Dysfunction of CYC2g is responsible for the evolutionary shift from radiate to disciform flowerheads in the Chrysanthemum group (Asteraceae: Anthemideae).

Evolutionary shifts among radiate, disciform and discoid flowerheads have occurred repeatedly in a number of major lineages across the Asteraceae phylogeny; such transitions may also appear within evolutionarily young groups. Although several studies have demonstrated that CYC2 genes partake in regulating floral morphogenesis in Asteraceae, the evolution of capitulum forms within a recently diverging lineage has remained poorly understood. Here, we study the molecular regulation of the shift from a radiate to a disciform capitulum within the Chrysanthemum group. This is a recently radiating group mainly comprising two genera, Chrysanthemum and Ajania, that are phylogenetically intermingled but distinct in flowerhead morphology: Chrysanthemum spp. with radiate capitula and Ajania spp. with disciform capitula. We found that the morphogenesis of zygomorphy in the marginal floret in Ajania was disrupted soon after floral primordium emergence; CYC2g, one of the CYC2 copies that was expressed prominently in the ray floret of Chrysanthemum was not expressed in flowerheads of Ajania. Weakening the expression of ClCYC2g in Chrysanthemum lavandulifolium led to the gradual transition of a ray flower toward the disc-like form. Molecular evolutionary analyses indicated that the disciform capitulum might have evolved only once, approximately 8 Mya, arising from dysfunction of the CYC2g orthologs. A 20-nt deletion, including a putative TATA-box of the Ajania-type CYC2g promoter, appeared to inhibit the expression of the gene. Considering the divergent habitats of Chrysanthemum and Ajania, we propose that the shift from radiate to disciform capitulum must have been related to changes in pollination strategies under selective pressure.

Lighting from Top and Side Enhances Photosynthesis and Plant Performance by Improving Light Usage Efficiency.

Light is a critical environmental factor that influences plant growth and development, ranging from seed germination to flowering and fruiting. This study was carried out to explore how the optimal combination of various lighting directions increases the light usage efficiency and influences the plant morphophysiology, by investigating the plant growth parameters, leaf anatomy, epidermal morphology, stomatal properties, chlorophyll content, key physiological changes, and correlated gene expressions. In closed-type plant growth chambers, rooted cuttings of two chrysanthemum (Chrysanthemum morifolium Ramat.) cultivars, "Pearl Egg" and "Gaya Glory", were subjected to a 10-h photoperiod with 600 µmol∙m-2·s-1 photosynthetic photon flux density (PPFD) provided by light-emitting diodes (LEDs) in each light-direction combination (top (1/1) (T), top (1/2) + side (1/2) (TS), top (1/2) + bottom (1/2) (TB), side (1/2) + bottom (1/2) (SB), and top (1/3) + side (1/3) + bottom (1/3) (TSB)). The TS lighting significantly enhanced the morphophysiological performance, compared to the other lighting direction combinations. Notably, the excellent branch formation and earlier flowering were induced by the TS lighting in both "Pearl Egg" and "Gaya Glory" plants.

CmCYC2-like transcription factors may interact with each other or bind to the promoter to regulate floral symmetry development in Chrysanthemum morifolium.

