Chemical variations of the essential oils in flower heads of Chrysanthemum indicum L. from China

The volatile compositions of hydrodistilled essential oils in the flower heads of Chrysanthemum indicum L. from eight populations in China were analyzed by GC/MS. A total of 169 compounds representing 88.79-99.53% of the oils were identified, and some remarkable differences were found in the constituent percentages of the eight populations. The predominant components of the essential oils were 1,8-cineole (0.62-7.34%), (+)-(1R,4R)-camphor (0.17-27.56%), caryophyllene oxide (0.54-5.8%), β-phellandrene (0.72-1.87%), (-)-(1S,2R,4S)-borneol acetate (0.33-8.46%), 2-methyl-6-(p-tolyl)hept-2-ene (0.3-8.6%), 4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-yl acetate (0.17-26.48%), and hexadecanoic acid (0.72-15.97%). The chemotaxonomic value of the essential-oil compositions was discussed according to the results of cluster analysis (CA) and principal-component analysis (PCA). The eight populations were divided into five groups as different chemotypes (Groups A-E), and the scores together with the loadings revealed clearly different chemical properties of each population. In conclusion, GC/MS in combination with chemometric techniques provided a flexible and reliable method for characterizing the essential oils of different populations of C. indicum L.     

中国菊属一新变种

报道了中国菊属(Chrysanthemum)一新变种——阔叶毛华菊(Chrysanthemum vestitum(Hem sl.)Stapf.var.latifolium J.Zhou et J.Y.Chen)。本变种与模式变种的区别在于直立生长,并且较多分枝,叶较狭,卵状披针形或匙形,长4~6 cm,宽2~3 cm。花序直径较原种为小,约3.5~4.5 cm。主要分布于湖北宜昌、河南伏牛山山脉。抗旱性较原变种强。而主要原产于安徽西部大别山麓之模式变种则铺散生长,较少分枝,叶圆形、卵圆形,长4~7cm,宽3~5 cm。花序直径较大,约4.5~5.0 cm。     

Altered expression of CmNRRa changes flowering time of Chrysanthemum morifolium

Flowering time is an important ornamental trait for chrysanthemum (Chrysanthemum morifolium, Dendranthema x grandiflorum) floricultural production. In this study, CmNRRa, an orthologous gene of OsNRRa that regulates root growth in response to nutrient stress in rice, was identified from Chrysanthemum and its role in flowering time was studied. The entire CmNRRa cDNA sequence was determined using a combinatorial PCR approach along with 5′ and 3′ RACE methods. CmNRRa expression levels in various tissues were monitored by real‐time RT‐PCR. CmNRRa was strongly expressed in flower buds and peduncles, suggesting that CmNRRa plays a regulatory role in floral development. To investigate the biological function of CmNRRa in chrysanthemums, overexpression and knockdown of CmNRRa were carried out using transgenic Chrysanthemum plants generated through Agrobacterium‐mediated transformation. CmNRRa expression levels in the transgenic plants were assayed by real‐time RT‐PCR and Northern blot analysis. The transgenic plants showed altered flowering times compared with nontransgenic plants. CmNRRa‐RNAi transgenic plants flowered 40–64 days earlier, while CmNRRa‐overexpressing plants exhibited a delayed flowering phenotype. These results revealed a negative effect of CmNRRa on flowering time modulation. Alteration of CmNRRa expression levels might be an effective means of controlling flowering time in Chrysanthemum. These results possess potential application in molecular breeding of chrysanthemums that production year‐round, and may improve commercial chrysanthemum production in the flower industry.     

