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

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.

2000 ◽  
Vol 77 (10) ◽  
pp. 1447-1453
Author(s):  
Shannon L Morrison ◽  
Jane Molofsky

Both genetic and environmental factors can determine whether an invasive plant species will establish. To determine how these factors influence the establishment of the invasive grass Phalaris arundinacea L. (reed canary grass), we grew three genotypes in 10 artificial environments and asked how a genotype's growth and survivorship was affected by environmental conditions. We found that genotype strongly influenced survivorship, but there was no significant effect of environment on survivorship. However, environmental conditions did significantly affect growth. Individual plants produced more aboveground and belowground biomass when grown singly than they did when grown with competitors. The identity of neighboring competitors had no effect. Although genotype had no significant efffect, there was a significant genotype × environment interaction. Clone 1 produced more root biomass than either clone 2 or clone 3 when there was no or little competition, but in competitive neighborhoods, clone 3 allocated relatively more biomass to roots than to shoots. Under ideal conditions in the greenhouse, clone 2 produced more tillers than the other two clones. Based on these results, it appears that clone 1 may have an advantage under sparse vegetative cover, but clone 3 may have a competitive advantage in highly competitive neighborhoods because it could preferentially allocate more biomass to roots. The presence of three growth patterns from such a small, localized sample suggests that different growth strategies are probably common within populations of reed canary grass and may be important for allowing reed canary grass to successfully invade new habitats.


2017 ◽  
Vol 54 (4) ◽  
pp. 651-654
Author(s):  
Florina Ardelean ◽  
Razvan Susan ◽  
Florin Borcan ◽  
Alina Moaca ◽  
Diana Simona Antal ◽  
...  

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.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11783
Author(s):  
Jacob W. Lawson ◽  
Mark Fennell ◽  
Mark W. Smith ◽  
Karen L. Bacon

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.


2022 ◽  
Author(s):  
Xiao Xiao ◽  
Linxuan He ◽  
Xiaomei Zhang ◽  
Yu Jin ◽  
Jinsong Chen

Abstract Transgenerational plasticity allows offsprings to be more adaptive in the environmental conditions experienced by their parents. It is suggested that differential effects of transgenerational plasticity on growth performance of offspring ramets may help to understand successful invasion of invasive plant with clonal growth comparing with its congeneric native one. A pot experiment using invasive herb Wedelia trilobata and its congeneric native species Wedelia chinensis was conducted to investigate differential effects of high/low light treatment experienced by mother ramets on morphological and photosynthetic properties of offspring ramets subjected to stressful low light treatment. For W. chinensis, stolon length and maximum carboxylation rate (Vmax) in offspring ramets from mother ramets subjected to low light treatment were significantly greater than those in offspring ramets from mother ramets subjected to high light treatment. For W. trilobata, leaf area and potential maximum net photosynthetic rate (Pmax) in offspring ramets from mother ramets subjected to low light treatment were significantly greater than those in offspring ramets from mother ramets subjected to high light treatment. We tentatively concluded that effects of transgenerational plasticity on morphological and photosynthetic properties among clonal plants could be species-specific. In addition, more favorable effect of transgenerational plasticity on growth performance was observed in the invasive plant than in its congeneric native species. It is suggested that transgenerational plasticity may be very important for successful invasion of invasive plant with clonal growth, especially in maternal environmental conditions. So, our experiment provides new insight into invasive mechanism of invasive plants.


2016 ◽  
Vol 5 (2) ◽  
pp. 136-144
Author(s):  
Wilaiporn Lao-Hakosol ◽  
John Walsh

999 is a Thai company that sells, distributes and supports medical equipment and supplies. It has achieved steady growth in its 30 years of existence but now faces unprecedented problems due to environmental change through the implementation of the most recent stage of the Association of Southeast Asian Nations (ASEAN) Economic Community (AEC) and other challenges. As an emerging, ageing, affluenza-suffering country, Thailand offers a number of interesting opportunities for a company in this sector but those opportunities also appeal to current and potential competitors. Should 999 be thinking of defending its current position or seeking to expand to new markets within the region?


2017 ◽  
Vol 4 (1) ◽  
pp. 148-160
Author(s):  
Arjun C.P ◽  
Anoop V.K ◽  
Tijo K.J ◽  
Anoopkumar T.K ◽  
Roshnath R

Butterfly diversity was recorded from Nov (2013) - May (2014) in Pookode region. A total number of 128 species recorded from the five families; Nymphalidae (46 species) Lycaenidae (28 species), Hesperiidae (22 species), Pieridae (17 species) and Papilionidae (15 species) respectively. During the survey invasive plant species were also recorded. There were 36 species of invasive plants from 18 families identified from the study area. More butterflies were attracted towards nectar offering invasive plants. Chromolaena odorata, Ipomea cairica, Lantana camara, Merremia vitifolia, Mikania micrantha, Mimosa diplotricha, Pennisetumpolystachyon, Pteridium aquilinum, Quisqualis indica and Sphagneticola trilobata were the major invasive plants found in the Pookode region and their flower attracts butterfly for pollination. Even though nectar offered by the plants are supportive for growth, in long run these species can affect butterfly population bydeclining native host larval plant species for butterfly reproduction. Invasive species compete with the native flora and reduce its population. Management practices like physical, chemical and modern bio control measures could be used for eradicating of invasive plants. Wise use of invasive plants for other economical purpose such as bio-fuel, medicinal purpose, bio-pesticide and handicraft could be suggested. Successful management of invasive species are needed for conserving Lepidoptera fauna and other native biota of the area.


Blood ◽  
1996 ◽  
Vol 88 (1) ◽  
pp. 319-327 ◽  
Author(s):  
K Sawada ◽  
M Ieko ◽  
A Notoya ◽  
T Tarumi ◽  
K Koizumi ◽  
...  

Abstract The clonal growth of progenitor cells from myelodysplastic syndromes (MDS) can be subdivided into four growth patterns: (1) normal, (2) no growth or low plating efficiency, (3) low colony and high cluster number, and (4) normal or high colony number with a large number of clusters. The former two (1 and 2) can be referred to as nonleukemic patterns and latter two (3 and 4) as leukemic. In a search for a role for cytokines in leukemic-type growth of MDS progenitor cells, marrow CD34+ cells were purified up to 94% for 8 normal individuals and 88% for 12 MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). The purified CD34+ cells were cultured for 14 days with various combinations of cytokines, including recombinant human macrophage colony-stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte-macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3), and stem cell factor (SCF; a ligand for c-kit) in serum-free medium. The clonal growth of MDS CD34+ cells supported by a combination of all of the above cytokines was subdivided into the two patterns of leukemic or nonleukemic, and then the role of individual or combined cytokines in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. Evidence we obtained showed that SCF plays a central role in the leukemic-type growth of MDS CD34+ cells and that G-CSF, GM-CSF; and/or IL-3 synergize with SCF to increase undifferentiated blast cell colonies and clusters over that seen in normal CD34+ cells. SCF is present in either normal or MDS plasma at a level of nanograms per milliliter, and this physiologic concentration of SCF can stimulate progenitor cells. This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blast cells. This depends, at least in part, on cytokines such as G-CSF, GM-CSF, IL-3, and SCF.


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