Aggressive Species Research Articles

Species‐specific responses of a marsh‐forest ecotone plant community responding to climate change

Ecotones are responsive to environmental change and pave a path for succession as they move across the landscape. We investigated the biotic and abiotic filters to species establishment on opposite ends of a tidal marsh-forest ecotone that is moving inland in response to sea level rise. We transplanted four plant species common to the ecotone to the leading or trailing edge of the migrating ecotone, with and without caging to protect them from ungulate herbivores. We found that species exhibited an individualistic response to abiotic and biotic pressures in this ecotone; three species performed better at the leading edge of the ecotone in the coastal forest, whereas one performed better at the trailing edge in the marsh. Specifically, grass species Phragmites australis and Panicum virgatum grew more in the low light and low salinity conditions of the leading edge of the ecotone (forest), whereas the shrub Iva frutescens grew better in the high light, high salinity conditions of the trailing edge of the ecotone (marsh). Furthermore, of the four species, only P. australis was affected by the biotic pressure of herbivory by an introduced ungulate, Cervus nippon, which greatly reduced its biomass and survival at the leading edge (forest). P. australis is an aggressive invasive species and has been observed to dominate in the wake of migrating marsh-forest ecotones. Our findings detail the role of lower salinity stress to promote and herbivory pressure to inhibit the establishment of P. australis during shifts of this ecotone, and also highlight an interaction between two non-native species, P. australis and C. nippon. Understanding migration of the marsh-forest ecotone and the factors controlling P. australis establishment are critical for marsh conservation in the face of sea level rise. More generally, our findings support the conclusion that the abiotic and biotic filters of a migrating ecotone shape the resulting community.

Competition between a native and introduced pollinator in unmanaged urban meadows

There is little understanding of the role of exotic bees in the observed pollinator decline. Recent models of species invasions predict that aggressive species have more impact; applying this theory to pollinators suggests that aggressive territorial Anthidium (Megachilidae) bees, whose range is expanding globally, could have high impacts on native bees. We examined exploitation and interference competition for floral resources between Anthidium and native bees in unmanaged urban meadows in Montreal, Canada. First, we conducted a survey of floral visits by Anthidium and native bee genera. We found high niche overlap with Megachile (Megachilidae), one of the most common genera of native pollinators in the area, suggesting high potential for exploitation competition. Second, we tested for interference competition between Anthidium and Megachile with behavioural observations of foraging on a common introduced host plant (Lotus corniculatus, Fabaceae). This presence of Anthidium decreased patch residence and number of floral visits by Megachile bees, suggesting that Anthidium has a significant per capita effect on foraging behavior of Megachile.

Synergistic impacts of aggressive species on small birds in a fragmented landscape

Abstract Attempts to conserve threatened species in fragmented landscapes are often challenging because factors such as habitat loss, habitat degradation and dominant species interact to reduce threatened species’ capacity to survive and reproduce. Understanding how threatening and mitigating processes interact is critical if conservation measures are to be effective. We used data from long‐term monitoring of bird populations and multivariate latent variable models to quantify how Australian woodland birds respond to the presence of the Noisy Miner, a despotic species known to exclude other bird species. We then investigated the extent to which the presence of other aggressive species exacerbates the impacts of the Noisy Miner, and to what extent these impacts can be mitigated by dense midstorey plantings. We found strong synergies between the Noisy Miner and two other aggressive species (Grey Butcherbird and Pied Butcherbird), despite weak effects of butcherbirds in isolation. The impacts of aggressive birds are most pronounced for small‐bodied species, but these impacts are lessened in the presence of high midstorey cover. Synthesis and applications. Accounting for interactions reveals that revegetation may be capable of improving conservation outcomes even when the proximate cause of species declines (i.e. exclusion or predation by aggressive bird species) cannot be managed directly.

A needle in a seedstack: an improved method for detection of rare alleles in bulk seed testing through KASP.

