[Objectives]To compare the leaf morphology and leaf venation patterns of Hedyotis auricularia L.and its adulterants,such as Mitracarpus hirtus(L.)DC.,Spermacoce pusilla Wall.and Spermacoce alata Aubl.,produced in Guan...[Objectives]To compare the leaf morphology and leaf venation patterns of Hedyotis auricularia L.and its adulterants,such as Mitracarpus hirtus(L.)DC.,Spermacoce pusilla Wall.and Spermacoce alata Aubl.,produced in Guangxi,so as to provide a simple and rapid identification method for the identification of H.auricularia L.in Guangxi.[Methods]LMVP(leaf morphology-venation pattern)identification method was used to study the characteristics of leaf morphology-venation pattern.[Results]Characteristics of leaf morphology-venation pattern:(i)H.auricularia L.:circular knotted-curved pinnate leaf venation without reaching the margin;the primary veins run straight without branches,the number of secondary veins is 5 to 9,and the angles included in tertiary veins are mostly near right angles or obtuse angles.(ii)M.hirtus(L.)DC.:curved pinnate leaf venation without reaching the margin;the primary veins run straight without obvious changes,the number of secondary veins is 3 to 5,and the tertiary veins are slender,and the included angles are mostly acute.(iii)S.pusilla Wall.:curved leaf venation without reaching the leaf margin;there are 4 to 5 pairs of secondary veins,most of which are opposite;the angle between the secondary veins and the primary veins in the middle and near the petiole is mostly medium acute angle,and the extension of the tertiary veins has no fixed direction.(iv)S.alata Aubl.:circular knotted-curved pinnate leaf venation;the primary veins are convex and straight without branches,and there are 4 to 6 pairs of secondary veins,alternating.The angle between secondary veins and primary veins is mostly medium acute angle,the angle between tertiary veins and secondary veins is near right angle,and the tertiary veins are mostly transversely extended.[Conclusions]The leaf morphology-venation patterns of the above-mentioned H.auricularia L.and M.hirtus(L.)DC.,S.pusilla Wall.,and S.alata Aubl.can be used as their identification features,and the identification method has certain operability,which provides an identification idea for the identification of Chinese herbal medicines.展开更多
Based on the analyses on arch and peltate venation structures, the design of reinforcing frames was improved. First, distribution rules of the arch structure were summarized. According to the load condition and the st...Based on the analyses on arch and peltate venation structures, the design of reinforcing frames was improved. First, distribution rules of the arch structure were summarized. According to the load condition and the structure of the frame, a mechanical model of arch structure was devel- oped, and two solutions for the model were analyzed and compared with each other. Through the a- nalysis, application rules of arch structure for improving the design were obtained. Then, distribu- tion rules of peltate venation structure were summarized. By using the same method, application rules of peltate venation structure for improving the design were also obtained. Finally, mechanical problem of the frame was described, and rib arrangement of the frame was redesigned. A parameter optimization for the widths of ribs in bionic arrangement was also carried out to accomplish the im- proving design. Comparison between bionic and conventional reinforcing frames shows that the weight is reduced by as much as 15.3%.展开更多
In this paper, we conduct research on the developmental venation of the calligraphy seal cutting art form from the perspectives of Chinese traditional culture and art form. Seal cutting art of composition is a word or...In this paper, we conduct research on the developmental venation of the calligraphy seal cutting art form from the perspectives of Chinese traditional culture and art form. Seal cutting art of composition is a word or group of words arranged on the surface of the printing art, complex and changeable, is one of the most important part of the seal cutting art. Complete the creation of the group, must all have change, should show more creators on the composition of work force, therefore when designing should be repeated according to the text specifi c stroke, handwriting, the form and the relationship between word and word to design the structure of the right. Cultivating must practice the socialist core values and should be based on the basis of the Chinese excellent traditional culture, in carrying forward and greater China outstanding traditional culture in the process of makes it obtain nourishes the spirit and the value of the national identity. Our research provides the countermeasure for further modifi cation and optimization that is meaningful and necessary.展开更多
