Identification of Senescence-associated Protein DpXTH1 and its Gene Cloning in Dahlia Petals

[Objective] This study aimed to explore the molecular mechanism of senescence in ethylene-insensitive flowers. [Method] The dahlia petals were used as matedal, and the senescence-associated proteins were isolated and identified using two-dimensional electrophoresis, mass spectrometry and an encoding gene was cloned using molecular biology techniques. [Result] In the two-dimensional elec- trophorogram of proteins from dahlia petals at building color, full flowering and flow- er senescence pedods, a total of 44 protein spots with differences in expression level more than two times were detected. From the 44 protein spots, xyloglucan （XTHs）, a senescence-associated protein, was iso- lated and identified and its expression level was increased continuously with the senescence process of dahlia petals. By using the total RNA of dahlia petals as matedal and a pair of degenerate pdmers, the cDNA sequence of XTH gene was cloned by RT-PCR. The encoding region of XTH gene has a full length of 882 bp, encoding 293 amino acid residues, and is named as DpXTH1 （Accession number： HM053613.1）. The cluster analysis showed that the amino acid sequence of DpXTH1 has high homology with those of XTHs in other plants. [Conclusion] The isolated and identified DpXTH1 from dahlia petals belonged to the XTH family in plants, and its biological function was associated with the senescence process and regulation of dahlia petals.

Rose Essential Oil Extraction from Fresh Petals Using Synergetic Microwave ＆ Ultrasound Energy： Chemical Composition and Antioxidant Activity Assessment

The aim of the present work was to investigate the synergetic effect of microwave and ultrasound treatment on the production, chemical composition and antioxidant activity of rose essential oil. The rose essential oil was extracted from fresh Rosa x damciscena Mill. petals by four methods, hydrodistillation, steam distillation, organic solvent extraction and ultrasounds followed by microwave hydrodistillation. The chemical composition of the extracts was analysed by GC-MS, and the antioxidant capacity by DPPH. It was found that both chemical composition and the antioxidant activity of the extracts depend on the extraction method. Overall it was found that microwaves coupled with ultrasonic treatment can be used effectively for the intensification of the extraction of monoterpenes and sesquiterpenes--fragrance bearing molecules--and equally, for increased antioxidant activity while using about 4 time shorter extraction time. The scale-up of the method was also evaluated. The results obtained in this research support the possible use of the US/MW method for the extraction of rose essential oil for the pharmaceutical and fragrance industry.

New Reported Flavonol Characterized by NMR from the Petals of Talipariti elatum S. w. in Cuba

From yellow petals of Blue Mahoe, besides the known flavonoids gossypetin and gossypitrin, a new one gossypetin derivative was isolated from ethanolic extracts after Soxhlet extraction. Hence, in this study, we present a validated, sensitive and reliable NMR method for the simultaneous identification of flavonoids in this flower drug. Structure analyses of this flavonoid, revealed the identical glycoside moiety attached to a flavonol skeleton like gossypitrin, for which the structure of gossypetin-3'-O-β-glucoside was deduced from extensive NMR experiments.

Anisotropic cell growth-regulated surface micropatterns in flower petals

Flower petals have not only diverse macroscopic morphologies but are rich in microscopic surface patterns, which are crucial to their biological functions. Both experimental measurements and theoretical analysis are conducted to reveal the physical mechanisms underlying the formation of minute wrinkles on flower petals. Three representative flowers, daisy, kalanchoe blossfeldiana, and Eustoma grandiflorurn, are investigated as examples. A surface wrinkling model, incorporating the measured mechanical properties and growth ratio, is used to elucidate the difference in their surface morphologies. The mismatch between the anisotropic epidermal cell growth and the isotropic secretion of surficial wax is found to dictate the surface patterns.

Study of variegated and white flower petals of Capparis spinosa expanded at dusk in arid landscapes

