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Aim: Woody ecosystems provide critical ecosystem functions and services but are increasingly threatened as invasive pathogens spread globally. Myrtle rust, caused by Austropuccinia psidii, arrived in New Zealand in 2017 and infects at least 12 of 18 species in the susceptible Myrtaceae plant family. Among these are species of structural, successional and cultural importance. We aim to assess whether the functional consequences of Myrtaceae loss could be mitigated if co‐occurring species with shared functional attributes are able to replace them. Location: New Zealand (but with concepts and methodologies that apply globally). Methods: Using a nationwide forest and shrubland plot data set, we assessed community vulnerability to the loss of Myrtaceae species by analysing proportional changes in average trait values when they are absent and produced spatial predictions indicating where species loss might have the greatest impact on community functionality. We then assessed whether compensatory infilling by co‐occurring species would mediate community vulnerability. Results: Forests and shrublands containing Kunzea ericoides and Leptospermum scoparium are highly vulnerable to their loss. Areas most vulnerable overall are the central and south‐eastern North Island, north‐eastern South Island and Stewart Island. For all species, compensatory infilling moderated the impact of their loss. However, if co‐occurring Myrtaceae were unable to respond, possibly if they were also infected, community vulnerability almost always increased because infilling species had different functional attributes, compounding the functional impact. Main Conclusions: Early successional woody plant communities and Myrtaceae‐dominated old‐growth forests are at most risk. Our spatial assessment of species‐level functional impacts from myrtle rust will facilitate better‐informed landscape‐level responses. Management actions and monitoring can now be targeted to areas and communities at greatest risk of losing ecosystem‐level processes. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effect of Iron tree (Prosopis africana) pods supplementation on the performance of Red Sokoto bucks fed Guinea grass (Panicum maximum) as basal diet for 105 days. Five diets were formulated thus: T1 (sole grass), T2 (600g grass +300g prosopis pods), T3(600g grass +350g prosopis pods), T4 (600g grass +400g prosopis pods), T5(600g grass +450g prosopis pods). Twenty (20) red sokoto bucks were assigned to the five treatment diets and replicated four times in a completely randomized design (CRD). The Red Sokoto bucks aged between 6 and 8 months with average weight ranging from 7.28 -10.12kg. Prosopis had values of 96.5, 19 and 29 for dry matter, crude protein and crude fibre, respectively while Guinea grass had corresponding values of 98.0, 19.5 and 7.5%. Growth performance showed that average daily feed intake was significantly different (P<0.05) across the treatment groups. Highest daily feed intake of 0.53kg/buck was obtained in T1 with 0% prosopis, while bucks fed 450g prosopis had least (0.48kg/buck). Total feed intake followed the same trend with the highest value (45.30kg) in T1 and least in T5(40.51kg). Average daily weight gain was significantly different (P<0.05) across the treatment groups with the highest value of 0.07kg obtained among bucks fed 400g and 450g prosopis pods in T4 and T5. Final weight and total body weight followed same trend. Nutrient intake increased with supplementation level as obtained with dry matter (210.67-260.18g/day), crude protein (4.67-6.93g/day) and crude fibre (52.90-87.36g/day) in T5. Acid detergent fibre and neutral detergent fibre reduced with level of supplementation (1.08-1.89 and 1.05 -1.78g). Significant difference (P<0.05) occurred with digestibility of crude protein, crude fibre, ether extract and ash, while none(P>0.05) was observed with dry matter and nitrogen free extract. All haematological and biochemical indices examined were not significantly (P>0.05) affected by the treatment. The feed cost was constant (N65.45kg) cross the treatments. Therefore, it could be concluded that up to 450g of prosopis pod can be included in the diets of bucks without adverse effect on the parameters evaluated. [ABSTRACT FROM AUTHOR]

In natural and agricultural systems, the plant microbiome-the microbial organisms associated with plant tissues and rhizosphere soils-has been shown to have important effects on host physiology and ecology, yet we know little about how these plant-microbe relationships play out in urban environments. Here we characterize the composition of fungal communities associated with living leaves of one of the most common sidewalk trees in the city of San Francisco, California. We focus our efforts on endophytic fungi (asymptomatic microfungi that live inside healthy leaves), which have been shown in other systems to have large ecological effects on the health of their plant hosts. Specifically, we characterized the foliar fungal microbiome of Metrosideros excelsa (Myrtaceae) trees growing in a variety of urban environmental conditions. We used high-throughput culturing, PCR, and Sanger sequencing of the internal transcribed spacer nuclear ribosomal DNA (ITS nrDNA) region to quantify the composition and structure of fungal communities growing within healthy leaves of 30 M. excelsa trees from six distinct sites, which were selected to capture the range of environmental conditions found within city limits. Sequencing resulted in 854 high-quality ITS sequences. These sequences clustered into 85 Operational Taxonomic Units (97% OTUs). We found that these communities encompass relatively high alpha (within) and beta (between-site) diversity. Because the communities are all from the same host tree species, and located in relatively close geographical proximity to one another, these analyses suggest that urban environmental factors such as heat islands or differences in vegetation or traffic density (and associated air quality) may potentially be influencing the composition of these fungal communities. These biogeographic patterns provide evidence that plant microbiomes in urban environments can be as dynamic and complex as their natural counterparts. As human populations continue to transition out of rural areas and into cities, understanding the factors that shape environmental microbial communities in urban ecosystems stands to become increasingly important. [ABSTRACT FROM AUTHOR]

