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1
Edmaier, K., P. Burlando et P. Perona. « Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment ». Hydrology and Earth System Sciences 15, no 5 (26 mai 2011) : 1615–27. http://dx.doi.org/10.5194/hess-15-1615-2011.
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Abstract. The establishment of riparian pioneer vegetation is of crucial importance within river restoration projects. After germination or vegetative reproduction on river bars juvenile plants are often exposed to mortality by uprooting caused by floods. At later stages of root development vegetation uprooting by flow is seen to occur as a consequence of a marked erosion gradually exposing the root system and accordingly reducing the mechanical anchoring. How time scales of flow-induced uprooting do depend on vegetation stages growing in alluvial non-cohesive sediment is currently an open question that we conceptually address in this work. After reviewing vegetation root issues in relation to morphodynamic processes, we then propose two modelling mechanisms (Type I and Type II), respectively concerning the uprooting time scales of early germinated and of mature vegetation. Type I is a purely flow-induced drag mechanism, which causes alone a nearly instantaneous uprooting when exceeding root resistance. Type II arises as a combination of substantial sediment erosion exposing the root system and resulting in a decreased anchoring resistance, eventually degenerating into a Type I mechanism. We support our conceptual models with some preliminary experimental data and discuss the importance of better understanding such mechanisms in order to formulate sounding mathematical models that are suitable to plan and to manage river restoration projects.
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Edmaier, K., P. Burlando et P. Perona. « Mechanisms of vegetation uprooting by flow in alluvial non-cohesive sediment ». Hydrology and Earth System Sciences Discussions 8, no 1 (28 janvier 2011) : 1365–98. http://dx.doi.org/10.5194/hessd-8-1365-2011.
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Abstract. The establishment of riparian pioneer vegetation is of crucial importance within river restoration projects. After germination or vegetative reproduction on river bars juvenile plants are often exposed to mortality by uprooting caused by floods. At later stages of root development vegetation uprooting by flow is seen to occur as a consequence of a marked erosion gradually exposing the root system and accordingly reducing the mechanical anchoring. How time scales of flow-induced uprooting do depend on vegetation stages growing in alluvial non-cohesive sediment is currently an open question that we conceptually address in this work. After reviewing vegetation root issues in relation to morphodynamic processes, we then propose two modelling mechanisms (Type I and Type II), respectively concerning the uprooting time scales of early germinated and of mature vegetation. Type I is a purely flow-induced drag mechanism, which causes alone a nearly instantaneous uprooting when exceeding root resistance. Type II arises as a combination of substantial sediment erosion exposing the root system and resulting in a decreased anchoring resistance, eventually degenerating into a Type I mechanism. We support our conceptual models with some preliminary experimental data and discuss the importance of better understanding such mechanisms in order to formulate sounding mathematical models that are suitable to plan and to manage river restoration projects.
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Perona, P., et B. Crouzy. « Resilience of riverbed vegetation to uprooting by flow ». Proceedings of the Royal Society A : Mathematical, Physical and Engineering Sciences 474, no 2211 (mars 2018) : 20170547. http://dx.doi.org/10.1098/rspa.2017.0547.
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Riverine ecosystem biodiversity is largely maintained by ecogeomorphic processes including vegetation renewal via uprooting and recovery times to flow disturbances. Plant roots thus heavily contribute to engineering resilience to perturbation of such ecosystems. We show that vegetation uprooting by flow occurs as a fatigue-like mechanism, which statistically requires a given exposure time to imposed riverbed flow erosion rates before the plant collapses. We formulate a physically based stochastic model for the actual plant rooting depth and the time-to-uprooting, which allows us to define plant resilience to uprooting for generic time-dependent flow erosion dynamics. This theory shows that plant resilience to uprooting depends on the time-to-uprooting and that root mechanical anchoring acts as a process memory stored within the plant–soil system. The model is validated against measured data of time-to-uprooting of Avena sativa seedlings with various root lengths under different flow conditions. This allows for assessing the natural variance of the uprooting-by-flow process and to compute the prediction entropy, which quantifies the relative importance of the deterministic and the random components affecting the process.