The complex capitulum of Chrysanthemum morifolium is often comprised of bilaterally symmetrical ray florets and radially symmetrical disc florets. The TCP transcription factor clade CYCLOIDEA2 (CYC2) appears to play a vital role in determining floral symmetry and in regulating floral organ development in Asteraceae. Our previous study identified six CmCYC2 genes from chrysanthemum and showed that CmCYC2c participated in the regulation of ray floret identity. However, the functions of other CmCYC2 genes and the underlying molecular mechanism of CmCYC2-mediated floral development regulation in chrysanthemums have not been elucidated. In this study, we analysed the function of CmCYC2 genes by ectopic expression of CmCYC2 in Arabidopsis. Then, we examined the protein-protein interaction using yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Finally, we analysed the protein-DNA interaction using yeast one-hybrid (Y1H) and dual-luciferase reporter assays. We found that ectopic expression of CmCYC2 genes in the Arabidopsis tcp1 mutant changed its floral symmetry and flowering time. Y2H and BiFC assays confirmed three pairs of interactions between CmCYC2 proteins, that is, CmCYC2b-CmCYC2d, CmCYC2b-CmCYC2e and CmCYC2c-CmCYC2d, suggesting that heterodimeric complexes may form between CmCYC2 proteins to increase their functional specificity. The results of Y1H and dual-luciferase reporter assays indicate that CmCYC2c can bind to the promoter of ClCYC2f. Our findings provided clues that CmCYC2-like transcription factors may interact with each other or bind to the promoter to regulate floral symmetry development in C. morifolium. KEY MESSAGE: CmCYC2-like transcription factors may interact with each other or bind to the promoter to regulate floral symmetry development in Chrysanthemum morifolium.

Discrimination of Chrysanthemum Varieties Using Hyperspectral Imaging Combined with a Deep Convolutional Neural Network.

Rapid and accurate discrimination of Chrysanthemum varieties is very important for producers, consumers and market regulators. The feasibility of using hyperspectral imaging combined with deep convolutional neural network (DCNN) algorithm to identify Chrysanthemum varieties was studied in this paper. Hyperspectral images in the spectral range of 874⁻1734 nm were collected for 11,038 samples of seven varieties. Principal component analysis (PCA) was introduced for qualitative analysis. Score images of the first five PCs were used to explore the differences between different varieties. Second derivative (2nd derivative) method was employed to select optimal wavelengths. Support vector machine (SVM), logistic regression (LR), and DCNN were used to construct discriminant models using full wavelengths and optimal wavelengths. The results showed that all models based on full wavelengths achieved better performance than those based on optimal wavelengths. DCNN based on full wavelengths obtained the best results with an accuracy close to 100% on both training set and testing set. This optimal model was utilized to visualize the classification results. The overall results indicated that hyperspectral imaging combined with DCNN was a very powerful tool for rapid and accurate discrimination of Chrysanthemum varieties. The proposed method exhibited important potential for developing an online Chrysanthemum evaluation system.

Generation of expressed sequence tags for discovery of genes responsible for floral traits of Chrysanthemum morifolium by next-generation sequencing technology.

BACKGROUND: Chrysanthemum morifolium is one of the most economically valuable ornamental plants worldwide. Chrysanthemum is an allohexaploid plant with a large genome that is commercially propagated by vegetative reproduction. New cultivars with different floral traits, such as color, morphology, and scent, have been generated mainly by classical cross-breeding and mutation breeding. However, only limited genetic resources and their genome information are available for the generation of new floral traits. RESULTS: To obtain useful information about molecular bases for floral traits of chrysanthemums, we read expressed sequence tags (ESTs) of chrysanthemums by high-throughput sequencing using the 454 pyrosequencing technology. We constructed normalized cDNA libraries, consisting of full-length, 3'-UTR, and 5'-UTR cDNAs derived from various tissues of chrysanthemums. These libraries produced a total number of 3,772,677 high-quality reads, which were assembled into 213,204 contigs. By comparing the data obtained with those of full genome-sequenced species, we confirmed that our chrysanthemum contig set contained the majority of all expressed genes, which was sufficient for further molecular analysis in chrysanthemums. CONCLUSION: We confirmed that our chrysanthemum EST set (contigs) contained a number of contigs that encoded transcription factors and enzymes involved in pigment and aroma compound metabolism that was comparable to that of other species. This information can serve as an informative resource for identifying genes involved in various biological processes in chrysanthemums. Moreover, the findings of our study will contribute to a better understanding of the floral characteristics of chrysanthemums including the myriad cultivars at the molecular level.

Morphological and physiological differences between dehiscent and indehiscent anthers of Chrysanthemum morifolium.