The ecologically and culturally vital tree species, ʻōhiʻa lehua (Metrosideros polymorpha), is threatened by the fungal pathogens Ceratocystis lukuohia and Ceratocystis huliohia, the causal agents of the disease complex called Rapid ʻŌhiʻa Death (ROD). Four invasive ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) species in the Xyleborini tribe colonize ROD Ceratocystis‐infested 'ōhiʻa and produce inoculum through their frass; however, the potential for direct transmission of the ROD fungi by these beetles was unknown. We fulfilled Leach's rules to support insect transmission of ROD by documenting the visitation of these ambrosia beetles to healthy 'ōhiʻa trees, culturing C. lukuohia and C. huliohia from the ROD‐associated beetles using three different collection methods at multiple study sites, and challenging healthy ʻōhiʻa seedlings with beetles that were exposed to both C. lukuohia and C. huliohia cultures. We documented all four invasive ROD‐associated ambrosia beetle species including Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, and Xyleborus perforans to regularly visit healthy ʻōhiʻa trees on sticky traps. Viable Ceratocystis propagules were isolated from all species, and C. lukuohia was most commonly isolated of the two ROD‐causing fungi. Consistently across all collection techniques, ROD Ceratocystis spp. were detected on just under 3% of all assayed beetles, with the highest detection rate from X. affinis. All four beetle species were capable of directly transmitting both pathogens to healthy ʻōhiʻa seedlings with a high rate of transfer. Ceratocystis spp. are highly virulent pathogens in trees, and a single inoculation can result in tree death, therefore any direct transmission is a cause for concern. After meeting the criteria of Leach's rules, we propose that Xi. saxesenii, X. affinis, X. ferrugineus, and X. perforans are vectors of C. lukuohia and C. huliohia, particularly in areas of high ROD pressure and tree stress. [ABSTRACT FROM AUTHOR]

Premise: The isolation of RNA from trees is challenging due to the interference of polyphenols and polysaccharides with downstream processes. Furthermore, many RNA extraction protocols are time consuming and involve hazardous chemicals. To address these issues, we aimed to develop a safe protocol for high‐quality RNA extraction from diverse Metrosideros taxa representing a broad range of leaf toughness, pubescence, and secondary metabolites. Methods and Results: We tested popular RNA isolation kits and protocols that were effective on other recalcitrant trees, including a broad range of optimization and purification steps. We optimized a protocol involving two silica‐membrane column‐based kits that yielded high‐quantity RNA with an RNA integrity number >7 and without DNA contamination. All RNA samples were used successfully in a follow‐on RNA‐Seq experiment. Conclusions: We present an optimized high‐throughput RNA extraction protocol that yielded high‐quality and high‐quantity RNA from three contrasting leaf phenotypes within a hyperdiverse woody species complex. [ABSTRACT FROM AUTHOR]

In natural and agricultural systems, the plant microbiome–the microbial organisms associated with plant tissues and rhizosphere soils–has been shown to have important effects on host physiology and ecology, yet we know little about how these plant-microbe relationships play out in urban environments. Here we characterize the composition of fungal communities associated with living leaves of one of the most common sidewalk trees in the city of San Francisco, California. We focus our efforts on endophytic fungi (asymptomatic microfungi that live inside healthy leaves), which have been shown in other systems to have large ecological effects on the health of their plant hosts. Specifically, we characterized the foliar fungal microbiome of Metrosideros excelsa (Myrtaceae) trees growing in a variety of urban environmental conditions. We used high-throughput culturing, PCR, and Sanger sequencing of the internal transcribed spacer nuclear ribosomal DNA (ITS nrDNA) region to quantify the composition and structure of fungal communities growing within healthy leaves of 30 M. excelsa trees from six distinct sites, which were selected to capture the range of environmental conditions found within city limits. Sequencing resulted in 854 high-quality ITS sequences. These sequences clustered into 85 Operational Taxonomic Units (97% OTUs). We found that these communities encompass relatively high alpha (within) and beta (between-site) diversity. Because the communities are all from the same host tree species, and located in relatively close geographical proximity to one another, these analyses suggest that urban environmental factors such as heat islands or differences in vegetation or traffic density (and associated air quality) may potentially be influencing the composition of these fungal communities. These biogeographic patterns provide evidence that plant microbiomes in urban environments can be as dynamic and complex as their natural counterparts. As human populations continue to transition out of rural areas and into cities, understanding the factors that shape environmental microbial communities in urban ecosystems stands to become increasingly important.

Abstract Premise The isolation of RNA from trees is challenging due to the interference of polyphenols and polysaccharides with downstream processes. Furthermore, many RNA extraction protocols are time consuming and involve hazardous chemicals. To address these issues, we aimed to develop a safe protocol for high‐quality RNA extraction from diverse Metrosideros taxa representing a broad range of leaf toughness, pubescence, and secondary metabolites. Methods and Results We tested popular RNA isolation kits and protocols that were effective on other recalcitrant trees, including a broad range of optimization and purification steps. We optimized a protocol involving two silica‐membrane column‐based kits that yielded high‐quantity RNA with an RNA integrity number >7 and without DNA contamination. All RNA samples were used successfully in a follow‐on RNA‐Seq experiment. Conclusions We present an optimized high‐throughput RNA extraction protocol that yielded high‐quality and high‐quantity RNA from three contrasting leaf phenotypes within a hyperdiverse woody species complex.