Amaranthus palmeri is an aggressive and prolific weed species with major impact on agricultural yield and is a prohibited noxious weed across the Midwest. Morphological identification of A. palmeri from other Amaranthus species is extremely difficult in seeds, which has led to genetic testing for seed identification in commercial seed lots. We created an inexpensive and reliable genetic test based on novel, species-specific, single nucleotide polymorphisms (SNPs) from GBS (Genotyping by Sequencing) data. We report three SNP-based genetic tests for identifying A. palmeri alone or in a mixed pool of Amaranthus spp. Sensitivity ranged from 99.8 to 100%, specificity from 99.59 to 100%. Accuracy for all three tests is > 99.7%. All three are capable of reliably detecting one A. palmeri seed in a pool of 200 Amaranthus spp. seeds. The test was validated across 20 populations of A. palmeri, along with eight other Amaranthus species, the largest and most genetically diverse panel of Amaranthus samples to date. Our work represents a marked improvement over existing commercial assays resulting in an identification assay that is (i) accurate, (ii) robust, (iii) easy to interpret and (iv) applicable to both leaf tissue and pools of up to 200 seeds. Included is a data transformation method for calling of closely grouped competitive fluorescence assays. We also present a comprehensive GBS dataset from the largest geographic panel of Amaranthus populations sequenced. Our approach serves as a model for developing markers for other difficult to identify species. © 2021 Society of Chemical Industry.

The State of the Ash-Leaved Maple (Acer negundo L.) in the Barnaul Ribbon Pine Forest

Ash-leaved maple is one of the most aggressive alien species in most Russian regions. It was first brought to the Altai Krai in 1933. For a long time, maple had been used in the urban and village greenery planting and tree belt areas. Nowadays, it is actively settling along riverbanks, roadsides, abandoned lands, etc. Ash-leaved maple is a danger as a transformer species, preventing the pine’s reproduction in the unique natural communities – ribbon pine forests. We studied the state of the Acer negundo L. populations as a transformer species in the Barnaul ribbon pine forest. The maple population status was assessed by the transect method at the selected registration sites. The age of plants was determined by the method of T. A. Rabotnov. The first ordered branches were used for a more detailed characterization of the maple populations. The introduction of maples into the Pinus sylvestris L. communities is associated with a significant anthropogenic impact on the natural communities of the ribbon pine forest. There are pure maple communities formed in some places in the northern part of the ribbon pine forest. Throughout the Barnaul ribbon pine forest, the maple populations are normal and invasive only in the south part. The first-ordered maple branches in the southern part of the ribbon pine forest have signs of apex change associated with adverse ecological factors. The development indicators of maple trees along the entire ribbon pine forest were evaluated for the first time. The results indicate the high adaptability of maple to various ecological factors.

The role of invasion and urbanization gradients in shaping avian community composition

Abstract The extent to which native species utilize urban environments depends on species responses to multiple threatening processes. Here, we aimed to quantify changes in bird communities in response to changing habitat structure, invasive species and aggressive native species. We conducted surveys in two independently invaded regions with similar patterns of urban development. The study regions were New South Wales (NSW) and Queensland (QLD), Australia. We observed 127 species in NSW and 144 species in QLD. Most species (NSW 83 and QLD 84) are urban adapters making use of some or all urban sub-environments. Urban avoiders, species only found in remnant vegetation, were the second largest group (urban avoiders: NSW 23 and QLD 31). We found the lowest richness in the most urban sites (urban exploiters: NSW 10 and QLD 15). Using generalized linear mixed models, we found a non-significant relationship between species richness and the abundance of aggressive species like the common myna and noisy miners, Manorina melanocephala, but a significant positive correlation with the percentage of shrub cover at a site. As there is a gradual loss of species with increasing urbanization, retaining higher complexity in vegetation structure in urban areas will support large numbers of species and could help mitigate the potential impacts of aggressive urban-adapted species and habitat loss.

