ABSTRACT We hypothesized that common ragweed has rapid growth and development in shoots and roots, which explains its high potential for establishment in the areas, as well as the high regrowth ...capacity after cutting or application of contact herbicides. This study aims to evaluate the growth of the specie Ambrosia artemisiifolia. The treatments consisted of collection periods of common ragweed plants at fixed intervals of ten days, from 15 to 95 days after emergence (DAE), totaling nine evaluations. In each collection, the aerial part and the roots were evaluated. In the aerial part, stature, leaf area, number of leaves, and dry mass were evaluated. From these data, the absolute growth rate, relative growth rate, net assimilation rate and leaf weight ratio were calculated. The length, surface area, volume, average diameter, number of root tips, and dry mass were evaluated in the root. The common ragweed plants show rapid growth after emergence, with a similar response in aerial parts and roots. The potential for competition with crops is expressive. Furthermore, due to growth and development characteristics, the potential for regrowth is high and impacts the difficulties in controlling this species. Thus, the authors indicate that control should be carried out within a maximum of 25 days after emergence.
Abstract The invasion of common ragweed in Slovakia was analysed based on 1635 collected records. More than 70 years have passed since the first record was sampled in 1949. Since then, it has spread ...in two waves, first in the lowlands, next to farmland and human settlements, and later in the mountains, on the roadsides. In the present, it is probably expanded in half of the territory of Slovakia. It is changing habitat preferences and adapting to new environments. Using eleven environmental and geographical variables, the species distribution modelling was performed to obtain probability of occurrence in high resolution (30 s) in Slovakia. Four predictions were calculated based on two models. The first prediction was based on the first model trained on ragweed records before the start of the second expansion wave in 2000. The second prediction is based on the first model and predicts the present distribution according to current climatic conditions, which have changed in twenty years. The third prediction was based on the second model, trained on all 1635 collected records from 1949 to 2022. The fourth prediction based on the second model shows the potential distribution in 2040–2061. Comparing the predictions, the climatic changes explain current expansion of common ragweed in mountains since the air temperature is the main factor shaping distribution of common ragweed in Slovakia.
Climate change may affect plant–herbivore interactions and their associated ecosystem functions. In an experimental evolution approach, we subjected replicated populations of the invasive Ambrosia ...artemisiifolia to a combination of simulated warming and herbivory by a potential biocontrol beetle. We tracked genomic and metabolomic changes across generations in field populations and assessed plant offspring phenotypes in a common environment. Using an integrated Bayesian model, we show that increased offspring biomass in response to warming arose through changes in the genetic composition of populations. In contrast, increased resistance to herbivory arose through a shift in plant metabolomic profiles without genetic changes, most likely by transgenerational induction of defences. Importantly, while increased resistance was costly at ambient temperatures, warming removed this constraint and favoured both vigorous and better defended plants under biocontrol. Climate warming may thus decrease biocontrol efficiency and promote Ambrosia invasion, with potentially serious economic and health consequences.
Will climate change increase or decrease biocontrol efficacy against a plant invader? We combined experimental evolution of field Ambrosia populations with tracking both their genomic and metabolomic changes across generations, and with common garden phenotyping experiments of the offspring generations. While selection by climate warming led to consistent changes in the genetic composition of the Ambrosia populations, beetle herbivory changed plant metabolomic profiles without corresponding genetic changes, with global warming to decrease the efficacy of biocontrol and increase the invasion potential of the plant invader.
Because common ragweed (Ambrosia artemisiifolia L., henceforth Ambrosia) has negative effects on human health, it is a common focus for management, which would benefit from a better understanding of ...the underlying mechanisms by which the species spreads. Road systems are known to be invasion corridors, but the conduit function of vehicles for the rapid spread of Ambrosia along roads and for population extension along roadside verges has not yet been demonstrated convincingly.