Mitogen-activated protein kinase （MAPK） cascades are universal signal transduction modules present in all eukaryotes. In plants, MAPK cascades were shown to regulate cell division, developmental processes, stress re...Mitogen-activated protein kinase （MAPK） cascades are universal signal transduction modules present in all eukaryotes. In plants, MAPK cascades were shown to regulate cell division, developmental processes, stress responses, and hormone pathways. The subgroup A of Arabidopsis MAPKs consists of AtMPK3, AtMPK6, and AtMPK10. AtMPK3 and AtMPK6 are activated by their upstream MAP kinase kinases （MKKs） AtMKK4 and AtMKK5 in response to biotic and abiotic stress. In addition, they were identified as key regulators of stomatal development and patterning. AtMPKIO has long been considered as a pseudo-gene, derived from a gene duplication of AtMPK6. Here we show that AtMPKIO is expressed highly but very transiently in seedlings and at sites of local auxin maxima leaves. MPK10 encodes a functional kinase and interacts with the upstream MAP kinase kinase （MAPKK） AtMKK2. mpklO mutants are delayed in flowering in long-day conditions and in continuous light. Moreover, cotyledons of mpk10 and mkk2 mutants have reduced vein complexity, which can be reversed by inhibiting polar auxin transport （PAT）. Auxin does not affect AtMPKIO expression while treatment with the PAT inhibitor HFCA extends the expression in leaves and reverses the mpklO mutant phenotype. These results suggest that the AtMKK2-AtMPK10 MAPK module regulates venation complexity by altering PAT efficiency.展开更多
A number of fossil leaves of the Lauraceae were collected from Tuantian flora of the late Pliocene strata in Yunnan, China. They have a whole leaf shape and well-preserved cuticles. In this paper, features of the arch...A number of fossil leaves of the Lauraceae were collected from Tuantian flora of the late Pliocene strata in Yunnan, China. They have a whole leaf shape and well-preserved cuticles. In this paper, features of the architecture and epidermis of three species of the Lauraceae family with ternate venation are reported. Results of the comparison between the venation characteristics of Lauraceae fossils from four fossil floras in the world and those of extant Lauraceae in China suggest that the proportion of Lauraceae species with ternate venation is increasing. The proportion has risen from 10% in the Eocene to 12.5% in the late Pliocene in China, whereas the proportion in the modern era is 21%. Moreover, the proportion of Australian floras with ternate venation has rised from 8.3% to 10% between the Eocene and the Miocene. Because of the effect of the global drought during the Cenozoic era, we suggested that species with ternate venation in Lauraceae have become increasingly prevalent between the Eocene era and the present day in China. Data on Nerriga flora and Maarlake flora since the Eocene era in the Southern Hemisphere show the same trend. While features of the leaf architecture and epidermis of Lindera acuminatissima differ in details. They all have similar identification characteristics with regard to basal eucamptodromous venation, interior 2° present, minor 2° simple brochidodromous, anticlinal walls, no surface ornamentation, lip-like guard cells, outer stomatal ledge plain or dimness, and paracytic stomatal aperture. These differences are also present in extant species. Compared with Lindera tonkinensis, the nearest living relative(NLR) of L. acuminatissima shows that these differences are relevant to the growth, position, and development of leaves. Leaf-type classification statistics of L. acuminatissima indicate that when all fossil leaves are taken into consideration, A-type leaves account for 24%, B-type leaves make up 56%, and C-typy leaves account for 20%. Comparing the above result with that of NLRs, A-type leaves are generally immature spires and cannot be preserved easily, B-type leaves are regular mature leaves and fossilize more easil, and C-type leaves are usually old leaves occurring at the bottom, broken, ill and consumed by worms.展开更多
The original or primitive venation of mayflies was not presented clearly upon living materials before,this mostly results from the deform of mayfly imaginal wingbase.Some nymphs of large mayflies of China,like Siphlur...The original or primitive venation of mayflies was not presented clearly upon living materials before,this mostly results from the deform of mayfly imaginal wingbase.Some nymphs of large mayflies of China,like Siphluriscus chinensis,Ephemera pictipennis and Siphlonurus davidi,however,show some clues.Together,they demonstrate that in mayflies,subcostal brace maybe originated from longitudinal vein Anterior Subcostal(ScA),stems of Radius(R)and Media(M)are always fused at base,Media Posterior(MP)leave them first,then the branch of Rs(Radial Section)+MA(Media Anterior),Cubitus(Cu)disconnected to any other veins.Additionally,all longitudinal veins of mayflies fused with their sclerotized base respectively but without any moveable sclerite.Instead,base of R+M of mayflies sclerotized into a single one big plate,and all sclerites of wingbase are fused together rigidly by sclerotized wingbase,which disables any possible folding of mayfly wings.Phylogenetically,in the order Ephemeroptera,the different positions of ScA and Cu leaded to different and diverse venations and lineages of Ephemeroptera.In the Pterygota,the Ephemeroptera has the same fused pattern of R+M and three axillary sclerites as the Neoptera while the Odonata has the fused Cu+M,which disproves the monophyly of Paleoptera.展开更多