The argan tree (Argania Spinosa) grows mainly in Morocco. This forest species, also called iron tree, covers about 830000 ha of Moroccan territory. Virtues of this argan oil are multiple: uses for cooking, medicines, or cosmetics. The objective of this work is the valorization of the argan tree, and especially in its shell, which remains poorly exploited and which is sold by the premises at low prices for use as a fuel in the Moorish baths and bakeries. Argan shell is the reinforcement of this bio-composite. For this, the shell is ground, sieved and separated into five different diameters d. Then, the preparations of the three ranges, each of which is composed of proportions (20%, 60%, 20%) of increasing diameter of particles. Each particle range is used as reinforcement in a matrix of urea formaldehyde and water as a non-polluting solvent. Using a traction machine, the Young module and the breaking stress of the three biomaterial ranges were determined. Our results show that the Young module of first range (R1) remains superior to that of other two ranges and also has a high breaking voltage. Then the bending measurements were made by the three-point machine MTS EM Flexion. Our results show that the R1 has a greater bending stress than the other two ranges. [ABSTRACT FROM AUTHOR]

Metrosideros excelsa (pōhutukawa) is an important native tree species in Aotearoa-New Zealand. Ceratocystis lukuohia is an aggressive wilt pathogen of the Hawaiian forest tree M. polymorpha ('ōhi 'a) and could be a threat to pōhutukawa. A host response study was conducted to evaluate the susceptibility of M. excelsa seedlings to C. lukuohia infection. Forty-eight M. excelsa seedlings from six parent trees were inoculated with C. lukuohia. Disease symptoms and mortality were observed in M. polymorpha positive controls inoculated with C. lukuohia, but not in the M. excelsa. Dissections of the inoculated M. excelsa revealed significantly lower disease severity (mean range: 3.9%-9.0%) comparable to a mean of 1.7% for the M. excelsa negative control treatment. In comparison, the mean disease severity for the M. polymorpha positive control plants was 43.3 ± 6.1%. Aleurioconidia were present in the stem tissue of 86–100% of C. lukuohia-inoculated M. excelsa selections compared to 100% of M. polymorpha and 0% of M. excelsa inoculated with sterile water. These results suggest that C. lukuohia can infect M. excelsa if introduced to a wound, but the pathogen is not aggressive enough to cause wilt and mortality. There is potential for wild M. excelsa to become infected with C. lukuohia if a pathway allowed for the accidental introduction of the pathogen into Aotearoa-New Zealand. Differential susceptibility of other M. excelsa genotypes or Metrosideros species also needs to be considered. Therefore, measures should be taken to avoid the introduction of this pathogen into the country. [ABSTRACT FROM AUTHOR]

Aims: The Myrtaceae is a woody family that plays an important role in forest ecosystems globally. The recent spread of myrtle rust, caused by a fungal pathogen (Austropuccinia psidii), from its native South America into New Zealand (NZ), highlights the need to quantify the ecological importance of Myrtaceae in NZ woody ecosystems. Location: New Zealand. Methods: Using NZ nationwide forest and shrubland inventory data, collected from 2009 to 2014, we quantified the ecological importance of Myrtaceae based on its richness and abundance relative to co-occurring woody families. We then explored how climate and forest stand structure affect Myrtaceae importance in general and by tribe and growth form. Finally, we compared functional traits associated with plant growth and reproductive strategies with other dominant woody families and determined Myrtaceae's contributions to community-weighted mean (CWM) trait values. Results: Myrtaceae occurred in 74% of the study plots and its importance value was the second highest across the woody families. It was the only one in which climbers substantially contributed to the importance value (17%). Greater Myrtaceae importance values were associated with warmer and more mesic climates and early forest successional stages. Climate associations were similar within tribes and growth forms, whereas forest structure effects varied. Myrtaceae was functionally distinct from most co-occurring woody families. Contributions to CWM wood density, maximum height, and specific leaf area values were significantly greater than expected from its importance value. Conclusions: Myrtaceae is the second most ecologically important woody family in NZ woody ecosystems. The family has a distinctive functional trait spectrum associated with high wood density and tall stature, ensuring large and enduring carbon stocks. There will potentially be large and deleterious outcomes in forest ecosystems if taxon-specific pathogens, such as Austropuccinia psidii, spread and significantly reduce Myrtaceae importance. [ABSTRACT FROM AUTHOR]

Metrosideros (Myrtaceae) comprises 58 woody species distributed across Oceania and with three singleton outliers in Philippines, South America and Africa. Centres of species richness occur in New Zealand and New Caledonia. This distribution accords with a proposed Gondwanan origin for the family. While the phylogeography of one component of the genus – subgenus Metrosideros – has received some examination, the rest of the genus has not been resolved. In this study, we improve resolution of the phylogeny of Metrosideros and consider origin, possible vicariant relationships, long‐distance dispersal events and dispersal routes for the genus. A Bayesian phylogeny, with all but one recently described species of Metrosideros, was constructed using concatenated ITS + ETS rDNA from samples we collected and sequenced. Relative to previous work on Metrosideros using ITS alone, here, using ITS plus ETS, we produce a more detailed and robust phylogeny with a near threefold increase in significant nodal support. Putative centres of origin/diversification, vicariant events and dispersals were considered with reference to the phylogeny, present‐day diversity and fossil record of Metrosideros. Metrosideros occurs as five clades, including the former genera Tepualia and Carpolepis. The paraphyletic and now superseded subgenus Mearnsia included elements of four of these clades, whereas subgenus Metrosideros forms a single clade with robust support. Our phylogeography indicates multiple dispersal/vicariant events within the history of the genus, a number of which involved New Zealand. Among other such events, we infer an exceptional 6300 km trans‐equatorial dispersal from Fiji to the Bonin Islands (Japan). Australia and New Zealand, respectively, are the likely landmasses of origin and diversification for Metrosideros. Typical patterns of floral dispersal proceed from large continental landmasses onto increasingly remote islands and with distance from continent species diversity usually declines. However, Metrosideros shows a countervailing pattern since relatively remote islands are the main centres of speciation and dispersal. [ABSTRACT FROM AUTHOR]

