Insect pollination of flowering plants (angiosperms) is responsible for the majority of the world's flowering plant diversity and is key to the Cretaceous radiation of angiosperms. Although both insects and angiosperms were common by the mid-Cretaceous, direct fossil evidence of insect pollination is lacking. Direct evidence of Cretaceous insect pollination is associated with insect-gymnosperm pollination. Here, we report a specialized beetle-angiosperm pollination mode from mid-Cretaceous Burmese amber (99 mega-annum [Ma]) in which a tumbling flower beetle (Mordellidae), Angimordella burmitina gen. et sp. nov., has many tricolpate pollen grains attached. A. burmitina exhibits several specialized body structures for flower-visiting behavior including its body shape and pollen-feeding mouthparts revealed by X-ray microcomputed tomography (micro-CT). The tricolpate pollen in the amber belongs to the eudicots that comprise the majority of extant angiosperm species. These pollen grains exhibit zoophilous pollination attributes including their ornamentation, size, and clumping characteristics. Tricolpate pollen grains attached to the beetle's hairs are revealed by confocal laser scanning microscopy, which is a powerful tool for investigating pollen in amber. Our findings provide direct evidence of insect pollination of Cretaceous angiosperms, extending the range insect-angiosperm pollination association by at least 50 million years. Our results support the hypothesis that specialized insect pollination modes were present in eudicots 99 million years ago.

Most orchid species exhibit an extreme case of hermaphroditism, owing to the fusion of male and female organs into a gynostemium. Exceptions to this rule have only been reported from the subtribes Catasetinae and Satyriinae. Here, I report an additional orchidaceous example whose flowers are not always hermaphroditic. In several Japanese populations of Eulophia zollingeri (Rchb.f.) J.J.Sm, a widespread Asian and Oceanian orchid, some flowers possess both the anther (i.e., anther cap and pollinaria) and stigma, whereas others possess only the stigma. Therefore, pollination experiments, an investigation of floral morphology and observations of floral visitors were conducted to understand the reproductive biology of E. zollingeri in Miyazaki Prefecture, Japan. It was confirmed that E. zollingeri studied here possesses a gynomonoecious reproductive system, a sexual system in which a single plant has both female flowers and hermaphroditic flowers. In addition, hermaphroditic flowers often possess an effective self-pollination system while female flowers could avoid autogamy but suffered from severe pollinator limitation, due to a lack of agamospermy and low insect-mediated pollination. The present study represents the first documented example of gynomonoecy within Orchidaceae. Gynomonoecy in E. zollingeri may be maintained by the tradeoff in reproductive traits between female flowers (with low fruit set but potential outcrossing benefits) and hermaphroditic flowers (with high fruit set but inbreeding depression in selfed offspring). This mixed mating is probably important in mycoheterotrophic E. zollingeri because it occurs in shaded forest understorey with a paucity of pollinators.

Floral color changes and retention of old flowers are frequently combined phenomena restricted to the floral guide or single flowers in few-flowered inflorescences. They are thought to increase the attractiveness over long distances and to direct nearby pollinators toward the rewarding flowers. In Tibouchina pulchra, a massively flowering tree, the whole flower changes its color during anthesis. On the first day, the flowers are white and on the next 3 days, they change to pink. This creates a new large-scale color pattern in which the white pre-changed flowers contrast against the pink post-changed ones over the entire tree. We describe the spectral characteristics of floral colors of T. pulchra and test bumblebees' response to this color pattern when viewed at different angles (simulating long and short distances). The results indicated the role of different color components in bumblebee attraction and the possible scenario in which this flower color pattern has evolved. We tested bumblebees' preference for simulated trees with 75% pink and 25% white flowers resembling the color patterns of T. pulchra, and trees with green leaves and pink flowers (control) in long-distance approach. We also compared an artificial setting with three pink flowers and one white flower (T. pulchra model) against four pink flowers with white floral guides (control) in short-distance approach. Bumblebees spontaneously preferred the simulated T. pulchra patterns in both approaches despite similar reward. Moreover, in short distances, pollinator visits to peripheral, non-rewarding flowers occurred only half as frequently in the simulated T. pulchra when compared to the control. Thefore, this exceptional floral color change and the retention of old flowers in T. pulchra favors the attraction of pollinators over long distances in a deception process while it honestly directs them toward the rewarding flowers at short distances possibly exploring their innate color preferences.

