire tree mortality of 64.6% and 28.1% in the unrestricted and restricted herbivory treatments, respectively. The fire did not negatively impact populations of the biological control agentOxyops vitiosa. [ABSTRACT FROM PUBLISHER]

Context: Melaleuca quinquenervia (Cav.) Blake (hereafter melaleuca) is an invasive tree from Australia that has spread over the freshwater ecosystems of southern Florida, displacing native vegetation, thus threatening native biodiversity. Suppression of melaleuca appears to be progressing through the introduction of insect species, the weevil, Oxiops vitiosa, and the psyllid, Boreioglycaspis melaleucae. Objective: To improve understanding of the possible effects of herbivory on the landscape dynamics of melaleuca in native southern Florida plant communities. Methods: We projected likely future changes in plant communities using the individual based modeling platform, JABOWA-II, by simulating successional processes occurring in two types of southern Florida habitat, cypress swamp and bay swamp, occupied by native species and melaleuca, with the impact of insect herbivores. Results: Computer simulations show melaleuca invasion leads to decreases in density and basal area of native species, but herbivory would effectively control melaleuca to low levels, resulting in a recovery of native species. When herbivory was modeled on pure melaleuca stands, it was more effective in stands with initially larger-sized melaleuca. Although the simulated herbivory did not eliminate melaleuca, it decreased its presence dramatically in all cases, supporting the long-term effectiveness of herbivory in controlling melaleuca invasion. Conclusions: The results provide three conclusions relevant to management: (1) The introduction of insect herbivory that has been applied to melaleuca appears sufficient to suppress melaleuca over the long term, (2) dominant native species may recover in about 50 years, and (3) regrowth of native species will further suppress melaleuca through competition. [ABSTRACT FROM AUTHOR]

L'huile essentielle de Niaouli est puissamment antivirale et cicatrisante, très utile en cas d'affections virales d'ordre respiratoire ou cutané. Elle est produite en Nouvelle-Calédonie et à Madagascar, principalement par distillation des feuilles d'une plante de la famille des Myrtacées. [ABSTRACT FROM AUTHOR]

Attack by the gall-forming biological control agentLophodiplosis trifidaGagné (Diptera: Cecidomyiidae), reducedMelaleuca quinquenerviasapling height by 10.1%, leaf biomass by 42%, woody biomass by 42.7%, and root biomass by 30.3%. This provided the first quantitative evidence of the potential ofL. trifidato suppress pre-reproductiveM. quinquenervia. [ABSTRACT FROM AUTHOR]

To improve the performance efficiency of subsurface constructed wetlands (CWs), a variety of media have been tested. Recently, there has been a rising interest in biochar. This research aims to develop the effectiveness of sand media amended with biochar and two plants species ( Melaleuca quinquenervia and Cymbopogon citratus ) in removing phosphorus from sewage effluent in CWs. The experimental design consisted of vertical flow (VF) mesocosms with seven media treatments based on the proportions of biochar in the sand media which ranged from 0 to 25% by volume. During the first 8 months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage was used for the remaining 8 months. Inflow and outflow were monitored for total phosphorus (TP) and PO 4 -P. Plants were harvested at the end of the experiment and TP biomass was determined. Removal efficiencies of TP in the mesocosms loaded with SCW and septage ranged from 42 to 91% and 30 to 83%, respectively. Removal efficiencies of PO 4 -P ranged from 43 to − 92% and 35 to 85% for SCW and septage, respectively. The results revealed that the sand media performed better than the biochar-amended media; increasing the proportion of biochar in the media decreased removal efficiency of phosphorus. However, after flushing due to major rain event, there was no significant difference between sand and sand augmented with 20% biochar. Total plant P ranged from 1.75 g in the 20% biochar mesocosm to 2.10 g in the sand only mesocosm. Plant uptake of P, at least in part, may be accredited for the better P removal efficiency in the sand media compared to the biochar-amended media. [ABSTRACT FROM AUTHOR]

Quantitative reconstructions of terrestrial climate are highly sought after but rare, particularly in Australia. Carbon isotope discrimination in plant leaves (Δleaf) is an established indicator of past hydroclimate because the fractionation of carbon isotopes during photosynthesis is strongly influenced by water stress. Leaves of the evergreen tree Melaleuca quinquenervia have been recovered from the sediments of some perched lakes on North Stradbroke and Fraser Islands, south-east Queensland, eastern Australia. Here, we examine the potential for using M. quinquenervia ∆leaf as a tracer of past rainfall by analysing carbon isotope ratios ( δ13C) of modern leaves. We firstly assess Δleaf variation at the leaf and stand scale and find no systematic pattern within leaves or between leaves due to their position on the tree. We then examine the relationships between climate and Δleaf for a 11-year time series of leaves collected in a litter tray. M. quinquenervia retains its leaves for 1-4 years; thus, cumulative average climate data are used. There is a significant relationship between annual mean ∆leaf and mean annual rainfall of the hydrological year for 1-4 years (i.e. 365-1460 days) prior to leaf fall ( r2 = 0.64, P = 0.003, n = 11). This relationship is marginally improved by accounting for the effect of pCO2 on discrimination ( r2 = 0.67, P = 0.002, n = 11). The correlation between rainfall and Δleaf, and the natural distribution of Melaleuca quinquenervia around wetlands of eastern Australia, Papua New Guinea and New Caledonia offers significant potential to infer past rainfall on a wide range of spatial and temporal scales. [ABSTRACT FROM AUTHOR]

