Petal Type Research Articles

Single-cell RNA sequencing reveals a high-resolution cell atlas of petals in Prunus mume at different flowering development stages.

Prunus mume (mei), a traditional ornamental plant in China, is renowned for its fragrant flowers, primarily emitted by its petals. However, the cell types of mei petals and where floral volatile synthesis occurs are rarely reported. The study used single-cell RNA sequencing to characterize the gene expression landscape in petals of P. mume 'Fenhong Zhusha' at budding stage (BS) and full-blooming stage (FS). Six major cell types of petals were identified: epidermal cells (ECs), parenchyma cells (PCs), xylem parenchyma cells, phloem parenchyma cells, xylem vessels and fibers, and sieve elements and companion cells complex. Cell-specific marker genes in each cell type were provided. Floral volatiles from mei petals were measured at four flowering development stages, and their emissions increased from BS to FS, and decreased at the withering stage. Fifty-eight differentially expressed genes (DEGs) in benzenoid/phenylpropanoid pathway were screened using bulk RNA-seq data. Twenty-eight DEGs expression increased from BS to FS, indicating that they might play roles in floral volatile synthesis in P. mume, among which PmBAHD3 would participate in benzyl acetate synthesis. ScRNA-seq data showed that 27 DEGs mentioned above were expressed variously in different cell types. In situ hybridization confirmed that PmPAL2, PmCAD1, PmBAHD3,5, and PmEGS1 involved in floral volatile synthesis in mei petals are mainly expressed in EC, PC, and most vascular tissues, consistent with scRNA-seq data. The result indicates that benzyl acetate and eugenol, the characteristic volatiles in mei, are mostly synthesized in these cell types. The first petal single-cell atlas was constructed, offering new insights into the molecular mechanism of floral volatile synthesis.

INFLUENCE FACTORS ON THE FORMATION OF MECHANICAL PROPERTIES AND STRUCTURE OF STEEL FOR MANUFACTURE OF RAILWAY AXES

The article investigated the features of the destruction and deformation of metal plates made of 30CrNi2Mo steel after ballistic tests. The peculiarity of the experiment was that during the test, the plates was additionally subjected to vibration at frequencies of 10 and 20 Hz. The perspective of the impact of vibration on the ballistic stability of plates has been revealed. After the experiment, through-holes of fragmentation and petal types with subsequent cracking were found in the static plates. Cracking propagates deep into the undeformed plate. The application of vibration showed a significant improvement in ballistic properties. When applying the combined test, a change in the resistance of the target was detected. Namely, the plastic component of the metal around the hole was increased and bullet fragments were found that remained on the surface of the plate after the test. It is shown that the further application of vibration is a promising direction for increasing the ballistic resistance of materials.

Roles of the APETALA3-3 ortholog in the petal identity specification and morphological differentiation in Delphinium anthriscifolium flowers.

The genus Delphinium (Ranunculaceae) with its unique and highly complex floral structure is an ideal system to address some key questions in terms of morphological and evolutionary studies in flowers. In D. anthriscifolium, for example, the original eight petal primordia differentiate into three types at maturity (i.e., two dorsal spurred, two lateral flat, and four ventral reduced petals). The mechanisms underlying their identity determination and morphological differentiation remain unclear. Here, through a comprehensive approach combining digital gene expression (DGE) profiles, in situ hybridization, and virus-induced gene silencing (VIGS), we explore the role of the APETALLATA3-3 (AP3-3) ortholog in D. anthriscifolium. Our findings reveal that the DeanAP3-3 not only functions as a traditionally known petal identity gene but also plays a critical role in petal morphological differentiation. The DeanAP3-3 gene is expressed in all the petal primordia before their morphological differentiation at earlier stages, but shows a gradient expression level difference along the dorsventral floral axis, with higher expression level in the dorsal spurred petals, intermediate level in the lateral flat petals and lower level in the ventral reduced petals. VIGS experiments revealed that flowers with strong phenotypic changes showed a complete transformation of all the three types of petals into non-spurred sepals. However, in the flowers with moderate phenotypic changes, the transformation of spurred petals into flat petals is associated with moderate silencing of the DeanAP3-3 gene, suggesting a significant impact of expression level on petal morphological differentiation. This research also shed some insights into the role of changes in gene expression levels on morphological differentiation in plants.