A total of seven phenolics and 44 metabolites was profiled in white flowers of Magnolia denudata and violet flowers of Magnolia liliiflora using high-performance liquid chromatography (HPLC), electrospray ionization-mass spectrometry (ESI-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOFMS). Seven phenylpropanoid compounds were identified in white flowers by liquid chromatography mass spectrometry (LC-MS). An HPLC analysis showed that phenylpropanoid accumulation in violet flowers was 1.48 times higher than that in white flowers. Furthermore, superoxide dismutase (SOD)-like activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were determined to investigate the antioxidant properties of secondary metabolites in different flowers. Violet flowers showed higher SOD-like and DPPH activity than white flowers. In addition, anti-inflammatory activity measured using a nitric oxide assay was higher in violet flowers than in white flowers. Our results provide valuable information on the relationship between primary and secondary metabolites, and synergistic antioxidant and anti-inflammatory properties derived from phenolic compounds in different colored flowers.

The plant kingdom is rich with a numerous number of plants with various medical properties which can be used to treat various medical issues. Sri Lanka is a country full of biodiversity which is gifted with many plant resources. It has a rich history of traditional medicine systems consisting of Ayurveda, Unani, and Deshiya Chikitsa, where these plant resources are used as remedies for the diseases. In the traditional medicine system, various plant parts such as leaves, roots, fruits, flowers, and bark are used to treat disease conditions. Although less attention is paid to the medicinal importance of the flowers, some of them have been used to treat many diseases from the ancient time. Some properties of the flowers may differ from the properties of the other plant parts. For example, Sesbania grandiflora (Katuru murunga) flowers have shown anticancer properties against various cell models whereas some flowers have shown antispermatogenic properties. Flowers of Woodfordia floribunda (Militta) are added as fermenting agents in the preparation of Arishtas in Ayurveda. Also the most popular Clove oil is obtained from the flower buds of Syzygium aromaticum (Karabu-neti) which is used to treat toothaches since it has antibiotic and antiseptic properties. This article gives an overview of herbal flowers used in the traditional medicine system of Sri Lanka and their pharmacological importance.

The images of different flower species had small inter-class variations across different classes as well as large intra-class variations within a class. Flower classification techniques are mainly based on the features of color, shape and texture, however, the procedure always involves too many heuristics as well as manual labor to tweak parameters, which often leads to datasets with poor qualitative and quantitative measures. The current study proposed a deep architecture of convolutional neural network (CNN) for the purposes of improving the accuracy of identifying the white flowers of Fragaria × ananassa from other three wild flower species of Androsace umbellata (Lour.) Merr., Bidens pilosa L. and Trifolium repens L. in fields.

Although the aesthetic appreciation of flowers is a well-known aspect of human behaviour, theories explaining its origin are missing. The only exception is the evolutionary theory of Heerwagen and Orians. Surprisingly, it has not yet been empirically tested. The authors suggest that humans aesthetically respond to flowers because they signal food availability. The logic of the theory implies that fruits are more reliable and direct food availability signals than flowers. Therefore, fruits should elicit stronger aesthetic responses than flowers. To test this assumption, we performed two online studies in the Czech Republic. The participants (n = 2792 and 744, respectively) indicated on a six-point scale their aesthetic response to photographs of 14 edible Czech plant species (study A) and 20 edible plant species from the African savannas (study B), varying in growth stage (flowering, fruiting). We found no difference between the Czech fruiting and flowering plants and a stronger aesthetic response to African flowering plants. A third study (n = 817) confirmed that flowers were preferred to fruits, using a forced-choice paradigm. Our results suggest that the theory cannot fully explain human aesthetic responses to flowers. We discuss alternative explanations. This topic deserves renewed attention from researchers working in related fields.

The flowers of Inula japonica (Inulae Flos) have long been used in traditional medicine for the treatment of inflammatory diseases. In the present study, we investigated the anti-inflammatory properties of Inulae Flos Extract (IFE).

Ethylene is a classical plant hormone and has appeared as a strong molecule managing many physiological and morphological reactions during the life of a plant. With laser-based photoacoustic spectroscopy, ethylene can be identified with high sensitivity, at a high rate and with very good selectivity. This research presents the dynamics of trace gases molecules for ethylene released by cherry flowers, apple flowers and strawberry flowers. The responses of distinctive organs to ethylene may fluctuate, depending on tissue sensitivity and the phase of plant development. From the determinations of this study, the ethylene molecules at the flowers in the nitrogen flow were established in lower concentrations when the value is correlated to the ethylene molecules at the flowers in synthetic air flow.

