Search

Abstract Dasiphora fruticosa (Rosaceae), commonly known as shrubby cinquefoil, is a flowering shrub of high ornamental value yet underutilized in East Asian landscapes. Given its broad elevational distribution range, D. fruticosa serves as an ideal model for studying genetic adaptations and speciation along elevation gradients. Here, we present a high-quality chromosome-scale assembly of D. fruticosa with a genome size of 249.23 Mb and a contig N50 length of 14.01 Mb. The genome sequence contains 32,613 protein-coding genes, of which 30,643 (93.96%) were functionally annotated. Compared to the published D. fruticosa genome sequence, our assembly demonstrates higher completeness and continuity. Furthermore, comparative genomic analyses provide insights into the phylogenetic relationship and high-altitude adaptation of D. fruticosa. Overall, our study offers a valuable genetic resource for both molecular and evolutionary research on shrubby cinquefoil.

ABSTRACTLow thermal conductivity and excellent high-temperature stability make lanthanum zirconate (La2Zr2O7, LZO) a very promising material for high-temperature insulation applications. In this study, LZO porous ceramics with ultra-high porosity and an open-pore structure were prepared by the replica method using a polyurethane template. The flowability and coating quality of the ceramic slurry were optimized. When the dispersant content of the slurry was 0.6 wt% and the alcohol to water ratio was 1:1, the slurry had low surface tension and low viscosity, leading to good coating quality of the ceramic slurry on the sponge template. The pore size between hollow skeletons was 100–500 μm with the hollow structure of the skeletons forming secondary pores. LZO porous ceramics showed high porosity of 87.6%-96.0%, low thermal conductivity of 0.048–0.126 W/(m·K), and compressive strength of 0.13–0.74 MPa by adjusting the ceramic content. A high temperature insulation performance test showed that the temperature difference between the cold side and the hot side of the sample was over 1000°C, indicating the excellent thermal insulation properties of LZO porous ceramics. LZO porous ceramics had good high-temperature stability without sintering shrinkage at heat treatment temperatures below 1500°C.

Local adaptation has been proven to be common in plants and extensively studied, from increasing plant yields to predicting species responses to the future changing climate. Compared to main crops and forest trees, however, investigations into the local adaptation of fruit trees across current and future climatic landscapes are still lacking. With the explosion of large-scale genomic data, landscape genomics has emerged as a new approach to identify candidate loci that are related to environmental variations (i.e., genotype-environment associations or GEA), while allowing for downstream analyses such as the calculation of adaptive indices and genetic offsets, which can be used to predict spatial-temporal shifts of populations in response to future environmental change. Here, by summarizing the cutting-edge methods for investigating species' local adaptation as well as evaluating the genetic offsets based on the current genotype-environment association, we call for more efforts on elucidating genomic and molecular underpinnings of local adaptation of fruit trees and forecasting the possible maladaptation under rapid climate change. In summary, the study of local adaptation in fruit trees is important for ensuring long-term sustainability and productivity. The emergence of landscape genomics has great potential to advance our understanding of the genomic and molecular mechanisms underlying local adaptation and to predict responses to environmental change.

α-SiAlON is a potential wave-transmittance material for radome materials, yet the comprehensive properties need to be improved. In this study, a series of SrxY0.5-xSi12-(m + n) Alm +nOnN16-n (x = 0.02, 0.04, 0.06, and 0.08) porous ceramics with porosities ranging from 44.15% to 58.62% were synthesized via tert-butanol gel-casting. The real part of the permittivity of porous ceramics was in the range of 3.13–4.18 (8.2–12.4 GHz) with over 70% wave transmittance in the thickness range of 5.5–9.5 mm. The thermal conductivity and flexural strength of porous ceramics were in the ranges of 1.063–1.703 W/(m·K) and 52.67–106.33 MPa, respectively. Compared with Y-α-SiAlON porous ceramics, the thermal insulation and mechanical properties of Sr/Y-α-SiAlON porous ceramics are improved without deteriorating wave transmittance properties. The results show that Sr/Y-α-SiAlON porous ceramics have the potential to be wave-transmittance materials by adjusting the wave transmittance, thermal insulation, and mechanical properties of α-SiAlON.