To quantify the effect of different traffic volumes on the dispersal and population extension of Ambrosia, we used two approaches: First, by combining field experiments along roads with records of the seed rain around single plants, we simulated a combined dispersal kernel that revealed the interactions between primary dispersal and traffic‐mediated secondary dispersal. Second, we recorded the seedling recruitment around isolated roadside populations over 2 years to determine how traffic‐related parameters affect population extension.
The longest traffic‐mediated dispersal distances exceeded those of primary dispersal by about one order of magnitude. Traffic volume had a significant positive effect on dispersal distances and on the lateral deposition of seeds on the road verge.
Seedling recruitment around isolated roadside populations was significantly higher in the driving direction than against, but only at the distance where the major seed rain of traffic‐mediated dispersal is to be expected according to the combined dispersal kernel (3–15 m).
Synthesis and applications. This study isolates the effects of road traffic from confounding mechanisms (e.g. mowing machinery, propagule pressure from infested fields) on common ragweed (Ambrosia artemisiifolia L.) invasions. Results demonstrate the traffic‐mediated dispersal in Ambrosia invasions as a routine and predictable process that facilitates population extension in the direction of traffic along roadsides, depending on traffic volume. This highlights the importance of prioritizing mowing along high use roads and mowing of isolated populations to prevent seed abscission and further spread of common ragweed.
Foreign Language Abstrakt
Das Beifußblättrige Traubenkraut (Ambrosia artemsiifolia L., im folgenden Ambrosia) übt einen starken negativen Einfluss auf die menschliche Gesundheit aus und ist daher im Fokus von Bekämpfungsmaßnahmen, die von einem besseren Verständnis der zugrundeliegenden Ausbreitungsmechanismen profitieren können. Straßennetzwerke sind zwar als Invasionskorridore für Neophyten bekannt, doch für Straßenfahrzeuge konnte bisher noch nicht überzeugend gezeigt werden, ob der Transport von Diasporen durch Fahrzeuge auch für die beschleunigte Ausbreitung von Ambrosia entlang der Straßen sowie ihres Populationswachstums am Straßenrand eine Rolle spielt.
Um den Effekt unterschiedlicher Verkehrsstärken auf die Diasporenausbreitung und das Populationswachstum zu untersuchen, nutzten wir zwei verschiedene methodische Ansätze: Zum einen verknüpften wir die Ergebnisse unserer Diasporenfreisetzungen in Straßenkorridoren mit der natürlichen Diasporenverteilung basierend auf isolierten Ambrosiapflanzen und verwendeten diese Daten zur Nachbildung eines kombinierten Ausbreitungsdistanzspektrums, der die Wechselwirkung zwischen Primär‐ und Sekundärausbreitung erkennbar macht. Zum anderen kartierten wir für einen Zeitraum von zwei Jahren die Sämlingsetablierung um isolierte Straßenrandpopulationen herum und analysierten, wie straßenfahrzeugbestimmte Parameter das Populationswachstum verändern.
Die erfassten Distanzen der am weitesten durch den Straßenverkehr ausgebreiteten Diasporen überschritten die der Primärausbreitung um etwa das Zehnfache. Das Verkehrsaufkommen hatte hierbei einen signifikant positiven Effekt auf die Ausbreitungsdistanzen sowie auf die laterale Ablagerung von Diasporen am Straßenrand.
Die Sämlingsetablierung um isolierte Straßenrandpopulationen herum war in Fahrtrichtung des Straßenverkehrs signifikant höher als entgegen der Fahrtrichtung, jedoch nur in dem Bereich, in dem sich die meisten von Fahrzeugen ausgebreiteten Diasporen gemäß unserem kombinierten Ausbreitungsdistanzspektrum angesammelt hatten (3–15 m).
