Improving the design of reinforcing frames by simulating the arch and peltate venation structures

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%.

Research on the Developmental Venation of Calligraphy Seal Cutting Art Form from the Perspectives of Chinese Traditional Culture and Art Form

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.

Timing Is Everything： Highly Specific and Transient Expression of a MAP Kinase Determines Auxin-Induced Leaf Venation Patterns in Arabidopsis

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.

The late Pliocene species with ternate venation of Lauraceae from Tuantian flora, Tengchong, Yunnan Province, China

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.

A New Family of Moths from the Middle Jurassic(Insecta:Lepidoptera)

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）.

Macro and Micromorphological Studies on Seven Species of <i>Heliotropium</i>L. (Boraginaceae Juss.) in South West of Saudi Arabia

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.

Seven Things We Think We Know about Auxin Transport

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.

On the vein-stiffening membrane structure of a dragonfly hind wing

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.

Leaf morphogenesis:The multifaceted roles of mechanics

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.

Geometric morphometric and molecular evidence suggest a new fruit fly species in Bactrocera(Zeugodacus) tau complex(Diptera: Tephritidae)

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.

Plant ontogenetic changes in vein and stomatal traits and their relationship with economic traits in leaves of three Mediterranean oaks

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.