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Calvani, Giulio, Paolo Perona, Simone Zen, Valentina Bau’ et Luca Solari. « Return period of vegetation uprooting by flow ». Journal of Hydrology 578 (novembre 2019) : 124103. http://dx.doi.org/10.1016/j.jhydrol.2019.124103.
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Edmaier, K., B. Crouzy et P. Perona. « Experimental characterization of vegetation uprooting by flow ». Journal of Geophysical Research : Biogeosciences 120, no 9 (septembre 2015) : 1812–24. http://dx.doi.org/10.1002/2014jg002898.
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Scholz, O. « Physicochemistry and Vegetation of Piccaninnie Ponds, a Coastal Aquifer-fed Pond in South-eastern South Australia ». Marine and Freshwater Research 41, no 2 (1990) : 237. http://dx.doi.org/10.1071/mf9900237.
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The aquatic vegetation and physicochemistry of Piccaninnie Ponds are described and recent annual losses of aquatic vegetation investigated. The aquifer-derived waters of the Ponds are characterized by their clarity, low nutrient content, low salinity, and lack of thermal and chemical stratification. In 1985, large areas of aquatic vegetation within the Ponds degraded and were lost. Subsequent faster regeneration of denuded areas by Ruppia polycarpa resulted in the displacement of Lepilaena cylindrocarpa. The annual uprooting of R. polycarpa, which has occurred since, results from Ruppia's comparatively poorer anchorage capacity in the loose sediment floc. Gradual expansion of L. cylindrocarpa into freshly uprooted regions restricts the regrowth of R. polycarpa and hence the area susceptible to denudation in the following year. It is expected that the displacement of R. polycarpa will continue until only small isolated stands remain, which will be prevented from uprooting by the root matrix of surrounding vegetation.
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Termini, Donatella, et Alice Di Leonardo. « Flow-induced vegetation uprooting in a meandering bend : Experimental investigation ». International Journal of Sediment Research 37, no 3 (juin 2022) : 399–410. http://dx.doi.org/10.1016/j.ijsrc.2021.10.003.
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Calvani, G., S. Francalanci et L. Solari. « A Physical Model for the Uprooting of Flexible Vegetation on River Bars ». Journal of Geophysical Research : Earth Surface 124, no 4 (avril 2019) : 1018–34. http://dx.doi.org/10.1029/2018jf004747.
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Acosta-Vargas, Luis, Adriana E. Rovere et Jorge Camacho-Sandoval. « Effectiveness of two treatments to promote tree regeneration : implications for forest restoration in the Isla del Coco National Park, Costa Rica ». Revista de Biología Tropical 68, S1 (24 mars 2020) : S103—S114. http://dx.doi.org/10.15517/rbt.v68is1.41172.
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Introduction: Isla del Coco is the only island in the Eastern Tropical Pacific with humid tropical forests; 296 plant species are reported, of them, 22% are endemic. Their ecology is poorly understood. Deforestation and the introduction of rats, feral pigs and white-tailed deer are the primary agents of forest degradation. After more than 120 years, the deforested areas have never recovered the native forest. Objective: To analyse if the deforested area keeps its resilience, we evaluated the natural regeneration and ecological processes associated. Methods: From August 2016 to June 2018, we conducted a restoration experiment consisting of a randomized complete blocks design including vegetation cutting, vegetation uprooting and controls as treatments. Plots were protected with an exclusion fence to avoid herbivores. Results: There were no differences between plant cutting and uprooting in stimulating natural regeneration. We only recorded the seedlings of two tree species, 35 individuals of Cecropia pittieri and three of Sacoglottis holdridgei, both endemic. Their regeneration established during the first 15 months mainly. At the end of the experiment, the structure and composition of the vegetation changed from bushes dominated by Entada gigas (28%) and Clidemia strigillosa (12%) to grasses dominated by Paspalum conjugatum (39%). Entada gigas has a high recolonizing potential with a growing rate of 1.6±0.2m/month. Conclusions: As filters for restoration we determined herbivores, which pose a strong negative impact in the development of the forest; the exhausted seed bank of tree species and scarce or null seed dispersion.
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Termini, Donatella, et Alice Di Leonardo. « Roots Characteristics of a flexible and mature vegetation : Preliminary results of experimental investigation in a meandering laboratory flume ». E3S Web of Conferences 40 (2018) : 02052. http://dx.doi.org/10.1051/e3sconf/20184002052.