The morphogenesis of gynoecium is crucial for propagation and productivity of fruit crops. For trioecious papaya (Carica papaya), highly differentiated morphology of gynoecium in flowers of different sex types is controlled by gene networks and influenced by environmental factors, but the regulatory mechanism in gynoecium morphogenesis is unclear. Gynodioecious and dioecious papaya varieties were used for analysis of differentially expressed genes followed by experiments using auxin and an auxin transporter inhibitor. We first compared differential gene expression in functional and rudimentary gynoecium at early stage of their development and detected significant difference in phytohormone modulating and transduction processes, particularly auxin. Enhanced auxin signal transduction in rudimentary gynoecium was observed. To determine the role auxin plays in the papaya gynoecium, auxin transport inhibitor (N-1-Naphthylphthalamic acid, NPA) and synthetic auxin analogs with different concentrations gradient were sprayed to the trunk apex of male and female plants of dioecious papaya. Weakening of auxin transport by 10 mg/L NPA treatment resulted in female fertility restoration in male flowers, while female flowers did not show changes. NPA treatment with higher concentration (30 and 50 mg/L) caused deformed flowers in both male and female plants. We hypothesize that the occurrence of rudimentary gynoecium patterning might associate with auxin homeostasis alteration. Proper auxin concentration and auxin homeostasis might be crucial for functional gynoecium morphogenesis in papaya flowers. These results will lead to further investigation on the auxin homeostasis and gynoecium morphogenesis in papaya.

Easter lily (Lilium longiflorum) flowers have been used in traditional medicine for alleviating many ailments. However, the chemical basis of its bioactivity has not been investigated. We have determined bioactive components in Easter lily flowers using lipid peroxidation and cyclooxygenase enzyme inhibitory assays and found to be kaempferol (1), kaempferol glycosides (2, 3, 4, 8, 9 and 10), quercetin glycosides (5, 6 and 7), a regaloside (11), a chalcone (12) and a fatty acid fraction (13). The structures of compounds were determined by NMR, IR, UV/VIS and mass spectroscopic studies. Compound 1 showed the highest COX-1 inhibition (94.1%) followed by 3, 8 and 12 with 38.7, 30.8 and 32.4%, respectively. Only compound 1 inhibited COX-2 enzyme by 36.9% at 80 ppm. In lipid peroxidation inhibitory assay, kaempferol showed 37 and 100 % inhibitions at 1 and 10 ppm, respectively. At 10 ppm, more than 20% inhibition was observed for compounds 4, 7, 10, 11 and 12 and 53% for compound 3. The compounds reported in here are isolated for the first time from Easter lily flowers including novel compounds 10, 11 and 12. Our results suggest that kaempferol and quercetin flavonoids contributed to the anecdotal medicinal properties of Easter lily flowers.

Floral food bodies (including edible trichomes) are a form of floral reward for pollinators. This type of nutritive reward has been recorded in several angiosperm families: Annonaceae, Araceae, Calycanthaceae, Eupomatiaceae, Himantandraceae, Nymphaeaceae, Orchidaceae, Pandanaceae and Winteraceae. Although these bodies are very diverse in their structure, their cells contain food material: starch grains, protein bodies or lipid droplets. In Pinguicula flowers, there are numerous multicellular clavate trichomes. Previous authors have proposed that these trichomes in the Pinguicula flower play the role of 'futterhaare' ('feeding hairs') and are eaten by pollinators. The main aim of this study was to investigate whether the floral non-glandular trichomes of Pinguicula contain food reserves and thus are a reward for pollinators. The trichomes from the Pinguicula groups, which differ in their taxonomy (species from the subgenera: Temnoceras, Pinguicula and Isoloba) as well as the types of their pollinators (butterflies/flies and bees/hummingbirds), were examined. Thus, it was determined whether there are any connections between the occurrence of food trichomes and phylogeny position or pollination biology. Additionally, we determined the phylogenetic history of edible trichomes and pollinator evolution in the Pinguicula species.

