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The natural pollinator of the major species of commercially-grown vanilla, Vanilla planifolia, is unknown, and the crop requires hand pollination to achieve significant levels of fruit set; however, the traditional technique (using a toothpick) is costly, as it requires skilled personnel. To overcome this problem, two native Australian bees, Tetragonula carbonaria and Austroplebeia australis, and the blowfly, Lucilia cuprina, were trialled as pollinators. Three alternatives to the toothpick method were also trialled. The appearance of vanilla flowers under ultraviolet radiation was examined to determine the presence of cryptic pollination guides, and the chemical composition of nectar from extrafloral nectaries and aroma volatiles from the flowers were characterised. None of the three insects effected pollination due to their small size and behaviour; other insect pollinators need to be identified. The alternative mechanical methods of pollination trialled resulted in fruit set; however, the percentages of fruit set were lower than the traditional toothpick method, and the fruit were of inferior quality. The nectar produced predominantly consisted of sucrose and melezitose. Melezitose is a strong attractant of various ant species, which may explain the concentration of ants around the nectaries and the apparent lack of nectar production in part of this study. The aroma volatiles included monoterpenoids, terpenes, sesquiterpenoids, aromatics, nitrogen-containing compounds and fatty acids, the most abundant being a-pinene and eucalyptol. Illumination of the flowers with UV-A radiation revealed fluorescence from the stamens, the column and the callus, which is located on the labellum. These observations may aid the identification and use of potential pollinators. [ABSTRACT FROM AUTHOR]

Background: Nectar is offered by numerous flowering plants to attract pollinators. To date, the production and secretion of nectar have been analyzed mainly in eudicots, particularly rosids such as Arabidopsis. However, due to the enormous diversity of flowering plants, further research on other plant species, especially monocots, is needed. Ananas comosus (monocot) is an economically important species that is ideal for such analyses because it produces easily accessible nectar in sufficient quantities. In addition, the analyses were also carried out with Nicotiana tabacum (dicot, asterids) for comparison. Results: We performed transcriptome sequencing (RNA-Seq) analyses of the nectaries of Ananas comosus and Nicotiana tabacum, to test whether the mechanisms described for nectar production and secretion in Arabidopsis are also present in these plant species. The focus of these analyses is on carbohydrate metabolism and transport (e.g., sucrose-phosphate synthases, invertases, sucrose synthases, SWEETs and further sugar transporters). In addition, the metabolites were analyzed in the nectar, nectaries and leaves of both plant species to address the question of whether concentration gradients for different metabolites exist between the nectaries and nectar The nectar of N. tabacum contains large amounts of glucose, fructose and sucrose, and the sucrose concentration in the nectar appears to be similar to the sucrose concentration in the nectaries. Nectar production and secretion in this species closely resemble corresponding processes in some other dicots, including sucrose synthesis in nectaries and sucrose secretion by SWEET9. The nectar of A. comosus also contains large amounts of glucose, fructose and sucrose and in this species the sucrose concentration in the nectar appears to be higher than the sucrose concentration in the nectaries. Furthermore, orthologs of SWEET9 generally appear to be absent in A. comosus and other monocots. Therefore, sucrose export by SWEETs from nectaries into nectar can be excluded; rather, other mechanisms, such as active sugar export or exocytosis, are more likely. Conclusion: The mechanisms of nectar production and secretion in N. tabacum appear to be largely similar to those in other dicots, whereas in the monocotyledonous species A. comosus, different synthesis and transport processes are involved. [ABSTRACT FROM AUTHOR]

Plants use extrafloral nectaries (EFNs) as indirect defence mechanisms against herbivores. These structures contain nectar that is offered to ants in exchange for their protection. EFNs display pronounced functional variation, but it is unknown how this variation comes together in phenotypes. Here, we characterized the main functional traits of EFNs and investigated the associations among them. This work was conducted at a study site in the Caatinga that hosts 14 species of woody plants. We characterized the following functional traits: EFN type, position, arrangement, size, and reducing-sugar level. We observed a marked degree of trait variation (~30%) that was manifested in species-specific trait combinations, giving rise to an 'ecological spectrum'. At one end were Fabaceae species with large, vascularized EFNs that occur individually on the leaf petiole and/or rachis and that produce high levels of reducing sugars. At the other end were Euphorbiaceae species with small, nonvascularized EFNs that are generally grouped on the leaf blade and that produce low levels of reducing sugars. Despite its limited geographical and phylogenetic scale, this study represents an important first step in describing an ecological spectrum that can inform our understanding of the ecological interactions and evolutionary history of this functionally relevant group of plants. [ABSTRACT FROM AUTHOR]

While floral signaling plays a central role in the reproductive success of all animal‐pollinated plants, it may also attract herbivores eager to feed on flowers. False nectaries with glossy surfaces reflecting incident light may produce signals that attract floral visitors guiding their movements to and within the flower. Whether false nectaries also attract herbivores that lower the reproductive success of natural populations requires attention. In this study, we focus on Parnassia wightiana, a subalpine species with a whorl of staminodes that act as false nectaries attracting bees, flies, and herbivorous beetles. We tested the functions of staminodes using controlled manipulative experiments under field and lab conditions. We found a significant decrease in pollinator visits, and subsequent seed set, in flowers in which we removed staminodes or staminode apices confirming the function of these organs. In our natural populations, we found that a beetle, Nonarthra variabilis (Alticinae; Chrysomelidae), chews first on staminode apices, then it eats the entire staminodes and other flower parts, but rarely feeds on ovaries. Additional experiments suggested these beetles preferred staminodes to ovaries. Our results suggest this is a case of selective florivory, in which staminodes play a dual role, attracting pollinators and herbivores at the same time causing the attractive dilemma. Although selective florivory by beetles did not directly damage fruits, it influenced plant‐pollinator interactions, decreasing reproductive success in plant populations. Our study highlights the importance of plant‐pollinator‐herbivore interactions in selecting floral traits. [ABSTRACT FROM AUTHOR]

Violafuscopurpurea (Violaceae), a new species from Karst landform of Chongqing in China, is described and illustrated. The new species is most similar to V. fukienensis, but can be distinguished by nearly glabrous, shiny, adaxially purple blades (vs pubescent, adaxially green blades), brown seeds with conspicuous tubercles (versus yellow seeds with smooth surface), and hook‐like nectaries (versus triangular nectaries), as well as by general habit. Our phylogenetic analysis, based on ITS sequences, confirms that the new species belongs to V. subsect. Rostratae, and is most closely related to V. fukienensis in the phylogeny. [ABSTRACT FROM AUTHOR]

Plant species bearing extrafloral nectaries (EFNs) may indirectly influence other plant species by sharing protective ants, potentially altering herbivory levels. However, the propagation of indirect effects in this type of mutualism has seldom been investigated.We investigated indirect effects via ant sharing among 21 EFN‐bearing plant species of the tribe Bignonieae distributed on 28 plots in the central Brazilian Amazon. We used an ecological network index to quantify potential indirect effects among plant species through shared dominant and subordinate ant species.Plant species that were more attractive to ants (promoter species) had the highest potential to indirectly influence ant visitation to less attractive plant species (receptor species) in the community, primarily through changes in the attraction of dominant ant species. However, these potential indirect effects did not result in significant differences in herbivory patterns among the studied plants. Ant attendance and herbivory levels were similar among promoter species, neighbouring plants, and non‐neighbouring plants. Unlike other mutualisms involving plants (e.g., pollination), the indirect effects among plant species that share protective ants had limited consequences. The low levels of herbivory and the small foraging areas of shared ant defenders could be responsible for the observed limited impact of indirect interactions among plant species in this system.Synthesis: This study demonstrates that plant species with EFNs can indirectly influence other plant species through ant sharing. The attractiveness of certain plants to ants enables them to affect the ant visitation patterns of less attractive plants in the community. However, these indirect effects did not significantly alter herbivory levels among plants. Overall, this study advances ecological understanding by showing that the sharing of protective ants among plant species can in some cases confer limited costs and benefits, leading indirect interactions to have minimal impact on herbivory patterns. [ABSTRACT FROM AUTHOR]