Two-stage deployment kinematics of petal type radio astronomical antenna

A two-stage deployment of the petal type antenna for space radio telescope has been proposed. At the first stage, preliminary unstressed low-precision deployment of the antenna has been carried out. At the second stage, high-precision fixation of the final state of open reflector has been realized. To fix the final state of the open antenna self-setting locks have been proposed. Results of computer and physical simulation of the new deployment system have been presented.

Multi-omics analysis reveals new insights into the bicolor flower phenotype of Paeonia suffruticosa ‘Erqiao’

The bicolor phenotype is conducive to revealing the changes in plant flower color and an important scientific model for studying the regulatory mechanism of flower color. The flowers of Paeonia suffruticosa ‘Erqiao’ have two colors, pink-white and purple-red, and bicolor flowers are rare, possessing unique ornamental value. The distribution of the two colors in a bicolor ‘Erqiao’ flower is similar to a pie chart and can be divided into two distinct parts, with the percentages of the two parts varying. We analyzed the mechanism of flower color formation in ‘Erqiao’ using transcriptomics, proteomics, and metabolomics. The results showed that the differentially abundant metabolites (DAMs), differentially abundant proteins (DAPs), and differentially expressed genes (DEGs) in the two petal types were primarily enriched in phenylpropanoid and flavonoid biosynthesis. Compared with purple-red petals, the PsF3′H protein content in pink-white petals was lower than that in purple-red petals. The content of PsF3′H’s downstream metabolites decreased, while that of some metabolites in the collateral branch of phenylpropanoid biosynthesis increased. The PsF3′H sequence analysis of different P. suffruticosa cultivars and ‘Erqiao’ tissues revealed that the 6 bp insertion mutation of PsF3′H existed only in ‘Erqiao’ and was stably expressed in the pink-white petals. Using virus-induced gene silencing to silence PsF3′H in ‘Erqiao’ petals, the color of the petals faded significantly. Therefore, through multi-omics analysis, we found that the insertion mutation of PsF3′H reduced the synthesis of the PsF3′H protein and led to the obstruction of anthocyanin synthesis; furthermore, other branches and metabolic pathways of the upstream pathway were more active, thus changing the synthesis direction of the entire metabolic pathway. The 6-bp insertion mutation of PsF3′H may be a reason for the rare appearance of bicolor flowers and the unstable ratio of two-colored petals in ‘Erqiao’. This study provides new insights into the formation of the bicolor flower phenotype in ‘Erqiao’.

Floral Development Stage-Specific Transcriptomic Analysis Reveals the Formation Mechanism of Different Shapes of Ray Florets in Chrysanthemum.

The formation mechanism of different ray floret shapes of chrysanthemum (Chrysanthemum × morifolium) remains elusive due to its complex genetic background. C. vestitum, with the basic ray floret shapes of the flat, spoon, and tubular types, is considered a model material for studying ray floret morphogenesis. In this study, the flat and tubular type lines of C. vestitum at specific stages were used to investigate the key genes that regulate morphological differences in ray florets. We found that the expression levels of genes related to auxin synthesis, transport, and response were generally higher in the tubular type than in the flat type. CvARF3 was highly expressed in the flat type, while CvARF5 and CvARF6 were highly expressed in the tubular type. Additionally, the transcription levels of Class B and E genes closely related to petal development, including CvPI, CvAP3, Cvdefh21, CvSEP3, and CvCDM77, were expressed at higher levels in the tubular type than the flat type. Based on the results, it is proposed that auxin plays a key role in the development of ray florets, and auxin-related genes, especially CvARFs, may be key genes to control the morphological difference of ray florets. Simultaneously, MADS-box genes are involved in the co-regulation of ray floret morphogenesis. The results provide novel insights into the molecular mechanism of different petal type formation and lay a theoretical foundation for the directional breeding of petal type in chrysanthemums.

INCREASING THE PERFORMANCE CHARACTERISTICS OF CLUTCHES OF VEHICLES WHEN USING FLUOROPLAST

In the work, a temperature study of friction discs, of the ring and petal type, made of metal asbestos, was carriedout. The SolidWorks program with the COSMOSWorks Designer software module was used to conduct the research.When performing the calculations, simplified models of overlays were created, grids of finite elements wereconstructed, thermal calculation was performed using heat flow. Next, we will conduct a similar study only with afluoroplastic coating applied to the surface of the pressure disc and the clutch flywheel. The use of fluoroplastic allowsto reduce the heat load on the corresponding surfaces with a coating thickness of 0.1 millimeter by at least 10%.