Differential flight responses of two ambrosia beetles to ethanol as indicators of invasion biology: the case with Kuroshio shot hole borer (Euwallacea kuroshio) and fruit‐tree pinhole borer (Xyleborinus saxesenii)

1. Host selection and utilization by ambrosia beetles ranges from healthy trees to weakened, dying, or dead trees. Compared to weakened trees, healthy trees emit little to no ethanol, which is stress‐induced and a by‐product of anaerobic respiration. The current study tested the attraction of two invasive ambrosia beetles, Kuroshio shot hole borer (KSHB), one member of the species complex, Euwallacea nr. fornicatus, and fruit‐tree pinhole borer, Xyleborinus saxesenii, to four treatments with or without ethanol.2. GC–MS analyses confirmed the release of ethanol from the ethanol lure and boxelder log filled with ethanol and not from the other two treatments. Kuroshio shot hole borer was not preferentially attracted to any ethanol treatment, whereas X. saxesenii responded positively to the ethanol treatments. The boxelder bolt infused with ethanol was the most attractive treatment to X. saxesenii.3. We propose that the differential behavioural responses of these two ambrosia beetles to ethanol correspond to their differential aggressiveness for attacking healthy trees: KSHB attacks healthy trees, whereas X. saxesenii attacks weakened trees. The proposal is further substantiated by a literature survey on bark and ambrosia beetles from Scolytinae. The survey also indicates that the majority of bark and ambrosia beetles from Scolytinae respond positively to ethanol.4. Although ethanol is widely used and is an effective lure for attraction of many bark and ambrosia beetles, findings from this current study and many others necessitate research and development of alternative lures for more aggressive species which are ecologically and economically more devastating.

Epidermis microstructure inspired mica-based coatings for smart corrosion protection

Two-dimensional (2D) graphene-like nanomaterials have gained interest in anticorrosion coatings due to their enable to act as physical barriers to aggressive species, yet 2D coatings are not always effective or sustainable. Inspired by the epidermis microstructure, herein we designed a high-performance anticorrosion coating with rapid self-healing ability via integrating the excellent adhesion property of polydopamine (PDA) and superior barrier properties of natural mica nanosheets (MNSs) for the first time. Such the coating comprises a protective hard top layer with MNSs constituents (“sealing” agents) and a bottom hybrid soft polymer multilayer, forming a stratified epidermis microstructure, can realize a complete restoration of coating defects under water owing to their mutual benefit. These MNSs not only can enhance the barrier performance of the coating matrix to retard the diffusion of aggressive species and hamper polymer release into water, but also induce an anisotropic diffusion to promote the self-healing of the polymer chains. The microstructures of the bioinspired coatings were systemically investigated by scanning electron microscopy (SEM) and optical microscopy (OM) measurements. Electrochemical results confirmed the anticorrosion performance of the coatings were significantly improved. This work provides a new insight for the design and fabrication of 2D nanomaterials reinforced high-performance and smart anticorrosion coatings.

Effect of low temperature culture on the biological characteristics and aggressiveness of Sclerotinia sclerotiorum and Sclerotinia minor

Sunflower White Mold caused by Sclerotinia sclerotiorum and Sclerotinia minor is a devastating disease worldwide. To investigate the effect of low temperature (4 °C) on biological characteristics and aggressiveness of isolates of the two species, which were collected from the same field in Baiyinchagan, Inner Mongolia, their mycelial growth rate, oxalic acid secretion level and polygalacturonase activity were compared under normal culture temperature (23 °C) and low temperature (4 °C). Aggressiveness was also evaluated on detached leaves by inoculating the isolates produced in both temperatures. The results suggested that culture of isolates at 4 °C not only promoted mycelial growth, but also enhanced secretion of oxalic acid and polygalacturonase activity of both S. sclerotiorum and S. minor isolates compared to that cultured at 23 °C. Additionally, the corresponding aggressiveness of tested isolates of the two species also increased after culture at 4 °C. However, S. sclerotiorum always showed faster mycelial growth, higher oxalic acid levels and greater polygalacturonase activity than S. minor at both 23 °C and 4 °C, indicating that S. sclerotiorum is generally the more aggressive species than S. minor.

