La especie introducida Fallopia japonica (Houtt.) Ronse Decr. es registrada por primera vez en las ciudades de Puerto Natales y Punta Arenas en la Patagonia chilena. En este trabajo se entregan ...evaluaciones de los envolventes climáticas en Patagonia y explora a las implicancias de la gestión ambiental en el control de esta especie invasora.
Reynoutria japonica (Japanese knotweed) is one of the most potent global invasive plant species; however, there is still insufficient knowledge on the impact of its invasion on arbuscular mycorrhizal ...fungi (AMF, Glomeromycota). The aim of our study was to assess the condition of AMF communities under the influence of R. japonica and determine the temporal and site-dependent variability of this influence. We studied AMF spore number, species richness, and composition as well as biomass in pairs of adjacent plots encompassing R. japonica and resident plant species. We established these pairs of plots in different habitat conditions (light and heavier soil conditions), and we sampled them four times (two spring and two summer seasons) to check if the potential impact of the invader on AMF communities is soil- and/or season-dependent. We found that the invasion reduced AMF spore number, species richness, and biomass, but had no effect on AMF species composition. AMF parameters varied over time (spore number, species composition and biomass) and depended on soil condition (species richness), but were barely affected by interactions between the studied factors. The lower performance of AMF communities in R. japonica plots was probably due to the displacement of resident mycorrhizal plant species. This displacement was not complete as some mycorrhizal plants, especially spring ephemerals, managed to survive the invasion. These were probably responsible for the maintenance of AMF communities in the patches of R. japonica. In conclusion, AMF communities are negatively affected by the invasion, but R. japonica does not entirely eliminate AMF, which is optimistic from the viewpoint of restoring sites invaded by this non-mycorrhizal alien plant species.
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•The impact of Reynoutria japonica invasion on AMF communities was studied.•The invasion reduced AMF spore number, species richness, and biomass.•R. japonica had no impact on AMF species composition.•The invasion effects on AMF did not interact with season and soil type.•R. japonica reduced AMF abundance but did not completely eliminate AMF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Reynoutria japonica is one of the most invasive plant species. Its success in new habitats may be associated with the release of secondary metabolites. The aim of this study was to compare phenolic ...concentrations in plant biomass and soils between plots with R. japonica and resident plants (control), and determine the effects of these compounds on soil microbial communities. Samples of plant shoots and rhizomes/roots, and soil were collected from 25 paired plots in fallow and riparian habitats in Poland. We measured concentrations of total phenolics, condensed tannins, catechin, chlorogenic acid, emodin, epicatechin, hyperoside, physcion, piceatannol, polydatin, procyanidin B3, quercetin, resveratrol, and resveratroloside. Soil microbial parameters were represented by acid and alkaline phosphomonoesterases, β-glucosidase, phenoloxidase, and peroxidase activity, culturable bacteria activity and functional diversity measured with Biolog Ecoplates, and microbial biomass and community structure measured with phospholipid fatty acid (PLFA) analysis. We found that concentrations of total phenolics and condensed tannins were very high in R. japonica leaves and rhizomes/roots, and concentrations of most phenolic compounds were very high in R. japonica rhizomes/roots when compared to resident plant species. Concentrations of most phenolics in mineral soil did not differ between R. japonica and control plots; the only exceptions were catechin and resveratrol which were higher and lower, respectively, under the invader. Total microbial and bacterial (G+, G–) biomass was decreased by approx. 30% and fungal biomass by approx. 25% in invaded soils in comparison to control. Among soil functional microbial parameters, only peroxidase activity and functional diversity differed between R. japonica and resident plant plots; peroxidase activity was higher, while functional diversity was lower in soil under R. japonica. The negative effects of R. japonica on microbial biomass may be related to catechin or its polymers (proanthocyanidins) or to other phenolics contained in high concentrations in R. japonica rhizomes.
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•Biomass of invasive Reynoutria japonica contained large amounts of phenolics.•Soil phenolic contents hardly differed between R. japonica and control.•Catechin was higher and resveratrol was lower in R. japonica relative to control soil.•Soil bacterial and fungal biomass were clearly reduced by invasion.•Invasion hardly affected the activity of soil microbial communities.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Microwave assisted preparation of activated carbon from Reynoutria japonica.•Xenobiotics removal from water by adsorption on active carbon was assessed.•Evaluation of sorption using ...nonlinear regression was carried out.•Type of activating agent had significant effect on sorbent characteristics.•H3PO4 agent gave the best active carbon for diclofenac and paracetamol sorption.