The Curvicubitidae is a Triassic cicada family with some taxa systematically debatable.Here a new curvicubitid species,Beaconiella tongchuanensis sp.nov.,is established from the Middle Triassic Tongchuan Entomofauna i...The Curvicubitidae is a Triassic cicada family with some taxa systematically debatable.Here a new curvicubitid species,Beaconiella tongchuanensis sp.nov.,is established from the Middle Triassic Tongchuan Entomofauna in NW China.Restudy of the two Australian species of Beaconiella Evans,1963(B.fennahi and B.multivenata)confirms that they are different species and first reveals the hindwing venation of B.multivenata.A detailed restudy of Curvicubitus triassicus Hong,1984 confirms the treatment of Curvicubitus as a junior synonym of Beaconiella.A key to all the six species of Beaconiella in Curvicubitidae is first given.Although reported from only three sites,the family Curvicubitidae potentially was globally distributed during the Middle-Late Triassic,implying that this family probably originated as early as the Early Triassic or even the Permian.展开更多
Three lepidopteran species, from the Middle Jurassic Daohugou beds （inner Mongolia, China）, are described in a new family, Mesokristenseniidae, and new genus, Mesokristensenia, which could represent the sister group...Three lepidopteran species, from the Middle Jurassic Daohugou beds （inner Mongolia, China）, are described in a new family, Mesokristenseniidae, and new genus, Mesokristensenia, which could represent the sister group of the Micropterigidae. Mesokristensenia differs from all extant Lepidoptera, but one genus （Agathiphaga, Agathiphagidae）, in retaining four median veins in the forewing, a plesiomorphy also present in many Trichoptera. Evidence for placing Mesokristensenia in the Lepidoptera includes four traits, notably a previously unrecorded autapomorphy of this insect order： beyond stem Ml＋2, vein M1 is bent and connected to cross-vein r-m （in both wing pairs）. Among 24 characters taken into account to assess the systematic position of Mesokristensenia, 12 are considered informative for a cladistic analysis involving this fossil taxon and the four suborders recognized in present-day Lepidoptera （Zeugloptera, Aglossata, Heterobathmiina, and Glossata）.展开更多
Aiming at exploring the excellent structural performance of the vein-stiffening membrane structure of dragonfly hind wings,we analyzed two planar computational models and three 3D computational models with cambered co...Aiming at exploring the excellent structural performance of the vein-stiffening membrane structure of dragonfly hind wings,we analyzed two planar computational models and three 3D computational models with cambered corrugation based on the finite element method.It is shown that the vein size in different zones is proportional to the magnitude of the vein internal force when the wing structure is subjected to uniform out-of-plane transverse loading.The membrane contributes little to the flexural stiffness of the planar wing models,while exerting an immense impact upon the stiffness of the 3D wing models with cambered corrugation.If a lumped mass of 10% of the wing is fixed on the leading edge close to the wing tip,the wing fundamental fre-quency decreases by 10.7%～13.2%;if a lumped mass is connected to the wing via multiple springs,the wing fundamental fre-quency decreases by 16.0%～18.0%.Such decrease in fundamental frequency explains the special function of the wing pterostigma in alleviating the wing quivering effect.These particular features of dragonfly wings can be mimicked in the design of new-style reticulately stiffening thin-walled roof systems and flapping wings in novel intelligent aerial vehicles.展开更多
Fruit flies in Bactrocera tau complex are important pests, but their morphological taxonomy is still unsettled. In this paper, specimens from gac fruits（Momordica cochinchinensis） are attempted to classify by geomet...Fruit flies in Bactrocera tau complex are important pests, but their morphological taxonomy is still unsettled. In this paper, specimens from gac fruits（Momordica cochinchinensis） are attempted to classify by geometric morphometric and genetic analyses. Geometric morphometric study of wing venation and aculeus shape among samples suggested a new species in this taxon. Sequences in the cytochrome oxidase I region were compared with reference material in this complex, as well as other taxa within the same subgenus. Phylogenetic analysis based on COI revealed a new species of the B. tau complex, B. tau form J. Therefore, the criteria of body color patterns proved to be taxonomically valid for species classification and identification in this species complex.展开更多
Genus Heliotropium L. (Heliotropiaceae) in south west of Saudi Arabia has been studied;seven species of H. arbainense Fresen, H. longiflorum (D.C.) Jauber & Spach, H. petrocarpum Hockst & Steud, H. strigosium ...Genus Heliotropium L. (Heliotropiaceae) in south west of Saudi Arabia has been studied;seven species of H. arbainense Fresen, H. longiflorum (D.C.) Jauber & Spach, H. petrocarpum Hockst & Steud, H. strigosium Willd, H. zeylanicum Lam., H. jizanense Al-Turki and H. lasiocarpum Fisch were collected, recognized, typed and nomenclatured. The most valuable characters were those of macro and distinct micromorphological data such as stomata, hairs, pollen grains and stem anatomy. Light microscopy has been used in these studies. From the obtained results, trichomes and pollen grains data in addition to stem anatomy indicated good taxonomic tools to differentiate between species of this genus. Different traditional measurements were strikingly also helpful for the discrimination of species. H. longiflorum was characterized by distinctive data such as prominent anatomical information, P/E (1.8 μm) in addition to presence of spindle hair which in turn can be separated as a taxonomic level. Also, the results revealed a complete affinity between the two species of H. jizanense and H. lasiocarpum. An artificial key is provided for the differentiation between the studied species.展开更多