Abstract Glasshouse plants are species that trap warmth via specialized morphology and physiology, mimicking a human glasshouse. In the Himalayan alpine region, the highly specialized glasshouse morphology has independently evolved in distinct lineages to adapt to intensive UV radiation and low temperature. Here we demonstrate that the glasshouse structure – specialized cauline leaves – is highly effective in absorbing UV light but transmitting visible and infrared light, creating an optimal microclimate for the development of reproductive organs. We reveal that this glasshouse syndrome has evolved at least three times independently in the rhubarb genus Rheum. We report the genome sequence of the flagship glasshouse plant Rheum nobile and identify key genetic network modules in association with the morphological transition to specialized glasshouse leaves, including active secondary cell wall biogenesis, upregulated cuticular cutin biosynthesis, and suppression of photosynthesis and terpenoid biosynthesis. The distinct cell wall organization and cuticle development might be important for the specialized optical property of glasshouse leaves. We also find that the expansion of LTRs has likely played an important role in noble rhubarb adaptation to high elevation environments. Our study will enable additional comparative analyses to identify the genetic basis underlying the convergent occurrence of glasshouse syndrome.

Abstract This research proposed the modular prefabricated permanent formwork system made of ultra-high-performance concrete (UHPC). Two kinds of modular formwork shapes were designed: the flat formwork and the ribbed. The experimental investigation on the axial compression performance of the composite columns that consist of the normal strength concrete (NSC) core and the modular UHPC permanent formwork was demonstrated. Compared with the flat formwork, the ribbed formwork exhibited better bonding with the NSC core. As observed from the test results, the composite column with the ribbed formwork presented a similar axial behavior as the NSC column with a slight improvement in ultimate loads. Therefore, the modular UHPC ribbed permanent formwork could be regarded as the additional cover to the conventional NSC column. In addition, the finite element analysis (FEA) model was also developed to simulate the composite columns numerically. The predicted capacities agreed with the experimental results, which validated the numerical models. The crack pattern estimated by the FEA model revealed that the interaction between the permanent formwork and the inner concrete introduced many tiny cracks to the concrete core. However, as protected by the UHPC permanent formwork, the overall durability of the composite columns can still be enhanced.

Abstract Lanthanum zirconate (LZO) has high‐temperature advantages, including a high melting point, low thermal conductivity, and high structure stability, which has the potential to be used in high‐temperature thermal insulation field. However, low mechanical properties of LZO porous ceramics have limited further applications. In this work, LZO nanofibrous membranes were prepared by electrospinning, and the preparation parameters, including PVP content, spinning voltage, feeding rate, received distance, and the heating process, were investigated to optimize the microstructure of the nanofibrous membranes. The LZO nanofibrous membranes with a grain size of 34.5 nm displayed good morphology after calcining at 1000°C. The LZO fibrous membranes had a very low thermal conductivity of 0.0716 W/m·K at room temperature, showing excellent insulating performance. This work indicates that LZO nanofibrous membranes are promising candidate materials for thermal insulation applications.

In order to seal the joints between the ultra-high-performance concrete (UHPC) permanent formworks, the high strength cementitious grout (HSCG) was investigated in the presented work. The water reducer content and the water to binding materials (W/B) ratio of the grout were modified to meet the grout fluidity requirement, and then the effects of three commonly used admixtures (i.e., hydrophobic powders (HP), expansive agents (EA), and redispersible polymer powders (RPP)) and PVA fibers on the compressive, tensile, flexural, and adhesive strengths of the HSCG were investigated. In addition to the normal condition, the adhesive strengths under the soaked condition and the thermal aging condition were also evaluated. The HP worsen all strength index, especially the adhesive strength, while the appropriate utilization of the EA could improve all strength indexes by more than 12%. With the addition of RPP, the adhesive strengths under the soaked and thermal aging conditions could be significantly enhanced by over 85%. The PVA fiber could also enhance the normal adhesive strength by 20.5%. Based on the experimental results, the recommended contents of the EA, RPP, and PVA fibers were 6%, 2%, and 0.3%, respectively, while the HP was not suggested for the HSCG due to its adverse effect on the mechanical performances.

The utilization of ultra-high-performance concrete (UHPC) permanent formwork could facilitate the construction of hydraulic concrete structures. However, the joints between UHPC formwork are the vulnerable parts of a whole permanent formwork system. This study aimed to develop a High Strength Cementitious Grout (HSCG) for filling these joints, integrating the formwork system, and minimizing the adverse influence on these joints. The aggregate size for the HSCG was optimized, and four kinds of admixtures (i.e., hydrophobic powder (HP), expansive agent (EA), redispersible polymer powder (RPP), and cellulose ether (CE)) and PVA fibers were used to improve the HSCG. The HSCG with different aggregate sizes, admixture dosages, and PVA fiber contents were experimentally investigated. By evaluating the compressive, tensile, flexural, and adhesive strengths of the prepared grout, the aggregate size range was recommended to be 0.15–0.30 ​mm, while the suggested contents of HP, EA, RPP, and CE were 0%, 6%, 2%, and 0.1%, respectively, by weight of binding materials. In addition, the optimal volume content of PVA fibers was 0.45%. In order to avoid the introduced foams, 0.2% of the defoamers were used in combination with the CE. After that, six combinations were tested to consider the coupled effect of different admixtures and PVA fibers on the HSCG. In consideration of the strengths, shrinkage, and abrasion resistance to water impact, the HSCG with the combination of (EA ​+ ​RPP ​+ ​CE), the aggregate size of 0.15–0.30 ​mm showed the optimal overall performance and was regarded as the most suitable HSCG for grouting.

