Dynamique de la végétation d'emprises de lignes de transport d'énergie

1984 ◽  
Vol 62 (8) ◽  
pp. 1730-1738
Author(s):  
M. Darveau ◽  
P. Bellefleur
Keyword(s):  
Woody Species ◽  
Power Line ◽  
Power Lines ◽  
Underlying Structure ◽  
Dichlorophenoxyacetic Acid ◽  
Border Line ◽  
Control Power ◽  
Composition And Structure ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

We made a preliminary study of the impact of phytocides on plant dynamics in the corridors of Hydro-Québec power lines. Three hypotheses were tested: the first assumed that the phytocides changed vegetation composition and structure in the corridors; the second assumed that the corridor under the power line favored the development of an ecotone at its border with the forest; the third assumed that the method used for initial cutting of the corridors (bulldozer or chain saw) affected the forthcoming vegetation for over 15 years. Vegetation was sampled on one control power line and four power lines maintained with mixtures of picloram, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, and sodium trichloroacetate. Multidimensional statistical analysis was used to show the underlying structure of the raw data and to test the hypotheses. We found out that phytocides are very efficient on woody species to the advantage of herbs, mostly grass, which invaded the corridors and created rather stable artificial communities. No significant ecotone was found at the border line of the corridors and the forest. The influence of the method for initial cutting of the corridors, although severe the first few years, disappeared after about 10 years under the action of the phytocides.

scholarly journals The impact of power lines on phytocenoses of the regional reserve “Uporovsky”, Tyumen Region, Russia

2020 ◽  
Vol 164 ◽  
pp. 07030
Author(s):  
Elena Popova
Keyword(s):  
Nature Reserve ◽  
Power Transmission ◽  
Electrical Power ◽  
Power Line ◽  
Power Lines ◽  
Individual Species ◽  
Right Of Way ◽  
Synanthropization Index ◽  
The Right ◽  
The Impact

The article reflects the results of anthropogenic impact on phytocenoses of the territory of the Uporovsky regional nature reserve (Uporovsky district, Tyumen region, Russia). On the territory of the Uporovsky regional nature reserve (Uporovsky district, Tyumen region) there is a 110 kV electrical power transmission line (power line) which has the length of 8 kilometers and the right-of-way width of about 30 meters. This power line is undoubtedly the main source of anthropogenic electromagnetic radiation in this area. The degree of participation of individual species in the herbage was determined by taking into account their relative abundance. When exposed to the power lines in the right-of-way area, flora biodiversity decreases due to the loss of a number of species. The effect of electromagnetic fields causes transformation of the vegetation cover, synanthropization and the subsequent complete destruction of natural vegetation. To determine the degree of anthropogenic load on the studied phytocenoses, the synanthropization index is determined. In the synanthropic fraction of the flora, 30 species belonging to 12 families were identified. The synanthropization index of the studied phytocenoses ranges from 6.6% to 81.2%. The largest number of synanthropic species is observed in the anthropogenic area.

scholarly journals An Assessment of Multiple Drivers Determining Woody Species Composition and Structure: A Case Study from the Kalahari, Botswana

Land ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 122 ◽  
Author(s):  
Meyer ◽  
Holloway ◽  
Christiansen ◽  
Miller ◽  
D’Odorico ◽  
...  
Keyword(s):  
Species Abundance ◽  
Woody Species ◽  
Environmental Variable ◽  
Woody Vegetation ◽  
Tobit Regression ◽  
Species Identity ◽  
Rainfall Gradient ◽  
Composition And Structure ◽  
Species Richness And Abundance ◽  
The Impact

Savannas are extremely important socio-economic landscapes, with pastoralist societies relying on these ecosystems to sustain their livelihoods and economy. Globally, there is an increase of woody vegetation in these ecosystems, degrading the potential of these multi-functional landscapes to sustain societies and wildlife. Several mechanisms have been invoked to explain the processes responsible for woody vegetation composition; however, these are often investigated separately at scales not best suited to land-managers, thereby impeding the evaluation of their relative importance. We ran six transects at 15 sites along the Kalahari transect, collecting data on species identity, diversity, and abundance. We used Poisson and Tobit regression models to investigate the relationship among woody vegetation, precipitation, grazing, borehole density, and fire. We identified 44 species across 78 transects, with the highest species richness and abundance occurring at Kuke (middle of the rainfall gradient). Precipitation was the most important environmental variable across all species and various morphological groups, while increased borehole density and livestock resulted in lower bipinnate species abundance, contradicting the consensus that these managed features increase the presence of such species. Rotating cattle between boreholes subsequently reduces the impact of trampling and grazing on the soil and maintains and/or reduces woody vegetation abundance.