We present results of numerical simulations of the tensor-valued elliptic-parabolic PDE model for biological network formation.The numerical method is based on a nonlinear finite difference scheme on a uniform Cartesi...We present results of numerical simulations of the tensor-valued elliptic-parabolic PDE model for biological network formation.The numerical method is based on a nonlinear finite difference scheme on a uniform Cartesian grid in a two-dimensional(2D)domain.The focus is on the impact of different discretization methods and choices of regularization parameters on the symmetry of the numerical solution.In particular,we show that using the symmetric alternating direction implicit(ADI)method for time discretization helps preserve the symmetry of the solution,compared to the(non-symmetric)ADI method.Moreover,we study the effect of the regularization by the isotropic background permeability(r>0),showing that the increased condition number of the elliptic problem due to decreasing value of r leads to loss of symmetry.We show that in this case,neither the use of the symmetric ADI method preserves the symmetry of the solution.Finally,we perform the numerical error analysis of our method making use of the Wasserstein distance.展开更多
Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past dec...Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.展开更多
Plants produce a rich diversity of biological forms,and the diversity of leaves is especially notable.Mechanisms of leaf morphogenesis have been studied in the past two decades,with a growing focus on the interactive ...Plants produce a rich diversity of biological forms,and the diversity of leaves is especially notable.Mechanisms of leaf morphogenesis have been studied in the past two decades,with a growing focus on the interactive roles of mechanics in recent years.Growth of plant organs involves feedback by mechanical stress:growth induces stress,and stress affects growth and morphogenesis.Although much attention has been given to potential stress-sensing mechanisms and cellular responses,the mechanical principles guiding morphogenesis have not been well understood.Here we synthesize the overarching roles of mechanics and mechanical stress in multilevel and multiple stages of leaf morphogenesis,encompassing leaf primordium initiation,phyllotaxis and venation patterning,and the establishment of complex mature leaf shapes.Moreover,the roles of mechanics at multiscale levels,from subcellular cytoskeletal molecules to single cells to tissues at the organ scale,are articulated.By highlighting the role of mechanical buckling in the formation of three-dimensional leaf shapes,this review integrates the perspectives of mechanics and biology to provide broader insights into the mechanobiology of leaf morphogenesis.展开更多
Aims We compared vein and stomatal traits of seedlings and adults of three Mediterranean Quercus species.Previous work suggests that gas-exchange rates tend to be higher at the seedling stage than in adults.Our object...Aims We compared vein and stomatal traits of seedlings and adults of three Mediterranean Quercus species.Previous work suggests that gas-exchange rates tend to be higher at the seedling stage than in adults.Our objective was to determine whether vein and stomatal traits vary throughout whole-plant ontogeny in parallel with the changes in gas-exchange rates.We addressed the following alternative hypotheses:hypothesis 1—seedlings show higher vein and stomatal densities than adults;and hypothesis 2—seedlings have lower investments in vascular tissues to reduce construction costs.Methods Ten specimens from each growth stage were randomly sampled for each species in a location in central-western Spain.We measured mean stomatal and vein traits(size and number of stomata per unit of leaf area,vein density,vein volume,vein to epidermis distance),leaf mass per area and lamina thickness.Important Findings Minor vein density and vein volume per area increased with tree age,which seems inconsistent with the ontogenetic trends in gas-exchange rates.This discrepancy is in support of our hypothesis 2,and it suggests that,at the seedling stage,reducing investments in vascular tissues in benefit of maximizing growth rates is a priority.Larger interveinal distances in seedlings were compensated by smaller vein to epidermis distances.The thin leaves of the seedlings may thus constitute as a necessary trait for achieving shorter path length distances for the transport of water to evaporation sites without the need for a strong investment in costly vascular tissues.展开更多
基金Supported by Guangxi Key Laboratory of Zhuang and Yao Medicine(GuiKeJiZi 201432)Zhuang and Yao Medicine Collaborative Innovation Center(GuiJiaoKeYan 201320)+3 种基金Guangxi Young Talent Project of Guangxi University of Chinese Medicine(2022C030)Ethnic Medicine Resources and Application Engineering Research Center in Guangxi Zhuang Autonomous Region(GuiFaGaiGaoJiHan 20202605)Key Discipline Project of Traditional Chinese Medicine in Guangxi—Zhuang Medicine(GZXK-Z-20-64)Guangxi First-class Discipline of Traditional Chinese Medicine—Ethnopharmacology(GuiJiaoKeYan 201812).