Objective To evaluate an essential oil with larvicide, adulticide and growth inhibitory activity against Aedes aegypti, Aedes albopictus and Culex quinquefasciatus mosquitoes, of medical importance. Methods Standardized methodology by WHO was used to determine the levels of susceptibility of mosquito larvae exposed to the essential oil. To evaluate the adulticide activity with the essential oil at different doses, bottles were impregnated according to the methodology CDC. To determine the development inhibitory activity of Melaleuca quinquenervia ( M. quinquenervia) oil in three mosquito species, third instar larvae were exposed to the LC 50 and LC 90 dose (calculated for each population) of M. quinquenervia oil in glass containers with a capacity of 500 mL. After 24 h exposure, the dead larvae were discarded. The mortality of larvae and pupae were recorded on a daily basis. Results The calculated LC 50 indicates an order of effectiveness of preferential oil for Culex quinquefasciatus (LC 50 = 0.002 1%), Aedes aegypti (LC 50 = 0.004 7%) and Aedes albopictus (LC 50 = 0.004 9%). Conclusions The adulticide activity was achieved with impregnated bottles at 40 and 50 mg/mL with the three mosquitoes species. In larvae, a growth inhibition was detected when exposed to sublethal doses. The results indicate that M. quinquenervia is a plant with promising environmentally sustainable source for vector control. [ABSTRACT FROM AUTHOR]

Infectious diseases are a major welfare issue, economically costly and, from a conservation perspective, threaten susceptible fish populations. Parasite control in aquaculture is over reliant on a limited range of treatments which tend to be low in efficacy, toxic to hosts and have negative consequences on human health and the environment. Here, we tested 22 botanical treatments alongside five controls against Gyrodactylus turnbulli ( Harris 1986), in vitro and in vivo, infecting guppies ( Poecilia reticulata Peters 1859). Survival of detached parasites was significantly reduced by all treatments with cajuput oil, bay rum oil, bladderwrack, octanoic acid, pine tree oil and barberry killing worms instantly. In vivo, cajuput oil applied with emulsifier was as effective as a licensed livestock dewormer, Levamisole, which is not routinely prescribed for use in fish; hence, cajuput can be considered for further research to replace Levamisole in UK research laboratories as well as in ornamental aquaculture. [ABSTRACT FROM AUTHOR]

Two chemotypes of Melaleuca quinquenervia (Cav.) S. T. Blake (Myrtales: Myrtaceae) saplings were planted in a common garden under 2 water treatments and exposed to either restricted or unrestricted herbivory from 2 insect herbivores. Chemotypes consisted of either a predominately E-nerolidol terpenoid complex or one that consisted primarily of viridiflorol; both types had influenced the performance or preference of both insect herbivores in laboratory studies. The densities of the 2 specialist herbivores Boreioglycaspis melaleucae Moore (Hemiptera: Psyllidae) and Oxyops vitiosa Pascoe (Coleoptera: Curculionidae) were monitored regularly as they colonized the plantings, as were plant responses like leaf abscission and tree height. Neither the chemotype nor the water treatments influenced the densities of B. melaleucae and O. vitiosa. Trees subjected to unrestricted herbivory shed more leaf biomass than those protected by insecticides from herbivory. There was no relationship between the amount of biomass shed via abscission and the density of either herbivore despite a significant correlation with a damage rating developed for O. vitiosa. There was a chemotype response to herbivory whereby more leaf biomass was shed by the E-nerolidol chemotype than by the viridiflorol chemotype when subjected to unrestricted herbivory. Tree height was influenced by herbivory but not chemotype or water, although there were separate 2-way interactions between all factors. Thus, despite equal herbivore pressure, the response of young M. quinquenervia trees to abiotic and biotic forces diverged at the plant variant level. [ABSTRACT FROM AUTHOR]