Some of the most spectacular adaptive radiations begin with founder populations on remote islands. How genetically limited founder populations give rise to the striking phenotypic and ecological diversity characteristic of adaptive radiations is a paradox of evolutionary biology. We conducted an evolutionary genomics analysis of genus Metrosideros, a landscape-dominant, incipient adaptive radiation of woody plants that spans a striking range of phenotypes and environments across the Hawaiian Islands. Using nanopore-sequencing, we created a chromosome-level genome assembly for Metrosideros polymorpha var. incana and analyzed whole-genome sequences of 131 individuals from 11 taxa sampled across the islands. Demographic modeling and population genomics analyses suggested that Hawaiian Metrosideros originated from a single colonization event and subsequently spread across the archipelago following the formation of new islands. The evolutionary history of Hawaiian Metrosideros shows evidence of extensive reticulation associated with significant sharing of ancestral variation between taxa and secondarily with admixture. Taking advantage of the highly contiguous genome assembly, we investigated the genomic architecture underlying the adaptive radiation and discovered that divergent selection drove the formation of differentiation outliers in paired taxa representing early stages of speciation/divergence. Analysis of the evolutionary origins of the outlier single nucleotide polymorphisms (SNPs) showed enrichment for ancestral variations under divergent selection. Our findings suggest that Hawaiian Metrosideros possesses an unexpectedly rich pool of ancestral genetic variation, and the reassortment of these variations has fueled the island adaptive radiation. [ABSTRACT FROM AUTHOR]

The management and removal of invasive species may give rise to unanticipated changes in plant-pollinator mutualisms because they can alter the composition and functioning of plant-pollinator interactions in a variety of ways. To utilize a functional approach for invasive species management, we examined the restoration of plant-pollinator mutualisms following the large-scale removal of an invasive nectar thief and arthropod predator, Vespula pensylvanica. We reduced V. pensylvanica populations in large plots managed over multiple years to examine the response of plant-pollinator mutualisms and the fruit production of a functionally important endemic Hawaiian tree species, Metrosideros polymorpha. To integrate knowledge of the invader's behaviour and the plant's mating system, we determined the efficacy of V. pensylvanica as a pollinator of M. polymorpha and quantified the dependence of M. polymorpha on animal pollination (e.g. level of self-compatibility and pollen limitation). The reduction of V. pensylvanica in managed sites, when compared to unmanaged sites, resulted in a significant increase in the visitation rates of effective bee pollinators (e.g. introduced Apis mellifera and native Hylaeus spp.) and in the fruit production of M. polymorpha. Apis mellifera, following the management of V. pensylvanica, appears to be acting as a substitute pollinator for M. polymorpha, replacing extinct or threatened bird and bee species in our study system. Synthesis and applications. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation managers to simultaneously minimize the negative and maximize the positive impacts (e.g. taxon substitution) of introduced species. Such novel restoration approaches are needed, especially in highly degraded ecosystems. Fruit production of the native M. polymorpha was increased after management of the invasive pollinator predator V. pensylvanica; however, the main pollinators were no longer native but introduced. This research thus demonstrates the diverse impacts of introduced species on ecological function and the ambiguous role they play in restoration. We recommend incorporating ecological function and context into invasive species management as this approach may enable conservation managers to simultaneously minimize the negative and maximize the positive impacts (e.g. taxon substitution) of introduced species. Such novel restoration approaches are needed, especially in highly degraded ecosystems. © 2012 British Ecological Society.

Stands of the landscape‐dominant tree, Metrosideros polymorpha ('ōhi'a) on the Island of Hawai'i, HI., USA, are dying from a phenomenon known as rapid 'ōhi'a death (ROD). Approximately 180,000 acres of forest have already been impacted by the disease, the majority of which is attributed to C. lukuohia, the more aggressive of the two Ceratocystis species responsible for ROD. Three isolates of C. lukuohia were compared for differences in aggressiveness. Mean disease severity and mean number of days to death did not differ among the three isolates of C. lukuohia. A single isolate was selected for use in a resistance screening of 128 plants across four varieties of M. polymorpha occurring on Hawai'i Island: incana, glaberrima, polymorpha and newellii. Disease severity was lower in early‐successional var. incana (38.84%) and riparian var. newellii (36.11%) compared to late‐successional var. glaberrima (61.27%) and high‐elevation var. polymorpha (70.27%). Var. incana and var. newellii also had the lowest mortality (63% and 77%, respectively) while var. glaberrima (86%) and var. polymorpha (100%) had the highest mortality. Eighty‐five per cent of the plants that died did so within 49 days post‐inoculation and mean number of days to death was significantly higher for var. glaberrima (46) compared to var. polymorpha (31). The results of this preliminary study suggest that some form of resistance might be present in natural populations of at least one variety of M. polymorpha on Hawai'i Island and should be investigated more intensively. [ABSTRACT FROM AUTHOR]

The global spread of invasive plant pathogens is increasing, putting natural forests and ecosystem services under threat. Spatial data can quantify range non‐overlap between invasive pathogens and their hosts to identify existing and potentially restorable refugia to enable 'escape' from the pathogen.In 2017, myrtle rust Austropuccinia psidii was detected in New Zealand. New Zealand has 27 native woody and liana species in the plant family susceptible to the disease (Myrtaceae), many of which are ecosystem dominants and economically important. Spatial methods were used to compare the current New Zealand distribution of myrtle rust with the modelled distributions of its potential native hosts. To guide management and set priorities for conservation of at‐risk species, areas of potential refugia where a Myrtaceae species is predicted to occur outside the pathogen range were identified under two myrtle rust distribution scenarios.Myrtle rust will thrive in New Zealand's warmer regions. Many native Myrtaceae are distributed within this area, but several species occur extensively outside the core range of the disease. Species distributed in cooler southern regions will be best placed to persist in refugia.Myrtaceae species with specific habitat requirements and narrow geographical ranges in warmer (northern) areas are likely to require ex situ or active in situ management. Even widely distributed species will benefit from the restoration of suitable habitat that supports multiple species outside the myrtle rust range.Synthesis and applications. Spatial data can be used to identify refugia and restoration opportunities, and thus inform landscape‐level management responses to invasive pathogens. This approach can guide decisions over where to implement in situ (e.g. fungicide spraying) versus ex situ (e.g. seed banking, botanic gardens) management efforts. [ABSTRACT FROM AUTHOR]