Most people like symmetry, and symmetry has been extensively used in visual art and architecture. In this study, we compared preference for images of abstract and familiar objects in the original format or when containing perfect bilateral symmetry. We created pairs of images for different categories: male faces, female faces, polygons, smoothed version of the polygons, flowers, and landscapes. This design allows us to compare symmetry preference in different domains. Each observer saw all categories randomly interleaved but saw only one of the two images in a pair. After recording preference, we recorded a rating of how salient the symmetry was for each image, and measured how quickly observers could decide which of the two images in a pair was symmetrical. Results reveal a general preference for symmetry in the case of shapes and faces. For landscapes, natural (no perfect symmetry) images were preferred. Correlations with judgments of saliency were present but generally low, and for landscapes the salience of symmetry was negatively related to preference. However, even within the category where symmetry was not liked (landscapes), the separate analysis of original and modified stimuli showed an interesting pattern: Salience of symmetry was correlated positively (artificial) or negatively (original) with preference, suggesting different effects of symmetry within the same class of stimuli based on context and categorization.

Scent bouquets produced by the flowers of Petunia spp. (petunia) are composed of a complex mixture of floral volatile benzenoid and phenylpropanoid compounds (FVBPs), which are specialized metabolites derived from phenylalanine (Phe) through an interconnected network of enzymes. The biosynthesis and emission of high levels of these volatiles requires coordinated transcriptional activation of both primary and specialized metabolic networks. The petunia R2R3-MYB transcription factor ODORANT 1 (ODO1) was identified as a master regulator of FVBP production and emission; however, our knowledge of the direct regulatory targets of ODO1 has remained limited. Using chromatin immunoprecipitation followed by sequencing (ChIP-seq) in petunia flowers, we identify genome-wide ODO1-bound genes that are enriched not only in genes involved in the biosynthesis of the Phe precursor, as previously reported, but also genes associated with the specialized metabolic pathways involved in generating phenylpropanoid intermediates for FVBPs. ODO1-bound genes are also involved in methionine and S-adenosylmethionine metabolism, which could modulate methyl group supplies for certain FVBPs. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and RNA-seq analysis in an ODO1 RNAi knockdown line revealed that ODO1-bound targets are expressed at lower levels when ODO1 is suppressed. A cis-regulatory motif, CACCAACCCC, was identified as a potential binding site for ODO1 in the promoters of genes that are both bound and activated by ODO1, which was validated by in planta promoter reporter assays with wild-type and mutated promoters. Overall, our work presents a mechanistic model for ODO1 controlling an extensive gene regulatory network that contributes to FVBP production to give rise to floral scent.

The flower is one of the most complex structures of angiosperms and is essential for sexual reproduction. Current studies using molecular genetic tools have made great advances in understanding flower development. Due to the lack of available antibodies, studies investigating the localization of proteins required for flower development have been restricted to use commercial antibodies against known antigens such as GFP, YFP, and FLAG. Thus, knowledge about cellular structures in the floral organs is limited due to the scarcity of antibodies that can label cellular components. To generate monoclonal antibodies that can facilitate molecular studies of the flower, we constructed a library of monoclonal antibodies against antigenic proteins from Arabidopsis inflorescences and identified 61 monoclonal antibodies. Twenty-four of these monoclonal antibodies displayed a unique band in a western blot assay in at least one of the examined tissues. Distinct cellular distribution patterns of epitopes were detected by these 24 antibodies by immunofluorescence microscopy in a flower section. Subsequently, a combination of immunoprecipitation and mass spectrometry analysis identified potential targets for three of these antibodies. These results provide evidence for the generation of an antibody library using the total plant proteins as antigens. Using this method, the present study identified 61 monoclonal antibodies and 24 of them were efficiently detecting epitopes in both western blot experiments and immunofluorescence microscopy. These antibodies can be applied as informative cellular markers to study the biological mechanisms underlying floral development in plants.

Honeybees (Apis mellifera) pollinate flowers and collect nectar from many important crops. White clover (Trifolium repens) is widely grown as a temperate forage crop, and requires honeybee pollination for seed set. In this study, using a quantitative LC-MS (Liquid Chromatography-Mass Spectrometry) assay, we show that the cyanogenic glucosides linamarin and lotaustralin are present in the leaves, sepals, petals, anthers, and nectar of T. repens. Cyanogenic glucosides are generally thought to be defense compounds, releasing toxic hydrogen cyanide upon degradation. However, increasing evidence indicates that plant secondary metabolites found in nectar may protect pollinators from disease or predators. In a laboratory survival study with chronic feeding of secondary metabolites, we show that honeybees can ingest the cyanogenic glucosides linamarin and amygdalin at naturally occurring concentrations with no ill effects, even though they have enzyme activity towards degradation of cyanogenic glucosides. This suggests that honeybees can ingest and tolerate cyanogenic glucosides from flower nectar. Honeybees retain only a portion of ingested cyanogenic glucosides. Whether they detoxify the rest using rhodanese or deposit them in the hive should be the focus of further research.