Gastrointestinal nematodes are an important problem in the small ruminant production and their control nearly exclusively depends on commercial anthelmintics. However, parasite resistance to those chemical formulations is an increasing global problem, so new plant-derived compounds are being studied for their potential use against gastrointestinal nematodes. Citrus sinensis and Melaleuca quinquenervia essential oils were evaluated against Haemonchus contortus Embrapa2010 resistant isolate, through the egg hatch test (EHT) and larval development test (LDT) at concentrations ranging from 0.02 mg/mL to 50 mg/mL and from 0.04 mg/mL to 3.12 mg/mL, respectively. All concentrations, positive controls (thiabendazole in EHT or ivermectin in LDT), and negative controls (2% Tween 80 in EHT or 0.5% DMSO in LDT) were performed in six replicates and in three independent experiments, for a total of 18 repetitions involving approximately 1800 parasites per treatment. Significant differences ( P ≤ 0.01) of inhibition percentages were identified by one-way analysis of variance followed by the Tukey test. Inhibitory concentration values (IC 50 and IC 90 ) were analyzed by the Probit procedure of SAS. The essential oils evaluated showed that C. sinensis presented limonene as major component (96.0%), while M. quinquenervia contained longifolene (32.95%) and 1,8-cineole (25.43%) as major components. In the EHT, the IC 50 and IC 90 of the essential oils were respectively 0.27 and 0.99 mg/mL for C. sinensis and, 1.52 and 5.63 mg/mL for M. quinquenervia . In the LDT, the IC 50 and IC 90 were 0.97 and 2.32 mg/mL for C. sinensis and, 0.44 and 0.94 mg/mL for M. quinquenervia . C. sinensis was five times more effective on eggs than M. quinquenervia . However, it was twice more effective on larvae than C. sinensis , indicating that bioactive essential oils have different modes of action. The results suggest that these compounds are good candidates for nematode control. However, alternative anthelmintics have to be safe to the host, promote parasite control in vivo and not generate residues. So, all these key points need to be elucidated before using any plant extract and/or components. [ABSTRACT FROM AUTHOR]

Cajeput tree bark derived activated carbon (TBAC) has been prepared and exploited for the electrochemical detection of vanillin (VAN). The physicochemical properties of the TBACs graphitized at different temperatures were characterized using a variety of analytical and spectroscopic techniques, which include X-ray diffraction, field emission-scanning/transmission electron microscopy (FE-SEM/TEM), N2 adsorption/desorption isotherm measurements, and thermogravimetric analysis (TGA). Utilized as VAN sensors, the electrochemical activities of various TBAC modified electrodes were assessed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The observed superior electrocatalytic activity for the oxidation of VAN is attributed to the high surface area and desirable porosities possessed by TBAC. The VAN sensor exhibited a wide linear range (5–1150 μM), low detection limit (0.68 μM), and excellent sensitivity (0.32 μA mM−1 cm−2), which surpass the existing carbon-based electrodes reported in the literature. The facile VAN sensor subsequently realized is also advantaged by its simplicity, stability, reliability, durability, and low cost, which render real sample analysis and practical industrial applications. [ABSTRACT FROM AUTHOR]

The broad-leaved paper bark treeMelaleuca quinquenerviais a major invader in the wetlands of the Florida Everglades, USA. In South Africa, this introduced species is known from eight locality records and is naturalising at two of these sites. The potential for its spread to other wetlands and estuaries is of concern. The naturalising population near Wolseley, Western Cape, was discovered in May 2009 and is confined to a mountain seep. Given that the Wolseley infestation is restricted to only 0.28 ha, extirpation seemed feasible, and a monitoring system was devised to record population characteristics and response to control measures. Suppression of seedling recruitment and reduction in the number of coppicing stems over a six-year period (2009-2014) suggest that it will be possible to extirpateM. quinquenerviafrom the Wolseley site. Factors that hinder or favour its successful extirpation are presented and the implications of this study for the management of other small populations of this species in South Africa are discussed. [ABSTRACT FROM PUBLISHER]

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Impervious surfaces can adversely alter the soil conditions encountered by tree roots in urban environments. However, these conditions may be rendered more suitable for tree growth by the use of permeable surfaces. This study assessed whether permeable pavements with varying depths (0, 100 or 300 mm) of underlying base layer affected the ecophysiological status of broad-leaf paperbark ( Melaleuca quinquenervia ) trees planted in sandy or clay soils. This study measured instantaneous leaf gas exchange, including photosynthesis ( A 1400 ), CO 2 concentration at the carboxylation site ( C i ), stomatal conductance ( g s ) and intrinsic water use efficiency (i WUE ), and assessed soil and leaf total nitrogen (TN) concentrations. This study also determined longer-term nitrogen cycling and water use efficiency by measuring nitrogen and carbon isotope compositions (δ 15 N and δ 13 C) of the soil and leaves. Each of these variables was then related to tree growth over the 18 months of the study. The study found that the different permeable pavement treatments often did not affect A 1400 , C i , g s or i WUE , and no significant correlation was found between these four variables and tree growth during the initial tree establishment phase when growth was slow. However, tree height and DBH growth during this phase did correlate with leaf δ 15 N in both soil types, suggesting that rapid nitrogen cycling was beneficial for initial growth. In contrast, trunk-diameter growth increments during the subsequent period of rapid growth were positively correlated with A 1400 , C i and g s , and negatively correlated with leaf δ 13 C, for trees in clay soil. Trees in clay soil were prone to waterlogging. However, installation of a base layer below the permeable pavement surface was found to reduce waterlogging, decrease leaf δ 13 C and increase tree growth. These results demonstrate that inclusion of a base layer is important for promoting tree growth when permeable pavements are installed over poorly draining soils such as clay. [ABSTRACT FROM AUTHOR]