Abstract Background Nectar is offered by numerous flowering plants to attract pollinators. To date, the production and secretion of nectar have been analyzed mainly in eudicots, particularly rosids such as Arabidopsis. However, due to the enormous diversity of flowering plants, further research on other plant species, especially monocots, is needed. Ananas comosus (monocot) is an economically important species that is ideal for such analyses because it produces easily accessible nectar in sufficient quantities. In addition, the analyses were also carried out with Nicotiana tabacum (dicot, asterids) for comparison. Results We performed transcriptome sequencing (RNA-Seq) analyses of the nectaries of Ananas comosus and Nicotiana tabacum, to test whether the mechanisms described for nectar production and secretion in Arabidopsis are also present in these plant species. The focus of these analyses is on carbohydrate metabolism and transport (e.g., sucrose-phosphate synthases, invertases, sucrose synthases, SWEETs and further sugar transporters). In addition, the metabolites were analyzed in the nectar, nectaries and leaves of both plant species to address the question of whether concentration gradients for different metabolites exist between the nectaries and nectar The nectar of N. tabacum contains large amounts of glucose, fructose and sucrose, and the sucrose concentration in the nectar appears to be similar to the sucrose concentration in the nectaries. Nectar production and secretion in this species closely resemble corresponding processes in some other dicots, including sucrose synthesis in nectaries and sucrose secretion by SWEET9. The nectar of A. comosus also contains large amounts of glucose, fructose and sucrose and in this species the sucrose concentration in the nectar appears to be higher than the sucrose concentration in the nectaries. Furthermore, orthologs of SWEET9 generally appear to be absent in A. comosus and other monocots. Therefore, sucrose export by SWEETs from nectaries into nectar can be excluded; rather, other mechanisms, such as active sugar export or exocytosis, are more likely. Conclusion The mechanisms of nectar production and secretion in N. tabacum appear to be largely similar to those in other dicots, whereas in the monocotyledonous species A. comosus, different synthesis and transport processes are involved.

Background and aims: Several works have shown that the petiole possesses useful anatomical characteristics for differentiating groups. Therefore, we carried out a descriptive and comparative anatomical study of the basal, middle, and apical regions of the petiole of 16 species belonging to 8 genera of Polypodioideae growing in Mexico, to identify anatomical characters that can contribute to their delimitation and identification M&M: Samples were collected from the basal, middle, and apical regions of the petiole and processed according to the paraffin embedding technique to obtain permanent preparations. The generated information was evaluated through a clustering analysis and a principal component analysis. Results: All petioles showed an unistratified epidermis, a cortex differentiated into external and internal, and vascular bundles with Polypodium-type distribution. Differences were registered in the petiole diameter, indument type, circumendodermal band, and number of vascular bundles. Four types of external cortex are recognized and the presence of nectaries in Campyloneurum amphostenon and C. costatum is reported for the first time, as well as the glandular hairs inserted at the base of the scales in Microgramma percussa. Identification keys were elaborated. Conclusions: The anatomical characteristics of the petiole allow us to differentiate taxonomically the genera and most of the species analyzed, the most important traits being the petiole diameter, the characteristics of the circumendodermal band, and the presence of aerophores and/or wings. [ABSTRACT FROM AUTHOR]

The diversification of hummingbirds (Trochilidae) has shaped the pollination strategies and floral trait evolution in at least 68 families of flowering plants in the Western Hemisphere. The trumpet creeper (Bignoniaceae) is the quintessential example of ornithophily in eastern North America. The mutualistic relationship between this orange‐flowered liana and the ruby‐throated hummingbird (Archilochus colubris) was illustrated as early as 1731. However, neither historical nor modern accounts accurately describe the feeding behavior of ruby‐throats at trumpet creeper flowers or the floral adaptations for ornithophily. This paper explores their surprisingly immersive mode of foraging at trumpet creeper flowers and quantitatively assesses floral traits in two populations in the Ozark Mountains. The ruby‐throat's bill is approximately one‐third the length of the trumpet‐shaped flowers, which counters the tendency for the corolla length of ornithophilous plants to match the bill length of their principal hummingbird pollinator. To access the nectary, ruby‐throats grasp or cling to the ventral petal lobe of the corolla with their claws and thrust their head and upper body into the flower. This immersive "floral‐diving" had not been formally documented among the 356 species of hummingbirds until now. The didynamous anthers and stigma are strategically positioned inside the corolla to brush the crown feathers when the ruby‐throat inserts its head. A narrow stricture in the corolla, about a third of the way up, allows the bill and tongue of hummingbirds to pass while blocking bumblebees and carpenter bees from reaching the nectary. As a result, the abundant sucrose‐rich floral nectar seems to be reserved for hummingbird pollinators. [ABSTRACT FROM AUTHOR]

Floral diversity of Croton, the second largest genus in Euphorbiaceae, is currently under-explored. Several clades demonstrate an unusual floral morphology, e.g., lower or higher stamen number, bilateral symmetry and reduced ovary, but have never been investigated in a comparative study with typical Croton. This study examined morphology and ontogeny of flowers in nine Croton species from different clades within the genus with light and scanning microscopy, resin sectioning and micro-computed tomography. In staminate flowers, great variations of stamen number and arrangement are observed. The ancestral androecium likely consisted of two or more whorls with the outermost antepetalous stamen whorl developing centrifugally. Modification by reduction of the antepetalous whorl resulted in an outer alternipetalous stamen whorl in Croton section Moacroton, subgenus Quadrilobi. Several species in the subgenus Geiseleria show an independent reduction of stamen numbers by absence of a centrifugal development with the antepetalous whorl the first whorl to develop. Petal losses are observed in the distantly related C. setiger and C. dioicus. Chaotic stamen arrangement is found in C. celtidifolius (subgenus Adenophylli) as a result of a secondary stamen increase. In pistillate flowers, reduction of carpel numbers happened three times in the subgenus Geiseleria. C. monanthogynus has a bicarpellate ovary, while in C. setiger and C. michauxii the ovary is monocarpellate. Reduction of carpel number is linked with merism change and perianth reduction. The ovary in C. michauxii has basal placentation which is unique among all Croton. Moreover, strong bilateral sepals and nectaries are observed in species from section Julocroton. Therefore, the floral diversity of some species in the genus Croton could be explained by developmental modification of an ancestral form via reduction, rearrangement of stamen whorls, and symmetry shifts. [ABSTRACT FROM AUTHOR]

Mutualistic symbioses between ants and plants are widespread in nature. Ants can deter unwanted pests and provide protection for plants in return for food or housing rewards. Using a long‐term demographic dataset in a tropical seasonal rain forest in Southwest China, we found that associations with ants positively influenced seedling survival and adult growth, and also, species with extrafloral nectaries experienced weaker conspecific negative density dependence compared with species without extrafloral nectaries. Furthermore, we found strong evidence suggesting that species in our forest experienced conspecific density dependence, which we interpreted as heavy pest pressure that may drive the development of anti‐pest symbioses such as the plant–ant relationship. Our findings suggest that ants and conspecific neighbors play important but inverse roles on plant survival and growth and that ants can buffer tree neighborhood interactions in this tropical forest. [ABSTRACT FROM AUTHOR]

