Red-flowered Plants Research Articles

Investigation of Phytochemical Composition, Antioxidant and Antibacterial Activity of Five Red Flower Extracts

The presence of bioactive compounds in plants with red flowers constitutes a valuable natural resource for the food, pharmaceutical, and medical industries. This paper aims to highlight these characteristics to facilitate the selection of extracts according to market needs. The analyzed parameters can provide valuable insights into the compositional variability of the five red flower plants, as new sources of bioactive compounds and natural antioxidants of plant origin. Five plants with red flowers (Magnolia liliiflora, Chrysanthemum morifolium, Hibiscus sabdariffa, Petunia grandiflora, Rosa hybrida L.) were selected and investigated regarding their polyphenol concentration, total anthocyanins, antioxidant activity, phenolic compounds, and antimicrobial activity. Total polyphenols were found in concentrations ranging from 75.17 ± 0.16 mgGAE/g (C. morifolium) to 107.49 ± 0.19 mgGAE/g (R. hybrida L.), and total anthocyanins between 14.99 ± 0.13 mg Cy-3-Glu/g and 21.66 ± 0.18 mg Cy-3-Glu/g. The antioxidant activity DPPH/IC50 mg/mL for the extract from R. hybrida L. flowers reached a value of 29.35 ± 0.17 mg/g, with ABTS and FRAP achieving maximum values of 49.89 ± 0.24 mmol TE/g and 48.68 ± 0.23 mmol TE/g, respectively. The antibacterial activity was particularly evident against strains commonly encountered in human pathology, Escherichia coli and Staphylococcus aureus, with reduced or no impact on strains of Pseudomonas fluorescens and Proteus mirabilis. The results demonstrated that the extracts from the selected, red-flowered plants contain valuable biologically active compounds in generous quantities, thus recommending their use in the food, pharmaceutical, and medical sectors.

Molecular approaches reveal speciation between red- and blue-flowered plants in the MediterraneanLysimachia arvensisandL. monelli(Primulaceae)

AbstractFlower colour has played a decisive role as an evolutionary force in many groups of plants by driving speciation. A well-known example of colour polymorphism is found across the Mediterranean populations of Lysimachia arvensis and L. monelli, in which blue- and red-flowered plants can be found. Previous studies recognized two lineages within L. arvensis differing in flower colour, but this variation has not yet been considered in a phylogenetic context. We have reconstructed the ancestral states of flower colour across Mediterranean Lysimachia spp. aiming at understanding its phylogenetic signal using the nuclear internal transcribed spacer (ITS) sequences and three plastid markers. All blue- and red-flowered specimens were nested in different clades in the ITS tree, thus supporting that L. arvensis and L. monelli are polyphyletic, whereas low phylogenetic resolution was found in plastid markers. Monophyly was reconstructed for blue-flowered L. arvensis and L. monelli samples, and similarly for red-flowered individuals of each species: (1) blue-flowered L. arvensis was reconstructed as sister to the strictly blue-flowered L. talaverae in a monophyletic clade sister to remaining Lysimachia; (2) red-flowered L. arvensis was resolved as sister to red-flowered L. monelli in a monophyletic clade; and (3) clade 2 was sister to blue-flowered L. monelli and the strictly blue-flowered L. foemina. Our results suggest that colour lineages in L. arvensis and L. monelli constitute different species, but flower colour did not promote the separation of these lineages. We propose a new name for blue-flowered L. arvensis (L. loeflingii) and a new combination for red-flowered L. monelli (L. collina), maintaining L. arvensis for red-flowered plants and L. monelli for blue-flowered plants.

Reproductive Assurance Maintains Red-Flowered Plants of Lysimachia arvensis in Mediterranean Populations Despite Inbreeding Depression.