Volatilomes emitted from edible flowers of two species of Agastache (A. aurantiaca (A.Gray) Lint & Epling, and A. mexicana (Kunth) Lint & Epling) and from two hybrids (Agastache 'Arcado Pink' and Agastache 'Blue Boa') were investigated using a solid-phase microextraction technique as well as the extraction of its essential oils. Oxygenated monoterpenes were almost always the predominant class (>85%) of volatile organic compounds (VOCs) in each sample of A. aurantiaca, A. 'Blue Boa' and A. mexicana, with the exception of A. 'Arcado Pink' (38.6%). Pulegone was the main compound in A. aurantiaca (76.7%) and A. 'Blue Boa' (82.4%), while geranyl acetate (37.5%) followed by geraniol (16%) and geranial (17%) were the principal ones in A. mexicana. The essential oil composition showed the same behavior as the VOCs both for the main class as well as the major constituent (pulegone) with the same exception for A. mexicana. Total soluble sugars, secondary metabolites (polyphenols, flavonoids and anthocyanins) and antioxidant activity were also investigated to emphasize the nutraceutical properties of these edible flowers.

Grapevine (Vitis vinifera L.) terpene synthases (VviTPS) are responsible for the biosynthesis of terpenic volatiles. Volatile profiling of nine commercial wine cultivars showed unique cultivar-specific variation in volatile terpenes emitted from grapevine flowers. The flower chemotypes of three divergent cultivars, Muscat of Alexandria, Sauvignon Blanc and Shiraz were subsequently investigated at two flower developmental stages (EL-18 and -26). The cultivars displayed unique flower sesquiterpene compositions that changed during flower organogenesis and the profiles were dominated by either (E)-β-farnesene, (E,E)-α-farnesene or (+)-valencene. In silico remapping of microarray probes to VviTPS gene models allowed for a meta-analysis of VviTPS expression patterns in the grape gene atlas to identify genes that could regulate terpene biosynthesis in flowers. Selected sesquiterpene synthase genes were isolated and functionally characterized in three cultivars. Genotypic differences that could be linked to the function of a targeted gene model resulted in the isolation of a novel and cultivar-specific single product sesquiterpene synthase from Muscat of Alexandria flowers (VvivMATPS10), synthesizing (E)-β-farnesene as its major volatile. Furthermore, we identified structural variations (SNPs, InDels and splice variations) in the characterized VviTPS genes that potentially impact enzyme function and/or volatile sesquiterpene production in a cultivar-specific manner.

The sepals, petals and stamens of Arabidopsis flowers detach via abscission zones formed at their boundaries with the underlying receptacle. The ASYMMETRIC LEAVES1 (AS1) MYB transcription factor plays a critical role in setting boundaries between newly formed leaf primordia and the shoot meristem. By repressing expression of a set of KNOTTED1-LIKE HOMEODOMAIN (KNOX) genes from developing leaf primordia, AS1 and its partner ASYMMETRIC LEAVES2 allow the patterning and differentiation of leaves to proceed. Here we show a unique role for AS1 in establishing the positions of the sepal and petal abscission zones in Arabidopsis flowers.

Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Variable annual rates of flowering and seed production were observed among meadows between northern and southern sides of the island and among years. Meadows on the northern shore consistently flowered more intensely and produced more seeds across the years of the survey. Inter-site variation in clonal diversity and size of clones, seed production, wind and surface currents during pollen and seed release, and the large, but variable, impact of seed predation are likely the principal drivers of successful recruitment into established meadows and in colonizing unvegetated sands. The prolific but variable annual reproductive investment increases the probability of low levels of continuous recruitment from seed in this seagrass, despite high rates of abiotic and biotic disturbance at seedling, shoot, and patch scales. This strategy also imparts a level of ecological resilience to this long-lived and persistent species.