Synthese und Anwendung. Diese Studie isoliert für das Beifußblättrige Traubenkraut (Ambrosia artemsiifolia L., im folgenden Ambrosia) die Effekte des Straßenverkehrs von den begleitenden Ausbreitungsmechanismen (z.B. Mahdmaschinen, Diasporeneinschleppungen von befallenen Äckern) auf den Invasionsprozess dieses Neophyten im Straßenkorridor. Die Ergebnisse zeigen, dass die Ausbreitung von Ambrosia durch Fahrzeuge ein häufiger und vorhersagbarer Prozess ist, der das Populationswachstum am Straßenrand in Verkehrsrichtung abhängig vom Verkehrsaufkommen fördert. Dies unterstreicht, wie wichtig eine prioritäre Mahd zur Unterbindung der Samenfreisetzung insbesondere in Straßen mit hoher Verkehrslast ist, wobei es entscheidend ist, auch isolierte Straßenrandpopulationen von Ambrosia mit in die Maßnahmen einzubeziehen. Nur so kann eine weitere Verbreitung dieses Neophyten im Straßennetzwerk eingedämmt werden.
This study isolates the effects of road traffic from confounding mechanisms (e.g. mowing machinery, propagule pressure from infested fields) on common ragweed (Ambrosia artemisiifolia L.) invasions. Results demonstrate the traffic‐mediated dispersal in Ambrosia invasions as a routine and predictable process that facilitates population extension in the direction of traffic along roadsides, depending on traffic volume. This highlights the importance of prioritizing mowing along high use roads and mowing of isolated populations to prevent seed abscission and further spread of common ragweed.
Common ragweed (Ambrosia artemisiifolia L.) is an invasive species, and is currently spread in different habitats over several regions in Turkey. However, no information exists on the seed ...germination biology of Turkish populations. Therefore, the seed germination niche (upper and lower limits of environmental conditions for seed germination) was determined for common ragweed populations in two climatic regions (Thrace and Black Sea) of Turkey. Seed germination was evaluated under different photoperiods, constant temperatures and levels of water stress, salinity and pH. Seedling emergence was recorded from various seed burial depths. Significant differences were observed among populations for the seed germination niche and seedling emergence. Seed germination niche helps explain the occurrence of the species in the diverse environmental conditions found across Turkey. Seeds from the Thrace populations were more tolerant to water and salinity stress and germinated under relatively higher pH levels than those from the Black Sea populations. Further, seeds from the Thrace region germinated to higher percentages at all temperatures than those from the Black Sea populations. Seeds from all populations germinated to higher percentages in light/dark than in dark. Seedling emergence was significantly retarded by a seed burial depth >4 cm. The results suggest that the species has extensive range expansion potential in the country and that immediate management of the naturalized populations is needed. In agricultural habitats, the species can be managed by shallow tillage and subsequent management of emerging seedlings to reduce the soil seed bank. Management strategies such as appropriate mowing time and mowing frequency need to be developed for control of roadside populations.
•Common ragweed has invaded considerable portions of Turkey.•Different populations exhibit significant differences in seed germination niche.•Seed germination niche indicates that species could expand its invasion range.•Integrated management efforts are required to manage the species.•Mowing regimes and tillage need to be thoroughly tested for control of the species.
Predicting plant distributions under climate change is constrained by our limited understanding of potential rapid adaptive evolution. In an experimental evolution study with the invasive common ...ragweed (Ambrosia artemisiifolia L.) we subjected replicated populations of the same initial genetic composition to simulated climate warming. Pooled DNA sequencing of parental and offspring populations showed that warming populations experienced greater genetic divergence from their parents, than control populations. In a common environment, offspring from warming populations showed more convergent phenotypes in seven out of nine plant traits, with later flowering and larger biomass, than plants from control populations. For both traits, we also found a significantly higher ratio of phenotypic to genetic differentiation across generations for warming than for control populations, indicating stronger response to selection under warming conditions. As a measure for evolutionary rate, the phenotypic and sequence divergence between generations were assessed using the Haldane metric. Our approach combining comparisons between generations (allochronic) and between treatments (synchronic) in an experimental evolutionary field study, and linking population genomic data with phenotyping analyses provided a powerful test to detect rapid responses to selection. Our findings demonstrate that ragweed populations can rapidly evolve in response to climate change within a single generation. Short‐term evolutionary responses to climate change may aggravate the impact of some plant invaders in the future and should be considered when making predictions about future distributions and impacts of plant invaders.