Rapid ʻŌhiʻa Death (ROD) is a deadly disease that is threatening the native Hawaiian keystone tree species, ʻōhiʻa lehua (Metrosideros polymorpha Gaudich). Ambrosia beetles (Curculionidae: Scolytinae) and their frass are hypothesized to play a major role in the spread of ROD, although their ecological niches and frass production within trees and across the landscape are not well understood. We characterized the beetle communities and associated frass production from bolts (tree stem sections) representative of entire individual ʻōhiʻa trees from multiple locations across Hawaiʻi Island by rearing beetles and testing their frass for viable ROD-causing fungi. Additionally, we estimated frass production for three beetle species by weighing their frass over time. We found that Xyleborinus saxesenii (Ratzburg), Xyleborus affinis Eichhoff, Xyleborus ferrugineus (Fabricius), Xyleborus perforans (Wollaston), and Xyleborus simillimus Perkins were commonly found on ROD-infected ʻōhiʻa and each produced frass containing viable Ceratocystis propagules. The Hawaiʻi Island endemic beetle and the only native ambrosia beetle associated with ʻōhiʻa, X. simillimus , was limited to high elevations and appeared to utilize similar tree heights or niche dimensions as the invasive X. ferrugineus. Viable Ceratocystis propagules expelled in frass were found throughout entire tree bole sections as high as 13 m. Additionally, we found that X. ferrugineus produced over 4× more frass than X. simillimus. Our results indicate the ambrosia beetle community and their frass play an important role in the ROD pathosystem. This information may help with the development and implementation of management strategies to control the spread of the disease. [ABSTRACT FROM AUTHOR]

A long-standing goal of evolutionary biology is to understand the mechanisms underlying the formation of species. Of particular interest is whether or not speciation can occur in the presence of gene flow and without a period of physical isolation. Here, we investigated this process within Hawaiian Metrosideros , a hypervariable and highly dispersible woody species complex that dominates the Hawaiian Islands in continuous stands. Specifically, we investigated the origin of Metrosideros polymorpha var. newellii (newellii), a riparian ecotype endemic to Hawaii Island that is purportedly derived from the archipelago-wide M. polymorpha var. glaberrima (glaberrima). Disruptive selection across a sharp forest-riparian ecotone contributes to the isolation of these varieties and is a likely driver of newellii's origin. We examined genome-wide variation of 42 trees from Hawaii Island and older islands. Results revealed a split between glaberrima and newellii within the past 0.3–1.2 My. Admixture was extensive between lineages within Hawaii Island and between islands, but introgression from populations on older islands (i.e., secondary gene flow) did not appear to contribute to the emergence of newellii. In contrast, recurrent gene flow (i.e., primary gene flow) between glaberrima and newellii contributed to the formation of genomic islands of elevated absolute and relative divergence. These regions were enriched for genes with regulatory functions as well as for signals of positive selection, especially in newellii, consistent with divergent selection underlying their formation. In sum, our results support riparian newellii as a rare case of incipient ecological speciation with primary gene flow in trees. [ABSTRACT FROM AUTHOR]

Seed banks serve the purpose of maintaining germplasm for ex situ species preservation. Herbarium vouchers may be a viable source of unique and/or additional seeds for restoration as they can sometimes be from larger and more representative populations compared with seed banks. Rapid 'ōhi'a death (ROD) has emerged as a serious threat against Hawaii's most iconic and foundational forest tree (Metrosideros spp.), and seed banking has been identified as an important strategy in preserving the genetic diversity of 'ōhi'a. With respect to 'ōhi'a we ask the following: (1) what is the long-term viability of 'ōhi'a seeds stored in herbarium conditions, (2) how do herbarium curation practices affect seed viability, and (3) how long do seeds survive using conventional storage methods? We placed fresh 'ōhi'a seeds in a herbarium dryer (57°C/5% relative humidity) for 5 days, freezer (−18°C/95% RH) for 2 weeks, and dryer then freezer, and compared against fresh control seeds. Seeds were harvested from a chronosequence of herbarium specimens, withdrawn from conventional storage conditions up to 3.75 and 6.5 years before experiments began, and germination assessed. There was no difference in the proportion germinated among treatments and control testing for herbarium entry (p = 0.56). Although no seeds from herbarium specimens germinated, freshly collected dried and frozen seeds germinated at a level equivalent to the control (p = 0.76). For seeds stored using conventional storage methods at 3.75 and 6.5 years, germination was equivalent to freshly harvested seeds. This suggests that seeds can survive the extreme climate conditions necessary to enter herbaria, but lose viability after storage at ambient conditions in 4 years or less. Although 'ōhi'a seeds may be plentiful in herbaria, we recommend using seeds deposited into seed banks using conventional storage methods for orthodox seeds for postdisturbance restoration, and to combat ROD. [ABSTRACT FROM AUTHOR]

ABC model, Clianthus, Eucalyptus, flowering, gibberellin, growth habit, heteroblasty, homoblasty, Metrosideros, microRNA, Pachycladon, phase change, Phormium, photoperiod, reproduction, Sophora. [Extracted from the article]