Transcriptomic analysis reveals the formation mechanism of anemone-type flower in chrysanthemum

BackgroundThe ray and disc florets on the chrysanthemum capitulum are morphologically diverse and have remarkably abundant variant types, resulting in a rich variety of flower types. An anemone shape with pigmented and elongated disk florets is an important trait in flower shape breeding of chrysanthemums. The regulatory mechanism of their anemone-type disc floret formation was not clear, thus limiting the directional breeding of chrysanthemum flower types. In this study, we used morphological observation, transcriptomic analysis, and gene expression to investigate the morphogenetic processes and regulatory mechanisms of anemone-type chrysanthemum.ResultScanning electron microscopy (SEM) observation showed that morphological differences between non-anemone-type disc florets and anemone-type disc florets occurred mainly during the petal elongation period. The anemone-type disc florets elongated rapidly in the later stages of development. Longitudinal paraffin section analysis revealed that the anemone-type disc florets were formed by a great number of cells in the middle layer of the petals with vigorous division. We investigated the differentially expressed genes (DEGs) using ray and disc florets of two chrysanthemum cultivars, 082 and 068, for RNA-Seq and their expression patterns of non-anemone-type and anemone-type disc florets. The result suggested that the CYCLOIDEA2 (CYC2s), MADS-box genes, and phytohormone signal-related genes appeared significantly different in both types of disc florets and might have important effects on the formation of anemone-type disc florets. In addition, it is noteworthy that the auxin and jasmonate signaling pathways might play a vital role in developing anemone-type disc florets.ConclusionsBased on our findings, we propose a regulatory network for forming non-anemone-type and anemone-type disc florets. The results of this study lead the way to further clarify the mechanism of the anemone-type chrysanthemum formation and lay the foundation for the directive breeding of chrysanthemum petal types.

Are the spurs more complex than other petal types in Epimedium? Evidence from development, micromorphology, and nectary structure

• Concavities deepen in the development of petals leading to their different shapes. • Three special types of epidermis cells are observed in spurred petals. • Petal development depends on both cell division and anisotropic expansion. • Spurred petals are more complex than others with 6 epidermal cell types and 10–16 vascular bundles. As important organs attracting pollinators, spurs are the tubular outgrowths of flowers with rich diversities in color, shape, and size, and can increase reproductive success. The spurred petals in Epimedium L. (Berberidaceae) have diverse shapes and lengths, and others such as flat, shallow pockets, or saccate structures can also be found. Different shapes of petals may mean different features and functions, but research on petal development and structure is lacking in this genus hindering further research. Here, the petal development, micromorphology, and nectary structures of 9 species in Epimedium are observed to clarify the petal diversity. The results indicate that petal development can be divided into 5 stages, a concavity occur at different positions and then deepens in varying degrees during stage 4, which leads to petal differentiation. Petal stereoscopic structures were influenced by both cell division and anisotropic expansion in early developmental stages, the latter contributed greatly to spur elongation. There are 7 types of cells observed in Epimedium , with only 1 type of secretory cell; tabular fusiform cells appear in all 9 species; conical cells are widely distributed on the petals with nectaries, while papillose conical cells are only observed in spurs. Nectaries are usually distributed at the tip of the petal stereoscopic structure, consisting of the secretory epidermis, 2 to 13 layers of secretory parenchyma cells, and vascular tissues. These results help us to understand the morphogenesis and development of Epimedium , and provide morphological evidence for future studies on the phylogeny and evolution within the genus.

Multi-Information Model for Large-Flowered Chrysanthemum Cultivar Recognition and Classification.

The traditional Chinese large-flowered chrysanthemum is one of the cultivar groups of chrysanthemum (Chrysanthemum × morifolium Ramat.) with great morphological variation based on many cultivars. Some experts have established several large-flowered chrysanthemum classification systems by using the method of comparative morphology. However, for many cultivars, accurate recognition and classification are still a problem. Combined with the comparative morphological traits of selected samples, we proposed a multi-information model based on deep learning to recognize and classify large-flowered chrysanthemum. In this study, we collected the images of 213 large-flowered chrysanthemum cultivars in two consecutive years, 2018 and 2019. Based on the 2018 dataset, we constructed a multi-information classification model using non-pre-trained ResNet18 as the backbone network. The model achieves 70.62% top-5 test accuracy for the 2019 dataset. We explored the ability of image features to represent the characteristics of large-flowered chrysanthemum. The affinity propagation (AP) clustering shows that the features are sufficient to discriminate flower colors. The principal component analysis (PCA) shows the petal type has a better interpretation than the flower type. The training sample processing, model training scheme, and learning rate adjustment method affected the convergence and generalization of the model. The non-pre-trained model overcomes the problem of focusing on texture by ignoring colors with the ImageNet pre-trained model. These results lay a foundation for the automated recognition and classification of large-flowered chrysanthemum cultivars based on image classification.