Flower color polymorphism, an infrequent but phylogenetically widespread condition in plants, is captivating because it can only be maintained under a few selective regimes but also because it can drive intra-morph assortative mating and promote speciation. Lysimachia arvensis is a polymorphic species with red or blue flowered morphs. In polymorphic populations, which are mostly Mediterranean, pollinators prefer blue-flowered plants to the red ones, and abiotic factors also favors blue-flowered plants. We hypothesize that the red morph is maintained in Mediterranean areas due to its selfing capacity. We assessed inbreeding depression in both color morphs in two Mediterranean populations and genetic diversity was studied via SSR microsatellites in 20 natural populations. Results showed that only 44–47% of selfed progeny of the red plants reached reproduction while about 72–91% of blue morph progeny did it. Between-morph genetic differentiation was high and the red morph had a lower genetic diversity and a higher inbreeding coefficient, mainly in the Mediterranean. Results suggest that selfing maintaining the red morph in Mediterranean areas despite its inbreeding depression. In addition, genetic differentiation between morphs suggests a low gene flow between them, suggesting reproductive isolation.

Flower colour segregation and flower discrimination under the bee vision model in the polymorphic Lysimachia arvensis

Floral colour determines pollinator behaviour, strongly affecting plant-mating systems. Lysimachia arvensis has blue- and red-flowered plants and colour inheritance remains largely unknown. A control of floral colour based on one locus, with the red allele as dominant, has been proposed. This proposal cannot explain the sporadic appearance of other floral colours in wild populations. We studied floral colour segregation in L. arvensis and assessed the possibility that pollinators can visually distinguish colour morphs by using Chittka’s hexagon model, sigmoidal model of bee discrimination and experimental studies on pollinator attendance for two years. Hand crossing between morphs originated a homogeneous F1 with salmon-coloured flowers. In the F2, blue, red, salmon morphs and other plants with intermediate colours appeared, suggesting that more than one single locus are involved in colour segregation. Results from the sigmoidal discrimination model suggest that blue, red and salmon flowers can be discriminated by pollinators. In fact, pollinators showed strong colour constancy and discriminated against the salmon morph. Our study shows that “Flower colour” is a natural marker to assess the rate of crossing between morphs. The extreme rarity of salmon flowers in wild populations and flower constancy of L. arvensis pollinators indicates assortative mating.

Flower colour divergence is associated with post-fire regeneration dimorphism in the fynbos heath Erica coccinea subsp. coccinea (Ericaceae)

The South African Cape fynbos heath Erica coccinea subsp. coccinea is polymorphic for post-fire regeneration mode (seeder/resprouter), flower colour (red/yellow), flowering time (summer-autumn/winter-spring), as well as anther size. These polymorphisms tend to occur between, rather than within, populations. Here, we aimed to understand flower colour divergence in this fynbos heath species and its association with post-fire regeneration. We tested for an association between these polymorphisms. We also examined whether yellow-flowered plants lacked anthocyanins and whether the lack of anthocyanins affected the concentration of other flavonoids, both in flowers and shoots. We found a strong association between flower colour, regeneration mode and flowering phenology. We also detected larger anthers and larger pollen in yellow- than in red-flowered plants, consistently for both resprouter and seeder regeneration strategies. Finally, we ascertained that being yellow-flowered is associated with loss in the capacity of synthesizing anthocyanins in both the flower and in the vegetative tissue. Considering that pollinator availability or preferences do probably not constitute a selection pressure, we propose that both enhanced reproductive success of anthocyaninless, yellow-flowered plants and the avoidance of likely negative pleiotropic effects (early senescence) in seeders would be key to understanding the flower colour divergence in E. coccinea subsp. coccinea.

Floral damage induces resistance to florivory in Impatiens capensis

Many plants produce defense chemicals that are induced in response to damage. In spite of the tight links between floral tissue and plant reproduction, very little is known about whether floral defenses are induced in response to floral damage. We manipulated Impatiens capensis flowers to determine whether floral damage reduces subsequent florivory, whether it induces anthocyanins or condensed tannins in floral tissues, and whether responses are localized or systemic. We damaged one flower per plant at one of three damage levels (0, 30, or 60 % tissue removal), collected subsequent flowers at set time intervals and branch locations, and measured whole-plant florivory for 3 weeks following damage. We also observed a flower color polymorphism and analyzed responses separately for red- and yellow-flowered plants. Moderate damage to a single flower reduced subsequent whole-plant florivory, but heavy damage did not. Moderate damage to a focal flower also increased anthocyanins in subsequent flowers on the same branch of red-flowered plants, but decreased anthocyanins on parallel-branch flowers of yellow-flowered plants. Damage did not affect floral tannins. Because the reduction in florivory was systemic and induced anthocyanins were not consistently induced systemically, there may be other secondary compounds not measured in this study that were systemically induced, or effects of visual or olfactory cues of damage itself that reduced subsequent florivory. This is the first study demonstrating that damage to a single flower can reduce subsequent whole-plant florivory in the field, indicating that initial damage can have cascading effects on subsequent interactions.