Database of anthropogenic vegetation of the Urals and adjacent territories

The main data on the geobotanical database – Database of antropogenic vegetation of Urals and adjacent territories registered in the Global Index of Vegetation-Plot Databases and the European Vegetation Archive are presented. The database includes more than 4,000 complete geobotanical relevés made between 1984 and 2020. The database contains the territories of 3 subjects of the Russian Federation (the Republic of Bashkortostan, Orenburg, Chelyabinsk regions) and 1 - the Republic of Kazakhstan (Aktobe region). For each relevés, a complete list of species with indication of abundance in points on the Braun-Blanquet scale. The main indicators (total cover, average height of the grass, etc.). For most descriptions, GPS coordinates and location are given. The ecological conditions were assessed with use of average values of E. Landolt scale. In the J. Braun-Blanquet classification system, all communities included in the database belong to nine vegetation classes (7 anthropogenic and 2 semi-natural), 75 associations and various types of communities. Geobotanical relevés with the dominance of such aggressive invasive species (Acer negundo, Ambrosia psylostachya, Echinocystis lobata, Elodea canadensis, Solidago canadensis, Heracleum sosnowskyi, Hordeum jubatum, Xanthium albinumetc.) are also included in the database.

Everything Like Before by Kjell Askildsen

BOOKS IN REVIEW Kjell Askildsen Everything Like Before Trans. Seán Kinsella. New York. Archipelago Books. 2021. 275 pages. “I LIVE IN A basement; a result of having come down in the world, in every sense.” So begins “A Sudden Liberating Thought,” one of thirty-seven stories that comprise Everything Like Before, Norwegian writer Kjell Askilden’s newest collection of fiction , which typifies his darkly ironic take on the absurd. Askilden’s characters tend to experience spiritual injury in the form of an amorphous stab from the distant past, unknowable and condemning, that is brought into the present through an almost arbitrary impetus: the page number of a book, opening a second bottle of wine, or sharing a park bench with a stranger. In the aforementioned story, an unnamed narrator’s peaceful walk through the park is interrupted by a stranger who seemstomirrorthenarrator’sownthoughts and actions. Only later is it revealed that the stranger is actually a judge and the narrator a convicted criminal from an age-old court case. Both crime and punishment are blurred by lack of detail, so this insight provides no resolution and instead preserves his life in the basement. Askilden’s interest in the condemned is further developed in “I’m not like this, I’m not like this.” While visiting his disabled sister, the dutiful narrator befriends her elderly neighbor, a man who appears strikingly familiar but is ultimately unplaceable. It takes another family member to recognize the man as an infamous convicted murderer from years before. This man later confides in the narrator about his anxiety, only to self-interrupt by politely asking if he is being a bother. The narrator exits in a flurry of silent confusion; meanwhile violence and punishment, lodged so far in the past as to be almost prehistoric, obscure the tortured condition of this man’s soul. Resolution cannot be realized without first pinpointing the origin of conflict, and that is not within the remit of Askilden’s fiction. Despite the dark subject matter, the stories make for bracing reading due to Askilden’s spare prose and the sly humor that arrives unexpectedly in the middle of a character’s downfall. One character’s bender is thus punctuated with a line such as “He drank, and it grew dark, and he got on well with himself,” and an old man at the park idly ponders, “If for some reason an airplane were to explode in the sky, I wouldn’t mind being one of the people— preferably the only one—who witnessed it.” Such rueful quips abound throughout this collection and lend a refreshing lightness to Askilden’s bleak vision of the absurd. Phillip Garland St. Louis, Missouri Yamen Manai The Ardent Swarm Trans. Lara Vergnaud. Seattle. Amazon Crossing. 2021. 204 pages. COMMITTED TO KEEPING Tunisian works available in Tunisia, Yamen Manai has hitherto published with Éditions Elyzad. Now, Amazon Crossing and award-winning translator Lara Vergnaud have brought The Ardent Swarm from the French into English, and we can only hope that Manai’s other novels will follow. Opening with “The Bee” from the Quran, The Ardent Swarm takes place in the fictional mountain village of Nawa, North Africa. We meet and quickly fall in love with the humble Sidi, a beekeeper devoted to the safety and prosperity of “his girls,” the honeybee hive he has grown and lovingly tends. A foreign threat has appeared, however. Unknown to importers , an aggressive species of hornets has stowed away in their cargo, goods that provide the link to the other component of Manai’s story. The country is in transition with its first democratic election on the horizon. Soldiers patrol the road from Nawa as the villagers make their way to the city to sell their meager harvest. A party of fundamentalists comes to solicit votes from the people, who would be wise to “beware Greeks bearing gifts.” The campaigners arrive with cargo crates full of food, blankets , and other luxuries as a preview of their platform and tell the people to simply “vote for the Pigeon on the ballot,” since most of the Nawa residents are unable to read and write. Shaw’s Major Barbara comes to mind...