Reconstructing an historical pollination syndrome: keel flowers

BackgroundKeel flowers are bilaterally symmetrical, pentamerous flowers with three different petal types and reproductive organs enclosed by keel petals; generally there is also connation of floral parts such as stamens and keel petals. In this study, the evolution of keel flowers within the order Fabales is explored to investigate whether the establishment of this flower type within one of the species-rich families, the Fabaceae (Leguminosae), preceded and could have influenced the evolution of keel flowers in the Polygalaceae. We conducted molecular dating, and ancestral area and ancestral state analyses for a phylogeny constructed for 678 taxa using published matK, rbcL and trnL plastid gene regions.ResultsWe reveal the temporal and spatial origins of keel flowers and traits associated with pollinators, specifically floral symmetry, the presence or absence of a pentamerous corolla and three distinct petal types, the presence or absence of enclosed reproductive organs, androecium types, inflorescence types, inflorescence size, flower size, plant height and habit. Ancestral area reconstructions show that at the time keel flowers appeared in the Polygaleae, subfamily Papilionoideae of the Fabaceae was already distributed almost globally; at least eight clades of the Papilionoideae had keel flowers with a functional morphology broadly similar to the morphology of the first evolving Polygaleae flowers.ConclusionsThe multiple origins of keel flowers within angiosperms likely represent convergence due to bee specialization, and therefore pollinator pressure. In the case of the Fabales, the first evolving keel flowers of Polygaleae have a functional morphology that corresponds with keel flowers of species of the Papilionoideae already present in the environment. These findings are consistent with the keel-flowered Polygaleae exploiting pollinators of keel-flowered Papilionoideae. The current study is the first to use ancestral reconstructions of traits associated with pollination to demonstrate that the multiple evolutionary origins of the keel flower pollinator syndrome in Fabales are consistent with, though do not prove, mimicry.

Petal development and elaboration.

Petals can be simple or elaborate, depending on whether they have complex basic structures and/or highly specialized epidermal modifications. It has been proposed that the independent origin and diversification of elaborate petals have promoted plant-animal interactions and, therefore, the evolutionary radiation of corresponding plant groups. Recent advances in floral development and evolution have greatly improved our understanding of the processes, patterns, and mechanisms underlying petal elaboration. In this review, we compare the developmental processes of simple and elaborate petals, concluding that elaborate petals can be achieved through four main paths of modifications (i.e. marginal elaboration, ventral elaboration, dorsal elaboration, and surface elaboration). Although different types of elaborate petals were formed through different types of modifications, they are all results of changes in the expression patterns of genes involved in organ polarity establishment and/or the proliferation, expansion, and differentiation of cells. The deployment of existing genetic materials to perform a new function was also shown to be a key to making elaborate petals during evolution.

Comprehensive Transcriptome and Metabolic Profiling of Petal Color Development in Lycoris sprengeri.

Lycoris sprengeri (L. sprengeri) is an important ornamental bulbous plant, and its numerous varieties in different color forms are widely planted. Multiple color types of petals in L. sprengeri provide us with possibilities to delineate the complicated metabolic networks underlying the biochemical traits behind color formation in this plant species, especially petal color. In this study, we sequenced and annotated a reference transcriptome of pink and white petals of L. sprengeri and analyzed the metabolic role of anthocyanin biosynthesis in regulating color pigment metabolism. Briefly, white and pink petal samples were sequenced with an Illumina platform, to obtain the reads that could be assembled into 100,778 unique sequences. Sequences expressed differentially between white vs. pink petals were further annotated with the terms of Gene Ontology (GO), Clusters of Orthologous Groups (COG), Kyoto Encyclopedia of Genes and Genomes (KEGG), and eggNOG. Gene expression analyses revealed the repression of anthocyanin and steroid biosynthesis enzymes and R2R3 MYB transcription factor (TF) genes in white petals compared to pink petals. Furthermore, the targeted metabolic profiling of anthocyanins revealed that color-related delphinidin (Del) and cyanidin (Cy) pigments are lower in white petals, which correlate well with the reduced gene expression levels of anthocyanin biosynthesis genes. Taken together, it is hypothesized that anthocyanin biosynthesis, steroid biosynthesis, and R2R3 MYB TFs may play vital regulatory roles in petal color development in L. sprengeri. This work provides a valuable genomic resource for flower breeding and metabolic engineering in horticulture and markers for studying the flower trait evolution of L. sprengeri.

