Rose Flowers Research Articles

Anti-Inflammatory Effects of Hexane Fraction from White Rose Flower Extracts via Inhibition of Inflammatory Repertoires

In this study, we determined the anti-inflammatory activity and mechanism of action of a hexane fraction (hWRF) obtained from white Rosa hybrida flowers by employing various assays such as quantitative real-time PCR, Western blotting, and Electrophoretic-Mobility Shift Assay (EMSA). The results revealed that the hWRF had excellent anti-inflammatory potency by reducing inflammatory repertoires, such as inducible nitric oxide synthase (iNOS), interleukin-, and cyclooxygenase-2 (COX-2) in RAW264.7 cells when stimulated with lipopolysaccharide (LPS), a pro-inflammatory mediator. The reduction of nitric oxide (NO) release from RAW 264.7 cells supported the anti-inflammatory effect of hWRF. Interestingly, hWRF effectively inhibited LPS-mediated nuclear factor- (NF-) p65 subunit translocation into the nucleus and extracellular signal-regulated kinase (ERK)1/2 phosphorylation, suggesting that hWRF anti-inflammatory activity may be based on inhibition of the NF- and MAPK pathways. Based on the findings described in this study, hWRF holds promise for use as a potential anti-inflammatory agent for either therapeutic or functional adjuvant purposes.

The expression level of Rosa Terminal Flower 1 (RTFL1) is related with recurrent flowering in roses

We examined the relationship between the recurrent flowering character and the expression patterns of TERMINAL FLOWER 1 (TFL1) homologs in roses, using flower buds of Rosa multiflora, R. rugosa, R. chinensis, and six other rose species and nine rose cultivars. RTFL1 (Rosa TFL1) genes were amplified from rose genomic DNA using a combination of degenerate and gene-specific primers by thermal asymmetric interlaced-PCR and normal PCR, respectively. Their copy numbers in different species were determined by Southern blots. We used real-time PCR to analyze the expression patterns of RTFL1 genes at four developmental stages (pre-sprouting, young, mid-aged, and mature flower buds). Our results show that there are at least three RTFL1 homologs in roses; RTFL1a, RTFL1b, and RTFL1c. The sequences of the homologs were more similar among the same homolog in different species than among the different homologs in the same species. For RTFL1a, we detected two copies in R. multiflora, two copies in R. rugosa, and one copy in R. chinensis. For RTFL1c, we detected one copy in R. multiflora, two copies in R. rugosa, and three copies in R. chinensis. We detected only one copy of RTFL1b in R. chinensis. RTFL1c was expressed at high levels at all four flowering stages in R. multiflora and R. rugosa, which are non-recurrent flowering species, whereas it was barely detected in R. chinensis (a recurrent flowering species) at any stage. These results were further verified in six other non-recurrent flowering species and nine recurrent flowering cultivars. These results suggest that the recurrent flowering habit in roses results from lower expression of RTFL1c, which may be related to recurrent flowering character in roses.

Endogenous Auxin Profile in the Christmas Rose (Helleborus niger L.) Flower and Fruit: Free and Amide Conjugated IAA

The reproductive development of the Christmas rose (Helleborus niger L.) is characterized by an uncommon feature in the world of flowering plants: after fertilization the white perianth becomes green and photosynthetically active and persists during fruit development. In the flowers in which fertilization was prevented by emasculation (unfertilized) or entire reproductive organs were removed (depistillated), the elongation of the peduncle was reduced by 20–30%, and vascular development, particularly lignin deposition in sclerenchyma, was arrested. Chlorophyll accumulation in sepals and their photosynthetic efficacy were up to 80% lower in comparison to fertilized flowers. Endogenous auxins were investigated in floral and fruit tissues and their potential roles in these processes are discussed. Analytical data of free indole-3-acetic acid, indole-3-ethanol (IEt), and seven amino acid conjugates were afforded by LC-MS/MS in floral tissues of fertilized as well as unfertilized and depistillated flowers. Among amino acid conjugates, novel ones with Val, Gly, and Phe were identified and quantified in the anthers, and in the fruit during development. Reproductive organs before fertilization followed by developing fruit at post-anthesis were the main source of auxin. Tissues of unfertilized and depistillated flowers accumulated significantly lower levels of auxin. Upon depistillation, auxin content in the peduncle and sepal was decreased to 4 and 45%, respectively, in comparison to fruit-bearing flowers. This study suggests that auxin arising in developing fruit may participate, in part, in the coordination of the Christmas rose peduncle elongation and its vascular development.