Attracting pollinators to achieve successful reproduction is a key challenge for wild plants that may be disturbed by complex multispecies interactions in nature. Pairwise plant–pollinator interactions have traditionally been studied for decades, while ignoring other ecological players may obscure a comprehensive understanding on how plants recruit partners or combat enemies in the pollination process. Hence, integrated studies considering the inherent complexity of ecological interactions are needed, which may open up new perspectives for deciphering intricate systems and predicting ecological consequences.We examined the presence of nectar yeasts using a combination of high‐throughput sequencing, cultivation and microscopy and quantified floral herbivory by evaluating the incidence of flowers with visible holes in 13 natural populations of Iris bulleyana in the Hengduan Mountains of southwest China during 2017–2022. We combined yeast inoculation and herbivore manipulation treatments to illustrate the isolated and combined impacts of two contrasting nectarivorous organisms, the ascomycetous yeast Metschnikowia reukaufii and adult sawflies, on pollinator visitation and plant reproductive success in two populations. In the lab, we first employed gas chromatography–mass spectrometry to profile the volatile metabolites of yeast‐inoculated nectar relative to control, followed by a behavioural bioassay to test the preference of honeybees for these microbial volatiles.Yeasts commonly inhabited floral nectar and insect herbivores frequently bit holes in the perianth tube to consume nectar and nectaries. Nectar yeasts indirectly facilitated plant reproduction through increased pollinator visits, probably because of microbial metabolism as honeybees preferred nectar volatiles produced by yeasts in behavioural bioassays. Insect herbivores increased total floral visits but reduced legitimate visits by inducing legitimate‐to‐robbing behavioural changes of honeybees, thus leading to lower seed production. The detrimental effect of herbivory was mitigated by the presence of yeasts, which diminished the relative proportion of robbing visits and thereby 'rescued' flowers from reproductive failure.Synthesis: Overall, we found contrasting effects of non‐pollinator species, including both micro‐ and macro‐organisms, on plant–pollinator interactions in a biodiversity hotspot, where pollination deficit may be a ubiquitous phenomenon. Our findings suggest that both microbial and herbivory effects are likely to be important in explaining the exact causes of pollen limitation in species‐rich areas, highlighting the biological context dependence of species interactions in natural ecosystems. [ABSTRACT FROM AUTHOR]

Rocklands are present in South Florida, both on the peninsula and in the Keys. Previous work has shown that extrafloral nectaries on pine rockland plants in the Florida Everglades and surrounding areas play a role in attracting ant protectors. Species with nectaries are more abundant and ant activity greater in more recently burned pine rockland habitats compared with longer undisturbed rockland hammock forest. The floristic composition and prevailing climate of Keys rocklands differs substantially from those on the mainland, so we sought to investigate ant activity and the abundance of plants with extrafloral nectaries in Big Pine Key rockland habitats. Standard baiting methods were used to assess ant abundance and potential predation activity in hardwood hammock, shrubby pine rockland, and open pine rockland sites. Ant activity was the lowest in open pine rockland, greatest in hardwood hammock, and intermediate in shrubby pine rockland, the opposite of what has been observed in previous studies in southern peninsular Florida and on Andros, Bahamas. Sampling vegetation at these same sites revealed a larger proportion of plant species with extrafloral nectaries in the pine rocklands than the hammock, as observed previously in Everglades habitats. Possible reasons for differences in ant activity in Keys rockland habitats are discussed. [ABSTRACT FROM AUTHOR]

Discussing homology relationships among secretory structures remains a relatively underexplored area in botanical research. These structures are widely dispersed within Malpighiales, one of the largest orders of eudicots. Within Malpighiales, both extranuptial and nuptial nectaries are present, and they do not seem homoplastic or share evolutionary connections. Particularly in Malpighiaceae, extensive research has focused on the ecological interactions mediated by glands. Botanists largely agree that elaiophores in sepals of Neotropical Malpighiaceae have evolved from extrafloral nectaries on leaves. However, the evolutionary origin of elaiophores has yet to be thoroughly examined, particularly in comparison to outgroups. This study provides empirical evidence on the ontogeny of elaiophores and investigates their evolutionary origins and homology relationships across different lineages of Malpighiales using comparative anatomy. Our findings suggest that elaiophores are likely homologous to extranuptial nectaries found in sepals of other Malpighiales lineages, originating from nectaries on leaves. This discussion is a starting point for future studies exploring the evolution of nectaries found in flowers, whether extranuptial or nuptial, and their potential origins from nectaries in vegetative organs such as leaves. Understanding these relationships could shed light on the selective pressures influencing floral morphologies. [ABSTRACT FROM AUTHOR]

Front cover: A puffed‐up fugu is wrestling with a toad. The body of the fugu has numerous spots that look like insulin secretory granules and a nucleus‐like pattern, just like the pancreatic β‐cells. Perhaps triggered by the wrestling, the fugu's body releases insulin. Inspired by a review article in this journal (Izumi (2023). Multiple pathways and independent functional pools in insulin granule exocytosis. Genes Cells 28: 471‐481, DOI: 10.1111/gtc.13029). Designed by TRAIS Co., Ltd. (Kobe, Japan). [ABSTRACT FROM AUTHOR]

Plant–herbivore interactions reciprocally influence species' evolutionary trajectories. These interactions have led to many physical and chemical defenses across the plant kingdom. Some plants have even evolved indirect defense strategies to outsource their protection to ant bodyguards by bribing them with a sugary reward (nectar). Identifying the evolutionary processes underpinning these indirect defenses provide insight into the evolution of plant-animal interactions. Using a cross-kingdom, phylogenetic approach, we examined the convergent evolution of ant-guarding nectaries across ferns and flowering plants. Here, we discover that nectaries originated in ferns and flowering plants concurrently during the Cretaceous, coinciding with the rise of plant associations in ants. While nectaries in flowering plants evolved steadily through time, ferns showed a pronounced lag of nearly 100 My between their origin and subsequent diversification in the Cenozoic. Importantly, we find that as ferns transitioned from the forest floor into the canopy, they secondarily recruited ant bodyguards from existing ant-angiosperm relationships. Some plants use nectar to attract ant bodyguards. Here, the authors use a cross-kingdom phylogenetic approach to find that ferns and angiosperms evolved nectaries in the Cretaceous, coinciding with ant evolution, and that ferns recruited ant-bodyguards from existing ant-angiosperm partnerships. [ABSTRACT FROM AUTHOR]

Fritillaria yalcinii (Liliaceae) is described as a new species from Diyarbakır Province, southeastern Turkey. It is superficially similar to F. carica, F. forbesii, F. minima, F. minuta, F. mughlae and F. sibthorpiana, but differs in several morphological characters, such as leaves, perigon, nectary, filament, stigma and anther. Diagnostic characteristics, a comprehensive description, photographs, geographical distribution, conservation assessment, observations and a distribution map are provided. [ABSTRACT FROM AUTHOR]

Extrafloral nectaried plants and myrmecophytes offer resources to ants that engage in protective mutualisms. The role of different ant species in herbivore deterrence has long been analyzed by using insect baits, and ants are regarded as effective plant guards if they attack the insects. Here, by performing a literature review, we conducted a comparative investigation on which ants display aggression toward experimental prey, which ants are better plant guards, and which plants (extrafloral nectaried plants or myrmecophytes) are better defended by ants. Data revealed that studies evaluating ant aggression toward insect baits have been performed on 37 extrafloral nectaried plant species and 19 myrmecophytes, and have involved over 30 genera of ants. Extrafloral nectaried plants and myrmecophytes rely on specific ant fauna to defend them from herbivores. In extrafloral nectaried plants, Camponotus and Crematogaster were regarded as the best plant protectors, as they attacked insects in nearly all plants. In myrmecophytes, Azteca, Pheidole, and Pseudomyrmex were the most important insect attackers. Myrmecophytes were better protected by ants, as all insects were attacked; in extrafloral nectaried plants, some ants failed to attack the insects. Plants are patrolled by several different ants, but there is a core of ants that excel in protection, and this varies according to plant type (extrafloral nectaried plants and myrmecophytes). With this knowledge, it may be possible to label different ants as effective plant guards, to anticipate their effects on plant performance, and even to understand their potential role as biological control agents. [ABSTRACT FROM AUTHOR]

