EDTA-assisted hydrothermal synthesis of flower-like CoSe_2 nanorods as an efficient electrocatalyst for the hydrogen evolution reaction

Hydrogen evolution reaction(HER) is a prospective method to generate pure hydrogen. The development of superior electrocatalysts based on earth-abundant materials, plays a critical role in the future.CoSe_2, one of the earth-abundant electrocatalysts, has been proved to be a promising catalyst for hydrogen generation. In our work, flower-like CoSe_2 nanorods with high quality are successfully synthesized through a facile ethylenediaminetetraacetic acid ligand(EDTA)-assisted hydrothermal process. The flower-like CoSe_2 nanorods show the brilliant electrochemical HER performance with 100 mA cm^(-2) at overpotential of 273 m V, a small Tafel slope of 35 mV dec^(-1) and strong durability in acid solution. The sparkly HER catalytic activity of CoSe_2 can be ascribed to its particular structure with large surface area and abundant active sites. Therefore, this work offers an outstanding candidate for improving hydrogen production capabilities by water electrolysis.

The Earliest Ascidiate Carpel and Its Implications for Angiosperm Evolution

According to the classic doctrine of angiosperm evolution,the archetype carpel in angiosperms is of plicate form.However,this concept is facing increasing challenges from the systematics based on molecular data,which now takes ascidiate carpel as ancestral.This reorientation in evolutionary thinking cannot be fully achieved unless there is supporting fossil evidence.Here a fruit, named Liaoningfructus,is reported from the famous Yixian Formation(Early Cretaceous,125 Ma), which yielded several pioneer angiosperms in the past decades.The configuration of the fruit suggests that the carpel giving rise to the fruit is most likely ascidiate,favoring the above reorientation.There are two seeds in the fruit,and at least one of them is served by a vascular bundle arising from the bottom of the fruit,implying a basal placentation in the former carpel,which again is different from the classic thinking.This discovery not only enhances the diversity of angiosperms in the Yixian Formation,but also accelerates the on-going switching of thinking on angiosperm evolution.

Chromosome-scale assembly of the Dendrobium chrysotoxum genome enhances the understanding of orchid evolution

As one of the largest families of angiosperms,the Orchidaceae family is diverse.Dendrobium represents the second largest genus of the Orchidaceae.However,an assembled high-quality genome of species in this genus is lacking.Here,we report a chromosome-scale reference genome of Dendrobium chrysotoxum,an important ornamental and medicinal orchid species.The assembled genome size of D.chrysotoxum was 1.37 Gb,with a contig N50 value of 1.54 Mb.Of the sequences,95.75%were anchored to 19 pseudochromosomes.There were 30,044 genes predicted in the D.chrysotoxum genome.Two whole-genome polyploidization events occurred in D.chrysotoxum.In terms of the second event,whole-genome duplication(WGD)was also found to have occurred in other Orchidaceae members,which diverged mainly via gene loss immediately after the WGD event occurred;the first duplication was found to have occurred in most monocots(tau event).We identified sugar transporter(SWEET)gene family expansion,which might be related to the abundant medicinal compounds and fleshy stems of D.chrysotoxum.MADS-box genes were identified in D.chrysotoxum,as well as members of TPS and Hsp90 gene families,which are associated with resistance,which may contribute to the adaptive evolution of orchids.We also investigated the interplay among carotenoid,ABA,and ethylene biosynthesis in D.chrysotoxum to elucidate the regulatory mechanisms of the short flowering period of orchids with yellow flowers.The reference D.chrysotoxum genome will provide important insights for further research on medicinal active ingredients and breeding and enhances the understanding of orchid evolution.

DNA methylation is involved in sexual differentiation and sex chromosome evolution in the dioecious plant garden asparagus