Aspects of gift giving in Denmark in the sixteenth century and the case of the Rose Flower Cup

The concept of an ancient system of gift exchange gradually being replaced by a market economy during the middle ages and early modern period has been rightly challenged by many recent studies. As it will appear from this essay on gift giving at the Danish court of King Frederik II (1559–88), gifts and favours continued to play an important role in the organisation of power and society. Several examples from sixteenth-century Denmark are discussed, including Frederik II’s patronage of the astronomer Tycho Brahe. Special emphasis is put on a gift from the Danish noble couple Hans Skovgaard and Anne Parsberg on the occasion of the baptism in 1577 of their godson, the eldest son of Frederik II. Donations at rites of passage like baptism were a convention at the time, yet the huge gilt silver cup known as the ‘Rose Flower’ was more than that. It was an elegant way of reciprocating an earlier, royal wedding gift. At the same time the cup and its symbolism hinted at the ideal of the generous lord, stressing the hospitality and accessibility expected from the king, an ideal as common to king and nobility at the renaissance court of the sixteenth century as it had been in the previous centuries. The more humble gifts mentioned in private account books of the time point to the fact that people did not necessarily give someone a gift to obtain something in return. Sometimes gifts were simply given to sustain the social order of which the donors were a part.

Comparative GC/MS Analysis of Rose Flower and Distilled Oil Volatiles of The Oil Bearing Rose Rosa Damascena

ABSTRACTThe accelerated and successful oil bearing rose breeding requires routine application of efficient procedure for analysis of flower volatiles, with capacity to extrapolate the obtained flower data to the volatile composition of the distilled rose oil. In the current study a procedure for solvent extraction and GC/MS analysis of rose flower and rose oil volatiles from oil bearing roses including Rosa damascena is presented. The procedure allows reliable identification of 68 volatiles in the rose flowers which are also detected in the distilled rose oil. The described procedure was further applied for comparative analysis of the flower and distilled rose oil volatiles from eight different genotypes of oil bearing roses. A data set consisting of ratios of the relative abundance of given volatile in the flower spectra to the relative abundance of the same volatile in the distilled rose oil spectra was generated. ANOVA test for a data subset of 27 volatiles detected in the flowers and rose oils of all analyzed oil bearing rose genotypes showed no significant influence of the genotype on the ratio of relative abundances of flower to rose oil volatiles. The average and relative standard deviation values of the obtained ratios between relative abundances of flower and rose oil volatiles for the analyzed genotypes were calculated for each identified flower compound. The results demonstrate that the described flower solvent extraction and GC/MS analysis procedure could be reliably applied for prediction of the volatile composition of distilled rose oils from wide range of oil bearing rose genotypes based on the extrapolation of GC/MS analysis data from single or few flowers from each studied plant. The possibilities for incorporation of the described procedure into oil bearing rose breeding and genetic resources characterization are discussed.

Functional characterization of rose phenylacetaldehyde reductase (PAR), an enzyme involved in the biosynthesis of the scent compound 2-phenylethanol

2-Phenylethanol (2PE) is a prominent scent compound released from flowers of Damask roses ( Rosa × damascena) and some hybrid roses ( Rosa ‘Hoh-Jun’ and Rosa ‘Yves Piaget’). 2PE is biosynthesized from l-phenylalanine ( l-Phe) via the intermediate phenylacetaldehyde (PAld) by two key enzymes, aromatic amino acid decarboxylase (AADC) and phenylacetaldehyde reductase (PAR). Here we describe substrate specificity and cofactor preference in addition to molecular characterization of rose-PAR and recombinant PAR from R. × damascena. The deduced amino acid sequence of the full-length cDNA encoded a protein exhibiting 77% and 75% identity with Solanum lycopersicum PAR1 and 2, respectively. The transcripts of PAR were higher in petals than calyxes and leaves and peaking at the unfurling stage 4. Recombinant PAR and rose-PAR catalyzed reduction of PAld to 2PE using NADPH as the preferred cofactor. Reductase activity of rose-PAR and recombinant PAR were higher for aromatic and aliphatic aldehydes than for keto-carbonyl groups. Both PARs showed that ( S)-[4- 2H] NADPH was preferentially used over the ( R)-[4- 2H] isomer to give [1- 2H]-2PE from PAld, indicating that PAR can be classified as short-chain dehydrogenase reductase (SDR).