文摘[Objectives]To compare the leaf morphology and leaf venation patterns of Hedyotis auricularia L.and its adulterants,such as Mitracarpus hirtus(L.)DC.,Spermacoce pusilla Wall.and Spermacoce alata Aubl.,produced in Guangxi,so as to provide a simple and rapid identification method for the identification of H.auricularia L.in Guangxi.[Methods]LMVP(leaf morphology-venation pattern)identification method was used to study the characteristics of leaf morphology-venation pattern.[Results]Characteristics of leaf morphology-venation pattern:(i)H.auricularia L.:circular knotted-curved pinnate leaf venation without reaching the margin;the primary veins run straight without branches,the number of secondary veins is 5 to 9,and the angles included in tertiary veins are mostly near right angles or obtuse angles.(ii)M.hirtus(L.)DC.:curved pinnate leaf venation without reaching the margin;the primary veins run straight without obvious changes,the number of secondary veins is 3 to 5,and the tertiary veins are slender,and the included angles are mostly acute.(iii)S.pusilla Wall.:curved leaf venation without reaching the leaf margin;there are 4 to 5 pairs of secondary veins,most of which are opposite;the angle between the secondary veins and the primary veins in the middle and near the petiole is mostly medium acute angle,and the extension of the tertiary veins has no fixed direction.(iv)S.alata Aubl.:circular knotted-curved pinnate leaf venation;the primary veins are convex and straight without branches,and there are 4 to 6 pairs of secondary veins,alternating.The angle between secondary veins and primary veins is mostly medium acute angle,the angle between tertiary veins and secondary veins is near right angle,and the tertiary veins are mostly transversely extended.[Conclusions]The leaf morphology-venation patterns of the above-mentioned H.auricularia L.and M.hirtus(L.)DC.,S.pusilla Wall.,and S.alata Aubl.can be used as their identification features,and the identification method has certain operability,which provides an identification idea for the identification of Chinese herbal medicines.
基金Supported by the National Natural Science Foundation of Chi- na （ 50975012 ） Research Fund for the Doctoral Program of Higher Education of China （ 20091102110022 ） Innovation Foundation of BUAA for PhD Graduates （YWF-12-RBYJ-015）
文摘Based on the analyses on arch and peltate venation structures, the design of reinforcing frames was improved. First, distribution rules of the arch structure were summarized. According to the load condition and the structure of the frame, a mechanical model of arch structure was devel- oped, and two solutions for the model were analyzed and compared with each other. Through the a- nalysis, application rules of arch structure for improving the design were obtained. Then, distribu- tion rules of peltate venation structure were summarized. By using the same method, application rules of peltate venation structure for improving the design were also obtained. Finally, mechanical problem of the frame was described, and rib arrangement of the frame was redesigned. A parameter optimization for the widths of ribs in bionic arrangement was also carried out to accomplish the im- proving design. Comparison between bionic and conventional reinforcing frames shows that the weight is reduced by as much as 15.3%.
文摘In this paper, we conduct research on the developmental venation of the calligraphy seal cutting art form from the perspectives of Chinese traditional culture and art form. Seal cutting art of composition is a word or group of words arranged on the surface of the printing art, complex and changeable, is one of the most important part of the seal cutting art. Complete the creation of the group, must all have change, should show more creators on the composition of work force, therefore when designing should be repeated according to the text specifi c stroke, handwriting, the form and the relationship between word and word to design the structure of the right. Cultivating must practice the socialist core values and should be based on the basis of the Chinese excellent traditional culture, in carrying forward and greater China outstanding traditional culture in the process of makes it obtain nourishes the spirit and the value of the national identity. Our research provides the countermeasure for further modifi cation and optimization that is meaningful and necessary.