DNA methylation is a crucial regulatory mechanism in many biological processes.However,limited studies have dissected the contribution of DNA methylation to sexual differentiation in dioecious plants.In this study,we investigated the variances in methylation and transcriptional patterns of male and female flowers of garden asparagus.Compared with male flowers,female flowers at the same stages showed higher levels of DNA methylation.Both male and female flowers gained DNA methylation globally from the premeiotic to meiotic stages.Detailed analysis revealed that the increased DNA methylation was largely due to increased CHH methylation.Correlation analysis of differentially expressed genes and differentially methylated regions suggested that DNA methylation might not have contributed to the expression variation of the sex-determining genes SOFF and TDF1 but probably played important roles in sexual differentiation and flower development of garden asparagus.The upregulated genes AoMS1,AoLAP3,AoAMS,and AoLAP5 with varied methylated CHH regions might have been involved in sexual differentiation and flower development of garden asparagus.Plant hormone signaling genes and transcription factor genes also participated in sexual differentiation and flower development with potential epigenetic regulation.In addition,the CG and CHG methylation levels in the Y chromosome were notably higher than those in the X chromosome,implying that DNA methylation might have been involved in Y chromosome evolution.These data provide insights into the epigenetic modification of sexual differentiation and flower development and improve our understanding of sex chromosome evolution in garden asparagus.

Genome assembly and resequencing analyses provide new insights into the evolution, domestication and ornamental traits of crape myrtle

Crape myrtle(Lagerstroemia indica)is a globally used ornamental woody plant and is the representative species of Lagerstroemia.However,studies on the evolution and genomic breeding of L.indica have been hindered by the lack of a reference genome.Here we assembled the first high-quality genome of L.indica using PacBio combined with Hi-C scaffolding to anchor the 329.14-Mb genome assembly into 24 pseudochromosomes.We detected a previously undescribed independent whole-genome triplication event occurring 35.5 million years ago in L.indica following its divergence from Punica granatum.After resequencing 73 accessions of Lagerstroemia,the main parents of modern crape myrtle cultivars were found to be L.indica and L.fauriei.During the process of domestication,genetic diversity tended to decrease in many plants,but this was not observed in L.indica.We constructed a high-density genetic linkage map with an average map distance of 0.33 cM.Furthermore,we integrated the results of quantitative trait locus(QTL)using genetic mapping and bulk segregant analysis(BSA),revealing that the major-effect interval controlling internode length(IL)is located on chr1,which contains CDL15,CRG98,and GID1b1 associated with the phytohormone pathways.Analysis of gene expression of the red,purple,and white flower-colour flavonoid pathways revealed that differential expression of multiple genes determined the flower colour of L.indica,with white flowers having the lowest gene expression.In addition,BSA of purple-and green-leaved individuals of populations of L.indica was performed,and the leaf colour loci were mapped to chr12 and chr17.Within these intervals,we identified MYB35,NCED,and KAS1.Our genome assembly provided a foundation for investigating the evolution,population structure,and differentiation of Myrtaceae species and accelerating the molecular breeding of L.indica.

The Cymbidium goeringii genome provides insight into organ development and adaptive evolution in orchids

Cymbidium goeringii is one of the important ornamental orchids,but its high-quality genome has not been previously published.Here,we report a chromosome-level genome of C.goeringii and report the gene family expansion,and contraction of the C.goeringii genome and the regulation mechanism of MADS-box genes in floral organ development.We constructed the pathways of carotenoids and anthocyanins that contribute to the different flower colors of C.goeringii and the metabolic pathways of the main components of flower fragrance.Moreover,we found the genes that regulate colourful leaves and analyzed the resistance genes involved in the adaptive evolution of C.goeringii.Our results provide valuable genomic resources for the improvement of orchids and other ornamental plants.

Early Cretaceous Archaefructus eoflora sp. nov. with Bisexual Flowers from Beipiao, Western Liaoning, China

Recently, whether Archaefructus has bisexual multi-parted flowers or just inflorescences of unisexual flowers, and whether it is ancestral to all angiosperms or a derived eudicot have been debated. Here, from the same Yixian Formation, NE China, we report a new Archaefructus species, A. eoflora sp. nov., with the generic characteristics of dissected leaves and bisexual reproductive axes. It is entirely preserved with roots, rhizome, shoots and protogynous reproductive organs at different developmental stages. Its lateral and main fertile shoots form a pseudo-indeterminate pattern, while the reproductive branches on the main shoot form a cymose inflorescence. Subtended by 1-2 bract-like leaves, the section of stamen clusters changes into a much shorter section of carpels that have one row of orthotropous ovules. Significantly, one cluster bearing two carpels and one stamen between the two sections demonstrates a true bisexual flower, an important step of the origin of floral bisexuality, and the homology between the stamen and carpel. The complex reproductive axes represent a mix between flowers and inflorescences, and suggest that A. eoflora sp. nov. possesses the potential to evolve into a variety of diverse flower types as found in modern basal and early fossil angiosperms. A comparison with other two species also leads to a revision of the generic diagnosis.