Spray cut chrysanthemums ornamental value and vase life are rapidly reduced with an increase in the pollen dispersal of the middle tubular bisexual flowers, and excessive pollen grains floating in the air are usually harmful to people. Thus, two cultivars were selected: the dehiscent 'Qx-097' and the indehiscent 'Qx-007', to investigate the morphological, structural and physiological differences in anthers. (1) Prior to the opening of the tubular flower, the anther was completely dehisced, and the pollen grains of 'Qx-097' were then released. 'Qx-007' inflorescences showed no pollen dispersal, and this cultivar was therefore not contaminated by its own pollen grains during flowering. (2) The anther cell structure of 'Qx-007' was abnormal, such that the entire anther wall exhibited hypertrophy due to the non-selective thickening of the endothecium cell size in different areas. Moreover, cracks did not form in the 'Qx-007' anther due to failure of septum degradation and stomium breakage, which resulted in the anther locules being inwardly crushed. Besides, the indehiscent anther accompanies partial pollen abortion due to the impairment of tapetum development, this is not conducive to pollen dispersal. (3) The 'Qx-007' anther contained higher water levels compared with 'Qx-097', and the dehydration of the 'Qx-007' anther was relatively moderate. Furthermore, the 'Qx-007' anther exhibited higher Ca2+ and Mg2+ levels compared with 'Qx-097' during dehiscing periods. (4) The 'Qx-007' anther showed significantly lower jasmonic acid levels and higher indole-3-acetic acid levels compare with the 'Qx-097' anther. These results suggest that the endothecium, septum and stomium constituent of the anther structure exhibit developmental abnormalities, which likely serve as the cellular basis of anther indehiscence. In addition, anther dehydration, the enhancement of anther cell toughness due to a high level of ions, and JA (IAA) dysregulation may be the determining physiological factors of anther indehiscence.

Morphological, Genome and Gene Expression Changes in Newly Induced Autopolyploid Chrysanthemum lavandulifolium (Fisch. ex Trautv.) Makino.

Autopolyploidy is widespread in higher plants and plays an important role in the process of evolution. The present study successfully induced autotetraploidys from Chrysanthemum lavandulifolium by colchicine. The plant morphology, genomic, transcriptomic, and epigenetic changes between tetraploid and diploid plants were investigated. Ligulate flower, tubular flower and leaves of tetraploid plants were greater than those of the diploid plants. Compared with diploid plants, the genome changed as a consequence of polyploidization in tetraploid plants, namely, 1.1% lost fragments and 1.6% novel fragments occurred. In addition, DNA methylation increased after genome doubling in tetraploid plants. Among 485 common transcript-derived fragments (TDFs), which existed in tetraploid and diploid progenitors, 62 fragments were detected as differentially expressed TDFs, 6.8% of TDFs exhibited up-regulated gene expression in the tetraploid plants and 6.0% exhibited down-regulation. The present study provides a reference for further studying the autopolyploidization role in the evolution of C. lavandulifolium. In conclusion, the autopolyploid C. lavandulifolium showed a global change in morphology, genome and gene expression compared with corresponding diploid.

Factors affecting quantity of pollen dispersal of spray cut chrysanthemum (Chrysanthemum morifolium).