The Ardent Swarm by Yamen Manai

BOOKS IN REVIEW Kjell Askildsen Everything Like Before Trans. Seán Kinsella. New York. Archipelago Books. 2021. 275 pages. “I LIVE IN A basement; a result of having come down in the world, in every sense.” So begins “A Sudden Liberating Thought,” one of thirty-seven stories that comprise Everything Like Before, Norwegian writer Kjell Askilden’s newest collection of fiction , which typifies his darkly ironic take on the absurd. Askilden’s characters tend to experience spiritual injury in the form of an amorphous stab from the distant past, unknowable and condemning, that is brought into the present through an almost arbitrary impetus: the page number of a book, opening a second bottle of wine, or sharing a park bench with a stranger. In the aforementioned story, an unnamed narrator’s peaceful walk through the park is interrupted by a stranger who seemstomirrorthenarrator’sownthoughts and actions. Only later is it revealed that the stranger is actually a judge and the narrator a convicted criminal from an age-old court case. Both crime and punishment are blurred by lack of detail, so this insight provides no resolution and instead preserves his life in the basement. Askilden’s interest in the condemned is further developed in “I’m not like this, I’m not like this.” While visiting his disabled sister, the dutiful narrator befriends her elderly neighbor, a man who appears strikingly familiar but is ultimately unplaceable. It takes another family member to recognize the man as an infamous convicted murderer from years before. This man later confides in the narrator about his anxiety, only to self-interrupt by politely asking if he is being a bother. The narrator exits in a flurry of silent confusion; meanwhile violence and punishment, lodged so far in the past as to be almost prehistoric, obscure the tortured condition of this man’s soul. Resolution cannot be realized without first pinpointing the origin of conflict, and that is not within the remit of Askilden’s fiction. Despite the dark subject matter, the stories make for bracing reading due to Askilden’s spare prose and the sly humor that arrives unexpectedly in the middle of a character’s downfall. One character’s bender is thus punctuated with a line such as “He drank, and it grew dark, and he got on well with himself,” and an old man at the park idly ponders, “If for some reason an airplane were to explode in the sky, I wouldn’t mind being one of the people— preferably the only one—who witnessed it.” Such rueful quips abound throughout this collection and lend a refreshing lightness to Askilden’s bleak vision of the absurd. Phillip Garland St. Louis, Missouri Yamen Manai The Ardent Swarm Trans. Lara Vergnaud. Seattle. Amazon Crossing. 2021. 204 pages. COMMITTED TO KEEPING Tunisian works available in Tunisia, Yamen Manai has hitherto published with Éditions Elyzad. Now, Amazon Crossing and award-winning translator Lara Vergnaud have brought The Ardent Swarm from the French into English, and we can only hope that Manai’s other novels will follow. Opening with “The Bee” from the Quran, The Ardent Swarm takes place in the fictional mountain village of Nawa, North Africa. We meet and quickly fall in love with the humble Sidi, a beekeeper devoted to the safety and prosperity of “his girls,” the honeybee hive he has grown and lovingly tends. A foreign threat has appeared, however. Unknown to importers , an aggressive species of hornets has stowed away in their cargo, goods that provide the link to the other component of Manai’s story. The country is in transition with its first democratic election on the horizon. Soldiers patrol the road from Nawa as the villagers make their way to the city to sell their meager harvest. A party of fundamentalists comes to solicit votes from the people, who would be wise to “beware Greeks bearing gifts.” The campaigners arrive with cargo crates full of food, blankets , and other luxuries as a preview of their platform and tell the people to simply “vote for the Pigeon on the ballot,” since most of the Nawa residents are unable to read and write. Shaw’s Major Barbara comes to mind...

