Invasive Japanese knotweed ( Reynoutria japonica Houtt.) and related knotweeds as catalysts for streambank erosion

2020 ◽  
Vol 36 (9) ◽  
pp. 1962-1969
Author(s):  
Brian Colleran ◽  
Shaw Nozaki Lacy ◽  
Maria Rafaela Retamal
Keyword(s):  
Japanese Knotweed ◽  
Reynoutria Japonica ◽  
Streambank Erosion

scholarly journals Synthesis and Physico-Chemical Evaluation of Polyurethane Microstructures for Transmembrane Delivery of Reynoutria japonica Extract

2017 ◽  
Vol 54 (4) ◽  
pp. 651-654
Author(s):  
Florina Ardelean ◽  
Razvan Susan ◽  
Florin Borcan ◽  
Alina Moaca ◽  
Diana Simona Antal ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Invasive Plant ◽  
Aqueous Solubility ◽  
Japanese Knotweed ◽  
Reynoutria Japonica ◽  
Good Thermal Stability ◽  
Starting Point ◽  
First Results ◽  
Polymer Microstructures ◽  
Transmembrane Delivery

Polymer microstructures containing plant extracts are a novel technique used to increase the bioavailability of active agents with low aqueous solubility. Japanese knotweed (Reynoutria japonica) is an invasive plant with multiple biomedical properties. The aim of the present study was to obtain and characterize polyurethane microstructures used as a drug delivery system of a Japanese knotweed extract. The results indicate the obtaining of microstructures with an almost neutral pH, with sizes between 540 and 1134 nm, with a medium stability against the tendency to form clusters and a very good thermal stability. These first results present the potential of the obtained polyurethane microstructures as candidates for the transmembrane drug delivery of Japanese knotweed extracts, as a starting point for further bioactivity investigations.

Chemical composition of the leaves of Reynoutria japonica Houtt. and soil features in polluted areas

2014 ◽  
Vol 9 (3) ◽  
pp. 320-330 ◽  
Author(s):  
Oimahmad Rahmonov ◽  
Andrzej Czylok ◽  
Anna Orczewska ◽  
Leszek Majgier ◽  
Tomasz Parusel
Keyword(s):  
Chemical Composition ◽  
Agricultural Practices ◽  
Japanese Knotweed ◽  
Soil System ◽  
Reynoutria Japonica ◽  
Habitat Transformation ◽  
Soil Features ◽  
Plant Soil ◽  
Study Sites ◽  
Physical Features

AbstractThe study was conducted on six sites that are dominated by Japanese knotweed (Reynoutria japonica) and that vary in the level of industrialization and habitat transformation by humans. The aim of the research was to investigate the chemical-physical features of soil under a closed and dense canopy of R. japonica, the chemical composition of the R. japonica leaves, and to compare the content of certain elements in the soil-plant-soil system. The soil organic carbon (Corg) content varied from 1.38±0.004% to 8.2±0.047% and the maximum in leaves was 49.11±0.090%. The lowest levels of total nitrogen (Ntot) in soil were recorded on the heavily disturbed sites (till 0.227±0.021%). Soil pH varied greatly, ranging from acidic (pH=4.0) to neutral (pH=7.7). Heavy metal content differed significantly among the study sites. At all of the sites, both in the case of soil and plant leaves, Zn was a dominant element and its concentration ranged from 41.5 to 501.2 mg·kg−1 in soils and from 38.6 to 541.7 mg·kg−1 in leaves. Maximum accumulations of P (2103.3±15.3 mg·kg−1) and S (2571.7±17.6 mg·kg−1) were observed on the site that had been influenced by agricultural practices. The results obtained showed that R. japonica is able to accumulate high levels of heavy metals.

scholarly journals Regeneration and growth in crowns and rhizome fragments of Japanese knotweed (Reynoutria japonica) and desiccation as a potential control strategy

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11783
Author(s):  
Jacob W. Lawson ◽  
Mark Fennell ◽  
Mark W. Smith ◽  
Karen L. Bacon
Keyword(s):  
Plant Material ◽  
Invasive Plant ◽  
Maximum Growth ◽  
Maximum Height ◽  
Japanese Knotweed ◽  
Reynoutria Japonica ◽  
Potential Control ◽  
The North ◽  
Growth Increments ◽  
Herbicide Treatment

Reynoutria japonica (Japanese knotweed) is a problematic invasive plant found in many areas of Europe and North America. Notably, in the UK, the species can cause issues with mortgage acquisition. Control of R. japonica is complicated by its ability to regenerate from small fragments of plant material; however, there remains uncertainty about how much (in terms of mass) rhizome is required for successful regeneration. This study investigated the ability of crowns and rhizomes with different numbers of nodes to regenerate successfully from three sites in the north of England, UK. Two of the sites had been subject to herbicide treatment for two years prior to sampling and the third site had no history of herbicide treatment. No significant differences were observed in regenerated stem diameter, maximum height of stem and maximum growth increments among crowns. All traits measured from the planted crowns were significantly greater than those of the planted rhizome fragments and at least one node was necessary for successful regeneration of rhizomes. The smallest initial fragment weight to regenerate and survive the experiment was 0.5 g. Subjecting all plant material to desiccation for 38 days resulted in no regrowth (emergence or regeneration) after replanting. These findings suggest that desiccation could be a valuable management strategy for small to medium scale infestations common in urban settings.