Accurate feature annotation as well as assembly contiguity are important requisites of a modern genome assembly. They allow large-scale comparison of genomes across and within species and identification of polymorphisms, leading evolutionary and functional studies. We report an updated genome resource for Metrosideros polymorpha, the most dominant tree species in the Hawaiian native forests and a unique example of rapid and remarkable ecological diversification of woody species. Ninety-one percent of the bases in the sequence assembly (304 Mb) were organized into 11 pseudomolecules, which would represent the chromosome structure of the species assuming the synteny to a close relative Eucalyptus. Our complementary approach using manual annotation and automated pipelines identified 11.30% of the assembly to be transposable elements, in contrast to 4.1% in previous automated annotation. By increasing transcript and protein sequence data, we predicted 27,620 gene models with high concordance from the supplied evidence. We believe that this assembly, improved for contiguity, and annotation will be valuable for future evolutionary studies of M. polymorpha and closely related species, facilitating the isolation of specific genes and the investigation of genome-wide polymorphisms associated with ecological divergence. [ABSTRACT FROM AUTHOR]

Aim: Little is known about how diversification occurs within long‐lived, highly dispersible and continuously distributed groups. We examined the distribution of genetic variation within the woody genus Metrosideros across the Hawaiian Islands for insights into how diversification occurs within this animal‐pollinated, wind‐dispersed group. Among Hawaiian plants, Metrosideros is unique in its formation of continuous stands within islands that span a remarkable range of environments and comprise numerous predominantly single‐island taxa. Location: Hawaiian Islands. Taxon: Metrosideros. Methods: We performed population genetic analyses of variation at nine nuclear microsatellite loci from 1,486 adults of 23 Metrosideros morphotypes sampled from five main Hawaiian Islands plus additional Pacific Island populations. Results: American Samoa and Tahiti populations clustered most closely with the older islands. Results also revealed isolation by distance across the archipelago, clustering of populations predominantly by island, and evidence of multiple colonizations or back‐colonizations of three islands. The number of genetic clusters peaked on islands of intermediate age, coincident with peak morphotype richness. All islands comprised a broad range of genetic distances among taxa with the greatest overall genetic distance observed on Oahu. The two taxa that are distributed broadly across the archipelago were weakly but significantly differentiated only on volcanically active Hawaii Island, where they partition early‐ and late‐successional environments. One of these taxa was positioned centrally both within individual‐island splitstree networks and across the archipelago‐wide network. Main conclusions: Distance‐dependent gene flow contributes to isolation of Metrosideros across islands, especially on terminal islands. Morphological diversity likely accumulates rapidly within this group, likely associated with differential adaptation across heterogeneous environments, but isolation of gene pools through speciation within continuous Metrosideros stands likely requires persistent disruptive selection where environments are stable for long periods. The generalist, wet‐forest M. polymorpha var. glaberrima may play a central role in the generation of the group's many, largely island‐endemic, taxa. [ABSTRACT FROM AUTHOR]

Variation in leaf micromorphology can aid delimitation of taxonomically difficult groups. The woody genus Metrosideros (Myrtaceae) dominates Hawai'i's native forests and comprises striking, predominantly infraspecific, macromorphological variation, including many forms unrecognized in current taxonomic treatments. On taxonomically rich O'ahu, 10 taxa (varieties or unnamed morphotypes of M. polymorpha and other species) occur in a predictable sequence with overlapping ranges from low to high elevation along the numerous leeward ridges of the Ko'olau Range. We used scanning electron and light microscopy to examine mature, nonsenescing sun leaves from each of these 10 taxa. Parametric and nonparametric tests were used to compare stomatal complex (SC) traits and those of a newly described secretory structure (SS) across taxa. Correlations among traits and discriminant analyses were also done. Density and length of SCs were inversely related overall, and both measures varied significantly across taxa. Although abaxial SSs were consistently present only in the two highest-elevation glabrous taxa, adaxial SSs were present in all 10 taxa. Length and density of adaxial SSs and density of abaxial SSs varied across taxa, and densities of both SCs and SSs were greatest at high elevation. Combined, the SC and SS traits differentiated 100% of four glabrous varieties and two of three pubescent varieties of M. polymorpha. Variation in leaf micromorphology, including presence and density of a newly described SS, aids delimitation of closely related Hawaiian Metrosideros taxa and may reflect differential local adaptation across a heterogeneous landscape. [ABSTRACT FROM AUTHOR]

The native 'ōhi'a lehua (Metrosideros polymorpha) has cultural, biological and ecological significance to Hawai'i, but it is seriously threatened by a disease commonly referred to as rapid 'ōhi'a death (ROD). Preliminary investigations showed that a Ceratocystis species similar to C. fimbriata s.lat. was the cause of the disease. In this study, we used a combination of the phylogenetic, morphological and biological species concepts, as well as pathogenicity tests and microsatellite analyses, to characterise isolates collected from diseased 'ōhi'a trees across Hawai'i Island. Two distinct lineages, representing new species of Ceratocystis, were evident based on multigene phylogenetic analyses. These are described here as C. lukuohia and C. huliohia. Ceratocystis lukuohia forms part of the Latin American clade (LAC) and was most closely associated with isolates from Syngonium and Xanthosoma from the Caribbean and elsewhere, including Hawai'i, and C. platani, which is native to eastern USA. Ceratocystis huliohia resides in the Asian-Australian clade (AAC) and is most closely related to C. uchidae, C. changhui and C. cercfabiensis, which are thought to be native to Asia. Morphology and interfertility tests support the delineation of these two new species and pathogenicity tests show that both species are aggressive pathogens on seedlings of M. polymorpha. Characterisation of isolates using microsatellite markers suggest that both species are clonal and likely represent recently-introduced strains. Intensive research is underway to develop rapid screening protocols for early detection of the pathogens and management strategies in an attempt to prevent the spread of the pathogens to the other islands of Hawai'i, which are currently disease free. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY:: The capsular‐fruited genus Metrosideros (Myrtaceae) is one of the most widely distributed flowering plant genera in the Pacific but is extinct in Australia today. The center of geographic origin for the genus and the reason for and timing of its extinction in Australia remain uncertain. We identify fossil Metrosideros fruits from the newly discovered Golden Fleece fossil flora in the Oligo‐Miocene of Tasmania, Australia, shedding further light on these problems. METHODS:: Standard paleopalynological techniques were used to date the fossil‐bearing sediments. Scanning electron microscopy and an auto‐montage camera system were used to take high‐resolution images of fossil and extant fruits taken from herbarium specimens. Fossils are identified using a nearest‐living‐relative approach. KEY RESULTS:: The fossil‐bearing sediments are palynostratigraphically dated as being Proteacidites tuberculatus Zone Equivalent (ca. 33–16 Ma) in age and provide a confident Oligo‐Miocene age for the macrofossils. Two new fossil species of Metrosideros are described and are here named Metrosideros dawsonii sp. nov. and Metrosideros wrightii sp. nov. CONCLUSIONS:: These newly described fossil species of Metrosideros provide a second record of the genus in the Cenozoic of Australia, placing them in the late Early Oligocene to late Early Miocene. It is now apparent not only that Metrosideros was present in Australia, where the genus is now extinct, but that at least several Metrosideros species were present during the Cenozoic. These fossils further strengthen the case for an Australian origin of the genus. [ABSTRACT FROM AUTHOR]