BACKGROUND: Spray cut chrysanthemum is a vital flower with high ornamental value and popularity in the world. However, the excessive quantity of pollen dispersal of most spray cut chrysanthemum is an adverse factor during its flowering stage, and can significantly reduce its ornamental value and quickly shorten its vase life. More seriously, excessive pollen grains in the air are usually harmful to people, especially for those with pollen allergies. Therefore, in order to obtain some valuable information for developing spray cut chrysanthemum with less-dispersed or non-dispersed pollen in the future breeding programs, we here investigated the factors affecting quantity of pollen dispersal of spray cut chrysanthemum with four cultivars, i.e. 'Qx-097', 'Noa', 'Qx-115', and 'Kingfisher', that have different quantity of pollen dispersal. RESULTS: 'Qx-097' with high quantity of pollen dispersal has 819 pollen grains per anther, 196.4 disk florets per inflorescence and over 800,000 pollen grains per inflorescence. The corresponding data for 'Noa' with low quantity of pollen dispersal are 406, 175.4 and over 350,000, respectively; and 219, 144.2 and nearly 160,000 for 'Qx-115' without pollen dispersal, respectively. 'Kingfisher' without pollen dispersal has 202.8 disk florets per inflorescence, but its anther has no pollen grains. In addition, 'Qx-097' has a very high degree of anther cracking that nearly causes a complete dispersal of pollen grains from its anthers. 'Noa' has a moderate degree of anther cracking, and pollen grains in its anthers are not completely dispersed. However, the anthers of 'Qx-115' and 'Kingfisher' do not crack at all. Furthermore, microsporogenesis and pollen development are normal in 'Qx-097', whereas many microspores or pollen degenerate in 'Noa', most of them abort in 'Qx-115', and all of them degrade in 'Kingfisher'. CONCLUSIONS: These results suggest that quantity of pollen dispersal in spray cut chrysanthemum are mainly determined by pollen quantity per anther, and capacity of pollen dispersal. Abnormality during microsporogenesis and pollen development significantly affects pollen quantity per anther. Capacity of pollen dispersal is closely related to the degree of anther dehiscence. The entire degeneration of microspore or pollen, or the complete failure of anther dehiscence can cause the complete failure of pollen dispersal.

[Study on inflorescences microscopic characteristics of five wild medicinal plants from Chrysanthemum genus in Anhui].

OBJECTIVE: To probe into the disparities in the microscopic characteristics of each part of inflorescences of five wild medicinal plants from Chrysanthemum genus in Anhui Province, and explore the correlation between the distribution of plants and ecological environment. METHODS: The transverse sections of peduncles of the five Chrysanthemum species were observed; The surface piles of the involucre, ray flower, and tubular flower were compared; The ultra-morphology of pollen was observed. RESULTS: There were evident differences, which were associated with ecological environment, among the structures of peduncles of the five species. The morphology of non-glandular hairs on the external involucre presented significant differences, but the morphology of non-glandular hairs tended to be similar gradually from the external to the internal layer of the involucre, and the morphology of surface piles of each part of the inflorescences also tended to converge from the external to the internal. The disparities of glandular hairs among different species were their sizes; As for each species, the size of glandular hairs grew bigger from the involucre to ray flower, and to tubular flower, the density of glandular hairs decreased from the external to the internal layer of the involucre, while it increased on ray flower and tubular flower. The ultra-morphology of pollen of C. zawadskii was distinctly different from that of other species, and disparities of pollen morphology also existed between C. nankingense and C. indicum. CONCLUSION: The structure of peduncles and the disparities in morphology of non-glandular hairs on the surface of external involucre can serve as significant basis for differentiating the inflorescences of Chrysanthemum plants. The categorizing of designating C. nankingense as an separate species is supported.

[Rapid identification system for seedlings of medicinal Chrysanthemum morifolium].

OBJECTIVE: To achieve the rapid identification for seedlings of medicinal Chrysanthemum morifolium, the discriminant equation was established and the software for rapid identification was designed. METHOD: Leaf structure of medicinal Chrysanthemum of 12 cultivars was analyzed to establish the discriminant equation based on variance analysis and discriminant analysis. On this basis, the identification program and software (based on the python language) were designed. RESULT: Through the analysis of variance and multiple comparisons for the 11 leaf parameter index data of 12 different cultivars, it was found that that the leaf parameters were significant different from each other and reached significant levels. The discriminant equation and the rapid identification software were set up based on the analysis of various indicators. CONCLUSION: The rapid identification system of seedlings of medicinal Chrysanthemum could be achieved through the establishment of discriminant equation combined with computer technology.

[Numerical analysis of morphological variation of germplasm resources of Chrysanthemum morifolium for medicine].