Flower colour polymorphism in Lysimachia arvensis: How is the red morph maintained in Mediterranean environments?

The maintenance of floral polymorphisms within natural populations is enigmatic, because directional selection imposed by biotic or abiotic selective agents combined with random genetic drift should lead to the rapid loss of floral variation. Lysimachia arvensis is a polymorphic species with red and blue flowers, red colour being genetically dominant. Both morphs show differences in fitness due to climatic factors, and the blue performs better in xeric Mediterranean environments where red-flowered plants persist in low proportion. Although the role of abiotic factors as selective agent has been studied, the selection mediated by pollinators has still not been considered. Experimental manipulations of morph frequencies were made to measure the effect of flower colour on pollinator visitation. Moreover, selection analyses on both male and female fitness were used in three populations with different morph proportions. Blue flowers are perceived by pollinators as UV-blue while red flowers are perceived as UV, but the contrast between blue flowers and the background is stronger than that of red flowers. Solitary bees were the main pollinators and exerted phenotypic selection on flower colour (quantified by bee vision) but not on flower size. Blue flowers were visited at a higher rate than expected, based on their frequency in populations. In the three populations studied, male success was markedly higher in the blue morph but colour had no consistent effect on female success. We found strong directional phenotypic selection for blue flowers through male function in the two blue-biased populations, and through female function only in the most blue-biased population. Therefore, in Mediterranean areas, not only is the blue morph favoured by climatic factors, but it is also selected by pollinators. Thus, selection by pollinators or climatic factors does not explain the maintenance of red flowered plants in Mediterranean areas. The delayed selfing mechanism of L. arvensis could offer reproductive assurance when outcross pollen is limited, mitigating the effects of both biotic and abiotic selective agents and protecting the red morph.

Investigation of the Chemomarkers Correlated with Flower Colour in Different Organs of Catharanthus roseus Using NMR‐based Metabolomics

Flower colour is a complex phenomenon that involves a wide range of secondary metabolites of flowers, for example phenolics and carotenoids as well as co-pigments. Biosynthesis of these metabolites, though, occurs through complicated pathways in many other plant organs. The analysis of the metabolic profile of leaves, stems and roots, for example, therefore may allow the identification of chemomarkers related to the final expression of flower colour. To investigate the metabolic profile of leaves, stems, roots and flowers of Catharanthus roseus and the possible correlation with four flower colours (orange, pink, purple and red). (1) H-NMR and multivariate data analysis were used to characterise the metabolites in the organs. The results showed that flower colour is characterised by a special pattern of metabolites such as anthocyanins, flavonoids, organic acids and sugars. The leaves, stems and roots also exhibit differences in their metabolic profiles according to the flower colour. Plants with orange flowers featured a relatively high level of kaempferol analogues in all organs except roots. Red-flowered plants showed a high level of malic acid, fumaric acid and asparagine in both flowers and leaves, and purple and pink flowering plants exhibited high levels of sucrose, glucose and 2,3-dihydroxy benzoic acid. High concentrations of quercetin analogues were detected in flowers and leaves of purple-flowered plants. There is a correlation between the metabolites specifically associated to the expression of different flower colours and the metabolite profile of other plant organs and it is therefore possible to predict the flower colours by detecting specific metabolites in leaves, stems or roots. This may have interesting application in the plant breeding industry.

Asymmetric pollen–pistil interactions contribute to maintaining floral colour polymorphism in a clonal aquatic plant (Butomus umbellatus L.)