Findings of invasive and potentially invasive plant species in the Western regions of the Republic of Bashkortostan

Invasions of aggressive alien plant species that have a high rate of expansion and pose a threat to ecosystems and their biodiversity have become more active in the 21st century due to anthropogenic disturbances of vegetation cover, the lack of systematic control of their numbers, the expansion of transport corridors, etc. Research for the search of new locations of adventitious plant species is carried out in the Republic of Bashkortostan especially intensively during the last 10 years. The result of this work was the publication of the "blacklist" flora of Bashkortostan [1] including 100 invasive and potentially invasive plants and "Synopsis of adventive species of the Republic of Bashkortostan" [13], who presented data on 457 localities of alien plant species, is not peculiar to the nature of Bashkortostan. This article is an addition to the previously published data obtained during the route expedition research in 2019-2020, conducted in the Western regions of the Republic. More than 150 new localities of 22 invasive and potentially invasive plant species were identified. 11 species are included in the “Black book of flora of Central Russia” [9]. The data obtained clarify and expand the understanding of the modern secondary range of invasive plants on the territory of the Republic.

УРБАНОФЛОРА ГОРОДА ЯНАУЛ (РЕСПУБЛИКА БАШКОРТОСТАН)

The work is based on the data of field studies carried out by the route method during 2017–2018 within the ad-ministrative boundaries of Yanaul city (Republic of Bashkortostan). According to research results, the flora of Yanaul includes 485 species of vascular plants from 286 genera and 81 families; 174 species are adventive, of which 38 can be classified as invasive and potentially invasive species. Among the most aggressive invasive species are Acer negundo, Echinocystis lobata, Elodea canadensis, Heracleum sosnowskyi, Hordeum jubatum, Lupinus polyphyllus, Xanthium album. Also, large areas within the city are occupied by an invasive species Soli-dago gigantea. 1 relict species (Campanula trachelium) was recorded, growing in the preserved areas with natu-ral vegetation. For each species, the attachment to certain habitats and the frequency of occurrence are given. For adventive species, information on the time, way of invasion and degree of naturalization are indicated. For inva-sive species, their status is indicated.

Resistance of graphene oxide-modified cement pastes to hydrochloric acid attack

This study investigated the hydration, rheology, and diffusion resistance of cement pastes involving up to 0.09 wt% graphene oxide (GO) under constant exposure to hydrochloric (HCl) acid for four weeks. Samples containing 0.09 wt% GO revealed a reduction in mass loss and sectional area loss when compared to the control sample without any GO, highlighting the potential of GO inclusion in improving the resistance of the cement matrix to acid attack. While higher GO dosages reduced the workability and hydration of the fresh paste, the use of GO improved the diffusion resistance of the cement matrix against HCl exposure by densifying the microstructure. The presence of alumina-silica hydrogel was observed in the altered zones of the acid exposed specimens. While this chemical change occurred in all GO-modified pastes, the micro-hardness of the sample containing 0.09 wt% GO was higher than the control sample (i.e. without any GO). The obtained results indicated that the inclusion of up to 0.045 wt% GO increased the micro-hardness and reduced the leaching of aluminium and silicon ions, which could effectively prevent the increased formation of microcracks and form a protective barrier against aggressive species in extreme environments.

Valorization of Gleditsia triacanthos Invasive Plant Cellulose Microfibers and Phenolic Compounds for Obtaining Multi-Functional Wound Dressings with Antimicrobial and Antioxidant Properties.

Gleditsia triacanthos is an aggressive invasive species in Eastern Europe, producing a significant number of pods that could represent an inexhaustible resource of raw material for various applications. The aim of this study was to extract cellulose from the Gleditsia triacanthos pods, characterize it by spectrophotometric and UHPLC–DAD-ESI/MS analysis, and use it to fabricate a wound dressing that is multi-functionalized with phenolic compounds extracted from the leaves of the same species. The obtained cellulose microfibers (CM) were functionalized, lyophilized, and characterized by ATR-FTIR and SEM. The water absorption and retention capacity as well as the controlled release of phenolic compounds with antioxidant properties evaluated in temporal dynamics were also determined. The antimicrobial activity against reference and clinical multi-drug-resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae, Candida albicans, and Candida parapsilosis strains occurred immediately after the contact with the tested materials and was maintained for 24 h for all tested microbial strains. In conclusion, the multi-functionalized cellulose microfibers (MFCM) obtained from the reproductive organs of an invasive species can represent a promising alternative for the development of functional wound dressings with antioxidant and antimicrobial activity, as well as being a scalable example for designing cost-effective, circular bio-economy approaches to combat the accelerated spread of invasive species.

