Decorative sterile flowers in nine Japanese species of Viburnum (Adoxaceae) and their influence on pollinator visits

Framed inflorescences are unique arrangements in which a cluster of small fertile flowers is surrounded by several larger, decorative sterile flowers. Viburnum (Adoxaceae) species vary in their inflorescence arrangements; some species exhibit framed inflorescences, whereas others do not. We hypothesize that the decorative flowers increase the pollinator-attracting functions of the inflorescences; as proved by previous studies, they additionally function as landing-sites for pollinators. To test our hypotheses, field manipulation experiments were carried out for nine Viburnum species, three with inherently framed inflorescences and six without them: sterile flowers were removed and mounted on species with and without framed inflorescences, respectively. Results show that inflorescences with decorative flowers had higher visit rates than inflorescences without them, and that insect flower visitors did not show landing preference for either flower type. These results suggest that decorative flowers appeared only in a subset of Viburnum species to increase their pollination chances by, mainly, enhancing the attractiveness of the inflorescence. It is likely that species without framed inflorescences use other attraction-enhancing mechanisms, such as a high flowering synchrony within a single cluster of fertile flowers, a trait found in most studied species without decorative flowers.     

Scalariform-to-simple transition in vessel perforation plates triggered by differences in climate during the evolution of Adoxaceae

Background and Aims Angiosperms with simple vessel perforations have evolved many times independently of species having scalariform perforations, but detailed studies to understand why these transitions in wood evolution have happened are lacking. We focus on the striking difference in wood anatomy between two closely related genera of Adoxaceae, Viburnum and Sambucus, and link the anatomical divergence with climatic and physiological insights.Methods After performing wood anatomical observations, we used a molecular phylogenetic framework to estimate divergence times for 127 Adoxaceae species. The conditions under which the genera diversified were estimated using ancestral area reconstruction and optimization of ancestral climates, and xylem-specific conductivity measurements were performed.Key Results Viburnum, characterized by scalariform vessel perforations (ancestral), diversified earlier than Sambucus, having simple perforations (derived). Ancestral climate reconstruction analyses point to cold temperate preference for Viburnum and warm temperate for Sambucus. This is reflected in the xylem-specific conductivity rates of the co-occurring species investigated, showing that Viburnum lantana has rates much lower than Sambucus nigra.Conclusions The lack of selective pressure for high conductive efficiency during early diversification of Viburnum and the potentially adaptive value of scalariform perforations in frost-prone cold temperate climates have led to retention of the ancestral vessel perforation type, while higher temperatures during early diversification of Sambucus have triggered the evolution of simple vessel perforations, allowing more efficient long-distance water transport.     

Cold-induced Chromosome Regions and Karyosystematics in Sambucus and Viburnum

The genera Viburnum, Sambucus and Lonicera have been investigated for chromosome number and karyomorphology including Giemsa-C-banding, fluorochrome (DAPI/CMA) banding and cold treatment. Cold-induced undercontracted chromosome regions (CIRs) are found in Viburnum and Sambucus for the first time and are apparently identical with larger hc regions, shown by Giemsa C-banding. Certain narrow C-bands are not cold-sensitive. CIRs frequently react brightly CMA-positive in Viburnum and Sambucus, while DAPI fluorescence is virtually ineffective. The occurrence of CIRs within plants is possibly linked to certain nuclear characters such as large chromosomes and continuous condensation behaviour. Cold-induction has possibly also some influence on euchromatin condensation characteristics in prophasic chromosomes. Several karyological characters point to a closer relationship between Viburnum, Sambucus and Adoxa: Relatively large chromosomes, continuous condensation behaviour, reticulate to semireticulate interphase nuclei and presence of CIRs. These genera appear isolated from Lonicera and the Caprifoliaceae s.str., which differ remarkably in karyomorphology.     