Abstract Floral colour polymorphism occurs in many species throughout the angiosperms but the mechanisms of selection remain unclear. In this study, we studied the pollen–pistil interactions between different Butomus umbellatus plants, a clonal aquatic plant with red and white-flowered individuals. Results indicated that red-flowered plants have lower asexual and sexual reproductive output compared to white-flowered plants in monomorphic populations, even though there are no differences in flower characteristics and pollination systems. On the other hand, in polymorphic populations, sexual reproductive output in red-flowered plants increases while asexual reproductive output decreases considerably. However, this remains unaffected in white-flowered plants. Artificial pollination treatments revealed asymmetric pollen–pistil interactions between red and white-flowered individuals. Inter-morph crosses increase seed production only when the red-flowered plant is maternal. Moreover, pollen grains of white-flowered plants significantly enhance not only female fitness by way of greater seed yields, but also male fitness by promoting fertility of pollen on stigma within a flower. Such special pollen–pistil interactions might form one kind of balancing selection and actively maintain both genotypes of the two morphs. These findings may enrich our understanding of mechanisms of maintaining plant reproductive polymorphism.

Paclobutrazol for Height Control of Petunias

A B S T R A C T The effects of paclobutrazol on the height of Petunia × hybrida hort. ex E. Vilm. were studied. An experiment on ‘Bravo F1’ was performed at the National Institute for Agricultural Technology (INTA), San Pedro Agricultural Experimental Station (33o4’ S, 59o4’ W), Buenos Aires Province, Argentina, in the spring of 2006. Treatments consisted of three colours of flower (white, red and blue), four concentrations of paclobutrazol by irrigation (0, 5, 10 and 15 mg L -1 and three application times (at 10-12, 18-20 and 26-28 leaves). Height at 45 d after transplanting (dat), days to appearance, opening and fall of the first flower and number of flowers at 21 and 45 dat were registered. Differences between control plants due to flower colour were detected, and would indicate the need of a differential management: at 45 dat, the height of red-flowered plants (22.3 cm) was less (P < 0.05) than white- (25.2 cm) or blue-flowered plants (26.4 cm). Paclobutrazol allowed for reducing height in all treated plants. The minimal concentrations that induced maximum effects were: 10 mg L -1 for blueflowered plants (56% shortening), 5 mg L -1 for whiteflowered plants (40% shortening) and 10 mg L -1 for redflowered plants (38% shortening). In order to minimize the slightly deleterious effects detected in the number of blue and red flowers at 45 dat, early application would be advisable (10-12 leaves) for blue-flowered plants and more delayed (at 18-20 leaves) for red-flowered plants.

How Does Mimulus verbenaceus (Phrymaceae) Set Seed in the Absence of Pollinators?

Mimulus verbenaceus has successfully invaded and/or competed for the very specialized habitats of desert seeps and springs characterized by scarce or no pollinators (personal observation). It has done so by evolving an ingenious mechanism of reproductive assurance in which the senescing epipetalous corolla bends down, abscisses and slides down its style dragging its anthers over the stigma lobes, resulting in self-pollination. This dragging mechanism both depends on the plants ability to self-pollinate and presumably promotes the evolution of self-pollination by providing an advantage—invasion of new habitats—to counter-balance the disadvantages of selfing. M. verbenaceus has evolved a second means of reproductive assurance that depends on the nearness of the anthers to the stigma lobes. They are close, even touching, in the red flowers, leading to much self-pollination and are well separated in the yellow flowers leading to little self-pollination. This advantage of the red-flowered plants likely explains the relative abundance of the red morph and the rarity of the yellow morph in nature as well as the greater seed set of the red-flowered morph than that of the yellow-flowered morph.

Production of red-flowered plants by genetic engineering of multiple flavonoid biosynthetic genes

Orange- to red-colored flowers are difficult to produce by conventional breeding techniques in some floricultural plants. This is due to the deficiency in the formation of pelargonidin, which confers orange to red colors, in their flowers. Previous researchers have reported that brick-red colored flowers can be produced by introducing a foreign dihydroflavonol 4-reductase (DFR) with different substrate specificity in Petunia hybrida, which does not accumulate pelargonidin pigments naturally. However, because these experiments used dihydrokaempferol (DHK)-accumulated mutants as transformation hosts, this strategy cannot be applied directly to other floricultural plants. Thus in this study, we attempted to produce red-flowered plants by suppressing two endogenous genes and expressing one foreign gene using tobacco as a model plant. We used a chimeric RNAi construct for suppression of two genes (flavonol synthase [FLS] and flavonoid 3'-hydroxylase [F3'H]) and expression of the gerbera DFR gene in order to accumulate pelargonidin pigments in tobacco flowers. We successfully produced red-flowered tobacco plants containing high amounts of additional pelargonidin as confirmed by HPLC analysis. The flavonol content was reduced in the transgenic plants as expected, although complete inhibition was not achieved. Expression analysis also showed that reduction of the two-targeted genes and expression of the foreign gene occurred simultaneously. These results demonstrate that flower color modification can be achieved by multiple gene regulation without use of mutants if the vector constructs are designed resourcefully.