THE COMPOSITION AND CONTENT OF PHENOLIC COMPOUNDS IN THE LEAVES OF A POTENTIALLY INVA-SIVE SPECIES PHYSOCARPUS OPULIFOLIUS (L.) MAXIM. AND ITS ORNAMENTAL CULTIVARS

The expansion of alien plant species in natural communities is now taking a global scale. Since most invasive plants have economically valuable properties, many researchers agree that these plants must be used as new sources of biological resources. The composition and content of biologically active compounds were studied in the leaves of potentially invasive species of Novosibirsk – Physocarpus opulifolius (L.) Maxim. and its ornamental cultivars Ph. opulifolius ‘Diabolo’, Ph. opulifolius ‘Luteus’ by the method of High-Performance Liquid Chromatography. For the first time an analysis of phenolic profiles of introduced, self-sown and cultivated Ph. opulifolius plants has been performed. Presence of 22 phenolic compounds represented by several groups of substances with predominating flavanols (hyperoside, rutin, astragalin and quercetin) has been established. Avicularin has been only revealed in the leaves of cultivars. The sum of identified flavonols greatly varies in different samples, the highest content is in the cultivar Ph. opulifolius ‘Diabolo’ (14.68 mg/g) and self-sown plants of Ph. opulifolius (14.22 mg/g). The content of the sum of identified flavons (vitexin, isovitexin, baicalin) and phenolic acid (сhlorogenic and caffeic acids) is almost the same in all Ph. opulifolius samples under study. The data obtained will allow to widen the idea of the resource potential of the aggressive invasive species and its ornamental cultivars in the secondary areal.

Mecanismos de defensa en plantas. Proteínas relacionadas con la patogenicidad

Desde sus orígenes, las plantas terrestres vasculares han coexistido con una amplia variedad de bacterias y hongos. Con la aparición de los insectos, de igual forma mantuvieron una estrecha relación con estos, tomando un carácter especial con la llegada de las plantas con flores en el período Cretácico temprano. Los diferentes procesos evolutivos han propiciado el desarrollo de una serie de relaciones interespecíficas, algunas de ellas beneficiosas para ambas partes como pudieran ser los variados mecanismos de polinización por medio de insectos en muchas especies de plantas y al mismo tiempo han surgido otros tipos de interacciones con especies capaces de producir enfermedades serias en las diferentes partes de las plantas. Esta presión de selección, unido a la imposibilidad de defensa que ofrece la locomoción, así como la carencia de un sistema de defensa basado en anticuerpos, han sido las principales responsables de la aparición en las plantas de complejos mecanismos de defensa, muchas veces rápidos y eficaces frente a las especies agresoras y otras veces no. La manifestación de las patologías en las plantas depende de complejas interacciones entre el huésped y el patógeno, lo que es un indicador de su evolución conjunta. De aquí la exquisita regulación de los mecanismos de agresión/defensa y la correspondiente selectividad en el reconocimiento de agentes agresores externos, lo que puede explicar la diferente sensibilidad de distintas especies o incluso diferentes variedades dentro de la misma especie. Desde hace un tiempo a la fecha, los investigadores han mostrado mucho interés en ciertas proteínas sintetizadas por la planta cuando es atacada por un microorganismo patógeno. Dado que aparecen en condiciones patológicas, han sido nombradas proteínas relacionadas con la patogenicidad o PR.