Responses by a generalist predator,the Balearic lizard <Emphasis Type="Italic">Podarcis lilfordi</Emphasis>, to chemical cues from taxonomically diverse prey

Specialist predators may respond strongly to sensory cues from preferred prey, but responses by generalist predators, although predicted to be less specific, are poorly known. Among squamate reptiles, diet and strength of response to chemical prey cues covary geographically in snakes that are specialist predators. There have been no previous studies of correspondence between diet and chemosensory response in lizards that are prey generalists. Actively foraging lizards discriminate between prey chemicals and control substances. It has been speculated that differential responses among prey species are unlikely in typical species that are dietary generalists. We examined this relationship in Podarcis lilfordi, an omnivorous lacertid that consumes a wide variety of animal prey. In experiments in which chemical stimuli were presented on cotton swabs, lizards responded more strongly to chemicals from a broad spectrum of prey types than to deionized water, an odorless control. These findings plus previous data showing that P. lilfordi is capable of prey chemical discrimination suggest that P. lilfordi can identify a wide range of potential prey using chemical cues. However, there was no evidence of differential response to stimuli among prey species, even in comparisons of prey included in the natural diet and potential prey not in the diet. The results, although limited to a single species, are consistent with the hypothesis that lizard species that are prey generalists do not exhibit the differential response strengths to chemical prey cues observed in snakes that have more specialized diets. Received in revised form: 17 July 2001 Electronic Publication     

The uncommon cavitated secretory trichomes in Bauhinia s.s. (Fabaceae): the same roles in different organs

Cavitated secretory trichomes are characterized by a short or absent stalk that is connected to a secretory hollow head. They are rare structures in angiosperms; in Fabaceae, they have been recorded in only seven genera, including Bauhinia s.s. Because B. curvula and B. rufa exhibit glands that are responsible for attracting pollinators to flowers, this study aimed to test whether the cavitated secretory trichomes present in the flowers of these species have an attraction function. As leaf trichomes are commonly related to plant defence, comparative analyses of the morphology, ontogeny, ultrastructure and chemical profile of the secretory trichomes present in flowers and leaves were conducted. It was found that cavitated secretory trichomes are similar in their external morphology and development, regardless of the organ or species analysed. However, interspecific differences were found in the secretion process and chemical profile of the exudate. The differences found in the cavitated secretory trichomes between species indicate that they secrete distinct compounds, whereas the similarities found in these structures between vegetative and reproductive organs indicate that the cavitated trichomes have equivalent ecological functions within a species, probably in plant defence during organ development. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 104–122.     

Metabolomic Profile of the Genus Inula

Plants have a long history as therapeutics in the treatment of human diseases and have been used as source of medicines for ages. Searching for new biologically active natural products, many plants and herbs are screened for natural products with pharmacological activities. In this field, the genus Inula, which comprises more than 100 species, several of them being used in traditional medicine, is very important, especially due to the finding that several of the isolated pure secondary metabolites proved to possess important biological activities. Inula species have been reported as rich sources of sesquiterpene lactones, including eudesmanes, germacranes, guaianes, and dimeric structures, and since 2006 ca. 400 secondary metabolites, including more than 100 new natural products, some of them with relevant pharmacological activities, have been identified. Herein, we critically compile and update the information regarding the types of secondary metabolites found in the genus Inula and the progress in their isolation.     

Fukinolic acid and cimicifugic acids: a review

During the last decades, the research on the biological activities of extracts from Cimicifuga/Actaea species and Petasites japonicus as well as their active ingredients has been intensified. Besides terpenoids as dominant natural product group, hydroxycinnamic acid esters such as fukinolic acid and several cimicifugic acids have been isolated from Actaea and Petasites species and their chemical structures have been elucidated. Investigations on the biological properties of these hydroxycinnamic acid esters are currently undertaken and some compounds might be promising therapeutic tools. In this review, we have gathered information on the genera Actaea and Petasites, the occurrence of cimicifugic and fukinolic acids and some aspects of their biosynthesis. Furthermore, we have summarized the medicinal aspects of fukinolic acid and cimicifugic acids. In connection with the biological activities of these compounds, structural features of the hydroxycinnamic acid derivatives move into the focus. The position of the hydroxyl group at the aromatic rings and the introduction of an electron-donating moiety may be important for anti-inflammatory, antiviral, cytotoxic and vasoactive effects of these compounds.