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Vegetation controls sediment dynamics and affects the kinematic characteristics of flow in rivers. The uprooting mechanism is strongly affected by mechanical properties, morphology and branching of the roots system. This work presents preliminary results of experimental work conducted in a laboratory meandering flume. The work aims to investigate how the geometrical and mechanical characteristics of the roots of a real, flexible and mature vegetation could vary along the bend. Results show that both the geometrical and the mechanical characteristics of the roots assume higher/lower values in peculiar sections of the bend suggesting that they could be affected by the kinematic characteristic of flow.
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Konôpka, B., et J. Konôpka. « Static stability of forest stands in the seventh altitudinal vegetation zone in Slovakia ». Journal of Forest Science 49, No. 10 (16 janvier 2012) : 474–81. http://dx.doi.org/10.17221/4719-jfs.
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Models evaluating static stability (resistance to breaking or uprooting of trees caused by wind, snow or ice) of forest stands in the seventh altitudinal vegetation zone were determined. The empirical material came from 180 research plots (High Tatra and Low Tatra Mountains) established within the research project Research on methods for mountain forest management based on sustainable Development. Static stability was characterized by the slenderness ratio that was calculated from the mean height and diameter of target trees. Then the particular forest stands were categorized with regard to slenderness ratio, mean diameter and absolute site class using either tables or graphic models. Particularly, four static stability classes were made up: 1 – very good, 2 – good, 3 – sufficient, and 4 – insufficient. Practical application of the models is shown for forest stands grown in the area of Vajsková and Lomnistá valleys.
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Krechowski, Janusz, Katarzyna Piórek, Michał Falkowski, Marek Wierzba et Katarzyna Mikułowska. « Vegetation of the ‘Mierzwice’ nature reserve and its protection ». Forest Research Papers 76, no 2 (1 juin 2015) : 168–79. http://dx.doi.org/10.1515/frp-2015-0016.
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Abstract The ‘Mierzwice’ nature reserve (forest district 206b, c and d of the Sarnaki Forest Inspectorate), situated in the area of the Podlaski Przełom Bug Landscape Park, is one of the most valuable natural assets of the central Bug river valley. The 12.98 ha reserve was established in 2010 to aid protection of the stand of xerothermic vegetation and its surrounding deciduous forest. In total, eight plant associations were identified within the reserve: Geranio-Peucedanetum cervariae, Geranio-Anemonetum sylvestris, Geranio-Trifolietum alpestris, Trifolio medii-Agrimonietum, Rubo fruticosi-Prunetum, Rhamno-Cornetum sanguinei, Potentillo albae-Quercetum and Tilio cordatae-Carpinetum betuli. Furthermore, 23 protected and 31 endangered species were found in the reserve including the following examples: Cephalanthera rubra, Thesium ebracteatum, Cypripedium calceolus, Gentiana cruciata, Anemone sylvestris, Cimicifuga europaea, Viola rupestris, Crepis praemorsa, Asperula tinctoria, Stachys recta, Laserpitium latifolium. Over the last few years, a regression of the species diagnostic number for thermophilous oak forests and xerothermic grasslands has been observed as a result of succession and expansion of Calamagrostis epigejos. Active protection of xerothermic vegetation such as uprooting of trees and bushes, regular grazing or mowing has been suggested in order to prevent the expansion of Calamagrostis epigejos.
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Sahib, Nargis. « Effect of two management techniques applied to the reduction of Juncus maritimus (Lam.) abundance in a selected temporary wetland ». Journal of Water and Land Development 41, no 1 (1 juin 2019) : 120–32. http://dx.doi.org/10.2478/jwld-2019-0035.
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Abstract Moderate management of temporary wetlands is one of the most proper methods for their restoration and conservation. The cessation of use may lead to high biomass domination by macrophytes as Juncus maritimus (Lam.) that changes plant community structure, threatens species biodiversity, and becomes a danger for their conservation. The experiment was carried out in Sidi Boughaba coastal reserve in Morocco. Two management techniques of wetlands were tested, cutting and uprooting of the rush. Four experimental plots (4.2 × 2.9 m) within the rush belt were set up, with intact plots as a control. Vegetation structure and water levels were monitored on 96 quadrats over two years. The six visits dates, three visits per year (February, April, June), were monitored over two years. The abundance and richness of species were studied, simultaneously with the density of the seed stock in each plot. Results showed that both techniques allowed the opening of the habitat with a significant increase of richness and abundance of species, particularly the restoration of characteristic species of the temporary wetland from the seed bank. The cut technique seems to have less of an effect on the seed stock, total seeds median value was 6.5 in cut plots versus 5 in uprooting plots, being regularly applied given the rapid encroachment of the rush.