In this study, we provide the first evidence of two pairs of petals of the rapidly expanded and short-lived nocturnal flowers of Capparis spinosa L. （caper） during the prolonged drought period in Eastern Mediterranean region. The corolla of the winter-deciduous, perennial C. spinosa consists of two pairs of petals： a pair of white dis- tinct petals and a pair of connate variegated petals with green basal parts. The results indicated the presence of substantially different amounts of chlorophyll in the two pairs of petals, while their carbohydrates＇ content is com- parable with that of the green sepals. High resolution imaging of petal surfaces of short-lived flowers of C. spinosa, obtained by using scanning electron microscopy, revealed stomata on the adaxial epidermis on both the white and the green parts of the variegated petals; while dense hairs were found on the surface ofthe abaxial green parts of the variegated petals. Adaxial, epidermal cells of the variegated petals, viewed using atomic force microscopy, pos- sess a submicron, cuticular microfolding that differs between the white and the green parts of the petals. It appears that microridges on the adaxial, white parts of petals of C. spinosa compensate for an increase in cell surface area of the short lived petals, while the roughness of the green parts of petals was found to be higher than that of the white parts. Thus, the micromorphology of surfaces of epidermal cells is expected to affect optical properties and wettability of the floral tissues. These findings may be particularly important for understanding the performance of the short-lived petals of C. spinosa, which are exposed to dryland environments.

Study on Mutant Induction of Gladiolus by in vitro Culture of Petals

Petals of Gladiolus ＇Rose Supreme＇ were used to establish regeneration system. Developmental characteristics of petals were observed. A total of 94 plantlets of petal somaclonal line were marked in Mj generation by ISSR molecular markers and traits were observed in M3 generation. The results showed that the best medium to induce callus was MS＋2, 4-D 4.0 rag＂ L-~＋6-BA 0.5 rag. L~ and the best medium to induce somatic embryogenesis was MS＋2, 4-D1.0 mg＇L-I＋TDZ0.3 mg-L-1. New petals could be formed from petal callus directly. Pigments of mother plant appeared on plantlets while they were formed from petals. Two mutants were obtained from petal somaclonal line in M3 generation which demonstrated the correctness of ISSR analysis in M1 generation.

Transcriptome and morphological analyses of double flower formation in Dianthus chinensis

The double flower developmental process is regulated via a complex transcriptional regulatory network.To understand this highly dynamic and complex developmental process of Dianthus spp.,we performed a comparative analysis of floral morphology and transcriptome dynamics in simple flowers and double flowers.We found that the primordium of double flowers of‘X’was larger in size compared to that of simple flowers of‘L’in Dianthus chinensis.RNA-seq and Weighted Gene Co-expression Network Analysis(WGCNA)during flower development,identified stage-specific gene network modules.Expression analysis by RNA-seq indicated that a group of genes related to floral meristem identity,primordia position and polarity were highly expressed in double flowers genotypes compared to simple flowers genotypes,suggesting their roles in double-petal formation.A total of 21 DEGs related to petal number were identified between simple and double flowers.The experiments of in situ hybridization revealed that DcaAP2L,DcaLFY and DcaUFO genes were expressed in the intra-sepal boundary and petal boundary.We proposed a potential transcriptional regulatory network for simple and double flower development.This study provides novel insights into the molecular mechanism underlying double flower formation in Dianthus spp.

Rose solutions with three petals for planar 4-body problems

For planar Newtonian 4-body problems with equal masses, we use variational methods to prove the existence of a non-collision periodic choreography solution such that all bodies move on a rose-type curve with three petals.

Activity Gel Analysis of Endopeptidases in Rose Petals

Poor resolution for the identification of endopeptidase(EP) activity in activity gel assays is a critical issue in the analysis of the postharvest physiology of rose petals. In this paper, major factors influencing EP activity gel assays were evaluated. The results showed that a phosphate(NaH_2PO_4/Na_2HPO_4) buffer favors the detection of clear EP bands, as compared to Tris–HCl buffer. Removal of salts and pigments with Sephadex G-25 columns was vital to the measurement of EP activity in rose petal extracts. For optimal resolution of bands, we show that before electrophoresis,samples should be treated for 10 min at 40 °C. Additionally, electrophoresis should be done in 12% SDS–PAGE co-polymerized with 0.15%(w/v) gelatin. After electrophoresis, the optimal incubation temperature and pH are 42 °C and 7.0, respectively. Using our optimized assay, Rh-EP1,Rh-EP2, Rh-EP3, three proteases with molecular masses of 200, 123.5, and 97.4 kD, respectively, were detected in rose petals. Experiments using EP class-specific inhibitors revealed that Rh-EP2 and Rh-EP3 were both serine proteases, while Rh-EP1 was a metalloprotease. In this study, we also measured changes in EP activity during flower opening, senescence, and water deficit stress(WDS) using our optimized activity gel assay,and found that Rh-EP3 may be more relevant to senescence in roses compared with Rh-EP1 or Rh-EP2. Changes occurring to EPs after WDS were similar to those during the period from flower opening to senescence, and Rh-EP3 activities were greatly increased by WDS treatment. Collectively, our results suggest that significant increases in Rh-EPs activities, especially increases in Rh-EP3 activity, may contribute to the flower senescence induced under WDS treatment.