Genotypic Variation in the Postharvest Performance and Ethylene Sensitivity of Cut Rose Flowers

Natural variation in the postharvest quality and longevity of ornamental plants can often be related to differences in their response to ethylene. In the present study, we determined the postharvest performance and ethylene sensitivity of cut flowers from 38 cultivated Hybrid Tea rose genotypes. The vase life of the cultivars varied considerably from 4.5 to 18.8 days at 21 °C. There was also substantial variation in the degree of flower opening among genotypes. Exposure to 1 μL·L−1 ethylene for 24 h at 21 °C reduced the longevity of 27 cultivars by 0.8 to 8.4 days (18% to 47%) by accelerating petal wilting and abscission. Ethylene treatment also significantly reduced rates of flower opening in 17 sensitive cultivars and in six cultivars that showed no ethylene-related reduction in vase life. Five cultivars showed no reduction in vase life or flower opening in response to ethylene exposure. Pre-treating stems with 0.2 mm silver thiosulfate liquid or 0.9 μL·L−1 1-methylcyclopropene (1-MCP) gas for 16 h at 2 °C reduced the deleterious effects of ethylene. The release of 1-MCP from two sachets containing EthylBloc™ into individual shipping boxes also protected flowers against ethylene applied immediately after a 6-d commercial shipment. The duration of protection afforded by the 1-MCP sachet treatment was greatest when flowers were maintained at low temperature.

Antimicrobial and Antioxidant Properties of Secondary Metabolites from White Rose Flower

Low-molecular-weight secondary metabolites from plants play an important role in reproductive processes and in the defense against environmental stresses or pathogens. In the present study, we isolated various volatiles and phenolic compounds from white Rosa rugosa flowers, and evaluated the pharmaceutical activities of these natural products in addition to their ability to increase survival in response to environmental stress and pathogen invasion. The DPPH and hydroxyl radical-mediated oxidation assay revealed that the white rose flower extract (WRFE) strongly scavenged free radicals in a dose dependent manner. Moreover, WRFE inhibited the growth of E. coli and fatally attacked those cells at higher concentration (>0.5 mg/mL). FITC-conjugated Annexin V stain provided further evidence that WRFE had strong antimicrobial activity, which may have resulted from a cooperative synergism between volatiles (e.g. 1-butanol, dodecyl acrylate and cyclododecane) and phenolic compounds (e.g. gallic acid) retained in WRFE. In conclusion, secondary metabolites from white rose flower hold promise as a potential natural source for antimicrobial and non-chemical based antioxidant agents.

Endogenous Gibberellin Profile During Christmas Rose (Helleborus niger L.) Flower and Fruit Development

Gibberellins (GAs) were identified and quantified during flower and fruit development in the Christmas rose (Helleborus niger L.), a native of southeastern Europe with a long international horticultural tradition. Physiologically, the plant differs from popular model species in two major respects: (1) following anthesis, the initially white or rose perianth (formed in this species by the sepals) turns green and persists until fruit ripening, and (2) the seed is shed with an immature embryo, a miniature endosperm, and a prominent perisperm as the main storage tissue. GA1 and GA4 were identified by full-scan mass spectra as the major bioactive GAs in sepals and fruit. LC-MS/MS system in accord with previously verified protocols also afforded analytical data on 12 precursors and metabolites of GAs. In the fruit, GA4 peaked during rapid pericarp growth and embryo development and GA1 peaked during the subsequent period of rapid nutrient accumulation in the seeds and continued pericarp enlargement. In the sepals, the flux through the GA biosynthetic pathway was highest prior to the light green stage when the photosynthetic system was induced. Unfertilized, depistillated, and deseeded flowers became less green than the seed-bearing controls; chlorophyll accumulation could be restored by applying GA1, GA4, and, less efficiently, GA3 to the deseeded fruit. The sepals of unfertilized and depistillated flowers indeed contained very low levels of GA4 and gradually decreasing levels of GA1. However, the concentrations of their precursors and metabolites were less affected. These data suggest that a signal(s) from the fruit stimulates GA biosynthesis in the sepals resulting in greening. The fruit-derived GAs appear to be mainly involved in pericarp growth and seed development.