Japanese knotweed (JK) is considered one of the most problematic invasive plants. Great attention was paid to research any possibilities of reducing its occurrence. This work deals with possibilities of easy transformation of JK into carbon adsorbent (AC), which is usable for sorption of diclofenac and paracetamol. Activated carbons were prepared by microwave heating using H3PO4, NaOH and sodium methanolate as the chemical agents. Characterization of AC’s was carried out using BET, ATR-FTIR, SEM, adsorption equilibrium and kinetics experiments. The pseudo-second-order model showed the best similarity criteria for all studied systems adsorbent/adsorbate. The sorption efficiency was influenced by the choice of activating agent, where the π-π interactions between the planes of the obtained adsorbent and the aromatic rings of adsorbate and the interactions between the adsorbate and AC functional groups of the surface played an important role. AC-H3PO4 exhibited highest adsorption capacity for both diclofenac (87.09 mg.g−1) and paracetamol (136.61 mg.g−1).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The expansion of invasive species challenges our understanding of the process of adaptation. Given that the invasion process often entails population bottlenecks, it is surprising that many invasives ...appear to thrive even with low levels of sequence‐based genetic variation. Using Amplified Fragment Length Polymorphism (AFLP) and methylation sensitive‐AFLP (MS‐AFLP) markers, we tested the hypothesis that differentiation of invasive Japanese knotweed in response to new habitats is more correlated with epigenetic variation than DNA sequence variation. We found that the relatively little genetic variation present was differentiated among species, with less differentiation among sites within species. In contrast, we found a great deal of epigenetic differentiation among sites within each species and evidence that some epigenetic loci may respond to local microhabitat conditions. Our findings indicate that epigenetic effects could contribute to phenotypic variation in genetically depauperate invasive populations. Deciphering whether differences in methylation patterns are the cause or effect of habitat differentiation will require manipulative studies.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•In their exotic range R. japonica and R. sachalinensis hybridize into R. × bohemica.•The Murakami population of Aphalara itadori performs best on R. × bohemica.•This psyllid ...population causes most damage to R. × bohemica and R. sachalinensis.•We advise releasing this biocontrol agent population against R. × bohemica.
Aphalara itadori is a biological control agent of the invasive Asian knotweeds Reynoutria japonica, Reynoutria sachalinensis and their hybrid Reynoutria × bohemica, which emerged across different areas of their introduced range, including Europe, North America and Oceania. The performance of A. itadori on these three target plants differs between geographically distant psyllid populations. A petition to release a population of this psyllid freshly collected in Murakami (Japan) to control the three target species in the Netherlands was approved in 2020. In order to optimize a biocontrol program using this A. itadori population, we assessed the effect of the three knotweed species on its performance, impact on plant growth and oviposition preference. The results of no-choice experiments indicated that the Murakami population performed best on R. × bohemica, where juveniles developed the fastest and the number of emerged adults was twice as high as that recorded on the other two Reynoutria hosts. These differences in performance between hosts were associated with a lower acceptance of R. sachalinensis for oviposition and a higher juvenile mortality on R. japonica. Infestation with the Murakami population had an overall negative impact on final stem length, so that infested plants were around 8 % shorter than control plants, and it reduced final rhizome fresh biomass by circa 50 % in R. sachalinensis and 35 % in R. × bohemica. When subjected to two-choice tests, females of the Murakami population did not show an oviposition preference for any of the Reynoutria species. These results suggest that in the Netherlands R. × bohemica is the best host to optimize the rearing of the Murakami population, and field releases should target this host species to promote establishment in the field. Based on these results, the Murakami population is expected to have the largest impact in the field on R. × bohemica and R. sachalinensis.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The role that epigenetic inheritance can play in adaptation may differ between sexuals and asexuals because (1) the dynamics of adaptation differ under sexual and asexual reproduction and the ...opportunities offered by epigenetic inheritance may affect these dynamics differently; and (2) in asexual reproduction epigenetic reprogramming mechanisms that are associated with meiosis can be bypassed, which could promote the buildup of epigenetic variation in asexuals. Here, we evaluate current evidence for an epigenetic contribution to adaptation in asexuals. We argue that two aspects of epigenetic variation should have particular relevance for asexuals, namely epigenetics-mediated phenotypic plasticity within and between generations, and heritable variation via stochastic epimutations. An evaluation of epigenetic reprogramming mechanisms suggests that some, but not all, forms of asexual reproduction enhance the likelihood of stable transmission of epigenetic marks across generations compared to sexual reproduction. However, direct tests of these predicted sexual–asexual differences are virtually lacking. Stable transmission of DNA methylation, transcriptomes, and phenotypes from parent to clonal offspring are demonstrated in various asexual species, and clonal genotypes from natural populations show habitat-specific DNA methylation. We discuss how these initial observations can be extended to demonstrate an epigenetic contribution to adaptation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Secondary metabolites play an important role in plant adaptation, because they can mitigate biotic and abiotic environmental stresses. However, their production and allocation incur different costs ...and benefits, and are therefore subject to trade‐offs, which are less studied.