     

CHEMOTAXONOMY IN MARINE ALGAE: CHEMICAL SEPARATION OF SOME LAURENCIA SPECIES (RHODOPHYTA) FROM THE GULF OF CALIFORNIA1

Species separation in the genus Laurencia (Rhodomelaceae, Rhodophyta) is complicated by the high degree of morphological variation within the species. Chemical investigations on a worldwide basis of over 15 species indicate that 1 or more of the halogenated natural products synthesized by Laurencia are unique to each species. Our chemical investigations of Laurencia pacifica, as presently understood from the Gulf of California, indicate that more than 1 species had been included under this name. Thin layer chromatographic (TLC) comparisons of the halogenated components of 3 recognizable forms of “L. pacifica” were completed. The results revealed 3 distinct forms, with halogenated products unique to each form. In each form the observed chemical characters had been previously isolated and identified and could now be positively assigned to their algal source. Comparisons were also conducted with L. pacifica Kylin (1941) from the type locality of the species, La Jolla, California, and revealed that it contained another halogenated product different from those isolated from the Gulf species. We conclude that 3 species of Laurencia have been elucidated in the Gulf of California and these are separate from L. pacifica Kylin. Each species can be distinguished by its characteristic array of halogenated compounds. Comparative thin layer chromatography of the lipid components of morphologically similar Laurencia species should prove to be a useful new taxonomic aid.     

Removal of invasive shrubs alters light but not leaf litter inputs in a deciduous forest understory

The establishment and spread of non‐native, invasive shrubs in forests poses an important obstacle to natural resource conservation and management. This study assesses the impacts of the physical removal of a complex of woody invasive shrub species on deciduous forest understory resources. We compared leaf litter quantity and quality and understory light transmittance in five pairs of invaded and removal plots in an oak‐dominated suburban mature forest. Removal plots were cleared of all non‐native invasive shrubs. The invasive shrubs were abundant (143,456 stems/ha) and diverse, dominated by species in the genera Ligustrum, Viburnum, Lonicera, and Euonymus. Annual leaf litter biomass and carbon inputs of invaded plots were not different from removal plots due to low leaf litter biomass of invasive shrubs. Invasive shrub litter had higher nitrogen (N) concentrations than native species; however, low biomass of invasive litter led to low N inputs by litter of invasive species compared to native. Light transmittance at the forest floor and at 2 m was lower in invaded plots than in removal plots. We conclude that the removal of the abundant invasive shrubs from a native deciduous forest understory did not alter litter quantity or N inputs, one measure of litter quality, and increased forest understory light availability. More light in the forest understory could facilitate the restoration of forest understory dynamics.     

Seasonal decline in plant defence is associated with relaxed offensive oviposition behaviour in the viburnum leaf beetle Pyrrhalta viburni

1. Plant defence of Viburnum shrubs against oviposition by its specialist herbivore, the viburnum leaf beetle [VLB Pyrrhalta viburni(Paykull)], involves an egg‐crushing wound response in twigs. Although the response is variable among Viburnum species, it can have a strong impact on egg survivorship. Beetles typically aggregate egg masses with conspecifics along infested twigs, forming clusters that can overwhelm the twig response. It was investigated whether twig responses and beetle oviposition behaviour vary seasonally. 2. In a field experiment, twig defences decreased towards the end of the VLB oviposition period: wound response of the North American Viburnum dentatum L. and the European V. opulus L. was reduced by 100% and 54%, respectively, in September compared with the July to August period. 3. Oviposition trials demonstrated a corresponding behavioural change: VLB females displayed aggregative oviposition in August, but not in September. 4. Further tests revealed that late‐season VLB females reverted to aggregative oviposition after being kept on uninfested twigs, whereas females kept on heavily infested twigs did not. This behavioural change suggests that relaxation of aggregative oviposition originates from cues associated with high densities of egg masses. 5. Relaxation of aggregative oviposition may be adaptive (and beneficial for invasion) on shrubs with low levels of defences by reducing intra‐specific competition.     