scholarly journals Impact of Ionic Liquids on Induction of Wheat Microspore Embryogenesis and Plant Regeneration

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 839
Author(s):  
Dorota Weigt ◽  
Idzi Siatkowski ◽  
Magdalena Magaj ◽  
Agnieszka Tomkowiak ◽  
Jerzy Nawracała
Keyword(s):  
Ionic Liquids ◽  
Plant Regeneration ◽  
Positive Impact ◽  
Microspore Embryogenesis ◽  
Green Plant ◽  
Induction Medium ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

Ionic liquids are novel compounds with unique chemical and physical properties. They can be received based on synthetic auxins like 2,4-dichlorophenoxyacetic acid or dicamba, which are commonly used hormones in microspore embryogenesis. Nevertheless, ionic liquids have not been adapted in plant in vitro culture thus far. Therefore, we studied the impact of ionic liquids on the ability to undergo microspore embryogenesis in anther cultures of wheat. Two embryogenic and two recalcitrant genotypes were used for this study. Ten combinations of ionic liquids and 2,4-dichlorophenoxyacetic acid were added to the induction medium. In most cases, they stimulated induction of microspore embryogenesis and green plant regeneration more than a control medium supplemented with only 2,4-dichlorophenoxyacetic acid. Two treatments were the most favorable, resulting in over two times greater efficiency of microspore embryogenesis induction in comparison to the control. The effect of breaking down the genotype recalcitrance (manifested by green plant formation) was observed under the influence of 5 ionic liquids treatments. Summing up, ionic liquids had a positive impact on microspore embryogenesis induction and green plant regeneration, increasing the efficiency of these phenomena in both embryogenic and recalcitrant genotypes. Herbicidal ionic liquids can be successfully used in in vitro cultures.

scholarly journals The impact of power line-related mortality on the Cape Vulture Gyps coprotheres in a part of its range, with an emphasis on electrocution

2011 ◽  
Vol 21 (3) ◽  
pp. 311-327 ◽  
Author(s):  
ANDRÉ F. BOSHOFF ◽  
JOHAN C. MINNIE ◽  
CRAIG J. TAMBLING ◽  
MICHAEL D. MICHAEL
Keyword(s):  
Mortality Rate ◽  
Power Line ◽  
Power Lines ◽  
National Database ◽  
Annual Growth Rate ◽  
Mortality Factors ◽  
Positive Growth ◽  
The Impact ◽  
Annual Mortality ◽  
Related Mortality

SummaryThe global population of the Cape Vulture Gyps coprotheres, a threatened southern African endemic, is known to be impacted by electrocutions and collisions on power line infrastructure, but to date this impact has not been estimated or quantified. Using data in a national database from the period prior to our study, conducted in the Eastern Cape Province of South Africa, we estimated a mean annual mortality rate from power line-related mortality of around 14 vultures per year. After applying an adjusted rate based on the results of a landowner survey, this estimate increased to around 80 vultures per year (i.e. a 5.7 fold increase). For a number of reasons, the estimated mean annual mortality rate is considered to under-represent the true situation, and must therefore be considered a minimum value. A simple model was constructed and run to investigate the potential impact of the mortality rate from electrocution on the study population. It distinguishes between vulture subpopulations in areas of high and low electrocution threat, and a migratory subpopulation that moves between these two areas. The model, simulated over 50 years and applying a constant theoretical maximum annual growth rate of 2%, indicates positive growth of the population in those areas where the electrocution threat from power lines is low, whereas the population in those areas where this threat is high is predicted to crash to extinction, from electrocution mortality alone, within a 20–35 year period. The regional population is predicted to show positive growth over the 50 year period. However, for a number of reasons that relate to the nature of certain parameters used in the model, the simulations must be considered to be conservative, at best. In addition, other unnatural mortality factors (notably inadvertent poisoning, drowning in high-walled farm reservoirs, harvesting for the traditional medicine trade, local food shortage), which are additive to power line-related mortality have not been taken into account. Management recommendations aimed at obtaining an improved estimate of the mean annual mortality rate from power lines, and at ameliorating the impact of electrocutions on the regional Cape Vulture population, are briefly mentioned. These address the former by documenting ways to improve the quantity and quality of the field data, and the latter by identifying areas where urgnt action needs to be taken to reduce or avoid the electrocution of vultures, by mitigating extant ‘unsafe’ power line infrastructure, and by ensuring that that only ‘safe’ infrastructure is used for new power lines.