Polygonaceae has a complex taxonomic history, although a few studies using plastid or nuclear DNA fragments have explored relationships within this family, intrafamilial relationships remain controversial. Here, we newly sequenced and annotated 17 plastomes representing 12 genera within Polygonaceae. Combined with previously published data, a total of 49 plastomes representing 22/46 Polygonaceae genera and 16/20 Polygonoideae genera were collected to infer the phylogeny of Polygonaceae, with an emphasis on Polygonoideae. Plastome comparisons revealed high conservation within Polygonoideae in structure and gene order. Phylogenetic analyses using both Maximum Likelihood and Bayesian methods revealed two major clades and seven tribes within Polygonoideae. BEAST and S-DIVA analyses suggested a Paleocene origin of Polygonoideae in Asia. While most genera of Polygonoideae originated and further diversified in Asia, a few genera experienced multiple long-distance dispersal events from Eurasia to North America after the Miocene, with a few dispersal events to the Southern Hemisphere also being detected. Both ancient vicariance and long-distance events have played important roles in shaping the current distribution pattern of Polygonoideae.

Highlights CRFA is used for preparing the lightweight concrete partition panels. The optimal ratio of the CRFA to the cement is 2.2 for the lightweight concrete. CRFA lightweight concrete needs to be cured for at least 10 days. The cost of lightweight concrete is reduced by 40% by using CRFA.

Abstract The flora of northern China forms the main part of the Sino‐Japanese floristic region and is located in a south–north vegetative transect in East Asia. Phylogeographic studies have demonstrated that an arid belt in this region has promoted divergence of plants in East Asia. However, little is known about how plants that are restricted to the arid belt of flora in northern China respond to climatic oscillation and environmental change. Here, we used genomic‐level data of Myripnois dioica across its distribution as a representative of northern China flora to reconstruct plant demographic history, examine local adaptation related to environmental disequilibrium, and investigate the factors related to effective population size change. Our results indicate M. dioica originated from the northern area and expanded to the southern area, with the Taihang Mountains serving as a physical barrier promoting population divergence. Genome‐wide evidence found strong correlation between genomic variation and environmental factors, specifically signatures associated with local adaptation to drought stress in heterogeneous environments. Multiple linear regression analyses revealed joint effects of population age, mean temperature of coldest quarter, and precipitation of wettest month on effective population size (Ne). Our current study uses M. dioica as a case for providing new insights into the evolutionary history and local adaptation of northern China flora and provides qualitative strategies for plant conservation.

Porous high-entropy ceramics are a new alternative material for thermal insulation. Their better stability and low thermal conductivity are due to lattice distortion and unique pore structures. In this work, rare-earth-zirconate ((La0.25Eu0.25Gd0.25Yb0.25)2(Zr0.75Ce0.25)2O7) porous high-entropy ceramics were fabricated by a tert-butyl alcohol (TBA)-based gel-casting method. The regulation of pore structures was realized through changing different initial solid loadings. The XRD, HRTEM, and SAED results showed that the porous high-entropy ceramics had a single fluorite phase without impurity phases, exhibiting high porosity (67.1–81.5%), relatively high compressive strength (1.02–6.45 MPa) and low thermal conductivity (0.0642–0.1213 W/(m·K)) at room temperature. Porous high-entropy ceramics with 81.5% porosity demonstrated excellent thermal properties, showing a thermal conductivity of 0.0642 W/(m·K) at room temperature and 0.1467 W/(m·K) at 1200 °C. The unique pore structure with a micron size contributed to their excellent thermal insulating performance. The present work provides the prospect that rare-earth-zirconate porous high-entropy ceramics with tailored pore structures are expected to be thermal insulation materials.