杭白菊的化学成分研究：正戊基果糖甙的结构测定

从杭白菊(Dendranthema morifolium(Ramat.)Tzvel.)的极性部分中分离出12个化合物。经波谱技术和化学方法证明其中之一为新成分,命名为正戊基-β-D-呋喃果糖甙。两个已知化合物咖啡酸丁酯和乙酯为5-lipoxygenase强拮抗剂。     

Application of in vitro techniques in mutation breeding of chrysanthemum

Rooted cuttings of Chrysanthemum morifolium cv. Maghi, a small flowered, late blooming cultivar, were treated with different doses of gamma rays. Somatic mutations in flower colour (light mauve, white, light yellow and dark yellow) and chlorophyll variegation in leaves were detected as chimeras in treated populations. Attempts were made to standardize a microtechnique for plant regeneration from mutated tissues of stem node, stem internode, shoot tip and ray floret. All these explants were cultured on Murashige and Skoog's medium with 3% sucrose, 0.8% agar and different concentrations and combinations of growth regulators. Plant regeneration was successful from all of the mutated tissues. Plants with chlorophyll variegation in leaves and two new flower colours (light mauve and white) were isolated in pure form with 64% and 100% efficiency of mutant recovery, respectively. Attempts are being made to use this technique to establish new varieties from chimeric tissues to meet the increasing demand of the floriculture trade.     

Identification and assay of pyrethrins in Chrysanthemum cinerariefolium calli

Summary Callus from four clones of Chrysanthemum cinerariaefolium have been investigated for pyrethrins biosynthesis. Calli from disc-flowers, bud-flowers, stems and leaves of clone HY D were cultivated. Best growth was obtained by initiating the culture on Murashige and Skoog medium containing 3% sucrose, 1% agar, 4 ppm -naphtoxy acetic acid (ANA) and 0.4 ppm 6- benzyl aminopurine (BAP) for 28 d, then transfering explants on i.e. at the beginning of the stationnary phase. Disc-flowers calli from two high-producers clones (HY C and HY D) and two low-producers clones (SY A and SY B) were also cultivated. Pyrethrin amounts found in callus cells showed a direct relationship between parental clone synthesis ability and callus cell production. Selection of high-producers clones is thus essential for optimisation of pyrethrin synthesis.     

Identification of chrysanthemum cultivars and stability of DNA fingerprint patterns

Several techniques of DNA analysis were applied to identify chrysanthemum cultivars. Unrelated cultivars could be distinguished by using RAPDs (random amplified polymorphic DNAs), inter-SSR (simple sequence repeat) PCR (polymerase chain reaction), hybridization-based DNA fingerprinting, as well as RFLPs (restriction fragment length polymorphisms). Cultivars with different flower colours and belonging to one family, i.e. vegetatively derived from 1 cultivar, appeared to have the same DNA fragment patterns, whichever technique was applied. The absence of polymorphisms between different accessions of the same cultivar indicated a high stability of the observed patterns.     

Polyamine metabolism,floral initiation and floral development in Chrysanthemum (Chrysanthemum morifolium Ramat.)

In the short-day plant Chrysanthemum (Chrysanthemum morifolium Ramat. variety Pavo) putrescine and spermidine conjugates appeared in the apical bud before the first observable transformation of the meristem into floral structures. These compounds accumulated on floral initiation and well before floral evocation. Spermidine conjugates were predominant during floral initiation whereas free amines did not accumulate to any significant extent. Different associations of amides were observed during floral initiation as compared with the reproductive phase. 3,4-Dimethoxyphenethylamine conjugates (water-insoluble compounds) were the predominant amine conjugates observed during flower development. These compounds decreased drastically after fertilization. In vegetative buds from plants grown in long days polyamine conjugates were very low and appeared as plants aged. We present evidence that ornithine decarboxylase (ODC) regulates putrescine biosynthesis during floral initiation and floral development. When ODC action was blocked by DFMO (-DL-difluoromethylornithine, a specific, irreversible inhibitor of ODC), flowering was inhibited, and free and conjugated polyamines were not detected. This treatment led to a slight enhancement of ADC activity. When putrescine was added, polyamine titers and flowering were restored. A similar treatment with DFMA (-DL difluoromethylarginine, a specific, irreversible inhibitor of ADC) did not affect flowering and the polyamine titers. The results suggest that ODC and polyamine conjugates are involved in regulating floral initiation in Chrysanthemum.Abbreviations ADC arginine decarboxylase - ODC ornithine decarboxylase - DFMA -DL-difluoromethylarginine - DFMO -DL-difluoromethylornithine