scholarly journals Auxins Regulations of Branched Spike Development and Expression of TFL, a LEAFY-Like Gene in Branched Spike Wheat (Triticum aestivum)

2017 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Wang Yue ◽  
Sun Fulai ◽  
Gao Qingrong ◽  
Zhang Yanxia ◽  
Wang Nan ◽  
...  
Keyword(s):  
Photosynthetic Pigment ◽  
Dry Mass ◽  
Dichlorophenoxyacetic Acid ◽  
Naphthaleneacetic Acid ◽  
Branched Spike ◽  
Spike Development ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact ◽  
Indole 3 Acetic Acid ◽  
Putative Homologue

Branched spike wheat is a hexaploid germplasm with branched rachis on its main rachises, and the crucial period for branched rachises occurrence and development is just after the two ridges stage of shoot apex. Natural [indole-3-acetic acid (IAA), indole-3butyric acid (IBA)] and synthetic [(1-naphthaleneacetic acid (NAA), 2,4-Dichlorophenoxyacetic acid (2,4-D)] auxins were applied at this period to investigate the spike traits, seedling growth and photosynthesis related characters and expression of a putative homologue of the LEAFY in branched spike wheat. The four types of experienced auxins induced similar effects on these foresaid characters, although the impact extents were different among the auxins treatments. More branched rachis, spikelets, fertile florets and longer branched rachis were obtained in plants with IAA and IBA at 0.1 mM or NAA and 2,4-D at 1.0mM than those plants with no auxin treated. Auxin treatments also increased fresh and dry mass, photosynthetic pigment and parameters. TFL, a LEAFY-like gene was cloned in branched spike wheat and TFL mRNA expression was quantified using real-time reverse transcriptase-PCR. Application of the auxins accelerated the rise in TFL expression during the periods of branched rachises occurrence and extension. The data supports the hypothesis that auxins play a central role in the regulation branched spike development and TFL might correlate with the development of branched rachises in branched spike wheat.

scholarly journals Differential regulation of GS-GOGAT gene expression by plant growth regulators in Arabidopsis seedlings

2016 ◽  
Vol 68 (2) ◽  
pp. 399-404 ◽  
Author(s):  
Milan Dragicevic ◽  
Ana Simonovic ◽  
Milica Bogdanovic ◽  
Angelina Subotic ◽  
Nabil Ghalawenji ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Expression Patterns ◽  
Nuclear Gene ◽  
Glutamate Synthase ◽  
Ammonium Assimilation ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

Primary and secondary ammonium assimilation is catalyzed by the glutamine synthetase-glutamate synthase (GS-GOGAT) pathway in plants. The Arabidopsis genome contains five cytosolic GS1 genes (GLN1;1 - GLN1;5), one nuclear gene for chloroplastic GS2 isoform (GLN2), two Fd-GOGAT genes (GLU1 and GLU2) and a GLT1 gene coding for NADH-GOGAT. Even though the regulation of GS and GOGAT isoforms has been extensively studied in response to various environmental and metabolic cues in many plant species, little is known about the effects of phytohormones on their regulation. The objective of this study was to investigate the impact of representative plant growth regulators, kinetin (KIN), abscisic acid (ABA), gibberellic acid (GA3) and 2,4-dichlorophenoxyacetic acid (2,4-D), on the expression of A. thaliana GS and GOGAT genes. The obtained results indicate that GS and GOGAT genes are differentially regulated by growth regulators in shoots and roots. KIN and 2,4-D repressed GS and GOGAT expression in roots, with little effect on transcript levels in shoots. KIN affected all tested genes; 2,4-D was apparently more selective and less potent. ABA induced the expression of GLN1;1 and GLU2 in whole seedlings, while GA3 enhanced the expression of all tested genes in shoots, except GLU2. The observed expression patterns are discussed in relation to physiological roles of investigated plant growth regulators and N-assimilating enzymes.