Predicting plant distributions under climate change is constrained by our limited understanding of potential rapid adaptive evolution. In an experimental evolution study with the invasive common ragweed (Ambrosia artemisiifolia L.) we subjected replicated populations of the same initial genetic composition to simulated climate warming. Pooled DNA sequencing of parental and offspring populations showed that warming populations experienced greater genetic divergence from their parents, than control populations. In a common environment, offspring from warming populations showed more convergent phenotypes in seven out of nine plant traits, with later flowering and larger biomass, than plants from control populations.
Key message
Being fed on
A. artemisiifolia
grown under elevated CO
2
and heat wave conditions resulted in the poor performance of
O. communa
(high mortality, long development period, and low ...reproduction).
Elevated CO
2
and heat waves resulted in the accumulation of secondary metabolites in
A. artemisiifolia
.
After feeding on the secondary metabolites accumulated by
A. artemisiifolia
, the mortality of
O. communa
increased.
To predict and mitigate the effects of climate change on communities and ecosystems, the joint effects of extreme climatic events on species interactions need to be understood. Using the common ragweed (
Ambrosia artemisiifolia
L.)—leaf beetle (
Ophraella communa
) system, we investigated the effects of heat wave and elevated CO
2
on common ragweed growth, secondary metabolism, and the consequent impacts on the beetle. The results showed that elevated CO
2
and heat wave facilitated
A. artemisiifolia
growth; further,
A. artemisiifolia
accumulated large amounts of defensive secondary metabolites. Being fed on
A. artemisiifolia
grown under elevated CO
2
and heat wave conditions resulted in the poor performance of
O. communa
(high mortality, long development period, and low reproduction). Overall, under elevated CO
2
, heat wave improved the defensive ability of
A. artemisiifolia
against herbivores. On the other hand, enhanced adaptability to climatic changes may aggravate invasive plant distribution, posing a challenge to the control of invasive plants in the future.
Rapid adaptive evolution and phenotypic plasticity are two mechanisms that often underlie invasiveness of alien plant species, but whether they can co‐occur within invasive plant populations under ...altered environmental conditions such as nitrogen (N) enrichment has seldom been explored. Latitudinal clines in plant trait responses to variation in environmental factors may provide evidence of local adaptation. Here, we inferred the relative contributions of phenotypic plasticity and local adaptation to the performance of the invasive plant Ambrosia artemisiifolia under different soil N levels, using a common garden approach. We grew A. artemisiifolia individuals raised from seeds that were sampled from six invasive populations along a wide latitudinal cline in China (23°42′ N to 45°43′ N) under three N (0, 5, and 10 g N m−2) levels in a common garden. Results show significant interpopulation genetic differentiation in plant height, number of branches, total biomass, and transpiration rate of the invader A. artemisiifolia across the N treatments. The populations also expressed genetic differentiation in basal diameter, growth rate, leaf area, seed width, root biomass, aboveground biomass, stomatal conductance, and intercellular CO2 concentration regardless of N treatments. Moreover, plants from different populations of the invader displayed plastic responses in time to first flower, hundred‐grain weight, net photosynthetic rate, and relative biomass allocation to roots and shoots and seed length under different N treatments. Additionally, individuals of A. artemisiifolia from higher latitudes grew shorter and allocated less biomass to the roots regardless of N treatment, while latitudinal cline (or lack thereof) in other traits depended on the level of N in which the plants were grown. Overall, these results suggest that rapid adaptive evolution and phenotypic plasticity in the various traits that we quantified may jointly contribute to invasiveness of A. artemisiifolia under different levels of N availability. More broadly, the results support the idea that phenotypic plasticity and rapid adaptive evolution can jointly enable invasive plants to colonize a wide range of environmental conditions.