商周春秋语言演变探略

语言演变与社会发展密切相关,春秋时“礼坏乐崩”,官府之学走向民间导致了春秋雅言取代商周古文的汉语语体第一次变革。《今文尚书》中不少词语是商周古文,春秋后罕用,反映了商周时期的语言面貌,具有上承商周下启秦汉的过渡性,从中或多或少可见商周与春秋后汉语的演变。

丝绸之路视域下唐代纺织品中鸟衔花纹样的起源与形式流变

文章以唐代纺织品中的鸟衔花纹样为研究对象,通过历史文献与考古实物等资料对其溯源。梳理丝绸之路打通后西方鸟衔花纹样的传播,并分析其传入唐代后的形式演变。研究表明,唐代纺织品中的鸟衔花纹样因受到了西方含绶鸟纹样题材、纬线显花织造技术等因素影响而形成。并经历了模仿、改造、定型三个发展阶段,完成从呆板程式向传神自由转变的本土化进程,该纹样在唐代的演变可进一步细分为“团窠对鸟”和“足踏花台”的双线发展模式。

Nuclear phylogenomics of angiosperms and insights into their relationships and evolution

Angiosperms(flowering plants) are by far the most diverse land plant group with over 300,000 species. The sudden appearance of diverse angiosperms in the fossil record was referred to by Darwin as the “abominable mystery,”hence contributing to the heightened interest in angiosperm evolution. Angiosperms display wide ranges of morphological, physiological,and ecological characters, some of which have probably influenced their species richness. The evolutionary analyses of these characteristics help to address questions of angiosperm diversification and require well resolved phylogeny. Following the great successes of phylogenetic analyses using plastid sequences,dozens to thousands of nuclear genes from next-generation sequencing have been used in angiosperm phylogenomic analyses, providing well resolved phylogenies and new insights into the evolution of angiosperms. In this review we focus on recent nuclear phylogenomic analyses of large angiosperm clades, orders, families,and subdivisions of some families and provide a summarized Nuclear Phylogenetic Tree of Angiosperm Families. The newly established nuclear phylogenetic relationships are highlighted and compared with previous phylogenetic results. The sequenced genomes of Amborella,Nymphaea, Chloranthus, Ceratophyllum, and species of monocots, Magnoliids, and basal eudicots, have facilitated the phylogenomics of relationships among five major angiosperms clades. All but one of the 64 angiosperm orders were included in nuclear phylogenomics with well resolved relationships except the placements of several orders. Most families have been included with robust and highly supported placements, especially for relationships within several large and important orders and families.Additionally, we examine the divergence time estimation and biogeographic analyses of angiosperm on the basis of the nuclear phylogenomic frameworks and discuss the differences compared with previous analyses. Furthermore,we discuss the implications of nuclear phylogenomic analyses on ancestral reconstruction of morphological, physiological, and ecological characters of angiosperm groups, limitations of current nuclear phylogenomic studies, and the taxa that require future attention.

The FLOWERING LOCUS T/TERMINAL FLOWER 1 Gene Family： Functional Evolution and Molecular Mechanisms

In plant development, the flowering transition and inflorescence architecture are modulated by two homol- ogous proteins, FLOWERING LOCUS T （FT） and TERMINAL FLOWER 1 （TFL1）. The florigen FT promotes the transition to reproductive development and flowering, while TFL1 represses this transition. Despite their importance to plant adaptation and crop improvement and their extensive study by the plant community, the molecular mechanisms controlling the opposing actions of FT and TFL1 have remained mysterious. Recent studies in multiple species have unveiled diverse roles of the FT/TFL 1 gene family in developmental processes other than flowering regulation. In addition, the striking evolution of FT homologs into flowering repressors has occurred independently in several species during the evolution of flowering plants. These reports indicate that the FT/TFL1 gene family is a major target of evolution in nature. Here, we comprehen- sively survey the conserved and diverse functions of the FTITFL1 gene family throughout the plant kingdom, summarize new findings regarding the unique evolution of FT in multiple species, and highlight recent work elucidating the molecular mechanisms of these proteins.