Background and Aims Extrafloral nectaries are nectar-secreting structures present on vegetative parts of plants which provide indirect defences against herbivore attack. Extrafloral nectaries in Clerodendrum chinense are patelliform-shaped specialized trichomatous structures. However, a complete understanding of patelliform extrafloral nectaries in general, and of C. chinense in particular, has not yet been established to provide fundamental insight into the cellular physiological machinery involved in nectar biosynthesis and secretory processes. Methods We studied temporal changes in the morphological, anatomical and ultrastructural features in the architectures of extrafloral nectaries. We also compared metabolite profiles of extrafloral nectar, nectary tissue, non-nectary tissue and phloem sap. Further, both in situ histolocalization and normal in vitro activities of enzymes related to sugar metabolism were examined. Key Results Four distinct tissue regions in the nectar gland were revealed from histochemical characterization, among which the middle nectariferous tissue was found to be the metabolically active region, while the intermediate layer was found to be lipid-rich. Ultrastructural study showed the presence of a large number of mitochondria along with starch-bearing chloroplasts in the nectariferous region. However, starch depletion was noted with progressive maturation of nectaries. Metabolite analysis revealed compositional differences among nectar, phloem sap, nectary and non-nectary tissue. Invertase activity was higher in secretory stages and localized in nectariferous tissue and adjacent region. Conclusions Our study suggests extrafloral nectar secretion in C. chinense to be both eccrine and merocrine in nature. A distinct intermediate lipid-rich layer that separates the epidermis from nectary parenchyma was revealed, which possibly acts as a barrier to water flow in nectar. This study also revealed a distinction between nectar and phloem sap, and starch could act as a nectar precursor, as evidenced from enzymatic and ultrastructural studies. Thus, our findings on changing architecture of extrafloral nectaries with temporal secretion revealed a cell physiological process involved in nectar biosynthesis and secretion. [ABSTRACT FROM AUTHOR]

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The Ranunculales are a hyperdiverse lineage in many aspects of their phenotype, including growth habit, floral and leaf morphology, reproductive mode, and specialized metabolism. Many Ranunculales species, such as opium poppy and goldenseal, have a high medicinal value. In addition, the order includes a large number of commercially important ornamental plants, such as columbines and larkspurs. The phylogenetic position of the order with respect to monocots and core eudicots and the diversity within this lineage make the Ranunculales an excellent group for studying evolutionary processes by comparative studies. Lately, the phylogeny of Ranunculales was revised, and genetic and genomic resources were developed for many species, allowing comparative analyses at the molecular scale. Here, we review the literature on the resources for genetic manipulation and genome sequencing, the recent phylogeny reconstruction of this order, and its fossil record. Further, we explain their habitat range and delve into the diversity in their floral morphology, focusing on perianth organ identity, floral symmetry, occurrences of spurs and nectaries, sexual and pollination systems, and fruit and dehiscence types. The Ranunculales order offers a wealth of opportunities for scientific exploration across various disciplines and scales, to gain novel insights into plant biology for researchers and plant enthusiasts alike. [ABSTRACT FROM AUTHOR]

Summary: Agapetes oxycoccoides J. Murata, Nob. Tanaka & Ohi‐Toma from Kachin State, Myanmar is described and illustrated. In its floral morphology, this species is very similar to Vaccinium oxycoccos L. Extrafloral nectaries on the margins of young leaves of this species and of A. moorei Hook.f. are reported here for the first time. [ABSTRACT FROM AUTHOR]

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrinopathy characterized by oligo or anovulation, hyperandrogenism, and/or polycystic ovarian morphology. While women in both developed and developing nations are affected, it is also the leading cause of ovulatory infertility among women of reproductive age. This article discusses the epidemiology, risk factors, pathophysiology, diagnosis, and particular emphasis to its treatment. Global prevalence of PCOS ranges from 4 to 21% whereas it is between 9.1 and 36% among adolescents. Clinical presentation of PCOS can be mainly attributed to hyperandrogenism and chronic anovulation. Symptoms of hyperandrogenism include hirsutism, acne, and/or male pattern alopecia. Chronic anovulation proceeds with features such as oligomenorrhea, amenorrhea, and/or infertility. Even though a specific gene responsible is not found yet, it's clear that women with PCOS have two major genetic alterations involving androgen synthesis, insulin action, and also an increased incidence of other genetic alterations. Family history, obesity, and an unhealthy diet are found to be significant risk factors for the development of PCOS. The fundamental pathological changes in PCOS include hyperandrogenism, abnormality of gonadotropin secretion, and insulin resistance. It has been noted that genes, HAS2 & CBLN1 that are associated with ovulation are expressed less in granulosa cells of PCOS patients. These cells also show significantly differentially expressed genes for transcription factors and secretory proteins in addition to having increased Toll-& NOD-like receptors. Presently, there is no universal treatment for PCOS. [ABSTRACT FROM AUTHOR]

The Primuloid clade or Primulaceae sensus lato is well supported and contains several pollination syndromes, including wind pollination and insect pollination with pollen, nectar, or oil as a reward. Previous studies have recognized two types of nectaries (floral and extrafloral) with different distributions (e.g. ovary, stigma, style, pedicel). This study aimed to reassess the diversity of nectary types, and their distribution and evolution within the clade. Flowers were selected to represent the four subfamilies Maesoideae, Theophrastoideae, Primuloideae, and Myrsinoideae. The flowers were investigated for nectary tissue with electron microscopy, light microscopy, and sugar tests. Nectar is mainly exuded by gynoecial nectarostomata (in Maeseoideae, Theophrastoideae, Primuloideae, and a few basal Myrsinoideae, such as Stimpsonia and Coris) distributed at the base, middle, and top part of the ovary. Myrsinoideae is the exception with an absence of a nectary linked to buzz-pollination, or presenting nectariferous or oil-producing trichomes on the perianth and stamens. The evolution of nectaries is variable in the Primuloid clade, with Primuloideae apparently the starting point of an evolutionary reversal in terms of nectary evolution within this clade, and a high diversity of nectaries within the Myrsinoideae representing various trends that are currently under-investigated. The evolution of floral nectaries in Primulaceae presents an exciting shift from nectar-producing flowers towards a loss of nectaries, and an evolutionary reversal with a shift to the co-option of either oil-producing trichomes or nectar-producing trichomes. [ABSTRACT FROM AUTHOR]

The net outcomes of mutualisms are mediated by the trade-offs between the costs and benefits provided by both partners. Our review proposes the existence of a trade-off in ant protection mutualisms between the benefits generated by the ants' protection against the attack of herbivores and the losses caused by the disruption of pollination processes, which are commonly not quantified. This trade-off has important implications for understanding the evolution of extrafloral nectaries (EFNs), an adaptation that has repeatedly evolved throughout the flowering plant clade. We propose that the outcome of this trade-off is contingent on the specific traits of the organisms involved. We provide evidence that the protective mutualisms between ants and plants mediated by EFNs have optimal protective ant partners, represented by the optimum point of the balance between positive effects on plant protection and negative effects on pollination process. Our review also provides important details about a potential synergism of EFN functionality; that is, these structures can attract ants to protect against herbivores and/or distract them from flowers so as not to disrupt pollination processes. Finally, we argue that generalizations regarding how ants impact plants should be made with caution since ants' effects on plants vary with the identity of the ant species in their overall net outcome. [ABSTRACT FROM AUTHOR]

Spiders, abundant and diverse arthropods which occur in vegetation, have received little attention in studies investigating spider–plant interactions, especially in plants which have extrafloral nectaries (EFNs). This study examines whether spiders attracted to EFNs on the plant Heteropterys pteropetala (Malpighiaceae) function as biological protectors, mitigating leaf herbivory and positively impacting plant fitness, through manipulative experiments. Spiders are attracted to EFNs because, in addition to consuming the resource offered by these structures, they also consume the herbivores that are attracted by the nectar. At the same time, we documented the reproductive phenology of the plant studied and the abundance of spiders over time. Our results revealed that the plant's reproductive period begins in December with the emergence of flower buds and ends in April with the production of samarids, fruits which are morphologically adapted for wind dispersal, aligning with the peak abundance of spiders. Furthermore, our results demonstrated that spiders are attracted to plants that exude EFNs, resulting in a positive impact on reducing leaf area loss but with a neutral effect on protecting reproductive structures. By revealing the protective function of spiders' vegetative structures on plants, this research highlights the ecological importance of elucidating the dynamics between spiders and plants, contributing to a deeper understanding of ecosystems. [ABSTRACT FROM AUTHOR]