OBJECTIVE: Botanical characters of germplasm resources of Chrysanthemum morifolium for medicine were observed and compared, which could offer reference for its genetic improvement and germplasm resources protection. METHOD: Based on the random blocks field experiments design, twenty-six morphological traits were observed. The morphological differences among germplasm resources were compared by principal component analysis and cluster analysis. RESULT: The coefficient of variation values for 17 of 26 traits indicated a high level of variation (above 20%). Six principal components which accounted for 77.14% of total variance were extracted from the principal component analysis. The 29 germplasm resources could be divided into two clusters. CONCLUSION: There were large morphological variation among germplasm resources on Ch. morifolium for medicine.

[Correlation of main physiological characteristics and active components in cultivars of medicinal Chrysanthemum morifolium].

OBJECTIVE: To investigate the dynamic changes of main physiological indexes, active constituent of Chrysanthemum morifolium and their correlation during the whole growing period and provided a reference basis for the field production. METHOD: Take Ch. morifolium cv. Xiaobaiju, Ch. morifolium cv. Hongxinju and Ch. morifolium cv. Changbanju were taken as the research objects, the main physiological and biochemical indexes were determined, the correlation among them was analyzed. RESULT: The trend of each main physiological index and active component were different during the whole growing period. Agronomic characters, physiological and biochemical indexes and economic characters had correlation in different degree. CONCLUSION: Varieties with higher plant height, more branch and cephaloid numbers may be used for breeding for high yield, and varieties with higher chlorophyll content and POD activity, lower GSH content and SOD activity may be used for breeding for high content of the active components.

[Comparative analysis on the configuration of vegetative organs of medicinal Chrysanthemum from different original locations and species].

OBJECTIVE: Compared the difference of the configuration of vegetative organs of medicinal Chrysanthemum in the same habitats but from various original locations and species, in order to provide scientific basis for the study of introduction, differentiation within the species, breeding and genetic diversity. METHODS: The experimental plot were divided into some groups randomly in design and the configuration of vegetative organs were observed, measureed and analysed. RESULTS: The differences of the type and shape of the leaves were obvious. All the Chrysanthemum morifolium cv. 'Gongju' had deep notch long-leaves; Chrysanthemum morifolium cv. 'Boju', Chrysanthemum morifolium cv. 'Chuju', Chrysanthemum morifolium cv. 'Hang bai ju' and Chrysanthemum morifolium cv. 'Hang huang ju' had deep notch correctitude-leaves; Chrysanthemum nakingense and Chrysanthemum indicum had long-leaves; Chrysanthemum indicum had clump-leaves. All the 12 medicinal Dendranthema material had auricle except Chrysanthemum morifolium cv. 'Boju' and Chrysanthemum morifolium cv. 'Chuju'. The young leaves of Chrysanthemum morifolium cv. 'Gongju', Chrysanthemum morifolium cv. 'Gongju' and Chrysanthemum morifolium cv. 'Hang bai ju' did not split and the rest were all splitting. CONCLUSION: The differences of the configuration of vegetative organs were obvious and the Key of Vegetative organs was built.

[Comparative study on botanical morphologic character of different cultivated types medicinal Chrysanthemum morifolium].

OBJECTIVE: Botanical character of different cultivated types medicinal Chrysanthemum morifolium were observed and compared, which can offer reference for its genetic diversity research and breeding. METHOD: Based on the random blocks field experiments design, the main character of leaf and capitulum of medicinal C. morifolium were observed, it was studied on that the botanical character of different cultivated types medicinal C. mortfolium in China were comparatively study with statistical means. RESULT AND CONCLUSION: There are some different of botanical character among different cultivated types medicinal C. morifolium in China, which can be divided into 7 colonies according as its diversity of the botanical and morphological character. The sawtooth number of lamina, leafstalk length and leaf division number are the important laminae morphologic character of different types medicinal C. morifolium, which are relative independent characters.

Chrysanthemum (Dendranthema x grandiflora).

