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.

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.

Sequential Aminopyralid and Imazapyr Applications for Japanese Knotweed (Fallopia japonica) Management

2017 ◽  
Vol 10 (3) ◽  
pp. 277-283 ◽  
Author(s):  
Nathan S. Boyd ◽  
Scott N. White ◽  
Todd Larsen
Keyword(s):  
Invasive Plant ◽  
Agricultural Land ◽  
Additional Benefit ◽  
Shoreline Erosion ◽  
Stem Density ◽  
Maximum Height ◽  
Japanese Knotweed ◽  
Fallopia Japonica ◽  
Shoot Height ◽  
Disturbed Areas

Japanese knotweed is an invasive plant that occurs along waterways, highways, abandoned agricultural land, and other disturbed areas. It reduces plant diversity and can increase shoreline erosion. An experiment was conducted in Bible Hill and Antigonish, NS, Canada to evaluate early POST aminopyralid at 120 g ae ha−1 and POST imazapyr applications at 720 g ae ha−1 at maximum shoot height, flowering, senescence, maximum height+flowering, maximum height+senescence, flowering+senescence, and maximum height+flowering+senescence. Early POST aminopyralid only provided 10% to 15% control at 52 wk after treatment (WAT) whereas 83% to 100% control occurred following imazapyr applications at all application timings. Percent control at 2, 4, and 8 WAT tended to be higher where imazapyr followed aminopyralid. By 52 WAT, equivalent damage ratings and reductions in stem density occurred at both sites in all plots where imazapyr was applied. The use of aminopyralid or multiple imazapyr applications provided no additional benefit over a single imazapyr application. We conclude that early POST aminopyralid suppresses knotweed growth, which should facilitate late-season imazapyr applications, especially in large stands.

scholarly journals Clonal growth strategies of Reynoutria japonica in response to light, shade, and mowing, and perspectives for management

NeoBiota ◽  
2020 ◽  
Vol 56 ◽  
pp. 89-110 ◽  
Author(s):  
François-Marie Martin ◽  
Fanny Dommanget ◽  
François Lavallée ◽  
André Evette
Keyword(s):  
Environmental Conditions ◽  
Clonal Growth ◽  
Invasive Plant ◽  
Light Stress ◽  
Growth Patterns ◽  
Control Measures ◽  
Growth Strategies ◽  
Japanese Knotweed ◽  
Reynoutria Japonica ◽  
Habitat Patches

Many of the most invasive plant species in the world can propagate clonally, suggesting clonality offers advantages that facilitate invasion. Gaining insights into the clonal growth dynamics of invasive plants should thus improve understanding of the mechanisms of their dominance, resilience and expansion. Belonging to the shortlist of the most problematic terrestrial invaders, Reynoutria japonica var. japonica Houtt. (Japanese knotweed) has colonized all five continents, likely facilitated by its impressive ability to propagate vegetatively. However, its clonal growth patterns are surprisingly understudied; we still do not know how individuals respond to key environmental conditions, including light availability and disturbance. To contribute to filling this knowledge gap, we designed a mesocosm experiment to observe the morphological variation in R. japonica growth in homogeneous or heterogeneous conditions of light stress (shade) and disturbance (mowing). Rhizome fragments were planted in the middle of large pots between two habitat patches that consisted of either one or a combination of the following three environmental conditions: full light without mowing, full light with frequent mowing, or shade without mowing. At the end of the experiment, biomass and traits related to clonal growth (spacer and rhizome lengths, number of rhizome branches, and number of ramets) were measured. After 14 months, all individuals had survived, even those frequently mowed or growing under heavy shade. We showed that R. japonica adopts a ‘phalanx’ growth form when growing in full light and a ‘guerrilla’ form when entirely shaded. The former is characteristic of a space-occupancy strategy while the latter is more associated with a foraging strategy. In heterogeneous conditions, we also showed that clones seemed to invest preferentially more in favorable habitat patches rather than in unfavorable ones (mowed or shaded), possibly exhibiting an escape strategy. These observations could improve the management of this species, specifically by illustrating how aggressive early control measures must be, by highlighting the importance of repeated mowing of entire stands, as this plant appears to compensate readily to partial mowing, and by informing on its potential responses towards the restoration of a cover of competitive native plants.

scholarly journals Efficacy of invasive alien plants in controlling Arionidae slugs

2020 ◽  
Vol 18 (1) ◽  
pp. e1001 ◽  
Author(s):  
Ziga Laznik ◽  
Tanja Bohinc ◽  
Kristijan Franin ◽  
Ivana Majić ◽  
Stanislav Trdan
Keyword(s):  
Plant Species ◽  
Field Trial ◽  
Plant Material ◽  
Invasive Plant ◽  
Control Method ◽  
Invasive Plant Species ◽  
Japanese Knotweed ◽  
Liquid Formulation ◽  
Plant Powders ◽  
Material Powder