Sunflower petals:Some physical properties and modeling distribution of their number,dimensions,and mass

Sunflower petal is one of the parts of the sunflower which has drawn attention and has several applications these days.These applications justify getting information about physical properties,mechanical properties,drying trends,etc.in order to design new machines and use new methods to harvest or dry the sunflower petals.For three varieties of sunflower,picking force of petals was measured;number of petals of each head was counted;unit mass and 1000-unit mass of fresh petals were measured and length,width,and projected area of fresh petals were calculated based on image processing technique;frequency distributions of these parameters were modeled using statistical distribution models namely Gamma,Generalized Extreme Value(G.E.V),Lognormal,and Weibull.Results of picking force showed that with increasing number of days after appearing the first petal on each head from 5 to 14 and decreasing loading rate from 150 gmin^-1 to 50 g min^-1 values of picking force were decreased for three varieties,but diameter of sunflower head had different effects on picking force for each variety.Length,width,and number of petals of Dorsefid variety ranged from 38.52 to 95.44 mm,3.80 to 9.28mm and 29 to 89,respectively.The corresponding values ranged from 34.19 to 88.18 mm,4.28 to 10.60 mm and 21 to 89,respectively for Shamshiri variety and ranged from 44.47 to 114.63 mm,7.03 to 20.31 mm and 29 to 89 for Sirena variety.Results of frequency distribution modeling indicated that in most cases,G.E.V and Weibull distributions had better performance than other distributions.

The roles of R2R3-MYBs in regulating complex pigmentation patterns in flowers

Pigmentation patterns are ubiquitous in nature.Visually striking pigmentation patterns are not only aesthetically appealing,but also crucial to pollinator interaction and plant fitness.The formation of complex floral pigmentation patterns mainly relies on the spatiotemporal expression of R2R3-MYB transcription factors and is often associated with certain floral development programs,such as floral organ identity,symmetry,which likely provide key information to initiate the patterning.For a complex pigmentation pattern to form,at least a pair of activator and inhibitor is required,despite their interaction might vary depending on the system being investigated.The regulation of pigmentation pattern involves multiple molecular mechanisms,such as transcriptional regulation,small RNA,transposon-mediated gene silencing,and methylation of gene body.Identifying these regulators can be facilitated by using single-cell and spatial transcriptomics as well as innovative plant transformation technologies.Moreover,plant organ development and pigmentation patterns are often interdependent,but current methods of describing patterns are static.Therefore,more precise and quantitative measurements are needed to elucidate the developmental mechanisms underlying complex pigmentation patterns in flowers.

The phased chromosome-scale genome of yellowhorn sheds light on the mechanism of petal color change

Yellowhorn(Xanthoceras sorbifolium), especially its varieties, is the red petal yellowhorn(X. sorbifolium var. purpurea), an important tree species with great ornamental value, and its flower petals change color throughout the flowering period. In this study, we mainly focused on the mechanism of the petal color change with transcriptomics and metabolomics data. A phased chromosome-scale assembly of the red petal yellowhorn genome was generated using the PacBio high-fidelity reads, Illumina short reads, and Phase genomics Proximo Hi-C data. The final de novo assembly yielded 533.67 Mb with a contig N50 of 5.42 Mb, and 27 501 protein-coding genes were predicted. Notably, an alternate haplotig assembly was also obtained. Furthermore, a variation database for the alleles within the genome was constructed. Subsequently, the expression pattern of flower pigmentation-related genes and allelic expression imbalance events were investigated. Apart from 6 genes involved in the anthocyanin biosynthesis pathway regulated by the activation of 15 MYB-bHLH-WD40s, the increased expression of senescencerelated gene 1(SRG1) and 2-oxoglutarate-dependent dioxygenase(DIOX5) might also result in decreasing content of lutein and increasing abundance of(E/Z)-phytoene, cyanidin-3-O-rutinoside, and cyanidin-3-O-sambubioside. These changes in genes and metabolites were most likely related to the petal color change in red petal yellowhorn. This phased chromosome-scale genome assembly provides more accurate genomic information for future molecular breeding and facilitates allele function studies of the red petal yellowhorn.