The Chrysanthemum nankingense Genome Provides Insights into the Evolution and Diversification of Chrysanthemum Flowers and Medicinal Traits

The Asteraceae (Compositae),a large plant family of approximately 24 000-35 000 species,accounts for^10% of all angiosperm species and contributes a lot to plant diversity.The most representative members of the Asteraceae are the economically important chrysanthemums (Chrysanthemum L.)that diversified through reticulate evolution.Biodiversity is typically created by multiple evolutionary mechanisms such as wholegenome duplication 0NGD)or polyploidization and locally repetitive genome expansion.However,the lack of genomic data from chrysanthemum species has prevented an in-depth analysis of the evolutionary mechanisms involved in their diversification.Here,we used Oxford Nanopore long-read technologyto sequence the diploid Chrysanthemum nankingense genome,which represents one of the progenitor genomes of domesticated chrysanthemums.Our analysis revealed that the evolution of the C.nankingense genome was driven by bursts of repetitive element expansion and WGD events including a recentWGD that distinguishes chrysanthemum from sunflower,which diverged from chrysanthemum approximately 38.8 million years ago.Variations of ornamental and medicinal traits in chrysanthemums are linked to the expansion of candidate gene families by duplication events including paralogous gene duplication.Collectively,our study of the assembled reference genome offers new knowledge and resources to dissect the history and pattern of evolution and diversification of chrysanthemum plants,and also to accelerate their breeding and improvement.

“潘安”考论

潘岳除了本名之外,还有一个知名度更广的称呼“潘安”,在某种程度上,“潘安”的影响力甚至超过了本名。从现有文献来看,至迟在广德元年杜甫创作《花底》时,“潘安”已经出现。“潘安”之接受在不同的文学体裁中出现分流,这种分流可进一步从雅、俗文学两面而分别关照。具体来看,在唐、宋两朝,雅文学影响较大,而元、明、清三朝,俗文学成为“潘安”接受的主要阵地。两者相比,俗文学的影响更为深远,使“潘安”乃潘岳几乎成为一种民族集体无意识。

安徽花鼓灯研究的热点主题与演进趋势——基于CiteSpace的知识图谱分析

安徽花鼓灯研究已成为学界研究的热点议题。基于CiteSpace可视化工具与CNKI数据平台,从文献计量学视角对安徽花鼓灯艺术现有的研究成果进行梳理,系统性地分析1957—2023年CNKI中关于安徽花鼓灯研究的494篇文献。通过对主要作者、研究机构、关键词等知识图谱的分析发现:安徽花鼓灯的研究热点主题包括历史渊源、民间舞蹈、传承保护、文化内涵、艺术特质、审美特征、农耕文化、创新和交互等。演化路径主要集中在2006年之后,在此之前,该领域的研究成果较少。此后,非遗保护、历史渊源和资源开发逐渐成为安徽花鼓灯研究的主要趋势。结合热点主题和时间线图谱,对未来安徽花鼓灯研究提出了优化建议。

探讨种间传粉在杜鹃花属自然杂交物种形成中的作用

自然杂交是物种形成的一个途径,在植物进化中起着重要的作用。自然杂交主要通过种间的基因交流,花粉传递则是基因交流的主要途径。马缨花(Rhododendron delavayi)、大白花杜鹃(R.decorum)、迷人杜鹃(R.agastum)和露珠杜鹃(R.irroratum)是在云南广泛分布的杜鹃花种类,马缨花与大白花杜鹃形态上区别明显,而它们的可能杂交种迷人杜鹃和露珠杜鹃在形态上基本介于二者之间。本文对这4种杜鹃花的开花物候和访花昆虫的种类进行了观察,并进行了其繁育系统和种子萌发的实验。我们发现马缨花的花期从3月初至5月底,迷人杜鹃与露珠杜鹃花期基本一致,为3月初至4月初,二者同大白花杜鹃基本不存在花期重叠,大白花杜鹃的花期为4月中旬至5月底。4种杜鹃花的开花期不同年份稍有变化,其单花开花周期都在一周以上。4种杜鹃花的传粉昆虫虽然种类和数量上有所不同,但都以膜翅目和双翅目昆虫为主,中华蜜蜂(Apis cerana cerana)是其共有的传粉昆虫。繁育系统研究发现,除露珠杜鹃外,其余3种自花不育,而种间杂交不存在任何生殖障碍,可以产生萌发率很高的种子。通过分析4种杜鹃花开花物候重叠、共有传粉昆虫及种间杂交可育等现象,探讨了传粉昆虫和异花授粉的机制在自然杂交物种形成中的作用及杂交种的适应能力。