Abstract: Whereas disruptive selection imposed by heterogeneous environments can lead to the evolution of extrinsic isolating barriers between diverging populations, the evolution of intrinsic postzygotic barriers through divergent selection is less certain. Long‐lived species such as trees may be especially slow to evolve intrinsic isolating barriers. We examined postpollination reproductive isolating barriers below the species boundary, in an ephemeral hybrid zone between two successional varieties of the landscape‐dominant Hawaiian tree, Metrosideros polymorpha, on volcanically active Hawai'i Island. These archipelago‐wide sympatric varieties show the weakest neutral genetic divergence of any taxon pair on Hawai'i Island but significant morphological and ecological differentiation consistent with adaptation to new and old lava flows. Cross‐fertility between varieties was high and included heterosis of F1 hybrids at the seed germination stage, consistent with a substantial genetic load apparent within varieties through low self‐fertility and a lack of self‐pollen discrimination. However, a partial, but significant, barrier was observed in the form of reduced female and male fertility of hybrids, especially backcross hybrids, consistent with the accumulation of genetic incompatibilities between varieties. These results suggest that partial intrinsic postzygotic barriers can arise through disruptive selection acting on large, hybridizing populations of a long‐lived species. [ABSTRACT FROM AUTHOR]

Genomewide markers enable us to study genetic differentiation within a species and the factors underlying it at a much higher resolution than before, which advances our understanding of adaptation in organisms. We investigated genomic divergence in Metrosideros polymorpha, a woody species that occupies a wide range of ecological habitats across the Hawaiian Islands and shows remarkable phenotypic variation. Using 1659 single nucleotide polymorphism ( SNP) markers annotated with the genome assembly, we examined the population genetic structure and demographic history of nine populations across five elevations and two ages of substrates on Mauna Loa, the island of Hawaii. The nine populations were differentiated into two genetic clusters distributed on the lower and higher elevations and were largely admixed on the middle elevation. Demographic modelling revealed that the two genetic clusters have been maintained in the face of gene flow, and the effective population size of the high-altitude cluster was much smaller. A FST-based outlier search among the 1659 SNPs revealed that 34 SNPs (2.05%) were likely to be under divergent selection and the allele frequencies of 21 of them were associated with environmental changes along elevations, such as temperature and precipitation. This study shows a genomic mosaic of M. polymorpha, in which contrasting divergence patterns were found. While most genomic polymorphisms were shared among populations, a small fraction of the genome was significantly differentiated between populations in diverse environments and could be responsible for the dramatic adaptation to a wide range of environments. [ABSTRACT FROM AUTHOR]

Simultaneous salinity and boron (B) excess often occur due to irrigation with water containing high levels of salts, including B. The effects of excess of NaCl and B in the nutrient solution on some agronomical and physiological parameters of Viburnum tinus (laurustinus) and Metrosideros excelsa (metrosideros) were studied. Potted plants were grown in a factorial combination of B (1 and 6 mg/l) and NaCl (2 and 6 dS/m). B toxicity (6 mg/l) caused tip/edge burn in the lower leaves of laurustinus, while these symptoms were absent in metrosideros. Toxicity by B reduced dry biomass in the two species, particularly the aerial part in metrosideros and the roots in laurustinus. Metrosideros accumulated a similar content of B in all leaves, while the laurustinus tended to accumulate more B in the lower leaves. The leaf B content in laurustinus was reduced by salinity to a greater extent than in metrosideros; however, this was not sufficient to prevent injuries to the laurustinus photosynthetic system.

Fifty male and fifty female Spargue-Dawley rats were randomly chosen and used to study the sexual dimorphisms of stomachic histological structures. The rat stomach consisted of the nonglandular part and the glandular part. The gender differences of the nonglandular part existed in the thicknesses of the stratified squamous epithelium and the longitudinal muscle. These findings revealed that the male rat stomach may storage more foods than the female. The gastric glands occupied all the lamina propria in the glandular part. The thicknesses of the gastric glands of the female and male rat were 525.0 ± 95.9 mm and 472.0 ± 158.7 mm respectively, and the difference was very significant (p<0.01). The gastric glands could be divided to two layers in the HE stain, i.e. the luminal and the basal layers. The thicknesses of the luminal layer of the female and male rat were 289.7 ± 95.9 mm and 300.0 ± 120.7 mm respectively, and the difference was insignificant (p>0.05). On the contrary, the thicknesses of the basal layer and the three muscle layers in the female glandular part were all thicker than those in male, and the differences were very significant (P<0.01). These findings indicated that the female rat stomachs may have a more powerful digestive ability than the male ones. The nucleus-glandular index of the gastric gland of the normal female and male rat were 0.19 ± 0.05 and 0.18 ± 0.04 respectively, and the difference was insignificant (p>0.05). [ABSTRACT FROM AUTHOR]