Aim of study: To develop an alternative slug control method, we explored the use of plant material from seven invasive plant species against Arion slugs.Area of study: The experiments were performed at the University of Ljubljana (Slovenia).Material and methods: In laboratory (exp. A-C) and semi-field studies (exp. D), we investigated the contact and barrier efficacy of plant material (powder or liquid formulation) of seven invasive plant species (Japanese knotweed, bohemian knotweed, Canadian goldenrod, giant goldenrod, staghorn sumac, tree of heaven, and false indigo) against Arion slugs. In order to test a contact efficacy of the substance (exp. A), slugs were rolled in a plant material powder. In exp. B, powder made from a plant material was used as a barrier for slugs. Antifeedant effect of the slugs was tested in exp. C, where lettuce leaves were treated with a liquid formulation of a plant material. In exp. D, all above mentioned techniques were used in a semi-field trial.Main results: The results of our studies showed that the plant material of staghorn sumac, giant goldenrod, and Japanese knotweed showed the strongest anti-feedant and barrier effects against the slugs. In the semi-field trial, only 7% of the plants treated with giant goldenrod plant material were attacked by slugs.Research highlights:  A contact efficacy of plant powders against Arion slugs was not confirmed in our investigation. Furthermore, several plant powders (goldenrods, staghorn sumac) showed good barrier efficacy. A semi-field trial showed that plant material (giant goldenrod) could represent an alternative solution in slug control.

scholarly journals Vertical structure and kinematics of the Galactic outer disk

2019 ◽  
Vol 72 (4) ◽  
Author(s):  
Nobuyuki Sakai ◽  
Takumi Nagayama ◽  
Hiroyuki Nakanishi ◽  
Nagito Koide ◽  
Tomoharu Kurayama ◽  
...  
Keyword(s):  
Dwarf Galaxy ◽  
Oscillatory Behavior ◽  
Maximum Height ◽  
Galactocentric Distance ◽  
The North ◽  
Vertical Density ◽  
Galactic Longitude ◽  
Maser Sources ◽  
Galactic Warp ◽  
North Galactic

Abstract We report on measurements of parallax and proper motion for four 22 GHz water maser sources as part of the VERA Outer Rotation Curve project. All the sources show Galactic latitudes of >2° and Galactocentric distances of >11 kpc at the Galactic longitude range of 95° < l < 126°. The sources trace the Galactic warp reaching to 200–400 pc, and also the signature of the warp to 600 pc toward the north Galactic pole. The new results, along with previous results in the literature, show that the maximum height of the Galactic warp increases with Galactocentric distance. Also, we examined velocities perpendicular to the disk for the sample, and found oscillatory behavior between the vertical velocities and Galactic heights. This behavior suggests the existence of bending (vertical density) waves, possibly induced by a perturbing satellite (e.g., the passage of the Sagittarius dwarf galaxy).

Effects of temperature and photoperiod on tropical soda apple (Solanum viarumDunal) and its potential range in the U.S.

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 404-408 ◽  
Author(s):  
David T. Patterson ◽  
Mike McGowan ◽  
J. Jeff Mullahey ◽  
Randy G. Westbrooks
Keyword(s):  
South Carolina ◽  
Leaf Area ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Shoot Biomass ◽  
Potential Range ◽  
Maximum Height ◽  
Temperature Regimes ◽  
Tropical Soda Apple ◽  
The U.S

Tropical soda apple is an exotic perennial pasture weed currently reported in the U.S. only from Florida, Georgia, Alabama, Mississippi, and South Carolina. In experiments to determine its environmental requirements and potential range, tropical soda apple was grown in growth chambers in 16 day/night temperature regimes ranging from 18/8 to 36/26 C. After 100 d of growth, maximum height, leaf area, and shoot biomass occurred at day/night temperatures ranging from 24/26 to 36/26 C. The plants achieved 50% or more of maximum leaf area, biomass, and height at 18/26, 24/20, 24/26, 30/26, and 36/26 C. Plants survived in 8 C nights with day temperatures of 18 to 36 C, but biomass and leaf area were only 3 to 10% of maximum. Leaf appearance rate was linearly related to mean temperature over the range of 11.3 to 29.3 C, with a slope coefficient of 0.018 leaves/day/degree C. Flowering was delayed by photoperiods shorter than 10 h or temperatures lower than 24/20 C. In favorable temperatures, plants flowered within 60 d after emergence in photoperiods ranging from 8 to 16 h. Artificially pollinated flowers produced fruit with germinable seeds within 6 to 7 wk, at temperatures ranging from 23/17 to 32/26 C. A regression equation relating vegetative growth to day and night temperatures indicated that tropical soda apple could achieve 30% or more of its maximum growth rate during 7 mo of the year in southern Alabama, Louisiana, and Texas and during 4 to 5 mo of the year at sites in Georgia, South Carolina, North Carolina, Virginia, Tennessee, Kentucky, Illinois, Arkansas, Missouri, Kansas, and Oklahoma. Neither temperature nor photoperiod will limit its further spread in the southern U.S. and adjacent regions.