Abstract Background Plastome-scale data have been prevalent in reconstructing the plant Tree of Life. However, phylogenomic studies currently based on plastomes rely primarily on maximum likelihood inference of concatenated alignments of plastid genes, and thus phylogenetic discordance produced by individual plastid genes has generally been ignored. Moreover, structural and functional characteristics of plastomes indicate that plastid genes may not evolve as a single locus and are experiencing different evolutionary forces, yet the genetic characteristics of plastid genes within a lineage remain poorly studied. Results We sequenced and annotated 10 plastome sequences of Gentianeae. Phylogenomic analyses yielded robust relationships among genera within Gentianeae. We detected great variation of gene tree topologies and revealed that more than half of the genes, including one (atpB) of the three widely used plastid markers (rbcL, atpB and matK) in phylogenetic inference of Gentianeae, are likely contributing to phylogenetic ambiguity of Gentianeae. Estimation of nucleotide substitution rates showed extensive rate heterogeneity among different plastid genes and among different functional groups of genes. Comparative analysis suggested that the ribosomal protein (RPL and RPS) genes and the RNA polymerase (RPO) genes have higher substitution rates and genetic variations among plastid genes in Gentianeae. Our study revealed that just one (matK) of the three (matK, ndhB and rbcL) widely used markers show high phylogenetic informativeness (PI) value. Due to the high PI and lowest gene-tree discordance, rpoC2 is advocated as a promising plastid DNA barcode for taxonomic studies of Gentianeae. Furthermore, our analyses revealed a positive correlation of evolutionary rates with genetic variation of plastid genes, but a negative correlation with gene-tree discordance under purifying selection. Conclusions Overall, our results demonstrate the heterogeneity of nucleotide substitution rates and genetic characteristics among plastid genes providing new insights into plastome evolution, while highlighting the necessity of considering gene-tree discordance into phylogenomic studies based on plastome-scale data.

Objective The effects of Pleurotus ostreatus on the feed utilization of broad bean stalks (BBS), rape straw (RS), paddy straw (PS), and corn stalk (CS) was examined. Methods The four roughages were co-cultured with Pleurotus ostreatus. The chemical composition; enzyme activities of laccase, carboxymethylcellulase (CMCase) and xylanase; carbohydrate and protein fractions (based on The Cornell Net Carbohydrate and Protein System [CNCPS]) were assessed at different days after inoculation (7, 14, 21, 28 d) and un-inoculated roughages (control, 0 d). The digestibility of nutrient components and the gas production of roughage with various incubation times were monitored at 0, 2, 4, 6, 9, 12, 24, 36, 48, 60, and 72 h using an in vitro ruminal fermentation method. Results A higher CMCase activity (0.1039 U/mL) and earlier time to peak (14 d) were detected in Pleurotus ostreatus cultured with CS (p0.05) in slowly-degradable carbohydrate (CB2) at different incubation times (p

Asexual lineages are perceived to be short-lived on evolutionary timescales. Hence, reports for exceptional cases of putative ‘ancient asexuals’ usually raise questions about the persistence of such species. So far, there have been few studies to solve the mystery in plants. The monotypic Kingdonia dating to the early Eocene, contains only K. uniflora that has no known definitive evidence for sexual reproduction nor records for having congeneric sexual species, raising the possibility that the species has persisted under strict asexuality for a long period of time. Here, we analyze whole genome polymorphism and divergence in K. uniflora. Our results show that K. uniflora is characterized by high allelic heterozygosity and elevated πN/πS ratio, in line with theoretical expectations under asexual evolution. Allele frequency spectrum analysis reveals the origin of asexuality in K. uniflora occurred prior to lineage differentiation of the species. Although divergence within K. uniflora individuals exceeds that between populations, the topologies of the two haplotype trees, however, fail to match each other, indicating long-term asexuality is unlikely to account for the high allele divergence and K. uniflora may have a recent hybrid origin. Phi-test shows a statistical probability of recombination for the conflicting phylogenetic signals revealed by the split network, suggesting K. uniflora engages in undetected sexual reproduction. Detection of elevated genetic differentiation and premature stop codons (in some populations) in genes regulating seed development indicates mutational degradation of sexuality-specific genes in K. uniflora. This study unfolds the origin and persistence mechanism of a plant lineage that has been known to reproduce asexually and presents the genomic consequences of lack of sexuality.