Beyond the gardens: The extended mutualism from ant‐garden ants to nectary‐bearing plants growing in Amazon tree‐fall gaps

AbstractThe regime of frequent small disturbances, such as the formation of tree‐fall gaps, is an important mechanism maintaining the diversity in tropical forests. Occurring primarily in forest gaps, or in riparian vegetation, ant gardens (hereafter AGs) are mutualistic associations involving several epiphytic plant species and ants. In the Amazon rainforest, a widespread AGs association is assembled by two aggressive species of parabiotic ants (Camponotus femoratus and Crematogaster levior). Working together, these ants aggressively monopolize food resources and attack any intruder on the AGs. Here, we demonstrated the extended protective effect of parabiotic ants on the leaf herbivory of neighboring plants, contrasting plants with and without extrafloral nectaries (hereafter EFNs). We performed the fieldwork in South Amazonia where we found 33 forest gaps, 16 with and 17 without AGs. Independently of the presence of AGs, plants possessing EFNs have less area removed by herbivores and fewer leaves with herbivore marks than those without EFNs. This decrease in herbivory was remarkable on EFN‐plants growing in gaps that also harbor AGs. Additional manipulative experiments confirmed this pattern: The AG‐ants were more efficient than no‐AG ants in removing live termite baits placed on EFN‐plants, but few attacks were observed on plants without EFNs. Thus, AG‐ants can extend their role in defending ant gardens from other plants growing in the same area, particularly those with EFNs. This extension of the mutualism benefits can affect the dynamics of the ecological succession and coevolutionary process in the Amazon forest.Abstract in Portuguese is available with online material

Modeling of MRP Protection Considering Chemical Inhibition, Electrochemistry, and Mass Transport

Aluminum alloy AA2024-T3 is widely used in aerospace applications due to its high strength-to-weight ratio. However, because of its heterogeneous microstructure, it is susceptible to microgalvanic corrosion and pitting in chloride containing environments, requiring additional corrosion protection methods. Organic coatings are the primary corrosion protection method used in aluminum alloys and they are usually composed of pigments embedded in a polymeric matrix. The polymeric matrix promotes a high resistance to ionic movement and it provides barrier against the ingress of aggressive species onto the substrate. The pigments can provide corrosion protection by inhibiting corrosion reactions, providing cathodic protection to the substrate, and/or depositing a protective layer on the surface of the substrate. Recently, a coating system containing a Mg-rich primer (MgRP) has emerged as an effective alternative to the chromate-based coatings commonly used for this purpose. Due to the lower potential of Mg, MgRP can protect aluminum alloys via galvanic coupling, serving as a sacrificial anode and preventing the corrosion of the Al substrate. Additionally, recent studies showed that the electrolyte chemistry resulting from Mg dissolution is beneficial to localized corrosion inhibition of AA2024, providing corrosion protection even after pigment depletion.Localized corrosion of coated Al alloys can be affected by a large number of variables, such as water layer thickness, salt loading, pigment volume concentration of primer, chemistry of the primer, galvanic effects of pigment. and component geometry. The efficacy of the organic coating also depends on many variables. Exposure of the coating to UV radiation and aggressive solutions causes degradation of the polymeric matrix, which reduces the resistance to ionic movement and protection of the substrate against aggressive species. Thus, it is difficult to predict and quantify damage by localized corrosion, in addition to the efficacy and lifetime of a coating system.In this context, modeling can be used as a valuable assessment of parameter space to increase efficiency of experimental work. The objective of this work was to model the protection mechanisms offered by a MgRP coating system in AA2024, and investigate the influence of different variables on the effectiveness of the protection mechanism. The mechanisms of importance include protection via (a) the Mg pigment particles acting as sacrificial anodes, (b) the barrier to ion transport effected by the organic coating, and (c) changes in the electrolyte chemistry from dissolution of the Mg pigment particles. The modeling considers each of these protection mechanisms in isolation as well as in combination. Ultimately, this model will provide a better understanding and prediction of the protection mechanisms of the MgRP system and serve as a framework to study new coating systems.AcknowledgementsFinancial support from the SERDP program through the Office of Naval Research (C. Sanders) via Contract N00173-19-1-G011 as well as the DOD Corrosion Program Office through the US Air Force Academy via Contract FA7000-18-2-0006 is gratefully acknowledged.