文摘Mitogen-activated protein kinase （MAPK） cascades are universal signal transduction modules present in all eukaryotes. In plants, MAPK cascades were shown to regulate cell division, developmental processes, stress responses, and hormone pathways. The subgroup A of Arabidopsis MAPKs consists of AtMPK3, AtMPK6, and AtMPK10. AtMPK3 and AtMPK6 are activated by their upstream MAP kinase kinases （MKKs） AtMKK4 and AtMKK5 in response to biotic and abiotic stress. In addition, they were identified as key regulators of stomatal development and patterning. AtMPKIO has long been considered as a pseudo-gene, derived from a gene duplication of AtMPK6. Here we show that AtMPKIO is expressed highly but very transiently in seedlings and at sites of local auxin maxima leaves. MPK10 encodes a functional kinase and interacts with the upstream MAP kinase kinase （MAPKK） AtMKK2. mpklO mutants are delayed in flowering in long-day conditions and in continuous light. Moreover, cotyledons of mpk10 and mkk2 mutants have reduced vein complexity, which can be reversed by inhibiting polar auxin transport （PAT）. Auxin does not affect AtMPKIO expression while treatment with the PAT inhibitor HFCA extends the expression in leaves and reverses the mpklO mutant phenotype. These results suggest that the AtMKK2-AtMPK10 MAPK module regulates venation complexity by altering PAT efficiency.
基金supported by the National Basic Research Program of China(2012CB822003)the National Natural Science Foundation of China(41172022 and 41172021)the Fundamental Research Funds for the Central Universities(lzujbky-2012-127)
文摘A number of fossil leaves of the Lauraceae were collected from Tuantian flora of the late Pliocene strata in Yunnan, China. They have a whole leaf shape and well-preserved cuticles. In this paper, features of the architecture and epidermis of three species of the Lauraceae family with ternate venation are reported. Results of the comparison between the venation characteristics of Lauraceae fossils from four fossil floras in the world and those of extant Lauraceae in China suggest that the proportion of Lauraceae species with ternate venation is increasing. The proportion has risen from 10% in the Eocene to 12.5% in the late Pliocene in China, whereas the proportion in the modern era is 21%. Moreover, the proportion of Australian floras with ternate venation has rised from 8.3% to 10% between the Eocene and the Miocene. Because of the effect of the global drought during the Cenozoic era, we suggested that species with ternate venation in Lauraceae have become increasingly prevalent between the Eocene era and the present day in China. Data on Nerriga flora and Maarlake flora since the Eocene era in the Southern Hemisphere show the same trend. While features of the leaf architecture and epidermis of Lindera acuminatissima differ in details. They all have similar identification characteristics with regard to basal eucamptodromous venation, interior 2° present, minor 2° simple brochidodromous, anticlinal walls, no surface ornamentation, lip-like guard cells, outer stomatal ledge plain or dimness, and paracytic stomatal aperture. These differences are also present in extant species. Compared with Lindera tonkinensis, the nearest living relative(NLR) of L. acuminatissima shows that these differences are relevant to the growth, position, and development of leaves. Leaf-type classification statistics of L. acuminatissima indicate that when all fossil leaves are taken into consideration, A-type leaves account for 24%, B-type leaves make up 56%, and C-typy leaves account for 20%. Comparing the above result with that of NLRs, A-type leaves are generally immature spires and cannot be preserved easily, B-type leaves are regular mature leaves and fossilize more easil, and C-type leaves are usually old leaves occurring at the bottom, broken, ill and consumed by worms.
文摘The original or primitive venation of mayflies was not presented clearly upon living materials before,this mostly results from the deform of mayfly imaginal wingbase.Some nymphs of large mayflies of China,like Siphluriscus chinensis,Ephemera pictipennis and Siphlonurus davidi,however,show some clues.Together,they demonstrate that in mayflies,subcostal brace maybe originated from longitudinal vein Anterior Subcostal(ScA),stems of Radius(R)and Media(M)are always fused at base,Media Posterior(MP)leave them first,then the branch of Rs(Radial Section)+MA(Media Anterior),Cubitus(Cu)disconnected to any other veins.Additionally,all longitudinal veins of mayflies fused with their sclerotized base respectively but without any moveable sclerite.Instead,base of R+M of mayflies sclerotized into a single one big plate,and all sclerites of wingbase are fused together rigidly by sclerotized wingbase,which disables any possible folding of mayfly wings.Phylogenetically,in the order Ephemeroptera,the different positions of ScA and Cu leaded to different and diverse venations and lineages of Ephemeroptera.In the Pterygota,the Ephemeroptera has the same fused pattern of R+M and three axillary sclerites as the Neoptera while the Odonata has the fused Cu+M,which disproves the monophyly of Paleoptera.