The R2R3-MYB transcription factor GaPC controls petal coloration in cotton

Although a few cases of genetic epistasis in plants have been reported, the combined analysis of genetically phenotypic segregation and the related molecular mechanism remains rarely studied. Here, we have identified a gene(named GaPC) controlling petal coloration in Gossypium arboreum and following a heritable recessive epistatic genetic model. Petal coloration is controlled by a single dominant gene,GaPC. A loss-of-function mutation of GaPC leads to a recessive gene Gapc that masks the phenotype of other color genes and shows recessive epistatic interactions. Map-based cloning showed that GaPC encodes an R2R3-MYB transcription factor. A 4814-bp long terminal repeat retrotransposon insertion at the second exon led to GaPC loss of function and disabled petal coloration. GaPC controlled petal coloration by regulating the anthocyanin and flavone biosynthesis pathways. Expression of core genes in the phenylpropanoid and anthocyanin pathways was higher in colored than in white petals. Petal color was conferred by flavonoids and anthocyanins, with red and yellow petals rich in anthocyanin and flavonol glycosides, respectively. This study provides new insight on molecular mechanism of recessive epistasis,also has potential breeding value by engineering GaPC to develop colored petals or fibers for multifunctional utilization of cotton.

Composition and antioxidant activity of Paeonia lactiflora petal flavonoid extract and underlying mechanisms of the protective effect on H_(2)O_(2)-induced oxidative damage in BRL3A cells

Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UHPLC-ESI-Q-Exactive HF MS/MS method was established for characterization, and 21 predominant flavonoid compounds were tentatively identified in PPF. Among them, isoscutellarein-7-(6’-acetylallosyl-(1->2)-glucoside) and scutellarin methylester were discovered in PPF for the first time. Pretreatment with PPF significantly reduced H2O2-induced cell damage, ROS accumulation, and malondialdehyde content and increased the activity of SOD, CAT, and GSH-Px in buffalo rat liver 3A(BRL3A) cells. Moreover, the expression of nuclear Factor E2-related factor(Nrf2) was upregulated by PPF, whose expression trend was consistent with that of heme oxygenase-1(HO-1), glutamate-cysteine ligase catalytic subunit(GCLC), and NAD(P)H quinone oxidoreductase-1(NQO1). These findings suggested that herbaceous peony flavonoids can be used as a natural bioactive agent to prevent oxidative stress.

Isolation and Characterization of Flavonols by HPLC-UV-ESI-MS/MS from Talipariti elatum S.w

The red petals of the flowers of Talipariti elatum, commonly named majagua is used as antitussive, expectorant and antasthmatic in phytotherapy, although the plants’ composition has not been determined in detail so far. Hence, in this study, we present a validated, sensitive, reliable, and cheap narrow-bore LC-UV-ESI-MS/MS coupled to PDA (photodiode array detectors) method for the simultaneous isolation and identification of flavonoids and their glycosidic derivatives in this flower drug. In addition, the structures of two compounds have been elucidated by LC-MS experiments after isolation. Structure analyses allow proposing the presence of gossypitrin (gossypetin-7-O-glucoside) or gossypetin-3'-O-glucoside, a quercetin derivative, possibly quercetin-3-O-glucoside and an unidentified compound with an impair number of m/z, probably an alkaloid.

Cloning and Analysis of the cDNA Sequence of XTH Gene from Chrysanthemum morifolium Petal

[Objective] This study aimed to investigate the structural character of xy- Ioglucan endotransglycosylase/hydrolase （XTH） gene in ethylene-insensitive feverfew. [Method] The total RNA was extracted from Chrysanthemum rnorifolium petal using Trizol reagent, and the cDNA fragment of XTH gene was cloned by RT-PCR and T/A cloning. [Result] The sequencing result showed that the cloned cDNA sequence was 911 bp. It was predicted to encode a polypeptide of 293 amino acids and had seven active sites of XTH family, and then named as CmXTH （gene accession number HM752243）. In addition, The BLAST analysis showed that the deduced amino acid sequence of CmXTH showed high homology with other 19 chosen plant XTHs. Among of these, CmXTH shared closer genetic relationship with Gerbera jamesonii, Solanum lycopersicum, whereas had relatively distant relationship with Populus euparatica, Fragaria ananassa, Actinidia deliciosa, etc. [Conclusion] The cloned fragment was certainly the cDNA of XTH gene, which was associated with the petal growth and senescence in Chrysanthemum morifolium.

Infestation of Micromycetes on the Flowers and Seeds of Rhododendron sp.