摘要
快速适应进化和表型可塑性是阐释外来植物入侵的两个机制，但是它们是否可以在变化的环境条件下(比如氮富集)同时作用于入侵种群，这方面的研究还不多。植物性状对环境因子变化响应的纬度趋势可能提供了局域适应的证据。本文采用同质园实验的方法，探究表现可塑性和局域适应对入侵植物豚草(Ambrosia artemisiifolia)在不同土壤氮水平下表现的相对贡献。我们沿中国纬度梯度(23°42′ N–45°43′ N)收集六个豚草入侵种群的种子，分别设置三个氮水平(0，5以及10 g N m−2)种植在同质园中。结果表明，在不同的氮水平下，入侵豚草的株高、分枝数、总生物量和蒸腾速率存在显著的种群间遗传差异。在三种氮处理水平下，基径、生长速率、叶面积、种子宽度、根生物量、地上生物量、气孔导度和胞间二氧化碳浓度在种群间也存在遗传分化。在不同的氮处理下，来自不同种群的豚草植株在开花时间、百粒重、净光合速率、根冠比以及种子长度上表现出可塑性响应。此外，在所有氮处理水平下，来自更高纬度种群的豚草个体株高较小，分配到根部的生物量较少，而其他性状的纬度差异取决于氮处理水平。总之，研究结果表明，我们测量的各种性状中的快速适应性进化和表型可塑性可能联合作用，共同促进豚草在不同的氮水平下的入侵。广而言之，研究结果支持表型可塑性和快速适应性进化可以共同促进入侵植物在不同环境条件下定殖。
Pollen from common ragweed is an important allergen source worldwide and especially in western and southern Romania. More than 100 million patients suffer from symptoms of respiratory allergy (e.g., ...rhinitis, asthma) to ragweed pollen. Among the eleven characterized allergens, Amb a 6 is a non-specific lipid transfer protein (nsLTP). nsLTPs are structurally stable proteins in pollen and food from different unrelated plants capable of inducing severe reactions. The goal of this study was to produce Amb a 6 as a recombinant and structurally folded protein (rAmb a 6) and to characterize its physicochemical and immunological features. rAmb a 6 was expressed in Spodoptera frugiperda Sf9 cells as a secreted protein and characterized by mass spectrometry and circular dichroism (CD) spectroscopy regarding molecular mass and fold, respectively. The IgE-binding frequency towards the purified protein was evaluated using sera from 150 clinically well-characterized ragweed-allergic patients. The allergenic activities of rAmb a 6 and the nsLTP from the weed Parietaria judaica (Par j 2) were evaluated in basophil activation assays. rAmb a 6-specific IgE reactivity was associated with clinical features. Pure rAmb a 6 was obtained by insect cell expression. Its deduced molecular weight corresponded to that determined by mass spectrometry (i.e., 10,963 Da). rAmb a 6 formed oligomers as determined by SDS-PAGE under non-reducing conditions. According to multiple sequence comparisons, Amb a 6 was a distinct nsLTP with less than 40% sequence identity to currently known plant nsLTP allergens, except for nsLTP from Helianthus (i.e., 52%). rAmb a 6 is an important ragweed allergen recognized by 30% of ragweed pollen allergic patients. For certain patients, rAmb a 6-specific IgE levels were higher than those specific for the major ragweed allergen Amb a 1 and analysis also showed a higher allergenic activity in the basophil activation test. rAmb a 6-positive patients suffered mainly from respiratory symptoms. The assumption that Amb a 6 is a source-specific ragweed allergen is supported by the finding that none of the patients showing rAmb a 6-induced basophil activation reacted with Par j 2 and only one rAmb a 6-sensitized patient had a history of plant food allergy. Immunization of rabbits with rAmb a 6 induced IgG antibodies which strongly inhibited IgE binding to rAmb a 6. Our results demonstrate that Amb a 6 is an important source-specific ragweed pollen allergen that should be considered for diagnosis and allergen-specific immunotherapy of ragweed pollen allergy.
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