To understand large‐scale geographic patterns of secondary metabolites, and their environmental drivers and trade‐offs, we studied 39 natural populations of the perennial herb Japanese knotweed (Reynoutria japonica) along a large latitudinal gradient in China. We measured the concentrations of six polyphenols in leaves and rhizomes of R. japonica, and associated the variation in these metabolites with biotic and abiotic environmental factors as well as with functional plant traits and putative costs of secondary metabolites.
We found that climate was an important driver of variation in secondary metabolites, both above‐ and below‐ground. Remarkably, the patterns of association differed between leaves and rhizomes, as well as between putative low‐cost versus high‐cost compounds. While annual mean temperature was a stronger predictor of above‐ground metabolites, annual precipitation was more frequently associated with variation in below‐ground metabolites. Moreover, annual temperature was positively associated with high‐cost metabolites, but negatively with low‐cost metabolites. Above‐ground secondary metabolites were generally more strongly associated with functional traits (e.g. specific leaf area) than below‐ground metabolites, and in all cases the directions of correlation were opposite for low‐cost versus high‐cost metabolites above‐ground. The patterns of association also varied with latitude such that leaf concentrations of low‐cost metabolites (quercetin) increased but those of high‐cost metabolites (resveratrol, piceid and emodin) decreased at higher latitudes. In rhizomes, in contrast, the concentrations of high‐cost metabolites (piceid and emodin) increased with latitude.
Synthesis. Our findings indicate that allocation strategies differ between above‐ and below‐ground tissues of Reynoutria japonica. As latitude increases, R. japonica invests relatively more into below‐ground metabolites. We propose that reduced high‐cost metabolites in the leaves at higher latitudes may help to conserve nutrients after defoliation, while maintaining high‐cost metabolites in rhizomes may be important for persistent allelopathic effects and resource conservation below‐ground. The divergent patterns of above‐ and below‐ground metabolite allocation thus likely reflect the multiple functions of metabolites and the plants' adaptation to different environments.