This chapter provides reproducible methods for the transformation of Dendranthema x grandiflora 'Shuhou-no-chikara' (standard) and 'Lineker' (spray) stem internode thin cell layers (TCLs) and conventional stem internode explants using Agrobacterium strains carrying a binary vector with beta-glucoronidase (GUS) reporter and nptII selector genes. Transformation efficiencies are reported at the kanamycin selection (callus formation and plantlet rooting), GUS assay, polymerase chain reaction (PCR), and Southern analysis levels. Notes on regeneration improvement through the use of TCLs, as well as the effective use of sonication for both regeneration and generation of transformants, stimulation of Agro-infection and elimination of Agrobacterium, are included.

Matching shapes with self-intersections: application to leaf classification.

We address the problem of two-dimensional (2-D) shape representation and matching in presence of self-intersection for large image databases. This may occur when part of an object is hidden behind another part and results in a darker section in the gray level image of the object. The boundary contour of the object must include the boundary of this part which is entirely inside the outline of the object. The Curvature Scale Space (CSS) image of a shape is a multiscale organization of its inflection points as it is smoothed. The CSS-based shape representation method has been selected for MPEG-7 standardization. We study the effects of contour self-intersection on the Curvature Scale Space image. When there is no self-intersection, the CSS image contains several arch shape contours, each related to a concavity or a convexity of the shape. Self intersections create contours with minima as well as maxima in the CSS image. An efficient shape representation method has been introduced in this paper which describes a shape using the maxima as well as the minima of its CSS contours. This is a natural generalization of the conventional method which only includes the maxima of the CSS image contours. The conventional matching algorithm has also been modified to accommodate the new information about the minima. The method has been successfully used in a real world application to find, for an unknown leaf, similar classes from a database of classified leaf images representing different varieties of chrysanthemum. For many classes of leaves, self-intersection is inevitable during the scanning of the image. Therefore the original contributions of this paper is the generalization of the Curvature Scale Space representation to the class of 2-D contours with self-intersection, and its application to the classification of Chrysanthemum leaves.

[The characters of various commodity of chrysanthemums].

OBJECTIVE: To provide basis for making the quality standard of medicinal chrysanthemums [Dendranthema morifolium (Ramat.) Tzvel.]. METHOD: The character of pharmacognosy. RESULT: The characters of many of chrysanthemums as well as the differences between them have been clarified.

[Pharmacognostic identification of Herba Chrysanthemi].

OBJECTIVE: To provide evidences for the identification and utilization of Herba Chrysanthemi. METHODS: Regular mehods for morphological and histological identification, TLC and UV were used. RESELTS: The descriptions characters of Herba Chrysanthemi were recounted. The histological characters of the stem and the leaf were also described. TLC showed Herba Chrysanthemi contained chlorogenic acid. UV spectrum showed Herba Chrysanthemi had absorbed peaks at 248 nm and 327 nm. CONCLUSION: All the above-mentioned characters provided evidences for the identification of Herba Chrysanthemi.

[Comparing identification of 3 kinds of flos chrysanthemi on surface morphology].

OBJECTIVE: To identify 3 kinds of commodities of famous traditional Chinese medicine flos chrysanthemi (FD) from different habitats. METHOD: The surface morphology of each part of Hangbaiju produced in Zhejiang province was studied and compared with other 2 kinds of FD. RESULT: The intricate morphology characters of each part of Hanbaiju were found. There are differences in very few characters though Hangbaiju, Gongju and Ganju are very similar in the surface morphology. CONCLUSION: The result would be useful to identify flos chrysanthemi.

[Study on selective breeding of medicinal Chrysanthemum morifolium].

OBJECTIVE: To investigate botanical characters and yield of four cultivars of Chrysanthemum morifolium for further study on their genetic diversity and selective breeding. METHOD: The characters were observed and yield was investigated by field randomized block and analysis of variance. RESULT AND CONCLUSION: The botanical characters are difference among four cultivars; the amount of single flower head is the main factor influencing on the output of Chrysanthemum morifolium (r = 0.925); the yield of "Hongxinju" and "Xiaobaiju" are remarkably higher than that of "Dabaiju" and "Changbanju".