Further Analysis of Ration and Growth Relationship of Plaice (Pleuronectes platessa)

1969 ◽  
Vol 26 (12) ◽  
pp. 3237-3241 ◽  
Author(s):  
Samir Zaky Rafail
Keyword(s):  
Maximum Growth ◽  
Growth Efficiency ◽  
Growth Increment ◽  
Mean Value ◽  
Pleuronectes Platessa ◽  
Growth Increments ◽  
Power Equation ◽  
The Mean ◽  
Relationship Of ◽  
Weight Groups

Evidence is given that the average daily rations (R) and fortnightly growth increments (ΔW) of six weight groups of Pleuronectes platessa fed on Mytilus edulis are related as in the power equation ±(ΔW−ΔWm) = ±b(|R–Rm|)B. Rm is the daily ration associated with the growth increment (ΔWm) at maximum growth efficiency; b and B are parameters. The power B has a mean value of about 0.5 and shows significant deviations from the mean especially in the case of smaller fish.

A STUDY OF THE MAY FLIES (HEXAGENIA) OF LAKE WINNIPEG

1932 ◽  
Vol 7 (1) ◽  
pp. 177-201 ◽  
Author(s):  
FERRIS NEAVE
Keyword(s):  
Economic Status ◽  
Maximum Growth ◽  
Economic Importance ◽  
Coregonus Clupeaformis ◽  
Large Area ◽  
Lake Winnipeg ◽  
The North ◽  
Different Seasons ◽  
North Part ◽  
Males And Females

The economic status of the May flies (Hexagenia) of lake Winnipeg is discussed. The nymphs are particularly important as food for sturgeon (Acipenser fulvescens), whitefish (Coregonus clupeaformis), light-backed cisco or tullibee (Leucichthys zenithicus), goldeye (Hiodon chrysopsis), and sauger (Lucioperca canadense). Two species are present in abundance, H. limbata occulta and H. rigida, but the former outnumbers the latter by a ratio of 7 to 1. Characters are given for the separation of all stages of these species and their habits are described. Eggs of occulta were hatched after artificial insemination. Later development of both species was followed by statistical measurements of nymphs secured at different seasons. The life cycle extends over two years. Sizes at which moults take place are indicated. Maximum growth is in August and is correlated with the amount of phytoplankton in the lake. No growth takes place in winter. The number of nymphs of occulta of 10 mm. and more is estimated at 62,000,000 per sq. kilometre in the southern part of the lake, and 93,000,000 in the neighbourhood of the Narrows. Corresponding estimates for rigida are 4,500,000 and 44,000,000. Both species are scarce or absent over a large area in the north part of the lake. H. occulta shows a 10 per cent, preponderance of females but is probably not parthenogenetic. Males and females of rigida occur in equal numbers. Parasites are noted, but are local in distribution. Occulta is of greater economic importance than is indicated by the numerical ratio between the two species.

scholarly journals The Concept of a Compact Profile Agricultural Tractor Suitable for Use on Specialised Tree Crops

Agriculture ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 123 ◽  
Author(s):  
Simone Pascuzzi ◽  
Alexandros Sotirios Anifantis ◽  
Francesco Santoro
Keyword(s):  
Soil Surface ◽  
Field Measurements ◽  
Maximum Growth ◽  
Front Axle ◽  
Maximum Height ◽  
Phenological Stages ◽  
Cultivation System ◽  
Table Grapes ◽  
The Times ◽  
Agricultural Tractor

This study firstly examined certain methods of vineyard management typically adopted in Apulia for both table grapes and wine grapes. In the later phenological stages, guyot or spurred cordon vineyards have extremely abundant vegetation, which drastically limits the space available between the rows for the passage of a tractor, even for a narrow-track vehicle. On the other hand, vegetation in tendone vineyards is situated at approximately 1.90 m above the soil surface, so that total tractor height must be compatible with this cultivation method. Foliage canopies in these types of vineyard cultivation system were evaluated at the times of their maximum growth in order to identify the maximum possible size of a prototype tractor that would be able to pass between vineyard rows without interfering in any way with the vegetation and fruits. Using the results of field measurements, it was established that the prototype tractor must have a maximum height of 1600 mm, with a minimum front axle track of less than 1100 mm and a back axle track of less than 1000 mm. A tractor built to these specifications is now being tested in order to compare its performance with that of other tractors commonly used in Apulia in various agricultural contexts.

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