Identification of rose phenylacetaldehyde synthase by functional complementation in yeast

Rose flowers, like flowers and fruits of many other plants, produce and emit the aromatic volatiles 2-phenylacetaldehyde (PAA) and 2-phenylethylalchohol (PEA) which have a distinctive flowery/rose-like scent. Previous studies in rose have shown that, similar to petunia flowers, PAA is formed from L: -phenylalanine via pyridoxal-5'-phosphate-dependent L: -aromatic amino acid decarboxylase. Here we demonstrate the use of a Saccharomyces cerevisiae aro10 mutant to functionally characterize a Rosa hybrida cv. Fragrance Cloud sequence (RhPAAS) homologous to petunia phenylacetaldehyde synthase (PhPAAS). Volatile headspace analysis of the aro10 knockout strain showed that it produces up to eight times less PAA and PEA than the WT. Expression of RhPAAS in aro10 complemented the yeast's mutant phenotype and elevated PAA levels, similar to petunia PhPAAS. PEA production levels were also enhanced in both aro10 and WT strains transformed with RhPAAS, implying an application for metabolic engineering of PEA biosynthesis in yeast. Characterization of spatial and temporal RhPAAS transcript accumulation in rose revealed it to be specific to floral tissues, peaking in mature flowers, i.e., coinciding with floral scent production and essentially identical to other rose scent-related genes. RhPAAS transcript, as well as PAA and PEA production in flowers, displayed a daily rhythmic behavior, reaching peak levels during the late afternoon hours. Examination of oscillation of RhPAAS transcript levels under free-running conditions suggested involvement of the endogenous clock in the regulation of RhPAAS expression in rose flowers.

Colour stability of the flowers of some rose varieties measured in CIEDE<sub>2000</sub>

A variety trial has been carried out to study the colour stability of the flowers of some modern garden roses, especially of Hungarian varieties. 100 floribundas and polyanthas were observed. Colours of the petals were examined at three phenological stages of flowering: at bud opening and at the phenophase of young open flowers and aged open flowers. The colours were described in the 40° rotated CIE LCh model, and the differences were compared according to the CIEDE<sub>2000</sub> standard. Our work has demonstrated Hungarian varieties with excellent colour stability present in each studied class. It has also been verified that the Hungarian bred floribundas had a lower colour shift than the polyanthas or climbing roses. The best Hungarian floribundas were Pest and Reményik Sándor emléke. None of the Western-European roses excelled them in the colour stability. The majority of the best roses are red, orange-red or dark red, which might indicate that the colour stability is not independent of the main hue of flowers.

Cell Wall Extensibility and Effect of Cell-Wall-Loosening Proteins during Rose Flower Opening

As flower opening involves the expansion of petal cells, the mechanisms of expansion growth were investigated in Rosa hybrida L. ‘FEbesa’ (syn. ‘Pretty Woman’) petals. Petal cell-wall extensibility was analyzed by creep extension analysis. Walls of the petal cells became loose at developing stage IV of completely separated sepals on an opening flower. Furthermore, cell-wall proteins extracted from rose petals at stage IV were suggested to have a positive effect on cell-wall loosening of stage III petals. Expansin and xyloglucan endotransglycosylase/hydrolase (XTH) proteins, which are located on apoplasts, are probably involved in cell-wall loosening in plants. Transcripts of these cell-wall proteins were extracted from rose petals with a view to elucidating their potential role in rose flower opening. Expansin and XTH transcript levels changed markedly during petal development. In particular, transcript levels of RhEXPA1 and RhXTH1 increased markedly during petal growth and were relevant to the typical growth in different part of the petals. Based on the present findings, we suggest that RhEXPA1 and RhXTH1 are the major paralogs involved in expansion growth of rose petals.