The histology and histochemistry of the adrenal gland of the African giant rat, AGR (Cricetomys gambianus Waterhouse) was carried out using ten adult male rats with the knowledge of providing information which could be helpful in an improved knowledge of the structure and function of the gland. The adrenal gland of the African giant rat has a distinct cortex and medulla surrounded by a thin rim of capsule. The adrenal cortex has three zones which are basically the zona glomerulosa, zona fasiculata and zona reticularis with the absence of zona intermedia. The zona glomerulosa contains polyhedral cells which form irregular clusters or cords while the zona fasiculata had radial cells of cuboidal or polyhedral shape. The cells of zona reticularis are similar to those of the zona fasiculata and in addition contain small cells as irregular cords and clusters. The cells of the adrenal medulla are composed of irregular epithelioid cells arranged in rounded groups or short cords and are mostly columnar or polyhedral chromaffin cells which are separated by sinusoids. The adrenal capsule, cortex and medulla were Periodic Acid-Schiff-positive.The adrenal capsule and adrenal medulla was Masson Trichrome-positive unlike the zona fasiculata and zona reticularis. The adrenal capsule and zona glomerulosa were Verhoeff-positive unlike the other zones of the gland. In conclusion the histology of the adrenal gland of the AGR is similar to those of other mammals with a few exceptions, the entire gland is rich in carbohydrate while the capsule and by extension, the outermost portion of the cortex are rich in collagen and elastic fibers. The outcome of this research provides information needed in the better improved understanding of the structure and function of the adrenal gland of the animal. [ABSTRACT FROM AUTHOR]

Foliar architecture of Myrtaceae native species of the Argentinian flora IV. Tribes Myrteae and Metrosidereae and key based on foliar characters. This work completes the leaf architecture of native species of Myrtaceae from Argentina. In this contribution are studied two native genus of the tribe Myrteae with uncertain position in the past, and the only one native genus of tribe Metrosidereae in South America. One species of Blepharocalyx and two species of Eugenia are simple, with variable apex and base, leathery texture and entire margin. First vein pinnate, simple and straight, without agrophic veins, second veins broquidodromous, with or without paramarginal and intramarginal veins, third and fourth veins random reticulate or percurrent, and fifth vein random reticulate, percurrent or dichotomized. With or without areoles, with venules branching one, two or more times. The last marginal venation can be complete or incomplete. The leaves of genus Metrosideros are characterized by simple, with acute apex and cuneate base, leathery texture and entire margin. First vein category suprabasal-acrodromous, with agrophic veins, second vein cladodromous or branched, without paramarginal veins and intramarginal veins, and third vein dichotomized. Not develop areoles. Venules branched two or more times. The last marginal venation can be incomplete. Finally, is presented a key to differentiate all native Argentinian species of Myrtaceae, based on characters or character combinations of foliar architecture. [ABSTRACT FROM AUTHOR]

Whole genome sequences, which can be provided even for non-model organisms owing to high-throughput sequencers, are valuable in enhancing the understanding of adaptive evolution. Metrosideros polymorpha, a tree species endemic to the Hawaiian Islands, occupies a wide range of ecological habitats and shows remarkable polymorphism in phenotypes among/within populations. The biological functions of genetic variations observed within this species could provide significant insights into the adaptive radiation found in a single species. Here de novo assembled genome sequences of M. polymorpha are presented to reveal basic genomic parameters about this species and to develop our knowledge of ecological divergences. The assembly yielded 304-Mbp genome sequences, half of which were covered by 19 scaffolds with >5 Mbp, and contained 30 K protein-coding genes. Demographic history inferred from the genome-wide heterozygosity indicated that this species experienced a dramatic rise and fall in the effective population size, possibly owing to past geographic or climatic changes in the Hawaiian Islands. This M. polymorpha genome assembly represents a high-quality genome resource useful for future functional analyses of both intra- and interspecies genetic variations or comparative genomics. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Myrtaceous fossil capsular fruits and flowers from the northwest of Tasmania, in the Early Oligocene-aged Little Rapid River (LRR) deposit, are described. The reproductive organs are found in association with Myrtaceous leaves previously thought to belong to a fleshy-fruited genus, Xanthomyrtus at both LRR, and an Eocene Tasmanian site at Hasties, which are reassessed with fresh morphological evidence. METHODS: Standard Light Microscopy (LM) and Scanning Electron Microscopy (SEM) were used to investigate cuticular characters and an auto-montage camera system was used to take high-resolution images of fossil and extant fruits. Fossils are identified using a nearest living relative (NLR) approach. KEY RESULTS: The fossil fruits and flowers share a number of characters with genera of capsular-fruited Myrtaceae, in particular sharing several synapomor-phies with species of Metrosideros subg. Metrosideros (tribe: Metrosidereae). The fossil is here described, and named Metrosideros leunigii, sp. nov. CONCLUSIONS: This research establishes the presence of Metrosideros (aff. subg. Metrosideros) in the Eocene-Oligocene (~40-30 mya) of Tasmania, Australia. This is the first fossil record of Metrosideros in Australia, as well as the oldest conclusive fossil record, and may provide evidence for an Australian origin of the genus. It is also yet another example of extinction in the Tertiary of a group of plants on the Australian mainland that is only found today on nearby Pacific landmasses. [ABSTRACT FROM AUTHOR]