Understanding the pattern of species extinction risk is key to biodiversity conservation. Previous studies showed extinction risk correlates strongly with taxon species richness. However, there is no consistent conclusion to this hypothesis, and patterns differ among different taxonomic groups. Here, we collated lists of vascular plant and terrestrial vertebrate species information on their threatened status in Yunnan Province and performed the first systematical analysis to test the relationship between the proportion of threatened or extinct species and species richness at the family-level of the two above taxa in Yunnan Province, China. We found that extinction risk was not randomly distributed among families and the estimated extinction risk was higher among closer phylogenetic families than expected by chance. Moreover, there were significant negative correlations between extinction risk and family size in vascular plants and terrestrial vertebrates. Our results suggest that family size is a good predictor of extinction risk and extinction risk is related to evolutionary history at family-level among vascular plants and terrestrial vertebrates in Yunnan.

Objectively evaluating different lines of evidence within a formalized framework is the most efficient and theoretically grounded approach for defining robust species hypotheses. Asteropyrum Drumm. et Hutch. is a small genus of perennial herb containing two species, A. cavaleriei and A. peltatum. The distinction of these two species mainly lies in the shape and size of leaf blades. However, these characters have been considered labile and could not differentiate the two species reliably. In this study, we investigated the variation of the leaf blades of 28 populations across the whole range of Asteropyrum using the landmark-based geometric morphometrics (GMM), sought genetic gaps within this genus using DNA barcoding, phylogenetic reconstruction and population genetic methods, and compared the predicted ecological niches of the two species. The results showed that the leaf form (shape and size) was overlapped between the two species; barcode gap was not detected within the genus Asteropyrum; and little ecological and geographical differentiation was found between the two taxa. Two genetic clusters detected by population genetic analysis did not match the two morphospecies. The results suggest that there are no distinct boundaries between the two species of Asteropyrum in terms of morphology, genetics and ecology and this present classification should be abandoned. We anticipate that range-wide population genomic studies would properly delineate the species boundaries and help to understand the evolution and speciation within Asteropyrum.

Myripnois is a monotypic shrub genus in the daisy family constricted to northern China. Although wild populations of Myripnois dioica are relatively rare, this plant may potentially be cultured as a fine ornamental. In the present study, we sequenced the complete plastome of M. dioica, generating the first plastome sequences of the subfamily Pertyoideae. The plastome of M. dioica has a typical quadripartite circular structure. A large ∼20-kb and a small ∼3-kb inversion were detected in the large single copy (LSC) region and shared by other Asteraceae species. Plastome phylogenomic analyses based on 78 Asteraceae species and three outgroups revealed four groups, corresponding to four Asteraceae subfamilies: Asteroideae, Cichorioideae, Pertyoideae and Carduoideae. Among these four subfamilies, Pertyoideae is sister to Asteroideae + Cichorioideae; Carduoideae is the most basal clade. In addition, we characterized 13 simple sequence repeats (SSRs) that may be useful in future studies on population genetics. Keywords: Myripnois, Asteraceae, Plastomes, Large inversion, Phylogenomic analyses

Abstract Background Saussurea DC. is one of the largest and most morphologically heterogeneous genera in Asteraceae. The relationships within Saussurea have been poorly resolved, probably due an early, rapid radiation. To examine plastome evolution and resolve backbone relationships within Saussurea, we sequenced the complete plastomes of 17 species representing all four subgenera. Results All Saussurea plastomes shared the gene content and structure of most Asteraceae plastomes. Molecular evolutionary analysis showed most of the plastid protein-coding genes have been under purifying selection. Phylogenomic analyses of 20 Saussurea plastomes that alternatively included nucleotide or amino acid sequences of all protein-coding genes, vs. the nucleotide sequence of the entire plastome, supported the monophyly of Saussurea and identified three clades within it. Three of the four traditional subgenera were recovered as paraphyletic. Seven plastome regions were identified as containing the highest nucleotide variability. Conclusions Our analyses reveal both the structural conservatism and power of the plastome for resolving relationships in congeneric taxa. It is very likely that differences in topology among data sets is due primarily to differences in numbers of parsimony-informative characters. Our study demonstrates that the current taxonomy of Saussurea is likely based at least partly on convergent morphological character states. Greater taxon sampling will be necessary to explore character evolution and biogeography in the genus. Our results here provide helpful insight into which loci will provide the most phylogenetic signal in Saussurea and Cardueae.