Environment and pollinator‐mediated selection on parapatric floral races of Mimulus aurantiacus

We tested whether selection by pollinators could explain the parapatric distribution of coastal red- and inland yellow-flowered races of Mimulus aurantiacus (Phrymaceae) by examining visitation to natural and experimental populations. As a first step in evaluating whether indirect selection might explain floral divergence, we also tested for local adaptation in early life stages using a reciprocal transplant experiment. Hummingbirds visited flowers of each race at similar rates in natural populations but showed strong (>95%) preference for red flowers in all habitats in experimental arrays. Hawkmoths demonstrated nearly exclusive (>99% of visits) preference for yellow flowers and only visited in inland regions. Strong preferences for alternative floral forms support a direct role for pollinators in floral divergence. Despite these preferences, measures of plant performance across environments showed that red-flowered plants consistently survived better, grew larger and received more overall pollinator visits than yellow-flowered plants. Unmeasured components of fitness may favour the yellow race in inland habitats. Alternatively, we document a marked recent increase in inland hummingbird density that may have caused a change in the selective environment, favouring the eastward advance of red-flowered plants.

Inheritance of Flower Color in Anagallis monelli L.

Plants of Anagallis monelli in their native habitat or in cultivation have either blue or orange flowers. Clonally propagated cultivars, seed obtained from commercial sources and the resulting plants were grown in a greenhouse at the University of New Hampshire. F2 progeny obtained from hybridization between blue- and orange-flowered plants had blue, orange or red flowers. There were no significant differences in petal pH of orange-, blue-, and red-flowered plants that could explain the differences in flower color. Anthocyanidins were characterized by high-performance liquid chromatography. Results indicated that blue color was due to malvidin, orange to pelargonidin, and red to delphinidin. Based on our segregation data, we propose a three-gene model to explain flower color inheritance in this species.

The Relationship Between Genotypes at the Red Flower Colour Loci (R1/R1 and R2/R2) and Four Basic Flower Colour Forms in Zonal Pelargoniums (&lt;I&gt;Pelargonium X Hortorum &lt;/I&gt;L.H. Bailey)

The relationship between genotypes at two red flower colour loci (R1/rl and R2/r2) and four basic flower colour forms (red, salmon, rose-pink and soft-pink) in zonal pelargoniums (Pelargonium x hortorum Bailey L.H.) was studied using complementation tests. The results confirmed that red flower colour is due to complementary gene interaction at the two loci hence R1-R2 plants with rose-pink and salmon colored flowers always complemented each other to produce red-flowered plants among theprogenies. The two flower colour forms were also the only ones that complemented each other to produce red-flowered progeny. The genotypes r1r1R2 and r1r1r2r2 always corresponded to salmon, rose-pick and soft-pink flower colours respectively. Thus genotypes at the two red flower colour loci (R1/r1 and R2/r2) were also directly responsible for salmon, rose-pink and soft-pink flower colours in zonal pelargoniums. UNISWA Research Journal of Agriculture, Science and Technology Vol 3 (2) 2000: pp 66-70

Non-reversion of Impatiens in the absence of meristem commitment

Purple-flowered plants of Impatiens balsamina maintained floral development on transfer from inductive short days (SD) to long days (LD), a treatment in which red-flowered plants of Impatiens are known to revert to leaf production. An investigation into the nonreverting nature of purple-flowered plants was carried out to establish whether these plants achieved meristem commitment or whether their non-reverting state was controlled by the leaves. When the leaves that had unfolded during the inductive SD treatment were removed at the time of transfer to LD, the purpleflowered plants did revert. This result suggests that, as in red-flowered Impatiens, meristem commitment is absent, but that purple-flowered plants maintain flowering in LD conditions because of a more permanent supply of signal from their leaves than occurs in red-flowered plants. A working hypothesis is proposed to explain how a signal from the leaves can retain a controlling role during flower development.