蓝色花植物花色素的着色机理

通过蓝色花植物花色素的结构和化学组成 ,综述了它们的着色机理 ,并分为两种类型 .即第一类是酰化花色素苷 ,它们遵守分子内辅助着色反应机理 ;另一类是酰化花色素苷与辅助色素以分子间辅助着色方式而形成的复合花色素 ,这类花色素经常包含金属离子参与的螯合反应 .并从生物化学代谢途径探讨了蓝色花植物的进化 .

被子植物叶绿体基因组的结构变异研究进展

叶绿体是绿色植物特有的细胞器,其基因组信息被广泛应用于植物系统发育和比较基因组学研究。目前,越来越多的物种有了叶绿体全基因组序列,人们对叶绿体基因组的结构及其变异规律有了更深入的了解。该文对近年来国内外有关被子植物叶绿体基因组插入/缺失、短片段倒位与重复、基因组结构重排以及基因丢失等结构变异式样的研究进展进行综述,并分析了叶绿体基因组结构研究中仍存在的问题以及该领域未来的发展趋势。

阿尔金断裂双层花状构造的厘定

阿尔金断裂带主要经历了两阶段的构造演化 ,形成不同层次且具有不同特点的典型花状构造型式。宏观断层构造组合、断层擦痕产状的变化以及节理组合充分反映出晚期阶段浅部层次花状构造的存在 ,早期阶段中部层次花状构造由反映区域应变型式的糜棱状岩石中其它应变标志性组合的存在表现出来。结合Ar Ar记年与矿物对测温结果 ,表明前者形成于距今 46Ma ,是一次规模最强烈的变形叠加事件 ;后者由距今 91～ 89Ma的韧性走滑运动形成 ,并伴有断层带内的低级变质作用 (温度 2 70～ 5 0 0℃ ,压力 0 .0 5～ 0 .45GPa)。两阶段双层花状构造并存充分说明区域性走滑作用过程及其调节作用的多阶段性与继承性 ,其出现部分地调节了由印度板块和欧亚板块陆—陆碰撞过程中区域性地壳物质的向东蠕散和隆升过程。

一种改进的新型元启发式花朵授粉算法

受自然界花朵授粉过程的启发,Yang提出了一种新的元启发式群智能算法——花朵授粉算法,该算法融合了现有其他智能算法的优点。首先阐述了花朵授粉的特征,从机理上描述了该算法的实现步骤,同时对该算法的寻优性能进行了剖析。其次,针对花朵授粉算法寻优精度低、收敛速度慢、易陷入局部极小的不足,提出一种基于差分进化策略的花朵授粉算法,该算法引入差分进化中的变异、交叉及选择操作,使缺乏变异机制的花朵授粉算法具有变异能力,增加种群的多样性,提高算法的全局寻优能力和避免种群个体陷入局部最优。通过十个标准测试函数进行测试,仿真结果表明,改进算法的寻优能力明显优于基本的花朵授粉算法、蝙蝠算法、粒子群算法及改进的粒子群算法。

被子植物异型花柱及其进化意义

异型花柱(heterostyly)是被子植物中一种特殊的花多态现象和雌雄异位形式,包括二型花柱(distyly)和三型花柱(tristyly)2种类型。据报道,在被子植物的约31个科中有异型花柱植物。该类型植物的花部特征在避免自交、促进准确的异交传粉以及通过降低雌雄功能干扰以提高亲本适合度等方面具有重要的进化意义。该文从以下3个方面总结和分析了异型花柱及其进化意义:(1)异型花柱植物的类型和花部特征、附属多态性和种群结构;(2)异型花柱植物在被子植物中的分布、起源和演化;(3)异型花柱植物的进化适应意义。结合目前作者开展的有关工作,对异型花柱植物研究中存在的一些问题进行讨论和展望,希望能为国内工作者开展该领域的研究提供一些参考。