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Lee, Chu, Lin, Kung, Lin et Lee. « Root Traits and Biomechanical Properties of Three Tropical Pioneer Tree Species for Forest Restoration in Landslide Areas ». Forests 11, no 2 (5 février 2020) : 179. http://dx.doi.org/10.3390/f11020179.
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Frequent earthquakes, monsoon torrential rains and typhoons cause severe landslides and soil erosion in Taiwan. Hibiscus taiwanensis, Macaranga tanarius, and Mallotus paniculatus are major pioneer tree species appearing on landslide-scarred areas. Thus, these species can be used to restore the self-sustaining native vegetation on forest landslides, to control erosion, and to stabilize slope. However, their growth performance, root traits and biomechanical properties have not been well characterized. In this study, root system and root traits were investigated using the excavation method, and biomechanical tests were performed to determine the uprooting resistance, root tensile strength and Young’s modulus of 1-year-old Hibiscus taiwanensis, Macaranga tanarius, and Mallotus paniculatus seedlings. The results reveal that relative to H. taiwanensis, M. tanarius and M. paniculatus seedlings had significantly larger root collar diameter, longer taproot length, higher root biomass, higher root density, higher root length density, heavier root mass, larger external root surface area, higher root tissue density, larger root volume, longer total root length, and a higher root tip number. Additionally, the height of M. paniculatus seedlings was significantly higher than those of H. taiwanensis and M. tanarius. Furthermore, the uprooting resistance and root tensile strength of M. paniculatus seedlings was significantly higher than those of H. taiwanensis and M. tanarius. Young’s modulus of M. paniculatus and M. tanarius seedlings was also significantly higher than that of H. taiwanensis. These growth characteristics and biomechanical properties demonstrate M. paniculatus and M. tanarius are superior than H. taiwanensis, considering growth performance, root anchorage capability, tensile strength and Young’s modulus. Taken as a whole, the rank order for species selection of these pioneer species for reforestation comes as: M. paniculatus M. tanarius H. taiwanensis. These results, along with knowledge on vegetation dynamics following landslides, allow us to better evaluate the effect of selective removal management of pioneer species on the resilience and sustainability of landslides.
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Lee, Jung-Tai, Shun-Ming Tsai, Yu-Jie Wu, Yu-Syuan Lin, Ming-Yang Chu et Ming-Jen Lee. « Root Characteristics and Water Erosion-Reducing Ability of Alpine Silver Grass and Yushan Cane for Alpine Grassland Soil Conservation ». Sustainability 13, no 14 (8 juillet 2021) : 7633. http://dx.doi.org/10.3390/su13147633.
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In Taiwan, intensive forest fires frequently cause serious forest degradation, soil erosion and impacts on alpine vegetation. Post-fire succession often induces the substitution of forest by alpine grassland. Alpine silver grass (Miscanthus transmorrisonensis Hay.) and Yushan cane (Yushania niitakayamensis (Hay.) Keng f.) are two main endemic species emerging on post-fire alpine grassland. These species play a major role in the recovery of alpine vegetation and soil conservation of alpine grassland. However, their root traits, root mechanical properties and water erosion-reducing ability have still not been well studied. In the present study, root characteristics were examined using a complete excavation method. Root mechanical characteristics were estimated by utilizing the uprooting test and root tensile test, and hydraulic flume experiments were performed to investigate the water erosion-reducing ability using 8-month-old plants. The results show that the root architecture system of Alpine silver grass belongs to fibrous root system, while the Yushan cane has sympodial-tufted rhizomes with a fibrous root system. Root characteristics reveal that relative to Alpine silver grass, Yushan cane has remarkably larger root collar diameter, higher root biomass, larger root volume, higher root density, and a higher root tissue density. Furthermore, uprooting resistance of Yushan cane is notably higher than that of Alpine silver grass. However, the root tensile strength of Alpine silver grass is significantly higher than that of Yushan cane. Additionally, hydraulic flume experiments reveal that Yushan cane has significantly lower soil detachment rates than that of Alpine silver grass. Collectively, these findings clearly show that Yushan cane has superior root characteristics and water erosion-reducing ability than Alpine silver grass and is thus more suitable for the conservation of alpine grassland.