Most species of Santalales (the sandalwood order) are hemiparasites, including both facultative and obligate hemiparasites. Despite its rich diversity, only a small fraction of the species in the sandalwood order have sequenced plastomes. The evolution of parasitism–associated plastome reduction in Santalales remains under-studied. Here, we report the complete plastomes of three facultative hemiparasites (Pyrularia edulis, Cervantesiaceae; Osyris wightiana, and Santalum album, Santalaceae), and two obligate hemiparasites (Viscum liquidambaricolum and Viscum ovalifolium, Viscaceae). Coupled with publicly available data, we investigated the dynamics of plastome degradation in Santalales hemiparasites. Our results indicate that these hemiparasites can be characterized by various degrees of plastome downsizing, structural rearrangement, and gene loss. The loss or pseudogenization of ndh genes was commonly observed in Santalales hemiparasites, which may be correlated to the lifestyle shift from photoautotroph to hemiparasitism. However, the obligate hemiparasites did not exhibit a consistently higher level of gene loss or pseudogenization compared to facultative hemiparasites, which suggests that the degree of plastome reduction is not correlated with the trophic level facultative or obligate hemiparasitism. Instead, closely related taxa tend to possess highly similar plastome size, structure, and gene content. This implies the parasitism-associated plastome degradation in Santalales may evolve in a lineage-specific manner.

Summary: Kingdonia uniflora, an alpine herb, has an extremely narrow distribution and represents a model for studying evolutionary mechanisms of species that have adapted to undisturbed environments for evolutionarily long periods of time. We assembled a 1,004.7-Mb draft genome (encoding 43,301 genes) of K. uniflora and found significant overrepresentation in gene families associated with DNA repair, underrepresentation in gene families associated with stress response, and loss of most plastid ndh genes. During the evolutionary process, the overrepresentation of gene families involved in DNA repair could help asexual K. uniflora reduce the accumulation of deleterious mutations, while reducing genetic diversity, which is important in responding to environment fluctuations. The underrepresentation of gene families related to stress response and functional loss of ndh genes could be due to lack or loss of ability to respond to environmental changes caused by long-term adaptation to a relatively stable ecological environment.

Dolomiaea is a medicinally important genus of Asteraceae endemic to alpine habitats of the Qinghai-Tibet Plateau (QTP) and adjacent areas. Despite significant medicinal value, genomic resources of Dolomiaea are still lacking, impeding our understanding of its evolutionary history. Here, we sequenced and annotated plastomes of four Dolomiaea species. All analyzed plastomes share the gene content and structure of most Asteraceae plastomes, indicating the conservation of plastome evolutionary history of Dolomiaea. Eight highly divergent regions (rps16-trnQ, trnC-petN, trnE-rpoB, trnT-trnL-trnF, psbE-petL, ndhF-rpl32-trnL, rps15-ycf1, and ycf1), along with a total of 51–61 simple sequence repeats (SSRs) were identified as valuable molecular markers for further species delimitation and population genetic studies. Phylogenetic analyses confirmed the evolutionary position of Dolomiaea as a clade within the subtribe Saussureinae, while revealing the discordance between the molecular phylogeny and morphological treatment. Our analysis also revealed that the plastid genes, rpoC2 and ycf1, which are rarely used in Asteraceae phylogenetic inference, exhibit great phylogenetic informativeness and promise in further phylogenetic studies of tribe Cardueae. Analysis for signatures of selection identified four genes that contain sites undergoing positive selection (atpA, ndhF, rbcL, and ycf4). These genes may play important roles in the adaptation of Dolomiaea to alpine environments. Our study constitutes the first investigation on the sequence and structural variation, phylogenetic utility and positive selection of plastomes of Dolomiaea, which will facilitate further studies of its taxonomy, evolution and conservation.

Understanding how species have adapted and responded to past climate provides insights into the present geographical distribution and may improve predictions of how biotic communities will respond to future climate change. Therefore, estimating the distribution and potentially suitable habitats is essential for conserving sensitive species such as Garuga forrestii W.W.Sm., a tree species endemic to China. The potential climatic zones of G. forrestii were modelled in MaxEnt software using 24 geographic points and nine environmental variables for the current and future (2050 and 2070) conditions under two climate representative concentration pathways (RCP4.5 and RCP8.5) scenarios. The resulting ecological niche models (ENMs) demonstrated adequate internal assessment metrics, with all AUC and TSS values being >0.79 and a pROC of >1.534. Our results also showed that the distribution of G. forrestii was primarily influenced by temperature seasonality (% contribution = 12%), elevation (% contribution = 27.5%), and precipitation of the wettest month (% contribution = 35.6%). Our findings also indicated that G. forrestii might occupy an area of 309,516.2 km2 in southwestern China. We note that the species has a potential distribution in three provinces, including Yunnan, Sichuan, and Guangxi. A significant decline in species range is observed under the future worst case of high-emissions scenario (RCP8.5), with about 19.5% and 20% in 2050 and 2070, respectively. Similarly, higher elevations shift northward to southern parts of Sichuan province in 2050 and 2070. Thus, this study helps highlight the vulnerability of the species, response to future climate and provides an insight to assess habitat suitability for conservation management.