Biomass allocation patterns in terrestrial, epiphytic and aquatic species of Utricularia (Lentibulariaceae)

Utricularia forms the largest genus of carnivorous plants and is characterized by the possession of typical traps (“bladders”). Total biomass allocation was examined in three aquatic, six terrestrial and one epiphytic species of Utricularia from natural habitats in West Africa and from the Botanical Gardens, Bonn. Total biomass of aquatic species was considerably higher than that of terrestrial or epiphytic species. Epiphytic Utricularia accumulate about 35% of their biomass in green leaves, in contrast to 65% of nearly chlorophylless reproductive structures and traps. Aquatic species allocated more than 85% of their total biomass to stolons, leaves and traps, but only 10–13% to reproductive structures. This is in stark contrast to the allocation patterns of terrestrial bladderworts. These species allocate nearly 90% of their total biomass in reproductive structures, and only about 10% to stolons, leaves and traps. This reduction of photosynthetically active plant tissue strongly suggests that as a consequence of the alternative resource of chemical energy, the carnivorous habit might have partly replaced autotrophy in certain terrestrial Utricularia species, especially in some smaller ones.     

Astringent tannins of Viburnum and Hydrangea species

The tannins of the leaves of Viburnum and Hydrangea species consist of proanthocyanidins only, but in each genus the range is very wide. In several species of Hydrangea the proanthocyanidins are of the A type, otherwise they are mostly tri- or tetrameric B type. Tannin content is correlated with evolutionary advancement, the more advanced and more widely dispersed species having the less. Species with most tannin occur in E. Asia and E. N. America, but species with little or no tannin are present in both areas. The occurrence in both genera of globose inflorescences with sterile flowers is correlated neither with morphological nor with chemical characters.     

Ergot alkaloids — Sources, structures and analytical methods

Natural sources,i.e. fungal strains and species producing ergot alkaloids (EA), are surveyed together with the chemical structures of EA and a list of new natural EA discovered in the last three decades. Other topics include new efficient chromatographic methods (HPLC) for the separation and isolation of new natural EA and also immunological methods of EA detection.     

NO• chemistry: a diversity of targets in the cell

Abstract

NO^? alone is a poorly reactive species; however, it is able to undergo secondary reactions to form highly oxidizing and nitrating species, NO₂^?, N₂O₃, and ONOO^?. These secondary reactive nitrogen species (RNS) are capable of modifying a diversity of biomolecular structures in the cell. The chemical properties of individual RNS will be discussed, along with their ability to react with amino acids, metal cofactors, lipids, cholesterol, and DNA bases and sugars. Many of the identified RNS-induced modifications have been observed both in vitro and in vivo. Several of these chemical modifications have been attributed with a functional role in the cell, such as the modulation of enzyme activity. Other areas in the field will be discussed, including the ability of RNS to react with metabolites, RNA, and substrates in the mitochondrion, and the cellular removal/repair of RNS-modified structures.     

Hydroid defenses against predators: the importance of secondary metabolites versus nematocysts