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Jerin, Tasnuba. « Biogeomorphic effects of woody vegetation on bedrock streams ». Progress in Physical Geography : Earth and Environment 43, no 6 (2 juin 2019) : 777–800. http://dx.doi.org/10.1177/0309133319851027.
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The dynamic interactions between fluvial processes and vegetation vary in different environments and are uncertain in bedrock settings. Bedrock streams are much less studied than alluvial in all aspects, and in many respects act in qualitatively different ways. This research seeks to fill this lacuna by studying bedrock streams from a biogeomorphic perspective. It aims to identify the impacts of woody vegetation that may be common to fluvial systems and rocky hillslopes in general, or that may be unique to bedrock channels. A review of the existing literature on biogeomorphology – mostly fluvial and rocky hillslope environments – was carried out, and field examples of biogeomorphic impacts (BGIs) associated with fluvial systems of various bedrock environments were then examined to complement the review. Results indicate that bedrock streams exhibit both shared and highly concentrated BGIs in relation to alluvial streams and rocky hillslopes. Bedrock streams display a bioprotective geomorphic form – root banks (when the root itself forms the stream bank) – which is distinctive, but not exclusive to this setting. On the other hand, shared biogeomorphic impacts with alluvial streams include sediment and wood trapping, and bar and island development and stabilization (i.e. bioconstruction/modification and protection). Shared impacts with rocky hillslopes also include bioprotection, as well as displacement of bedrock due to root and trunk growth, and bedrock mining caused by tree uprooting (i.e. bioweathering and erosion). Two BGI triangles were developed to graphically display these relationships. Finally, this paper concludes that bedrock streams exhibit some BGIs that also occur in either alluvial channels or on rocky hillslopes. Therefore, no BGIs were identified that are absolutely unique to bedrock fluvial environments.
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Bartenev, Ivan M., et Michael V. Drapalyuk. « Improving the Technology of Reforestation in Cuttings with the Use of Energy-Efficient Tractors ». Lesnoy Zhurnal (Forestry Journal), no 5 (15 octobre 2021) : 117–33. http://dx.doi.org/10.37482/0536-1036-2021-5-117-133.
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Currently applied partial reforestation in cuttings and removal of stumps by uprooting have a number of significant technological, environmental and economic disadvantages. These are removal of the humus layer of soil outside the cleared strips, compaction and reduction of soil porosity; formation of understump holes and their local waterlogging; littering of noncleared belts of trees between strips with felling debris and uprooted stumps; low productivity of uprooting machines and high energy consumption of stump uprooting; termination of agrotechnical tending after 2–3 years after planting and impossibility of cleaning stands due to their obstruction for tractor units; low level of traction force of special forest tractors and their insufficient power for uprooting stumps. Technology, machines and tools for reforestation in cuttings become the subjects of the research. The aim of the research is to provide a comprehensive mechanization of the reforestation process in order to improve work productivity, reduce energy and material consumption of the technology and create conditions for the effective use of machines and tools in combination with energy-efficient tractors of the traction-energy concept, ensuring the elimination of harmful effects on soil and plants ecology. The results of achieving the set aim and objectives are substantiation of forestry and ecological, technical, and economic feasibility of using the technology based on the complete clearing of cuttings from felling residues, dead wood and coppice of shrub vegetation by their crushing using mobile mulchers; removal of stumps in cuttings through crushing them at a depth of 0.15–0.20 m by an upgraded MUP-4A machine with scattering chips over the planting area and subsequent continuous tillage with a disk harrow BDK-2.5. Harmful effects on the ecology of soil and plants are practically eliminated with an increase in productivity, and the grinded woody biomass mixed with the soil turns into an organic fertilizer. The elimination of mechanical obstacles such as felling residues, fallen trees and stumps makes it possible to effectively use energy-efficient tractors by combining technological operations and performing them in one pass of the unit, as well as increasing the working width and operating speeds. Conditions for efficient operation of forestry machines and tools on tractormotor traction to protect the forest from pests, diseases, and fires, and for mechanization of various types of thinning are being created. For citation: Bartenev I.M., Drapalyuk M.V. Improving the Technology of Reforestation in Cuttings with the Use of Energy-Efficient Tractors. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 117–133. DOI: 10.37482/0536-1036-2021-5-117-133
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Wang, Hang, Yun Zhang, Guanglei Chen, Christian Hettenhausen, Zhengya Liu, Kun Tian et Derong Xiao. « Domestic pig uprooting emerges as an undesirable disturbance on vegetation and soil properties in a plateau wetland ecosystem ». Wetlands Ecology and Management 26, no 4 (5 décembre 2017) : 509–23. http://dx.doi.org/10.1007/s11273-017-9588-1.