Purification and Characterization of β-Glucosidase Involved in the Emission of 2-Phenylethanol from Rose Flowers

Beta-glucosidase was partially purified from Rosa 'Hoh-Jun' petals. The enzyme was highly specific for such beta-D-glucopyranosides as 2-phenylethyl beta-D-glucopyranoside. The optimal activity was observed at pH 6.0 and 35 degrees C. The enzymes were composed with two proteins (160 and 155 kDa) by blue native-PAGE, and were classified in a family 1 glucosidase based on LC-MS/MS analyses.

Colour stability of the flowers in some modern rose varieties in Hungary

A variety trial has been carried out to study the colour changing — colour stability of the flowers of some modern roses, especially of Hungarian varieties. 100 floribundas and polyanthas were observed. Colours of the petal surface were examined at three fenological stages of the flowers: at the bud, at the young open flowers and at the aged open flower stages. The colour difference was described in HLS standard. Our work shows that valuable Hungarian varieties can be found in both studied classes, but more floribundas bred in Hungary had good colour stability than polyanthas. The best Hungarian floribundas were 'Pest' and 'Remenyik Sándor emléke', although 'Regen', `Szent Lász1ó em­léke' and 'Szabó Dezső emléke' were quite good. The best Western-European floribunda rose was 'Perneille Poulsen'. Their colour stability was reliable in different situations. Colour changing of the two best varieties was almost unperceivable from the bud to the young petals and from the young to the aged petals. In the polyantha class there was only one perfect variety: the Czech `Cs1 Cerveny Kriz'. The 'Fairy Damsel' was almost excellent as well. The best Hungarian polyanthas were `Domokos Pál Péter emléke' and 'Savaria'.

Research on Optimum Greenhouse Utilization for the Production of Cut Rose Flowers : How to Secure Agricultural Income before the Price Increase of Heavy Oil A for Heating

Research on Optimum Greenhouse Utilization for the Production of Cut Rose Flowers : How to Secure Agricultural Income before the Price Increase of Heavy Oil A for Heating

Effects of the Temperature of Vase Water on the Vase Life of Cut Rose Flowers

Cut rose (Rosa hybrida L.) ‘Sonia’ flowers were placed in vases of which water temperatures were kept at 10, 15 and 23°C under constant air temperature of 23°C. Vase life of cut roses became longer with lowering water temperature; the vase life was 5.2, 6.7 and 7.5 days at 23, 15 and 10°C, respectively. Fresh weight of cut flowers increased over the first 3, 4 and 5 days during the experimental period at 23, 15 and 10°C, respectively and decreased thereafter. Temperature of flower part was very slightly lowered by lowering water temperature. Hydraulic conductance of stem segments decreased on the third day after harvest, and this decrease was suppressed by lowering the temperature of vase water. Bacterial number in vase water increased with time, and this increase was suppressed by lowering the temperature of vase water. These results show that low temperature of vase water might improve the stem water relation and extended the vase life of cut rose flowers.

Effect of Irrigation Frequency on Rose Flower Production and Quality

A better understanding of the effects of irrigation frequency on flower production and quality of rose plants can help to propose optimal irrigation scheduling. For this purpose, experiments were conducted on a soilless rose crop (Rosa hybrida, cv. First Red), with a closed hydroponic system, in a greenhouse located near Volos, on the continental area of eastern Greece. The plants were grown following the bending technique, on rockwool slabs. Irrigation scheduling was based on crop transpiration, and irrigation was performed whenever accumulative solar radiation outside the greenhouse reached 1600 kJ m−2 [high irrigation frequency (HIF)] and 3200 kJ m−2 (low irrigation frequency). The amount of water applied was 0·2 and 0·4 mm for high and low irrigation frequencies, respectively. Accordingly, the total water applied was equal for both cases. In order to study the effects of irrigation frequency on rose crop, measurements of fresh and dry weight of the cut flower shoots, number of harvested flowers and flowering stem's length, as well as measurements of microclimate variables were carried out. The total period of measurements ended 100 days after the last severe shoot bending (which was performed 60 days after planting). The results showed that irrigation frequency influenced cut flower fresh and dry weight, since the total fresh and dry weight of cut flower shoots measured at the end of the experimental period was about 33% higher in the HIF treatment. Statistical analysis revealed that there was no significant difference between the mean fresh or dry weight of cut flower shoots of the two treatments. As far as the number of shoots harvested is concerned, the results showed that the higher the irrigation frequency, the higher the production, as the total number of cut flowers measured at the end of the experimental period was 20·7 and 16·2 per greenhouse m−2 for high and low irrigation frequencies, respectively, namely about 28% higher in the HIF. Furthermore, the results showed that the length of rose flowering shoots was not affected by the irrigation frequency. In conclusion, it seems that the higher irrigation frequency improved the biomass production but did not affect the quality of harvested flowers.