Marine hydroids are commonly thought to be defended by stinging organelles called nematocysts that penetrate predator tissues and inject proteinaceous venoms, but not all hydroids possess these nematocysts. Although an increasing number of bioactive secondary metabolites have been isolated from marine hydroids, ecological roles of these compounds are poorly known. To test the hypothesis that nematocysts and noxious secondary metabolites represent alternative defenses against predation, we examined hydroids from North Carolina, United States for: (1) the palatability of whole polyps before and after nematocysts had been deactivated; (2) the palatability of their chemical extracts; and (3) their nutritional value in terms of organic content, protein content, and levels of refractory structural material (chitin). All hydroids were avoided by a generalist predator, the pinfish Lagodon rhomboides, compared with palatable control foods. Two of these (Halocordyle disticha and Tubularia crocea) became palatable after being treated with potassium chloride to discharge their nematocysts, suggesting that these species rely on nematocysts for defenses against predators. Chemical extracts from nematocyst-defended species had no effect on fish feeding. The four species that remained unpalatable after nematocysts had been discharged (Corydendrium parasiticum, Eudendrium carneum, Hydractinia symbiolongicarpus, Tridentata marginata) possessed chemical extracts that deterred feeding by pinfish. We have isolated and characterized the structures of the deterrent metabolites in two of these species. We found no differences in nutritional content or levels of chitin between nematocyst-defended and chemically defended species, and no evidence that either of these played a role in the rejection of hydroids as prey. Our results suggest that, among hydroids, chemical defenses may be at least as common as nematocyst-based defenses and that the two may represent largely alternative defensive strategies. The four hydroid species with deterrent extracts represent four families and both sub-orders of hydroids, suggesting that chemical defenses in this group may be widespread and have multiple origins. Received: 25 May 1999 / Accepted: 1 February 2000     

Saccharopolyspora: an underexplored source for bioactive natural products

Actinomycetes are a rich source for secondary metabolites with a diverse array of biological activities. Among the various genera of actinomycetes, the genus Saccharopolyspora has long been recognized as a potential source for antibiotics and other therapeutic leads that belong to diverse classes of natural products. Members of the genus Saccharopolyspora have been widely reported from several natural sources including both terrestrial and marine environments. A plethora of this genus has been chemically investigated for the production of novel natural products with interesting pharmacological effects. Therefore, Saccharopolyspora is considered one of the pharmaceutical important genera that could provide further chemical diversity with potential lead compounds. In this review, the literature from 1976 until December 2018 was covered, providing a comprehensive survey of all natural products derived from this genus and their semi-synthetic derivatives along with their biological activities, whenever applicable. Moreover, the biological diversity of Saccharopolyspora species and their habitats were also discussed.     

Phytoserological systematic survey of the caprifoliaceae

Although several investigators have presented data suggesting that the Caprifoliaceae is polyphyletic in origin, the family has been retained as a taxon in recent classifications. Serological analyses of the taxa included within the family have been undertaken to provide additional taxonomic data. Precipitin techniques of double diffusion (Ouchterlony) and nephelometry (Boyden Procedure) were used to analyse serological similarities of seed proteins from representatives of the family. Three distinct groupings were detected for the taxa included in the Caprifoliaceae. AlthoughViburnum exhibited greatest serological similarity withSambucus, Viburnum was quite distinct from all members of the family investigated.Sambucus also was somewhat distinct from the other genera and exhibited about as much serological correspondence withCornus of the Cornaceae as with any tested member of the Caprifoliaceae. The remaining species examined formed a very close serological grouping. These data can be interpreted as supporting either a monophyletic or polyphyletic origin of the family as presently composed, because of the different arrangements of the families Caprifoliaceae and Cornaceae in the various systems of classification.     

Differences in the fruit structure and the location and content of bioactive substances in <Emphasis Type="Italic">Viburnum opulus</Emphasis> and <Emphasis Type="Italic">Viburnum lantana</Emphasis> fruits