Non-reversion of Impatiens in the absence of meristem commitment

Purple-flowered plants of Impatiens balsamina maintained floral development on transfer from inductive short days (SD) to long days (LD), a treatment in which red-flowered plants of Impatiens are known to revert to leaf production. An investigation into the non-reverting nature of purple-flowered plants was carried out to establish whether these plants achieved meristem commitment or whether their non-reverting state was controlled by the leaves. When the leaves that had unfolded during the inductive SD treatment were removed at the time of transfer to LD, the purple-flowered plants did revert. This result suggests that, as in red-flowered Impatiens, meristem commitment is absent, but that purple-flowered plants maintain flowering in LD conditions because of a more permanent supply of signal from their leaves than occurs in red-flowered plants. A working hypothesis is proposed to explain how a signal from the leaves can retain a controlling role during flower development.

Variation and Taxonomy of Aesculus pavia L. (Hippocastanaceae) in Texas

The status of Aesculus pavia var. flavescens, a set of yellow-flowered populations endemic to the Edwards Plateau of central Texas, was evaluated on the basis of comparative morphology, geography, flowering phenology, and pollination ecology. Plants of typical A. pavia have red, tubular flowers with exserted stamens and are effectively pollinated by ruby-throated hummingbirds. Plants of var. flavescens have yellow, campanulate flowers with included stamens that can be pollinated effectively by large bees. These ethological reproductive isolating mechanisms are further augmented by a difference in flowering time between the two sets of populations and by geographical restriction of the yellow-flowered plants to localities on the Edwards Plateau. The yellow and red-flowered plants constitute two morphologically distinct groups, despite evidence of limited introgression in counties along the Balcones Escarpment. A yellow-flowered plant discovered in coastal east Texas may indicate the mechanism by which var. flavescens originated, but this plant is much more closely comparable to typical red-flowered var. pavia than to the yellow-flowered plants on the Edwards Plateau. An evolutionary history of section Pavia of Aesculus is presented, and it is concluded that the yellow-flowered plants of central Texas are best regarded as a taxonomic variety.

The Primary Color-Factors of Lychnis and Color-Inhibitors of Papaver Rhoeas

Dominant and recessive whites have been discovered in a number of different plants and animals. Both the dominant whites and the recessive whites may be of different kinds, though externally indistinguishable. Dominance does not necessarily indicate presence of an added gene, but when the absence of a character appears to be dominant over its presence, the action of an inhibiting factor may usually be inferred. An alternative hypothesis is always available, however, which should prevent a too dogmatic assertion that dominance is synonymous with presence. A white-flowered form (Melandrium album) of Lychnis dioica L. from Germany, when crossed with the purple-flowered form (M. rubrum) from the same country, produced 23 white-flowered and 4 purple-flowered offspring, but in certain crosses with a white-flowered strain derived from plants growing at Cold Spring Harbor, the German white-flowered plants produced purple-flowered offspring in the F1, in other crosses only white-flowered offspring were produced. In the "Shirley" poppies (Papaver Rhoeas L.), the presence of a white margin of the petals is a dominant character and is probably due to an inhibitor limited in its effective action to the margins of the petals. These white margins and doubleness of the flowers are the only characters in the garden poppies which were found dominant over the corresponding characters of the wild type from which they were derived. They may represent the results of progressive mutations, but here again caution is necessary because of the alternative hypothesis. There is also an inhibitor which affects the body of the petals in the "Shirley" poppies, producing what is essentially a dominant white, though the inhibition is often very imperfect, in which case the flowers are more or less washed and striated with color, though generally whitish. This supposed inhibitor was evident only in crosses involving at least one red-flowered or striated parent. The same white-flowered plant which was a dominant white in crosses with red-flowered and striated plants was a recessive white in crosses with pink-flowered and red-orange-flowered plants. In several cases red-flowered plants crossed together produced a whitish progeny and a similar result was produced when two striated plants were mated or when striated was crossed with red. Two hypotheses to account for these facts are considered: (a) that there is one inhibitor affecting only the pure spectrum-red and having no effect on pink and red-orange; the minus-fluctuations of this inhibitor pass the limit of visibility; (b) that there are two factors, A and B, which have no visible effect when existing alone, but which act as an inhibitor when brought together. These two hypotheses must be tested by further breeding.