Effects of LED and LD at Different Wavelengths on the Growth and Flowering of Roses

We cultured rose tissues under irradiation of LED and LD at different wavelengths, and examined their effects on the growth and flowering of roses. As a result, flower-bud differentiation was rarely observed under irradiation of red (660 nm) and green (517 nm) LED, but it was enhanced by irradiation of blue (465 nm) and bluegreen (502 nm) LED. In particular, flowering was observed in 76% of the samples irradiated with blue-green LED, which was the highest flowering rate. However, flowering occurred earlier by irradiation of blue LED than by that of blue-green LED, and the flowering position (node position) was lower by the former irradiation than by the latter irradiation. The irradiation of LD (445 nm) demonstrated a higher flowering rate and earlier flowering than the irradiation of LED, but the growth rate was lower by the former irradiation than by the latter irradiation. This may be because there are photoreceptors that absorb blue to blue-green light and induce flower-bud formation. Since the wavelength width of LD is smaller than that of LED, energy for the increase in the growth rate may have been suppressed, and used for the reproductive growth, resulting in the enhancement of flowering.

Shortage of Soluble Carbohydrates is Largely Responsible for Short Vase Life of Cut 'Sonia' Rose Flowers

To clarify to what extent vascular occlusion or shortage of soluble carbohydrate shortens vase life of cut 'Sonia' roses (Rosa hybrida L.), cut flowers were continuously treated with 200 mg·liter-1 8-hydroxyquinoline sulphate (HQS group), 20 g·liter-1 sucrose (Sue group) or 20 g·liter-1 sucrose plus 200 mg·liter-1 HQS (Sue + HQS group), whereas control flowers were kept in water. All cut flowers were kept at 23°C, 70% RH and 12 hr photoperiod, with 10 μmol·m-2·s-1 irradiance. Although all treatments extended the vase life, sucrose was more effective than HQS. Treatment with sucrose promoted unfolding of petals, suppressed the decrease in fresh weight of cut flowers, and inhibited the occurrence of blueing more than did HQS. Water conductivity of stem segments in the control and Sue groups decreased rapidly after harvest, but that in the HQS and Sue + HQS groups was maintained near the initial level for seven days. The number of bacteria in the stem segments increased in the control and Sue groups, but this increase was suppressed by HQS. Glucose, fructose and sucrose concentrations in petals in the Sue and Sue + HQS groups were much higher than those in the control or HQS groups. These results show that decrease in the soluble carbohydrate concentration in petals was more important than vascular occlusion in determining the vase life of cut 'Sonia' roses under our experimental conditions.

Biogenesis of 2-phenylethanol in rose flowers: incorporation of [2H8]L-phenylalanine into 2-phenylethanol and its beta-D-glucopyranoside during the flower opening of Rosa 'Hoh-Jun' and Rosa damascena Mill.

To clarify the biosynthetic pathway to 2-phenylethanol (2), the deuterium-labeled putative precursor, [2H8]L-phenylalanine ([2H8-1]), was fed to the flowers of Rosa 'Hoh-Jun' and R. damascena Mill. throughout maturation, ceasing feeding at the commencement of petal unfurling and at full bloom. Based on GC-MS analyses, [2H8]-1 was incorporated into both 2 and 2-phenylethyl beta-D-glucopyranoside (3) when the flowers were fed until full bloom, whereas no such incorporation into 2 was apparent when feeding was ceased earlier. In both species of rose, the labeling pattern for 2 was almost identical to that for 3, and indicated the presence of [2H6]-, [2H7]- and [2H8]-2, and [2H6]-, [2H7]- and [2H8]-3. This may be ascribed to the equilibrium between 2 and 3. The labeling pattern for 2 and 3 also indicated that these compounds were produced from 1 via several routes, the route involving phenylpyruvic acid being the major one.