基金supported by the National Natural Science Foundation of China(42293280)the Fundamental Research Funds for the Liaoning Universities and Shenyang Normal University(BS202209).
文摘The Curvicubitidae is a Triassic cicada family with some taxa systematically debatable.Here a new curvicubitid species,Beaconiella tongchuanensis sp.nov.,is established from the Middle Triassic Tongchuan Entomofauna in NW China.Restudy of the two Australian species of Beaconiella Evans,1963(B.fennahi and B.multivenata)confirms that they are different species and first reveals the hindwing venation of B.multivenata.A detailed restudy of Curvicubitus triassicus Hong,1984 confirms the treatment of Curvicubitus as a junior synonym of Beaconiella.A key to all the six species of Beaconiella in Curvicubitidae is first given.Although reported from only three sites,the family Curvicubitidae potentially was globally distributed during the Middle-Late Triassic,implying that this family probably originated as early as the Early Triassic or even the Permian.
基金the National Natural Science Foundation of China(grants nos.40672013 and 40632010)the Chinese Academy of Sciences(grant no.KZCX2-YW-QN104)the Major Basic Research Projects of China's Ministry of Science and Technology(no.2006CB806400)
文摘Three lepidopteran species, from the Middle Jurassic Daohugou beds （inner Mongolia, China）, are described in a new family, Mesokristenseniidae, and new genus, Mesokristensenia, which could represent the sister group of the Micropterigidae. Mesokristensenia differs from all extant Lepidoptera, but one genus （Agathiphaga, Agathiphagidae）, in retaining four median veins in the forewing, a plesiomorphy also present in many Trichoptera. Evidence for placing Mesokristensenia in the Lepidoptera includes four traits, notably a previously unrecorded autapomorphy of this insect order： beyond stem Ml＋2, vein M1 is bent and connected to cross-vein r-m （in both wing pairs）. Among 24 characters taken into account to assess the systematic position of Mesokristensenia, 12 are considered informative for a cladistic analysis involving this fossil taxon and the four suborders recognized in present-day Lepidoptera （Zeugloptera, Aglossata, Heterobathmiina, and Glossata）.
基金Project supported by the National Natural Science Foundation of China(No. 50408022)the Visiting Scholarship from the Future Academic Star Project of Zhejiang Universitythe Scientific Research Foundation for the Returned Overseas Chinese Scholars,MOE and Zhejiang Province,China
文摘Aiming at exploring the excellent structural performance of the vein-stiffening membrane structure of dragonfly hind wings,we analyzed two planar computational models and three 3D computational models with cambered corrugation based on the finite element method.It is shown that the vein size in different zones is proportional to the magnitude of the vein internal force when the wing structure is subjected to uniform out-of-plane transverse loading.The membrane contributes little to the flexural stiffness of the planar wing models,while exerting an immense impact upon the stiffness of the 3D wing models with cambered corrugation.If a lumped mass of 10% of the wing is fixed on the leading edge close to the wing tip,the wing fundamental fre-quency decreases by 10.7%～13.2%;if a lumped mass is connected to the wing via multiple springs,the wing fundamental fre-quency decreases by 16.0%～18.0%.Such decrease in fundamental frequency explains the special function of the wing pterostigma in alleviating the wing quivering effect.These particular features of dragonfly wings can be mimicked in the design of new-style reticulately stiffening thin-walled roof systems and flapping wings in novel intelligent aerial vehicles.
基金supported by Center of Excellence on Biodiversity(BDC),Office of Higher Education Commission(BDC-PG2-160007)
文摘Fruit flies in Bactrocera tau complex are important pests, but their morphological taxonomy is still unsettled. In this paper, specimens from gac fruits（Momordica cochinchinensis） are attempted to classify by geometric morphometric and genetic analyses. Geometric morphometric study of wing venation and aculeus shape among samples suggested a new species in this taxon. Sequences in the cytochrome oxidase I region were compared with reference material in this complex, as well as other taxa within the same subgenus. Phylogenetic analysis based on COI revealed a new species of the B. tau complex, B. tau form J. Therefore, the criteria of body color patterns proved to be taxonomically valid for species classification and identification in this species complex.