摘要
次生代谢产物在植物适应环境及应对生物和非生物环境压力方面发挥着重要作用。植物产生次生代谢产物需要权衡其合成成本和收益，然而目前相关研究相对缺乏。
为了解植物地上和地下次生代谢产物的大尺度地理格局以及与环境因子的关系，我们测定了多年生草本植物——虎杖(Reynoutria japonica)39个中国自然种群叶片和根状茎中六种多酚的含量，并从代谢产物成本角度将这些次生代谢产物含量的纬度变化格局与环境因子及植物功能特性进行关联分析。
研究发现，虎杖地上和地下次生代谢产物分配模式随纬度而变化:在高纬度地区，叶片中低成本代谢产物含量增加，而高成本代谢物含量下降；相反，随纬度增加，根状茎中的高成本代谢产物含量增加。气候是次生代谢产物分配模式纬度格局的重要驱动因素。年均温与地上代谢产物含量显著相关，而年降水量与地下代谢物更为相关；此外，年均温与高成本代谢产物呈正相关，与低成本代谢产物呈负相关。地上次级代谢产物与功能植物性状(如比叶面积)的相关性大于地下代谢产物，而地上低成本与高成本代谢产物与功能性状间的相关性呈相反趋势。
本研究结果表明，虎杖地上和地下组织中次生代谢产物的分配策略存在差异。随着纬度的增加，虎杖对地下次生代谢产物的投入相对更多。我们推测，在高纬度地区，叶片中高成本代谢产物的减少可能有助于减少落叶所造成的营养损失，而在根茎中保持高成本代谢产物可能对其维持化感作用和地下资源具有重要作用。因此，地上和地下代谢产物分配模式不同的纬度格局可能反映了植物不同部位代谢产物的不同功能，以及植物采用不同的策略应对环境变异。
Our findings indicate that allocation strategies differ between above‐ and below‐ground tissues of Reynoutria japonica. As latitude increases, R. japonica invests relatively more into below‐ground metabolites. We propose that reduced high‐cost metabolites in the leaves at higher latitudes may help to conserve nutrients after defoliation, while maintaining high‐cost metabolites in rhizomes may be important for persistent allelopathic effects and resource conservation below‐ground. The divergent patterns of above‐ and below‐ground metabolite allocation thus likely reflect the multiple functions of metabolites and the plants' adaptation to different environments.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This contribution is based on a survey conducted among environmental associations in the Corniche des Forts forest in Romainville between November 2018 and March 2019. This forest and the Gagarin ...housing estate that overlooks it were destined to be destroyed following the urban development project to create an “eco-neighbourhood” and a “leisure island” as part of the “Grand Paris”. However, as ecologists have shown, this forest contains a so-called invasive rhizome, Japanese knotweed. This plant, which only grows in highly polluted soils, especially those containing lead and copper, is of obvious ontological interest: on the one hand, it signals the existence of an anthropized nature, historicized and modified by human activities, a “historical nature” therefore; but on the other hand, it testifies to the engendering power of organisms capable of emerging within the most transformed and polluted environments. It is as if this nature, destroyed by two centuries of extractivist activities, were capable of reasserting its ontological power, despite and against the capitalist mode of production that is exploiting it. This wildness appearing among “the ruins of capitalism” will allow us to evaluate the anthropologist Anna Tsing’s thesis of the “third nature”. While the idea of an ontological potentiality capable of deploying itself against the social activities that are destroying it is convincing, I will hypothesize that the philosopher Ernst Bloch’s “speculative materialism” offers the possibility of considering the dynamis of nature without reintroducing a step-by-step philosophy of its history (the “first”, the “second” and then the “third” nature). This study of Japanese knotweed will enable us to defend the relevance of a materialist philosophy of nature adapted to ecological disaster.
The Japanese knotweed (
Reynoutria japonica
Houtt.) is considered as one of the most aggressive and highly successful invasive plants with a negative impact on invaded habitats. Its uncontrolled ...expansion became a significant threat to the native species throughout Europe. Due to its extensive rhizome system, rapid growth, and allelopathic activity, it usually forms monocultures that negatively affect the nearby vegetation. The efficient regulation of partitioning and utilization of energy in photosynthesis enables invasive plants to adapt rapidly a variety of environmental conditions. Therefore, we aimed to determine the influence of light conditions on photosynthetic reactions in the Japanese knotweed. Plants were grown under two different light regimes, namely, constant low light (CLL, 40 μmol/m
2
/s) and fluctuating light (FL, 0–1,250 μmol/m
2
/s). To evaluate the photosynthetic performance, the direct and modulated chlorophyll
a
fluorescence was measured. Plants grown at a CLL served as control. The photosynthetic measurements revealed better photosystem II (PSII) stability and functional oxygen-evolving center of plants grown in FL. They also exhibited more efficient conversion of excitation energy to electron transport and an efficient electron transport beyond the primary electron acceptor Q
A
, all the way to PSI. The enhanced photochemical activity of PSI suggested the formation of a successful adaptive mechanism by regulating the distribution of excitation energy between PSII and PSI to minimize photooxidative damage. A faster oxidation at the PSI side most probably resulted in the generation of the cyclic electron flow around PSI. Besides, the short-term exposure of FL-grown knotweeds to high light intensity increased the yield induced by downregulatory processes, suggesting that the generation of the cyclic electron flow protected PSI from photoinhibition.
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