An integrated transcriptomic and proteomic approach to dynamically study the mechanism of pollen-pistil interactions during jasmine crossing

Jasmine (Jasminum sambac Aiton, Oleaceae) flowers are widely consumed in many countries for their tea-making, medicinal and ornamental properties. To improve the quality and yield of flowers, it is very important to carry out cross-breeding between different petal types of jasmine. However, because of the difficulty of sexual reproduction, there is no report on the success of jasmine crosses. In this paper, single- and double-petal jasmine plants were crossed artificially. The stigmas of single-petal plants post pollination, including those at 0 h after pollination (CK), 1 h after pollination (T1) and 6 h after pollination (T2), were sequenced by transcriptomic combined with proteomic analyses. A total of 178,098 gene products were assembled. Simultaneously, a total of 2337 protein species were identified. Some regulatory gene products and functional protein species were identified that may be involved in the process of pollen-pistil interactions. These findings suggest that the identified differentially expressed gene products and differentially accumulated protein species may play vital roles in jasmine plants in response to pollen-pistil interactions, providing important genetic resources for further functional dissection of the molecular mechanisms of these interactions. SignificanceThese results have important scientific significance to take effective measures to overcome pre-fertilization barriers and to guide the cross breeding of jasmine. Further, they can also be used for reference in other plant breeding with the same fertilization barriers.

Study on Adaptability of Hibiscus mutabilis Germplasm Resources in Chengdu Region

The adaptability of 171 Hibiscus mutabilis resources from 14 provinces were studied in Chengdu. The results showed that: (1) Most of the resources (80.70%, distributed in the south of 32°06'53N) had good adaptability in Chengdu area. (2) Among the preserved resources, the proportion of single petal type (including single-petal red, single-petal white and single-petal white to red) was 57.25%, which was slightly higher than that of double-petal resources (42.75%). (3) 63.04% of the preserved Hibiscus mutabilis resources were firm, of which 62.07% were single petal and 40.23% were from Fujian. These results will be of great significance for the conservation and popularization of Hibiscus mutabilis germplasm resources.

Plastid genome data provide new insights into the phylogeny and evolution of the genus Epimedium

IntroductionEpimedium L., the largest herbaceous genus of Berberidaceae, is one of the most taxonomically difficult representatives. The classification and phylogenetic relationships within Epimedium are controversial and unresolved. ObjectivesFor the first time, we systematically studied the phylogeny and evolution of Epimedium based on plastid genome (plastome) data for better understanding this enigmatic genus. MethodsWe explored the molecular phylogeny, assessed the infrageneric classification, estimated the divergence times, and inferred the ancestral states for flower traits of Epimedium based on 45 plastomes from 32 species. ResultsThe Epimedium plastome length ranged from 156,635 bp to 159,956 bp. Four types of plastome organization with different inverted repeat boundary changes were identified. Phylogenetic analysis revealed a strong support for the sister relationship of sect. Macroceras and sect. Diphyllon but did not provide a distinct route for petal evolution in sect. Diphyllon. Disharmony between phylogenetic relationships and traditional classification of sect. Diphyllon was observed. Results from divergence time analysis showed that Epimedium diverged in the early Pleistocene (~2.11 Ma, 95% HPD = 1.88–2.35 Ma). Ancestral character state reconstructions indicated transitions from long spur (large-flowered group) to other petal types (small-flowered group) in Epimedium. ConclusionThese findings provide new insights into the relationships among Epimedium species and pave the way for better elucidation of the classification and evolution of this genus.