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Popikov, Petr, Leonid Bukhtoyarov, Alexei Platonov et Elena Vakula. « Mathematical model of the dynamic modes of the hydraulic manipulator performance when uprooting unwanted vegetation in young forest stands ». Resources and Technology 18, no 2 (2021) : 32–47. http://dx.doi.org/10.15393/j2.art.2021.5643.
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Lee, Jung-Tai, Lin-Zhi Yen, Ming-Yang Chu, Yu-Syuan Lin, Chih-Chia Chang, Ru-Sen Lin, Kung-Hsing Chao et Ming-Jen Lee. « Growth Characteristics and Anti-Wind Erosion Ability of Three Tropical Foredune Pioneer Species for Sand Dune Stabilization ». Sustainability 12, no 8 (20 avril 2020) : 3353. http://dx.doi.org/10.3390/su12083353.
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Rainstorms frequently cause runoff and then the runoff carries large amounts of sediments (sand, clay, and silt) from upstream and deposit them on different landforms (coast, plain, lowland, piedmont, etc.). Afterwards, monsoons and tropical cyclones often induce severe coastal erosion and dust storms in Taiwan. Ipomoea pes-caprae (a vine), Spinifex littoreus (a grass), and Vitex rotundifolia (a shrub) are indigenous foredune pioneer species. These species have the potential to restore coastal dune vegetation by controlling sand erosion and stabilizing sand dunes. However, their growth characteristics, root biomechanical traits, and anti-wind erosion abilities in sand dune environments have not been documented. In this study, the root growth characteristics of these species were examined by careful hand digging. Uprooting test and root tensile test were carried out to measure their mechanical strength, and wind tunnel (6 m × 1 m × 1.3 m, L × W × H) tests were executed to explore the anti-wind erosion ability using one-year-old seedlings. The results of root growth characteristics demonstrate that I. pes-caprae is superior to S. littoreus and V. rotundifolia. Moreover, uprooting resistance of V. rotundifolia seedlings (0.074 ± 0.032 kN) was significantly higher than that of I. pes-caprae (0.039 ± 0.015 kN) and S. littoreus (0.013 ± 0.005 kN). Root tensile strength of S. littoreus (16.68 ± 8.88 MPa) and V. rotundifolia (16.48 ± 4.37 MPa) were significantly higher than that of I. pes-caprae (6.65 ± 2.39 MPa). In addition, wind tunnel tests reveal that sand wind erosion rates for all three species decrease with increasing vegetation cover, but the anti-wind erosion ability of S. littoreus seedlings is significantly higher than I. pes-caprae and V. rotundifolia. Results of root tensile strength and anti-wind erosion ability clearly show that S. littoreus is superior to I. pes-caprae and V. rotundifolia. Taken together, our results suggest that I. pes-caprae and S. littoreus are beneficial for front line mixed planting, while V. rotundifolia is suitable for second line planting in foredune areas. These findings, along with the knowledge on adaption of foredune plants following sand accretion and erosion, provide us critical information for developing the planting strategy of foredune pioneer plants for the sustainable management of coastal foredune ecosystem.