文摘Genus Heliotropium L. (Heliotropiaceae) in south west of Saudi Arabia has been studied;seven species of H. arbainense Fresen, H. longiflorum (D.C.) Jauber & Spach, H. petrocarpum Hockst & Steud, H. strigosium Willd, H. zeylanicum Lam., H. jizanense Al-Turki and H. lasiocarpum Fisch were collected, recognized, typed and nomenclatured. The most valuable characters were those of macro and distinct micromorphological data such as stomata, hairs, pollen grains and stem anatomy. Light microscopy has been used in these studies. From the obtained results, trichomes and pollen grains data in addition to stem anatomy indicated good taxonomic tools to differentiate between species of this genus. Different traditional measurements were strikingly also helpful for the discrimination of species. H. longiflorum was characterized by distinctive data such as prominent anatomical information, P/E (1.8 μm) in addition to presence of spindle hair which in turn can be separated as a taxonomic level. Also, the results revealed a complete affinity between the two species of H. jizanense and H. lasiocarpum. An artificial key is provided for the differentiation between the studied species.
文摘We present results of numerical simulations of the tensor-valued elliptic-parabolic PDE model for biological network formation.The numerical method is based on a nonlinear finite difference scheme on a uniform Cartesian grid in a two-dimensional(2D)domain.The focus is on the impact of different discretization methods and choices of regularization parameters on the symmetry of the numerical solution.In particular,we show that using the symmetric alternating direction implicit(ADI)method for time discretization helps preserve the symmetry of the solution,compared to the(non-symmetric)ADI method.Moreover,we study the effect of the regularization by the isotropic background permeability(r>0),showing that the increased condition number of the elliptic problem due to decreasing value of r leads to loss of symmetry.We show that in this case,neither the use of the symmetric ADI method preserves the symmetry of the solution.Finally,we perform the numerical error analysis of our method making use of the Wasserstein distance.
基金This work was funded by the National Science Foundation，A.S.M.and Purdue Agriculture Research Foundation grant to W.A.P
文摘Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.
基金support from Nanyang Technological University(grant no.M4082428)K.J.H.and C.H.acknowledge support from Nanyang Technological University under its Accelerating Creativity and Excellence(ACE)grant(grant no.NTU-ACE2020-07)+2 种基金supported by the Center for Engineering Mechano Biology,an National Science Foundation(NSF)Science and Technology Center,under grant agreement No.CMMI:15-48571supported by the U.S.Department of Energy(grant no.DE-FG2-84ER13179)support from the Ministry of Education-Singapore,under its Academic Research Fund Tier 1(RT11/20 and RG32/20).
文摘Plants produce a rich diversity of biological forms,and the diversity of leaves is especially notable.Mechanisms of leaf morphogenesis have been studied in the past two decades,with a growing focus on the interactive roles of mechanics in recent years.Growth of plant organs involves feedback by mechanical stress:growth induces stress,and stress affects growth and morphogenesis.Although much attention has been given to potential stress-sensing mechanisms and cellular responses,the mechanical principles guiding morphogenesis have not been well understood.Here we synthesize the overarching roles of mechanics and mechanical stress in multilevel and multiple stages of leaf morphogenesis,encompassing leaf primordium initiation,phyllotaxis and venation patterning,and the establishment of complex mature leaf shapes.Moreover,the roles of mechanics at multiscale levels,from subcellular cytoskeletal molecules to single cells to tissues at the organ scale,are articulated.By highlighting the role of mechanical buckling in the formation of three-dimensional leaf shapes,this review integrates the perspectives of mechanics and biology to provide broader insights into the mechanobiology of leaf morphogenesis.
基金This work was supported by the European Regional Development Fund–Ministerio de Ciencia e Innovacion(CGL2016-79861-P).
文摘Aims We compared vein and stomatal traits of seedlings and adults of three Mediterranean Quercus species.Previous work suggests that gas-exchange rates tend to be higher at the seedling stage than in adults.Our objective was to determine whether vein and stomatal traits vary throughout whole-plant ontogeny in parallel with the changes in gas-exchange rates.We addressed the following alternative hypotheses:hypothesis 1—seedlings show higher vein and stomatal densities than adults;and hypothesis 2—seedlings have lower investments in vascular tissues to reduce construction costs.Methods Ten specimens from each growth stage were randomly sampled for each species in a location in central-western Spain.We measured mean stomatal and vein traits(size and number of stomata per unit of leaf area,vein density,vein volume,vein to epidermis distance),leaf mass per area and lamina thickness.Important Findings Minor vein density and vein volume per area increased with tree age,which seems inconsistent with the ontogenetic trends in gas-exchange rates.This discrepancy is in support of our hypothesis 2,and it suggests that,at the seedling stage,reducing investments in vascular tissues in benefit of maximizing growth rates is a priority.Larger interveinal distances in seedlings were compensated by smaller vein to epidermis distances.The thin leaves of the seedlings may thus constitute as a necessary trait for achieving shorter path length distances for the transport of water to evaporation sites without the need for a strong investment in costly vascular tissues.