Although flower pollinator interactions are known to be mediated by floral traits, not enough attention has been paid to the research of secretory tissues and volatile components of sunflower disc florets as potentially important parameters in breeding programs. (1) To our knowledge, this is the first integrated study aimed at better understanding the attractiveness of sunflower capitula to insects. In the study, we have made a very detailed comparative analysis of secretory tissues and the characterization of the volatile components (VOCs) of disc florets in 10 wild perennial Helianthus species. (2) For anatomical analyses, cross-sections were obtained from the nectary zone of disc florets using a cryotechnique procedure. Micromorphological observation and morphological and anatomical analysis of disc florets were performed using light and scanning electron microscopy. For VOCs, we applied headspace, GC-FID, and GC/MS analyses. (3) The obtained results indicate that there is a difference between the analyzed traits among studied species. H. eggertii, H. hirsutus, H. mollis, H. resinosus, and H. tuberosus had high disc diameter values, a high cross-section area and disc floret corolla length, as well as the largest cross-section area and thickness of the disc florets nectary. In the analyzed VOCs, 30 different compounds were detected. The highest yield and quantity of α-Pinene was observed in H. mollis. (4) Inflorescence features, such as receptacle diameter, corolla and secretory tissue properties, and floret VOCs production and characterization, provided valuable information that can be used as guidelines in sunflower breeding programs to maximize pollinator attractiveness and increase seed yield. [ABSTRACT FROM AUTHOR]

The plant family Brassicaceae is exceptional as far as their nectaries are concerned. Although the nectaries are consistently of the mesophyllary receptacular type, as is common in the rosids, the occurrence of a varying number of glands (1 to 8) in different positions and the high diversification in shape and size is unusual. It is therefore not surprising that in the 19th and early 20th centuries the nectaries played an important role in the various classifications of the family. Since the early 1990s, the incorporation of molecular data has shown that morphological characters in Brassicaceae are highly homoplasious (the same morphological feature has evolved independently in parallel). Although the nectary character can no longer be used to characterise higher taxonomic units such as tribes, one objective of this study is to demonstrate the possible numbers and positions of nectar glands, since there has been no comprehensive description of Brassicaceae nectaries for about 120 years. Using SEM, the nectaries of 172 species from 112 genera (covering 49 tribes of the 58 currently accepted tribes) are studied in such a way that the receptacle with the nectar glands was seen in either the median or transversal view. A total of 40 nectar types were identified. In addition to SEM images, a floral diagram (in which the shape of the nectar glands is sketched in simplified form) is provided for each nectary type. For ease of use, these are grouped into seven sets of diagrams, which are plotted onto a generalized (existing) phylogenetic tree based on nuclear genomic data. The distribution and frequency of the nectary types are discussed. All the different arrangements of the 1 to 8 nectar glands have in common that there are always nectar glands in the transversal area: either four (one nectar gland on each side of the two transversal stamens), or two nectar glands (extrastaminal, intrastaminal, or annular encircling the transversal stamen). Another objective of the study is to identify simple processes by which the various possible arrangements of the nectar glands can be achieved, irrespective of the systematic position of the taxa (the two forms found in the basal tribe Aethionemeae are the starting points). The following (hypothetical) processes have been defined: 1. expansion of the nectary protrusions, 2. intrastaminal dislocation and confluence of the nectary protrusions, 3. extrastaminal dislocation and confluence of the nectary protrusions, 4. ring closure of the nectary protrusions around the transversal stamens, 5. increase in the number of nectary protrusions, 6. confluence of all nectary protrusions, 7. loss of connections of the nectary protrusions, 8. loss of expansion. [ABSTRACT FROM AUTHOR]

The morphologically heterogeneous family Rosaceae is, among others, characterized by differently shaped floral axes through different growth of the same. A central conical proliferation bearing the choricarpous gynoecium (as in Fragaria, Geum, Potentilla or Rubus) may also be missing. Members of tribe Maleae (as Crataegus, Malus, Pyrus) have an inferior ovary, i.e. a gynoecial hypanthium. One character, however, distinguishes all representatives of Rosaceae: a perigynous hypanthium, on which upper rim perianth members and stamens are borne. Its shape varies from discto bowl- to tube- to urn-shaped. Studying the nectary in 19 genera (36 species) covering all presently accepted subfamilies and a large part of the tribes of Rosaceae (for six smaller tribes within Amygdaloideae reliable data were evaluated from the literature) we can conclude that if nectar is present in flowers of Rosaceae, it is secreted from a mesophyllary nectary located in or on the inner side of the perigynous hypanthium (receptacle). The differences of the hypanthial nectaries in the various genera/species lie only in the size of the nectary tissue, its exact location on the perigynous hypanthium, its degree of protrusion (flush or non-flush with the inner hypanthial wall), in the nectary slits (sunken between the epidermal cells or not), hairs around the nectary (present or absent on perigynous hypanthium or on/among carpels) and the striation of the nectary epidermal cells. We found no evidence of involvement of other tissues in the nectary. In many cases, the nectary extends from beneath the filament bases to the gynoecium. In some cases, filament bases interrupt the nectary and cause an undulating upper border of the nectary (e.g. in Crataegus, Fragaria, Geum). In Cydonia and Pyrus, a distinct proliferation of the upper part of the hypanthium bears part of the nectary and surrounds as annular bulge the styles, but stylar or ovarian tissue do not contribute to the nectary. Some genera can be characterized by a unique position of the nectary in correlation with the shape of the perigynous hypanthium. In Geum and Waldsteinia (Colurneae), the nectary is formed as a groove in front of the inner filaments along the upper edge of the perigynous hypanthium. The genus Rosa is characterized by an urn-shaped perigynous hypanthium, whose throat usually is almost closed by a thick proliferation of the floral axis that may be the site of only remnants of a nectary. The urn-shaped perigynous hypanthium of Rosa, unique in Rosaceae, forces the long styles of the individual carpels to "squeeze" through the narrow orifice. This achieves the advantageous close proximity of the stigmata, so that the capitate stigmas an outer compitum, a compensation of the disadvantage of a choricarpous gynoecium. What is the selective advantage of nectar secretion in pollen flowers? Nectar production In Rosaceae may be poor and limited mainly to the female phase of the mostly proterogynous flowers. In this way, the attractiveness of the flower is also assured in the non-pollen presenting phase. In addition, during searching for the sparse nectar the insect may come into contact with several stigmata thus compensating the economic disadvantage of a choricarpous compared to a coenocarpous gynoecium. [ABSTRACT FROM AUTHOR]

In Indochina the species diversity of Cyatheaceae remains insufficiently known. Here we demonstrate the scaly tree fern Gymnosphaera salletii in Vietnam to be an assemblage of three distinct species based on molecular and morphological data, and report for the first time the occurrence of foliar nectaries in Gymnosphaera. The true G. salletii is morphologically unique based on the protuberant glands present on the petiole. Gymnosphaera phankelocii sp. nov. and G ymnosphaera vietnamensis sp. nov. are recognized as new species; G. phankelocii is characterized by its distant two-rowed sori and G. vietnamensis by the sub-tripinnate fronds. Our phylogenetic analyses indicated that G. phankelocii is a relatively isolated species, while G. vietnamensis is a member of the G. salletii clade along with G. austroyunnanensis , G. salletii , and G. saxicola. The two new species and members of the G. salletii clade are all local endemics, and provide good examples to understand the frequent local endemics and their evolution in scaly tree ferns. Eleven species of Gymnosphaera are now known from Indochina; we provide a diagnostic key to these species. [ABSTRACT FROM AUTHOR]