Many Viburnum species are popular ornamental shrubs and, simultaneously, highly valued medicinal plants as a source of many bioactive compounds, including antioxidants. Viburnum bark, flowers, and fruits are widely used in traditional and folk medicine, and the fruits of some species are used as cooking ingredients. The knowledge of the microstructure of Viburnum fruits and the accumulation sites of bioactive substances in these organs is rather poor. Comparative analyses of the microstructure of ripe Viburnum opulus and Viburnum lantana drupes were carried out using light, scanning, and transmission electron microscopes. The location of various groups of metabolites in the fruits of both species was determined with the use of histochemical tests and fluorescence microscopy. Additionally, the major antioxidants, i.e. carotenoids, polyphenols, and flavonoids, were quantified and a number of morphometric traits of the drupes were presented. The V. opulus and V. lantana fruits were found to differ in some morphological traits and in many characteristics of the pericarp anatomy and ultrastructure. It was shown that the Viburnum fruits contained lipids and lipid compounds (carotenoids, essential oils, steroids, and saponins), polyphenols (tannins, flavonoids, and anthocyanins), pectins, and proteins. The fruits of V. opulus contained greater quantities of carotenoids, polyphenols, flavonoids, steroids, and pectins than the V. lantana drupes, whereas the latter were characterised by higher contents of essential oils, saponins, and proteins. The metabolites were located in different pericarp layers, but the greatest amounts were identified in the drupe skin.     

Predation contributes to invasion resistance of benthic communities against the non-indigenous tunicate <Emphasis Type="Italic">Ciona intestinalis</Emphasis>

Marine anthropogenic structures offer novel niches for introduced species but their role in the subsequent invasion to natural habitats remains unknown. Upon arrival in new environments, invaders must overcome biotic resistance from native competitors and predators if they are to establish successfully in natural habitats. We tested the hypotheses that (1) artificial structures (e.g., suspended aquaculture installations) present a niche opportunity for invasive species by providing a refuge from native benthic predators, and (2) native predators in natural benthic habitats suppress successful colonization by invaders. A recruitment experiment showed that the ascidians Pyura chilensis (native) and Ciona intestinalis (invasive) could recruit to both suspended artificial structures and natural benthic habitats. Ciona, however, was only able to establish adult populations on artificial structures. In natural benthic habitats Ciona only recruited and grew in predator-exclusion cages, because without this protection predation prevented its establishment. In predation experiments, native invertebrate and fish predators removed all invasive ascidians (recruits and adults) in benthic habitats, which contrasted with the high adult survival of the native ascidian P. chilensis. The refuge from a number of benthic predators facilitates the establishment of large populations of invasive species on suspended structures. We present a conceptual model of the invasion processes that includes the anthropogenic structures as a transitional stepping-stone that facilitates invasion by enhancing and prolonging propagule supply to surrounding natural communities. Those established invaders might then overcome biotic resistance during time periods when populations of consumers or competitors are weakened by natural or anthropogenic disturbances. Our results suggest that the conservation of natural habitats with a high diversity of native predators can be an effective means to prevent the spread of invasive species growing on suspended structures.     

Contact zone of two different chloroplast lineages and genetic guidelines for seed transfer in Quercus serrata and Quercus crispula

Within their natural distribution ranges, plant species exhibit a genetic structure that has been created by global climate change and natural selection over long periods. This genetic structure needs to be conserved for sustainable use of genetic resources. To conserve local forests with different genetic structures, genetic guidelines for seed and seedling transfer in individual species are necessary. Genetic guidelines have been published for 43 Japanese tree species using population genetic data; however, for practical use, more detailed genetic borders between important genetic lineages should be clarified to inform seed collection and planting. Thus, we investigated in detail the genetic borders between two important Japanese oak species, Quercus serrata and Quercus crispula, in the Chubu region of Japan using chloroplast and nuclear DNA markers, and we discuss the factors that influenced border creation using the results of species distribution modeling (SDM). The chloroplast DNA (cpDNA) haplotype was clearly different within the Chubu region of Japan but the difference in nuclear DNA between northern and southern haplotype populations was very small, both in Q. serrata and Q. crispula. The results of SDM showed that during the last glacial maximum (LGM) Q. serrata was distributed mostly along the coastline but Q. crispula was distributed not only along the coast but also in mountainous areas further inland. The cpDNA genetic borders of these two oak species are complex and seem to have been influenced by topography and their distribution during the LGM. We propose and discuss genetic guidelines for these two oak species based on the results of this study.