Response of Woody Species to 2,4-D, 2,4,5-T, and Picloram as a Function of Treatment Method

Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 40-46 ◽  
Author(s):  
H. D. Coble ◽  
R. P. Upchurch ◽  
J. A. Keaton
Keyword(s):  
Propylene Glycol ◽  
Woody Species ◽  
Treatment Method ◽  
Dichlorophenoxyacetic Acid ◽  
Butyl Ether ◽  
Shoot Height ◽  
White Ash ◽  
Foliar Sprays ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Ether Ester

Naturally-established individual specimens of 12 woody plant species occurring in North Carolina were treated with foliar, dormant stem, and basal applications of the propylene glycol butyl ether ester formulation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), the propylene glycol butyl ether ester of 2,4-dichlorophenoxyacetic acid (2,4-D), and the potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram). The triethanolamine salt of 2,4,5-T also was applied as a foliar treatment. Three rates of each herbicide were used. Responses measured were percent control of original shoots, percent regrowth, shoot height, and number of live stems per plant. No differences were observed between the amine and ester formulations of 2,4,5-T applied as foliar sprays except on rhododendron (Rhododendron maximum L.) where the ester produced 86% control compared to 28% for the amine salt. Foliar sprays of picloram were effective in controlling all species except white ash (Fraxinus americana L.), sweet gum (Liquidambar styraciflua L.), sweet bay (Magnolia virginiana L.), and rhododendron. Control of these species averaged only 45% compared to 96% on all other species studied. No species was effectively controlled by dormant stem or basal applications of picloram. All species considered, the propylene glycol butyl ether ester of 2,4,5-T applied as a dormant stem or basal application provided the most consistent results, giving 89% and 91% control, respectively.

scholarly journals Modeling of Ice-Shedding from ACSR Power Line

2017 ◽  
Vol 67 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Juraj Hrabovský ◽  
Roman Gogola ◽  
Justín Murín ◽  
Tibor Sedlár
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Double Bundle ◽  
Power Line ◽  
Power Lines ◽  
Jump Height ◽  
Effective Material Properties ◽  
Ice Shedding ◽  
Overhead Power Lines ◽  
The Impact

Abstract In this contribution, the analysis of ice-shedding from Aluminium Conductor Steel Reinforced (ACSR) power lines is presented. The impact of the icing position on the overhead power lines, the resulting jump height, and impact on attachment tension points after ice-shedding is examined. In the numerical simulations the effective material properties of the ACSR conductor is calculated using the homogenisation method. Numerical analysis of one power line and double-bundle power lines with icing over the whole range or only on certain sections of single and double-bundle power lines are performed

scholarly journals Phytotoxicity in Seedlings of Rhizophora mangle (L.) Exposed to 2,4-Dichlorophenoxyacetic Acid under Experimental Conditions

2021 ◽  
Vol 9 (12) ◽  
pp. 1417
Author(s):  
Carlos A. Chan-Keb ◽  
Claudia M. Agraz-Hernández ◽  
Román A. Pérez-Balan ◽  
Eduardo J. Gutiérrez-Alcántara ◽  
Raquel Muñiz-Salazar ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Biomass Production ◽  
Agricultural Practices ◽  
Rhizophora Mangle ◽  
Dichlorophenoxyacetic Acid ◽  
Inhibitory Effects ◽  
Experimental Conditions ◽  
Environmental Goods ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
The Impact

Mangroves are considered one of the most productive ecosystems worldwide, providing multiple environmental goods and services; however, in recent years, there have been modifications and deterioration in the structure and function of these ecosystems, caused by various natural events and anthropic activities, such as the construction of roads, wastewater discharge, unsustainable livestock, and agricultural practices, as well as the impact of chemicals, such as heavy metals, oil spills, and the use of herbicides. In this research, phytotoxic effects on seedlings of Rhizophora mangle were evaluated at an exposure of five dilutions w/v (5%, 10%, 25%, 50%, and 100%) of the commercial presentation of 2,4-dichlorophenoxyacetic acid (2,4-D). Propagules grown in a greenhouse under local tidal regimes were used, so the growth of stem diameter, height, biomass production in root, leaves, and stems, as well as the concentration of chlorophyll a of the exposed seedlings were measured. The comparison of these parameters in seedlings with only seawater presented significant differences (p ≤ 0.05) and inhibitory effects on growth (diameter), the stem concentration of chlorophyll a, and the production of biomass of leaves, stems, and roots. The inhibitory effect of exposure to 2,4-D on chlorophyll production and root biomass is highlighted, with an average decrease of 45% relative to the control. The sensitivity of the Rhizophora mangle seedlings to the applied concentrations of herbicide evidence the inhibitory effects on the morphological variables of biomass production and chlorophyll a production in mangrove leaves.

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