The genus Sanjappa, previously with the single species S. cynometroides in southern India, is expanded to include S. umbrosa, comb. nov., in northeastern India, Bangladesh, Myanmar and China (Yunnan) and S. vietnamica, sp. nov., in southern Vietnam. Sanjappa differs from Thailentadopsis, its sister genus in the Zapoteca clade, by having leaves with extrafloral nectaries in the form of sessile (versus stipitate) glands and elastically dehiscent, not moniliform pods (versus pods not elastically dehiscent and submoniliform). Sanjappaumbrosa and S. vietnamica differ from S. cynometroides by having bipinnate leaves with one pair of pinnae (versus simply pinnate leaves with two leaflets only) and a four‐lobed (versus three‐lobed) corolla. In S. umbrosa each pinna is 2–3‐foliolate and paired stipular spines are mainly present on younger growth, whereas in S. vietnamica each pinna is (3–)4–5‐foliolate and branches, including major ones, are armed with numerous paired spines with thickened bases. Synonymies, images and notes on distribution, habitat, taxonomy and conservation for the three species of Sanjappa are provided, and all names are typified. With the taxonomic changes proposed here, all Asian species previously treated as members of Calliandra have been accommodated outside this genus. [ABSTRACT FROM AUTHOR]

Ceropegia lenewtonii (Plowes) Bruyns (=Huernia keniensis), currently belonging to the Huernia section of the genus Ceropegia, is a stapeliad species distributed in Africa and the Arabian Peninsula; but it is widely cultivated as ornamental in most parts of the world. This species of stapeliad presents "carrion flowers" associated with a sapromyophilous pollination syndrome since the flowers emit an unpleasant odor. In this work, we describe the floral morphology and anatomy of the calyx, corolla, and corona of this species based on bright-field and scanning electron microscope techniques. We detected the presence of diverse floral secretor tissues, and based on different histochemical tests, the principal component of the secreted substance was identified. We interpret the functions of the glands and compare with other related species of stapeliads. Our results indicate that flowers of C. lenewtonii present colleters in sepals, osmophores in corolla, and primary and secondary nectaries in corona. All these floral glands have specific functions that involve the processes of pollination and reproduction of this species, as well as protection and defense mechanisms. [ABSTRACT FROM AUTHOR]

Floral nectar contains sugars and numerous other compounds, including amino acids, but little is known about their function and origin in nectar. Therefore, the amino acid, sugar, and inorganic ion concentrations, as well as the activity of alanine aminotransferase (AlaAT) and glutamine synthetase (GS) in nectar, nectaries, and leaves were analyzed in 30 Pitcairnia species. These data were compared with various floral traits, the pollinator type, and the phylogenetic relationships of the species to find possible causes for the high amino acid concentrations in the nectar of some species. The highest concentrations of amino acids (especially alanine) in nectar were found in species with reddish flowers. Furthermore, the concentration of amino acids in nectar and nectaries is determined through analyzing flower color/pollination type rather than phylogenetic relations. This study provides new insights into the origin of amino acids in nectar. The presence of almost all amino acids in nectar is mainly due to their transport in the phloem to the nectaries, with the exception of alanine, which is partially produced in nectaries. In addition, active regulatory mechanisms are required in nectaries that retain most of the amino acids and allow the selective secretion of specific amino acids, such as alanine. [ABSTRACT FROM AUTHOR]

Abstract Ocotea velloziana (Lauraceae) is a species with cryptic dioecy. The staminate flowers of this species have a pistillode and pistillate flowers have staminodes, which often makes it difficult to describe circumscribe the reproductive system correctly. Therefore, to understand the evolution of dioecy in this species, the morphology of both floral morphotypes needs to be described. We apply traditional and modern approaches to describe the comparative floral anatomy of the two floral morphotypes in O. velloziana. We found that the pistillate flowers have fewer (three) vascular traces in the tepals (compared to five traces in the tepals of the staminate flowers). The pistillode and the staminodes in the flowers of O. velloziana are smaller and less vascularized than their homologous, fertile counterparts, the pistils and stamens. In addition, even though the nectaries are smaller in pistillate flowers, their basic morphology and vascularization are similar in the two floral morphotypes. Our results suggest androtepaly in O. velloziana, however future ontogenetic studies and investigation of the vascularization are necessary in other Lauraceae species to clarify this issue. The nectaries have originated from the hypanthium and may be characterized as nectar-secreting emergencies not homologous to the stamens.

• Xeromorphic characteristics found in Acridocarpus may be correlated with the arid environments where the species occurs. • Anatomical characters can contribute to distinguish the analyzed species and can represent evolutionary novielties for genus. • The occurrence of anatomical patterns of leaf nectaries in different biogeographic groups in Acridocarpus may reflect a functional independence of the sepal and petal nectaries of the genus. The Paleotropical genus Acridocarpus stands out among the lineages recovered in the most recent phylogeny of the Malpighiaceae. Its 30 species occur disjunctively in Africa and only one species in New Caledonia, exhibiting a coincidence between the period of dispersion/diversification with the increase of arid areas in Africa. This study aims to investigate whether the anatomical leaf of the Acridocarpus can support the hypothesis of diversification of the genus in response to environmental, besides the contribution to systematic approaches. Leaves from 21 species were submitted to the usual methodologies for analysis under light microscope. Coded anatomical characters were also mapped in the phylogenetic tree of Acridorcarpus. Ericoid leaves, compact mesophyll, adaxial epidermis with elongated cells, epidermal cells with thick outer periclinal walls, were found in most species. These xeromorphic features would be correlated to the arid environments where the species occurs. The presence, distribution, and position of nectaries on the leaf, the contour of both petiole and midrib, the conformation of both petiole and midrib vascular system, the presence of sheath extending laterally between the palisade and spongy parenchyma, the presence and location of druse crystal in the petiole and mesophyll, the presence of stomatal ridges and distribution of stomata on the blade were recognized as useful characters for the taxonomy that contribute to the interspecific distinction. The lateral extension of the bundle sheath in the mesophyll was interpreted as a synapomorphy for the genus and amphistomatic leaves were considered an autapomorphy in A. spectibilis. These findings allowed the construction of an identification key and may contribute to new evolutionary interpretations in Malpighiaceae. [ABSTRACT FROM AUTHOR]

Biotic interactions play an important role in shaping species geographic distributions and diversity patterns. However, the role of mutualistic interactions in shaping global plant diversity patterns remains poorly understood, particularly with respect to interactions with invertebrates. It is unclear how the nature of different mutualisms interacts with abiotic drivers and affects the distribution of mutualistic organisms. Here, we present a global‐scale biogeographic analysis of three distinct ant‐plant mutualisms, differentiating between plants bearing domatia, extrafloral nectaries (EFNs), and elaiosomes, based on comprehensive geographic distributions of ~ 19 000 flowering plants and ~ 13 000 ant species. Domatia and extrafloral nectaries involve indirect plant defences provided by ants, while elaiosomes attract ants to disperse seeds. Our results reveal distinct biogeographic patterns of different ant‐plant mutualisms, with domatium‐ and EFN‐bearing plant diversity decreasing sharply from the equator towards the poles, while elaiosome‐bearing plants prevail at mid‐latitudes. Present climate, especially mean annual temperature and precipitation, emerge as the strongest predictors of ant‐associated plant diversity. In hot and moist regions, typically the tropics, the representation of EFN‐bearing plants increases with the proportion of potential ant partners while domatium‐bearing plants show no correlation with ants. In dry regions, plants with elaiosomes are strongly linked to interacting ant seed dispersers. Our results suggest that ants in combination with climate drive the spatial variation of plants bearing domatia, extrafloral nectaries, and elaiosomes, highlighting the importance of mutualistic interactions for understanding plant biogeography. [ABSTRACT FROM AUTHOR]

Lophopterys floribunda is a Neotropical species of Malpighiaceae endemic to Brazil, occurring in both the Amazon and Atlantic Forest. Instead of the typical bi-glandular sepals reported for Neotropical Malpighiaceae, this species presents a single, large gland on the lateral sepals. In addition, ant patrolling was observed at the apex of bracts and bracteoles during fieldwork. Thus, this work aimed to describe the sepalar gland of L. floribunda and other secretory structures in its flowers and inflorescence. Samples of bracts, bracteoles, sepals, petals, and anther were collected and submitted to usual anatomical techniques. Unexpected nectaries at the apex of bracts and bracteoles, not visible to the naked eye, were described and represent a new type of structure for the family due to both their position and size. Mutualistic ants consume the exudate produced by these tiny nectaries, and such structures enable a specific visitation pattern for Lophopterys. Typical epithelial elaiophores occur on the lateral sepals, formed by an invaginated epidermis, which predominantly produce lipid secretion. The petal marginal glands are anatomically similar to the standard type of colleter, which exude mucilaginous substances. The exudate produced by the petal marginal glands was considered to have an additional role of contributing to the maintenance of the closed bud during the beginning of development. The globose epidermal cells containing lipids, proteins, and polysaccharides observed in the connective may be responsible for the typical aroma emitted by these flowers. The diversity of secretory structures reported here has application in both systematic and ecological studies of Malpighiaceae. [ABSTRACT FROM AUTHOR]