УДОСКОНАЛЕННЯ ГЕОМЕТРИЧНОЇ ФОРМИ НЕЗАЛЕЖНО КЕРОВАНОГО ЕЛЕМЕНТУ МАНІПУЛЯТОРА

Nowadays, manipulators have been widely used in construction, medicine, industrial production and research. This paper considers the use of a manipulator with independently controlled individual elements. This design provides ease of installation of the entire device and a significant reduction in the time required to adjust the manipulator in the event of a change in the technical task. The most studied are manipulators with elements of the petal type, in which the clutch is due to the creation of high or low pressure. Such a system is sensitive to the settings and the number of elements. Another common type is centrally controlled manipulators, in which the adhesion of adjacent elements occurs through the use of electromagnets. The disadvantage of such a system is the need to use a large number of control cables, which significantly limits the number and flexibility of structural elements. To increase the flexibility of the whole structure, the question of increasing the possibility of bending the manipulator by changing the geometry of the shape of its independently controlled element is considered. It is proposed to use the disk shape of the element, which will allow you to use the manipulator in the tunnel holes that intersect at right or acute angles. The question of providing the general rectilinear arrangement of all device due to alternate coupling of mobile elements of the manipulator in various axial planes is considered. The paper provides an approximate estimate of the relative increase in the diameter of the entire manipulator relative to the diameter of the disk element depending on the angle of the working face of the surface to the base plane of the disk. The dependence of the relative increase in diameter on the number of simultaneously connected in one axial plane of the structural elements is considered. Keywords: manipulator, remote controlled element, disk form of manipulator element.

Metabolomics Analysis Reveals the Role of Cyanidin Metabolism in Plumbago auriculata Flower Color

Blue flowers, which are rare, have long been a focus for researchers engaged in colored flower breeding. In this study, Plumbago auriculata, a plant with blue flowers, and its white flower forma Plumbago auriculata f. alba were used as research materials. Flower color quantification, environmental scanning electron microscopy (ESEM) observation of petal epidermal cells, and determination of the cell sap pH were carried out; moreover, metabolomic analysis was used to analyze the flavonoid metabolites of both types of petals. The results showed that the flower color of P. auriculata was bluish violet, and there was no significant difference in the epidermal cell distribution of the white and blue petals. The key substance that determined the bluish violet flower color was cyanidin-3-O-(6″-p-coumaroylglucoside) (Cy3-pC·G). Compared to the white petal cells, the blue petal cells exhibited up to 40 upregulated flavonoid compounds that were copigments. Together with the significantly increased pH (5.92 ± 0.12) of the petal cell sap, these copigments affected the color presentation of Cy3-pC·G, causing the final petal color of P. auriculata to be bluish violet. The results of this study indicate that cyanidin is an important anthocyanidin in blue flowers, which provides new insights into the breeding of blue flowers.

Theoretical Analysis of Bulletproof Capability of Multilayer Ceramic Composites Subjected to Impact by an Armor Piercing Projectile

Inspired by the theories of Tate and Zaera, a theoretical analysis model including the erosion of the projectile, the cracking of ceramic composites, and the deformation of metal backplate was established in this study to investigate the bulletproof capability of the ceramic composites under impact by an armor piecing projectile (AP). The analysis results were verified by ballistic tests. As for the ceramic composites, the volume of the cracked ceramic conoid and the change in the compressive strength were included. Regarding the deformation of the metal backplate, the plastic deformation work, the external work, and the conservation of kinetics were considered. Based on the thickness of the target plate, failure modes were separated into the plug type and the petal type. The ordinary differential equation solver of MATLAB, ode45, was adopted to solve relevant ordinary differential equations. In this study, the powder metallurgy was used to produce the Al2O3/ZrO2 multilayered ceramic composites of three layers; each layer was 3 mm in thickness. The ceramic composites were paired with a backplate made of 6061‐T6 aluminum alloy with a thickness of either 1 mm or 4 mm. The ballistic tests were executed by using 0.30″ AP projectiles to impact the specimens. The results from theoretical model and ballistic tests were compared and shown consistent in the field of residual velocity, residual bullet mass, and the failure modes of the metal backplate.

New design of precise deployable reflector. Technologies for manufacturing of physical model

The new design of petal space antenna is considered in the paper. Various versions of solid petal-type mirrors have been considered and investigated in a number of articles and space projects. The classical scheme of petal type deployable space reflector was proposed and developed by Dornier Corporation within FIRST space project and was used in the Radioastron project to create a 10-meter antenna of space radio telescope. However, the classical petal mirror design has two significant drawbacks. Firstly, in the open state, the petals are cantilevered on the central mirror, what leads to low rigidity of the structure in open state. Secondly, in the classical design, the accuracy of the reflecting surface of the open mirror strongly depends on small errors in the operation of the deployment system. To overcome these drawbacks a new design of petal type mirror and a new system for precise opening of the mirror were proposed and studied. To test a new technical solution, a physical model of a deployable reflector was developed. The model contains a central mirror, a set of petals, hinges, locks and actuators for opening the mirror. 3D printing technology, CNC (computer numerical control) milling, plastic injection molding and carbon fiber technologies have been tested for central mirror and petals of the model fabrication. The results of computer and physical simulation are presented in the paper.