Understanding how species adapt to extreme environments is an extension of the main goals of evolutionary biology. While alpine plants are an ideal system for investigating the genetic basis of high-altitude adaptation, genomic resources in these species are still limited. In the present study, we generated reference-level transcriptomic data of five Saussurea species through high-throughput sequencing and de novo assembly. Three of them are located in the highland of the Qinghai-Tibet Plateau (QTP), and the other two are close relatives distributed in the lowland. A series of comparative and evolutionary genomics analyses were conducted to explore the genetic signatures of adaptive evolution to high-altitude environments. Estimation of divergence time using single-copy orthologs revealed that Saussurea species diversified during the Miocene, a period with extensive tectonic movement and climatic fluctuation on the QTP. We characterized gene families specific to the alpine species, including genes involved in oxidoreductase activity, pectin catabolic process, lipid transport, and polysaccharide metabolic process, which may play important roles in defense of hypoxia and freezing temperatures of the QTP. Furthermore, in a phylogenetic context with the branch model, we identified hundreds of genes with signatures of positive selection. These genes are involved in DNA repair, membrane transport, response to UV-B and hypoxia, and reproductive processes, as well as some metabolic processes associated with nutrient intake, potentially responsible for Saussurea adaptation to the harsh environments of high altitude. Overall, our study provides valuable genomic resources for alpine species and gained helpful insights into the genomic basis of plants adapting to extreme environments.

Abstract Background Among the 13 families of early-diverging eudicots, only Circaeasteraceae (Ranunculales), which consists of the two monotypic genera Circaeaster and Kingdonia, lacks a published complete plastome sequence. In addition, the phylogenetic position of Circaeasteraceae as sister to Lardizabalaceae has only been weakly or moderately supported in previous studies using smaller data sets. Moreover, previous plastome studies have documented a number of novel structural rearrangements among early-divergent eudicots. Hence it is important to sequence plastomes from Circaeasteraceae to better understand plastome evolution in early-diverging eudicots and to further investigate the phylogenetic position of Circaeasteraceae. Results Using an Illumina HiSeq 2000, complete plastomes were sequenced from both living members of Circaeasteraceae: Circaeaster agrestis and Kingdonia uniflora . Plastome structure and gene content were compared between these two plastomes, and with those of other early-diverging eudicot plastomes. Phylogenetic analysis of a 79-gene, 99-taxon data set including exemplars of all families of early-diverging eudicots was conducted to resolve the phylogenetic position of Circaeasteraceae. Both plastomes possess the typical quadripartite structure of land plant plastomes. However, a large ~49 kb inversion and a small ~3.5 kb inversion were found in the large single-copy regions of both plastomes, while Circaeaster possesses a number of other rearrangements, particularly in the Inverted Repeat. In addition, infA was found to be a pseudogene and accD was found to be absent within Circaeaster, whereas all ndh genes, except for ndhE and ndhJ, were found to be either pseudogenized (ΨndhA, ΨndhB, ΨndhD, ΨndhH and ΨndhK) or absent (ndhC, ndhF, ndhI and ndhG) in Kingdonia. Circaeasteraceae was strongly supported as sister to Lardizabalaceae in phylogenetic analyses. Conclusion The first plastome sequencing of Circaeasteraceae resulted in the discovery of several unusual rearrangements and the loss of ndh genes, and confirms the sister relationship between Circaeasteraceae and Lardizabalaceae. This research provides new insight to characterize plastome structural evolution in early-diverging eudicots and to better understand relationships within Ranunculales .

The undesirable properties of conventional recycled fine aggregate (RFA) often limit its application in the construction industry. To overcome this challenge, a method for preparing completely recycled fine aggregate (CRFA), which crushes all concrete waste only into fine aggregate, was proposed. The obtained CRFA had high apparent density, and its water absorption was lower than that of the conventional RFA. To take advantage of the CRFA, this paper introduced the modified packing density method for the CRFA concrete mix design. The modified packing density method took account of the powder with a particle size of smaller than 75 μm in the CRFA and balanced both the void ratio and the specific surface area of the aggregate system. Concrete (grade C55) was prepared using the CRFA to validate the feasibility of the proposed method. The unit price of the prepared CRFA concrete was around 12.7% lower than that of the natural aggregate concrete. Additionally, the proposed procedure for the concrete mixture design could recycle all concrete waste into the new concrete and replace all the natural fine aggregate in the concrete mixture.