Leaf glands are found in many Rhamnaceae species, the buckthorn family, and are frequently used in taxonomic studies of the group, especially because they are easily visible to the naked eye. Despite the many records and extensive use in the taxonomy of the family, few studies deal with the classification of these glands and their roles for the plant. Thus, this study aimed to unravel the type, functioning, and putative functions of the leaf glands of three Brazilian forest species: Colubrina glandulosa Perkins, Gouania polygama (Jacq.) Urb., and Rhamnidium elaeocarpum Reissek. Leaves were collected and processed for surface, anatomical, histochemical, and ultrastructural analyses. In addition, the presence of visitor animals was registered in the field. The leaf glands of C. glandulosa and G. polygama are defined as extrafloral structured nectaries due to their anatomical structure, interaction with ants, and the presence of reduced sugars and of a set of organelles in the secretory cells. The unusual mechanism of nectar release and exposure in an apical pore stands out in G. polygama. The glands of R. elaeocarpum are ducts or cavities that secrete phenolic oil resin. Their presence is an atypical condition in the family, although they are often confused with mucilage reservoirs, much more common in Rhamnaceae. The extrafloral nectary, secretory cavity, and duct are associated with plant protection against phytophages, either by attracting patrol ants or by making the organs deterrent. Our data, combined with other previously obtained data, attest to the great diversity of gland types found in Rhamnaceae species. [ABSTRACT FROM AUTHOR]

Context-dependence in mutualisms is a fundamental aspect of ecological interactions. Within plant-ant mutualisms, particularly in terms of biotic protection and pollination, research has predominantly focused on elucidating the benefits while largely overlooking potential costs. This notable gap underscores the need for investigations into the drawbacks and trade-offs associated with such mutualistic relationships. Here, we evaluated the role of pericarpial nectaries (PNs) in shaping the dynamics of ant-pollinator mutualisms. Specifically, we investigated whether ants visiting the PN of Palicourea rigida (Rubiaceae) could deter hummingbirds and disrupt pollination, ultimately influencing fruit production. Our research involved manipulative experiments and observation of ant-pollinator interactions on P. rigida plants in the Brazilian savannah. We found that visiting ants can deter hummingbirds and/or disrupt pollination in P. rigida, directly influencing fruit set. However, these results are species-specific. The presence of very aggressive, large predatory ants, such as E. tuberculatum, had a negative impact on hummingbird behavior, whereas aggressive mid-sized ants, such as C. crassus, showed no effects. Our study illuminates the multifaceted aspects of ant-plant mutualisms and underscores the importance of evaluating costs and unexpected outcomes within these ecological relationships. [ABSTRACT FROM AUTHOR]

A new species of Tacinga from semi-arid Eastern Brazil, Tacinga paiaia, is here described on the basis of material collected several years ago and cultivated at the Cactarium Guimarães Duque of the Instituto Nacional do Semiárido. A detailed description, original illustrations, distribution map, a taxonomic discussion for the new taxon, and a key to all known species of Tacinga are given. We also assessed the IUCN risk of extinction category for the new species. It is here preliminarily classified as Vulnerable to extinction due to its small population size and restricted distribution. Finally, we also report the presence of extrafloral nectaries in the pericarpel areoles of the new taxon. [ABSTRACT FROM AUTHOR]

Sapindales is a large order with a great diversity of nectaries; however, to date, there is no information about extrafloral nectaries (EFN) in Sapindaceae, except recent topological and morphological data, which indicate an unexpected structural novelty for the family. Therefore, the goal of this study was to describe the EFN in Sapindaceae for the first time and to investigate its structure and nectar composition. Shoots and young leaves of Urvillea ulmacea were fixed for structural analyses of the nectaries using light and scanning electron microscopy. For nectar composition investigation, GC-MS and HPLC were used, in addition to histochemical tests. Nectaries of Urvillea are circular and sunken, corresponding to ocelli. They are composed of a multiple-secretory epidermis located on a layer of transfer cells, vascularized by phloem and xylem. Nectar is composed of sucrose, fructose, xylitol and glucose, in addition to amino acids, lipids and phenolic compounds. Many ants were observed gathering nectar from young leaves. These EFNs have an unprecedented structure in the family and also differ from the floral nectaries of Sapindaceae, which are composed of secretory parenchyma and release nectar through stomata. The ants observed seem to protect the plant against herbivores, and in this way, the nectar increases the defence of vegetative organs synergistically with latex. [ABSTRACT FROM AUTHOR]

Burmannia shows a set of floral traits that suggest elaborate mechanisms of animal mediated pollen transfer. These include flower coloration, septal nectaries and a long and narrow floral chamber. The stamens are synorganized with the common style restricting the entrance to the floral chamber, sometimes forming a gynostegium. Contrary to this apparent zoophilous floral syndrome, several species of Burmannia were reported to perform self-pollination via cleistogamy. Understanding of reproductive systems in Burmannia is complicated by scarcity of available results of direct observations on pollination process. Here we present data on pollination biology of B. disticha obtained during field investigations in Vietnam followed by laboratory analyses of ecologically important floral traits and the captured flower visitors. We found that the anthetic perianth is open, i.e. the flower is chasmogamous. The flowers are visited by various Diptera, Hymenoptera, Lepidoptera and Orthoptera. Of them, the bumblebees (Bombus burmensis), a bee (Coelioxys sp.) and some lepidopterans were revealed to carry pollen of B. disticha. Based on the amount of carried pollen, insect behavior during the visits and general knowledge on biology of these insect taxa, we concluded that the bumblebees act as the principal pollinators of B. disticha, whereas the lepidopterans are considered as its possible pollinators. We compared the lengths of proboscises of the captured insects to the depth of the floral chamber, and found that only the bumblebees and lepidopterans should be able to reach the nectar. Finally, we estimated the pollen-ovule ratio of B. disticha as 6.84, which is comparable to the ratio known in autogamous angiosperms. Based on its flower organization and pollination mechanism, we consider B. disticha an entomophilous and predominantly xenogamous species. Its gynostegium is likely an adaptation for pollen transfer by insects with long proboscises. At the same time, earlier investigations together with pollen-ovule ratio indicate that B. disticha possesses a labile pollination strategy, and autogamy sometimes occurs. Since Burmannia is one of the few angiosperm genera that comprise both mycoheterotrophic (achlorophyllous) and autotrophic (green) species, our study provides important evidence for reconstructions of ecological and morphological evolutionary pathways in relation to the mode of organic nutrition. [ABSTRACT FROM AUTHOR]

Summary: The black nectar produced by Melianthus flowers is thought to serve as a visual attractant to bird pollinators, but the chemical identity and synthesis of the black pigment are unknown.A combination of analytical biochemistry, transcriptomics, proteomics, and enzyme assays was used to identify the pigment that gives Melianthus nectar its black color and how it is synthesized. Visual modeling of pollinators was also used to infer a potential function of the black coloration.High concentrations of ellagic acid and iron give the nectar its dark black color, which can be recapitulated through synthetic solutions containing only ellagic acid and iron(iii). The nectar also contains a peroxidase that oxidizes gallic acid to form ellagic acid. In vitro reactions containing the nectar peroxidase, gallic acid, hydrogen peroxide, and iron(iii) fully recreate the black color of the nectar. Visual modeling indicates that the black color is highly conspicuous to avian pollinators within the context of the flower.Melianthus nectar contains a natural analog of iron‐gall ink, which humans have used since at least medieval times. This pigment is derived from an ellagic acid‐Fe complex synthesized in the nectar and is likely involved in the attraction of passerine pollinators endemic to southern Africa. See also the Commentary on this article by Gong et al., 239: 1542–1544. [ABSTRACT FROM AUTHOR]