Gebietsfremde Staudenknöteriche im Schweizer Wald – Auswirkungen und Massnahmen

2014 ◽  
Vol 165 (6) ◽  
pp. 150-157
Author(s):  
Esther Gerber ◽  
Urs Schaffner
Keyword(s):  
Ornamental Plants ◽  
Plant Invasions ◽  
Classical Biological Control ◽  
Native Plant ◽  
Japanese Knotweed ◽  
Negative Effects ◽  
Management Options ◽  
Alien Plant ◽  
Reynoutria Japonica ◽  
Native Plant Species

Exotic knotweeds on Swiss forest sites: consequences and measures to take Natural areas in Switzerland are home to an increasing number of non-native plant species, so-called neophytes. Some are highly prolific, causing damage to the environment and the economy. Especially some species originally imported as ornamental plants have been accidentally introduced into forest habitats, where their spread has become increasingly problematic. Using the example of exotic knotweeds (Reynoutria spp., Syn Fallopia spp.), which are among the most aggressive neophytes in Europe, we outline potential consequences of alien plant invasions in forests and give management recommendations to mitigate their negative effects on native ecosystems. Management options discussed include mechanical, chemical and biological methods of control. In regard to the latter, Japanese knotweed (Reynoutria japonica) is of particular interest as there is an ongoing classical biological control project against this species in Great Britain.

Enhancing Japanese knotweed control and longterm habitat restoration post-treatment

2021 ◽  
Author(s):  
◽  
Sophie C. Hocking
Keyword(s):  
Microbial Diversity ◽  
Environmental Impacts ◽  
Native Species ◽  
Species Abundance ◽  
Post Treatment ◽  
Japanese Knotweed ◽  
Herbicide Application ◽  
Soil Microbial Diversity ◽  
Reynoutria Japonica

Japanese knotweed (Reynoutria japonica var. japonica) is among the most problematic invasive plants worldwide due to its negative impacts on recipient ecosystems and propensity for rapid spread, eliciting substantial control costs. As global focus on sustainability intensifies in response to the current biodiversity and climate crises, the value of long-term ecological monitoring and planning is increasingly evident. As a long-lived perennial species, the Japanese knotweed invasion highlights this. While empirical evidence of effective knotweed management measures is growing, there is conflict between knotweed management and the wider ecological and environmental impacts of this. The focus of this thesis was to investigate the long-term effects of Japanese knotweed invasion and subsequent management in a large-scale, long-term knotweed field trial, and assess avenues for post-treatment restoration. Long-term plant community dynamics, soil abiotic characteristics and microbial diversity were investigated at a site in Taff’s Well, south Wales, UK. This study found that the diversity of native flora was largely limited to ruderal species, potentially hindering regeneration potential of native plants. The rare hybrid Conolly’s knotweed (x Reyllopia conollyana) was also discovered in the seed bank. Secondary invasion by Himalayan balsam also occurred. Native species diversity significantly increased in response to knotweed management (i.e., herbicide application). Soil abiotic characteristics showed varied response to knotweed treatment; spatial variation explained changes to most parameters measured. There was no discernible effect of knotweed cover or herbicide application on soil microbial diversity. Restoration trials found that active restoration may be a valuable tool for enhancing post-knotweed community recovery. Native species abundance and target community composition can be enhanced by revegetation. While functional composition of revegetation seed mixes did not enhance knotweed suppression, this may provide insight into the coexistence of native and invasive species to enhance biodiversity. Physical covering using geotextiles increased native species abundance but did not suppress knotweed. Finally, a comparative life cycle assessment (LCA) of knotweed treatment methods found that the simplest and most effective knotweed management method (annual glyphosate foliar spray) elicited the lowest environmental impacts to produce. LCA of restoration methods found that geotextile matting and revegetation contributed the greatest environmental impacts. The results of this thesis can inform sustainable, long-term knotweed management and enhance practical alignment with priorities around ecological and environmental sustainability.

scholarly journals Evaluation of Light-Dependent Photosynthetic Reactions in Reynoutria japonica Houtt. Leaves Grown at Different Light Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Selma Mlinarić ◽  
Lidija Begović ◽  
Neven Tripić ◽  
Antonija Piškor ◽  
Vera Cesar
Keyword(s):  
Electron Transport ◽  
Excitation Energy ◽  
Invasive Plants ◽  
Electron Flow ◽  
Cyclic Electron Flow ◽  
Light Conditions ◽  
Japanese Knotweed ◽  
Reynoutria Japonica ◽  
Short Term Exposure ◽  
Photosynthetic Reactions

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/m2/s) and fluctuating light (FL, 0–1,250 μmol/m2/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 QA, 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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