Spacers are important components in reinforced concrete structures to provide cover between the steel reinforcement and the formwork. Cementitious spacers are of particular interest for coastal engineering structures, as they are compatible with cement-based chloride-resistant high-performance concrete compared to plastic and steel spacers. However, the cementitious spacer–concrete interface was found to be highly porous and microcracked. This study investigated the effect of surface treatment on the chloride ion transport at the cementitious spacer–concrete interface. A surface treatment technique for potential mass production was introduced and the state-of-practice tests of the hardened concrete were modified to evaluate the performance of the spacer–concrete composite specimens. The results showed that the surface treatment on a cementitious spacer improved the bonding between the spacer and concrete at the interface. The surface treatment of the spacer improved the compressive strength and the chloride resistance of the composite specimen locally compared to those without surface treatment. The advantage of surface treatment on the chloride resistance was partially represented in either the diffusion coefficient or the column electric flux. The maximum chloride ion penetration depth at the spacer–concrete interface was recommended as an additional proxy for the evaluation of the chloride resistance performance of composite specimens.

Biogeographic regionalization can help to better understand diversity in biogeography, conservation, and macroecology. Historical regionalization schemes typically focus on species distributions, often rarely considering the rich context that phylogeographic information can provide. We investigated whether phylogeographic data could help to delineate floristic regions in the Qinghai-Tibet Plateau (QTP)-Hengduan Mountains (HDM) region by analyzing phylogeographic structure in the herb Parasyncalathium souliei (Asteraceae). We sequenced the plastid psbA-trnH and trnL-rpl32 spacer regions for 417 individuals in 36 populations across the geographic range of the species. To estimate the phylogeographic history of this species, a series of population genetic, phylogenetic, molecular dating, and haplotype network analyses were conducted, as were tested for historical demographic expansions. Using occurrence data, species distribution modeling was used to estimate geographic distributions at three time points: the present, the Mid-Holocene and the Last Glacial Maximum. Significant phylogeographic structure was evident (NST> GST; P < 0.05) among the 37 haplotypes detected. Four major haplogroups were identified based on phylogenetic analyses. Private haplotypes were restricted to geographically distinct regions that generally corresponded to previously identified biogeographic subregions within the QTP-HDM region. Our results imply Pliocene-Pleistocene diversification of P. souliei and suggest that the species may have been geographically widespread early in its history. This study may provide valuable evidence for phylogeographic regionalization using chloroplast genetic data in a common, widespread endemic species from the QTP-HDM.

Adenocaulon (Asteraceae) is a small genus with only five species but has a broad amphi-Pacific distribution pattern with three species distributed disjunctly in South America, Central America, and North America and two endemic species spanning from eastern Asia to the Himalayas. To trace the biogeographic pattern of the genus, we reconstructed its phylogenetic relationships and diversification history based on one nuclear and eight plastid gene regions. Our results showed that Adenocaulon is monophyletic and may have originated in Central America during the Miocene, dispersed into North America and finally reached the Himalayas via the Bering Land Bridge. The hypothesized trajectory implies that long-distance dispersal may have played an important role in the formation of the distribution of this group of species. This hypothesis seems to have gained support from the special morphological structure of fruits of the genus.

Actinidia eriantha Benth. is a diploid perennial woody vine native to China and is recognized as a valuable species for commercial kiwifruit improvement with high levels of ascorbic acid as well as having been used in traditional Chinese medicine. Due to the lack of genomic resources for the species, microsatellite markers for population genetics studies are scarce. In this study, RNASeq was conducted on fruit tissue of A. eriantha, yielding 5,678,129 reads with a total output of 3.41 Gb. De novo assembly yielded 69,783 non-redundant unigenes (41.3 Mb), of which 21,730 were annotated using protein databases. A total of 8,658 EST-SSR loci were identified in 7,495 unigene sequences, for which primer pairs were successfully designed for 3,842 loci (44.4%). Among these, 183 primer pairs were assayed for PCR amplification, yielding 69 with detectable polymorphism in A. eriantha. Additionally, 61 of the 69 polymorphic loci could be successfully amplified in at least one other Actinidia species. Of these, 14 polymorphic loci (mean NA = 6.07 ± 2.30) were randomly selected for assessing levels of genetic diversity and population structure within A. eriantha. Finally, a neighbor-joining tree and Bayesian clustering analysis showed distinct clustering into two groups (K = 2), agreeing with the geographical distributions of these populations. Overall, our results will facilitate further studies of genetic diversity within A. eriantha and will aid in discriminating outlier loci involved in local adaptation.