The study of micromycetes infestation on flower buds, flower petals and seeds from 10 taxa of Rhododendron sp. was conducted during 2010-2012. Mycological analysis was comprised of 1,500 specimens of buds and petals and 500 seeds of Rhododendron sp.. It was shown that the necrosis and dieback of buds were caused by complex micromycetes （43 species）, with dominants Pestalotiopsis sydowiana, Alternaria alternata, Truncatella truncata and Epicoccum nigrum. Watery brown spots on the flower petals, resulting in the dieback of flowers, were caused by 38 species, including the most common P. sydowiana, A. alternata and Trichoderma viride. The seeds were contaminated by 18 species, and in addition to the above, the following species were associated： Oidiodendron tennuissimum, Davidiella macrocarpa and Phoma leveillei. The results of the mycological analysis confirmed the diversity spectrum of micromycetes species that inhabit the infested Rhododendron buds, flowers and seeds. The research revealed which taxa attracted the largest number of colonies and species of fungi.

New Phytochemical Profile of Ethanolic Extract from Talipariti elatum （Sw.）

Genus Talipariti has long history of use in various traditional medicine therapeutic applications in Cuba, especially intreatment of bronchial asthma and flu. Petals of genus Talipariti are rich source of secondary metabolites and most of these metabolitesare reported to possess expectorant, antasthmatic, appetitive, antioxidant, and antibacterial properties. Hence, in our study, we present avalidated, sensitive, reliable, and cheap narrow-bore UHPLC-UV-ESI-MS/MS coupled to PDA （photodiode array detectors） methodfor the simultaneous isolation and identification of flavonoids and their glycosidic derivatives in this flower drug. In addition, abouttwelve compounds were identified in this specie based on chromatography retention time （tR）, UV and MS/MS spectra and comparedwith those of isolated authentic compound and literature data. About eighth constituents were reported for the first time from Taliparitielatum. Our results demonstrated the developed method could be employed as a rapid and versatile analytical technique foridentification of chemical constituents and quality control of Talipariti elatum.

An Ethylene-inhibited NF-YC Transcription Factor RhNF-YC9 Regulates Petal Expansion in Rose

The speed of flower opening is closely related to their ornamental period.Ethylene functions as a negative regulator involved in the regulation of the petal expansion process.In this study,we isolated a NF-YC transcription factor gene,RhNF-YC9,fromrose petals.RhNF-YC9 expression was induced at the early stages of flower opening but was inhibited by ethylene treatment.Silencing RhNF-YC9 decreased the speed of petal expansion from stage 2 to stage 5.The expressions of 11 cell expansion-related genes involved in cell wall loosening,cell turgor modulation,and cytoskeleton remodeling were significantly down-regulated in RhNF-YC9-silenced petals.We also found that silencing RhNF-YC9 decreased the expression of gibberellin acid(GA)biosynthetic gene RhGA20ox while significantly increasing the transcripts of GA catabolic gene RhGA2ox,reducing the accumulation of GA4 and GA7.The influence of ethylene treatment on the expression of RhGA20ox and RhGA2ox showed the same trend.These results together suggested that RhNF-YC9 positively regulated the speed of petal expansion and mediated the crosstalk between ethylene and GA.Our findings revealed a new insight into the function of NF-YC transcription factors involved in ethylene-regulated petal expansion.

Light induces petal color change in Quisqualis indica(Combretaceae)

Petal color change, a common phenomenon in angiosperms, is induced by various environmental and endogenous factors. Interestingly, this phenomenon is important for attracting pollinators and further reproductive success. Quisqualis indica L.(Combretaceae) is a tropical Asian climber that undergoes sequential petal color change from white to pink to red. This color changing process is thought to be a good strategy to attract more pollinators. However, the underlying physiological and biochemical mechanisms driving this petal color change phenomenon is still underexplored. In this context, we investigated whether changes in pH, pollination, light, temperature or ethylene mediate petal color change. We found that the detected changes in petal pH were not significant enough to induce color alterations. Additionally, pollination and temperatures of 20-30℃did not alter the rate of petal color change; however, flowers did not open when exposed to constant temperatures at 15℃ or 35℃.Moreover, the application of ethylene inhibitor, i.e., silver thiosulphate, did not prevent color change. It is worth mentioning here that in our study we found light as a strong factor influencing the whole process of petal color change, as petals remained white under dark conditions. Altogether, the present study suggests that petal color change in Q. indica is induced by light and not by changes in petal pH, pollination, ethylene, or temperature, while extremely low or high temperatures affect flower anthesis. In summary, our findings represent the probable mechanism underlying the phenomenon of petal color change, which is important for understanding flower color evolution.