Background and aims: The onion (Allium cepa var. cepa) is an allogamous species in which male-sterile lines have been developed. However, the structure of the flower and floral nectaries have only been briefly described. The objective of this study is to update the floral anatomy data, comparing the gynoecium and androecium of male-fertile and male-sterile lines, and to analyze the three-dimensional structure of the floral nectary. M&M: Conventional optical and scanning electron microscopy techniques were used. Results: Fertile and sterile male flowers have the same structural organization. The septal or gynopleural nectary is organized in three zones: 1) production area formed by the glandular tissue arranged radially in the septa of the ovary, 2) discharge zone: a small channel at the apex connects the nectariferous tissue with the pocket formed between the ovary wall and the overlying ridge, and 3) presentation and harvest zone, where the excreted nectar accumulates, formed between the widened base of the inner staminal filaments opposite the ovary. Conclusions: The only anatomical differences in the flowers sterile male lines are the lack of pollen production and the absence of dehiscence, despite having a normal stomium and anther wall. The floral nectaries of onion are a clear example of secondary presentation of nectar. [ABSTRACT FROM AUTHOR]

Few studies have explored the phenotypic plasticity of nectar production on plant attractiveness to ants. Here, we investigate the role of extrafloral nectary (EFN) size on the productivity of extrafloral nectar in three sympatric legume species. We hypothesized that plant species with larger EFNs (i) have higher induced nectar secretion after herbivory events, and (ii) are more likely to interact with more protective (i.e. dominant) ant partners. We target 90 plants of three Chamaecrista species in the field. We estimated EFN size and conducted field experiments to evaluate any differences in nectar traits before and after leaf damage to investigate the phenotypic plasticity of nectar production across species. We conducted multiple censuses of ant species feeding on EFNs over time. Plant species increased nectar descriptors after leaf damage, but in different ways. Supporting our hypothesis, C. duckeana , with the largest EFN size, increased all nectar descriptors, with most intense post-herbivory-induced response, taking its place as the most attractive to ants, including dominant species. EFN size variation was an excellent indicator of nectar productivity across species. The higher control over reward production in plants with larger sized EFNs reflects an induction mechanism under damage that reduces costs and increases the potential benefits of indirect biotic defences. [ABSTRACT FROM AUTHOR]

The passion fruit cultivar in Lucban, Quezon, Philippines is poorly described. To address this knowledge gap, this study characterized the phenotypic features and variability that exists in the plantation of passion fruit in Lucban. A total of 68 morpho-agronomic descriptors (32 quantitative and 36 qualitative) were used for the characterization. The results showed that the distinguishing characteristics of the cultivar were light green branch color, long and wide leaf with trilobate division and nectaries on the petiole, campanulate hypanthium, wavy corona filament, nectaries on the sepal, white color of the perianth and corona ring filaments with deep purple color at the base, and yellow peel and pulp color. Based on these characteristics, this study confirmed that the identity of the passion fruit cultivar is Passiflora edulis f. flavicarpa Degener. Some notable variants were observed - including purplish green branches, scarce anthocyanin on the reproductive parts, and fruit with oval fruit shape and lenticels arranged in a striated pattern. The scaled principal component analysis identified nine principal components (PCs) that explain at least 80% of the total variation in quantitative characters, whereas three PCs explain about 78% of the total variation in qualitative characters. Further characterization using molecular markers could be done to supplement the results of this study. Nevertheless, the results are significant for reintroduction, pre-breeding, and ex situ conservation of passion fruit germplasm. [ABSTRACT FROM AUTHOR]

Floral microbes, including bacteria and fungi, alter nectar quality, thus changing pollinator visitation. Conversely, pollinator visitation can change the floral microbial community.Most studies on dispersal of floral microbes have focused on bees, ants or hummingbirds, yet Lepidoptera are important pollinators.We asked (a) where are microbes present on the butterfly body, (b) do butterflies transfer microbes while foraging, and (c) how does butterfly foraging affect microbial abundance on different floret structures.The tarsi and proboscis had significantly more microbes than the thorax in wild‐caught Glaucopsyche lygdamus (Lepidoptera: Lycaenidae) and Speyeria mormonia (Lepidoptera: Nymphalidae). Glaucopsyche lygdamus, a smaller‐bodied species, had fewer microbes than S. mormonia.As a marker for microbes, we used a bacterium (Rhodococcus fascians, near NCBI Y11196) isolated from a S. mormonia that was foraging for nectar, and examined its dispersal by G. lygdamus and S. mormonia visiting florets of Pyrrocoma crocea (Asteraceae). Microbial dispersal among florets correlated positively with bacterial abundance in the donor floret. Dispersal also depended on butterfly species, age, and bacterial load carried by the butterfly.Recipient florets had less bacteria than donor florets. The nectaries had more bacteria than the anthers or the stigmas, while anthers and stigmas did not differ from each other. There was no differential transmission among floral organs.Lepidoptera thus act as vectors of floral microbes. Including Lepidoptera is thus crucial to an understanding of plant–pollinator–microbe interactions. Future studies should consider the role of vectored microbes in lepidopteran ecology and fitness. [ABSTRACT FROM AUTHOR]

Fritillaria karakocanensis (Liliaceae) is described as a new species from Turkey. It is morphologically similar to F. michailovskyi, F. reuteri and F. rhodocanakis, but differs from F. michailovskyi mainly by its longer stem, canaliculate and narrower leaves, papillose style, and the caducous tepals, from F. reuteri by its many bulblets, canaliculate leaves, longer lower leaves, fewer flowers, and longer tepals, and from F. rhodocanakis by its longer and narrower lower leaves, longer tepals, nectaries and style, and the obovoid capsule. A detailed taxonomic description, diagnostic characters, original photographs, geographical distribution, habitat and ecology, conservation assessment, and taxonomic comments regarding the new species are given. [ABSTRACT FROM AUTHOR]

Plant diversity can increase productivity. One mechanism behind this biodiversity effect is facilitation, which is when one species increases the performance of another species. Plants with extrafloral nectaries (EFNs) establish defense mutualisms with ants. However, whether EFN plants facilitate defense of neighboring non‐EFN plants is unknown. Synthesizing data on ants, herbivores, leaf damage, and defense traits from a forest biodiversity experiment, we show that trees growing adjacent to EFN trees had higher ant biomass and species richness and lower caterpillar biomass than conspecific controls without EFN‐bearing neighbors. Concurrently, the composition of defense traits in non‐EFN trees changed. Thus, when non‐EFN trees benefit from lower herbivore loads as a result of ants spilling over from EFN tree neighbors, this may allow relatively reduced resource allocation to defense in the former, potentially explaining the higher growth of those trees. Via this mutualist‐mediated facilitation, promoting EFN trees in tropical reforestation could foster carbon capture and multiple other ecosystem functions. [ABSTRACT FROM AUTHOR]

Croton is the largest genus of Crotonoideae Burmeist. (ca. 1200 species), with approximately 300 species distributed in all the phytogeographic domains in Brazil. The Chapada of Araripe Environmental Protection Area (CA-EPA) is one of the largest protected areas in northeastern Brazil and comprises many different types of vegetation. Considering the expressive representation of Croton in that northeastern region and its morphological complexity, we carried out a taxonomic study of the species occurring in the CA-EPA. The analysis of collections deposited in regional herbaria, together with field observations, revealed 18 Croton species, five of which had never been cited as occurring in the study area; seven of those taxa are endemic to the Brazilian semiarid region. Croton species were recorded in all of the vegetation types in the CA-EPA, especially in the "carrasco" and "caatinga" vegetation. The plants habits, the shapes of their stipules, extrafloral nectaries, indumenta, and staminate and pistillate sepals were important characteristics for their differentiation. [ABSTRACT FROM AUTHOR]