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Pryadkin, Vladimir, Ivan Bartenev et Viktor Posmetev. « EVALUATION OF SUSTAINABILITY AND ECOLOGICAL PROPERTIES OF A ROBOTIZED STUMP REMOVER EQUIPPED WITH WIDE-SECTION TYRES ». Forestry Engineering Journal 10, no 1 (6 avril 2020) : 244–55. http://dx.doi.org/10.34220/issn.2222-7962/2020.1/18.
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The article analyzes the technical means for uprooting trees. Tools aggregated with wheel and caterpillar tractors of various traction classes are the most popular ones in Russia. Abroad, self-propelled stump removers with high engine power and high performance are used, which are in demand in various industries (forestry, agricultural and oil and gas complexes, road construction), when laying high-voltage power lines and their maintenance, as well as in other areas of the national economy. The analysis of technical means for uprooting trees has shown that the dominant trend is creation of stump removers that ensure safety of the process, its high productivity and decrease in the number of personnel on felling. Self-propelled robotic stump remover equipped with wide-profile low-pressure tires has been developed to implement innovative technologies in the forest complex. Ensuring the technological process is carried out by robot-eradicator in unmanned mode. It is achieved by using a technical vision system, navigation equipment, automated control of technological equipment, transmission and steering. The aim of the study was to evaluate the longitudinal stability of a robotic self-propelled stump remover during vertical transportation of a tree and environmental compatibility of its wheeled mover with soil and vegetation cover. Conducted theoretical studies have found that the proposed layout scheme of a self-propelled stump remover provides longitudinal stability when moving with a tree in an upright position without the use of ballast counterweights behind the rear axle. It was also found that the wheel mover of the stump remover equipped with wide-profile low-pressure tires is environmentally friendly when performing technological operations in the summer-autumn period
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Ghirardi, Nicola, Rossano Bolpagni, Mariano Bresciani, Giulia Valerio, Marco Pilotti et Claudia Giardino. « Spatiotemporal Dynamics of Submerged Aquatic Vegetation in a Deep Lake from Sentinel-2 Data ». Water 11, no 3 (18 mars 2019) : 563. http://dx.doi.org/10.3390/w11030563.
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We mapped the extent of submerged aquatic vegetation (SAV) of Lake Iseo (Northern Italy, over the 2015–2017 period based on satellite data (Sentinel 2 A-B) and in-situ measurements; the objective was to investigate its spatiotemporal variability. We focused on the southern sector of the lake, the location of the shallowest littorals and the most developed macrophyte communities, mainly dominated by Vallisneria spiralis and Najas marina. The method made use of both in-situ measurements and satellite data (22 Sentinel 2 A-B images) that were atmospherically corrected with 6SV code and processed with the BOMBER (Bio-Optical Model-Based tool for Estimating water quality and bottom properties from Remote sensing images). This modeling system was used to estimate the different substrate coverage (bare sediment, dense stands of macrophytes with high albedo, and sparse stand of macrophytes with low albedo). The presented results substantiate the existence of striking inter- and intra-annual variations in the spatial-cover patterns of SAV. Intense uprooting phenomena were also detected, mainly affecting V. spiralis, a species generally considered a highly plastic pioneer taxon. In this context, remote sensing emerges as a very reliable tool for mapping SAV with satisfactory accuracy by offering new perspectives for expanding our comprehension of lacustrine macrophyte dynamics and overcoming some limitations associated with traditional field surveys.
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B.N., Ramesh, Sunil Kumar R., Pramod R. et Jayaramiah R. « Harmful Effects of Parthenium hysterophorus and Management Through Different Approaches”- A review ». Annals of Plant Sciences 6, no 05 (1 mai 2017) : 1614. http://dx.doi.org/10.21746/aps.2017.05.002.
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Parthenium hysterophorus is commonly known as congress grass or carrot weed in India. It belongs to Asteraceae family and native to subtropics of North and South America. It is an invasive plant species that disturbs cultivated areas, roadside vegetation, gardens etc. P. hysterophorus is considered as one of the worst weeds responsible for causing health problems in animals and humans viz., dermatitis, asthma and bronchitis besides loss to agriculture and ecosystem. Nowadays, it has become one of the major weeds in almost all types of agricultural lands and other areas. Many control methods ranging from preventive, physical methods by manual uprooting, burning and allelopathic management through competitive plants like Cassia tora, Cassia uniflora Cassia sericea, have been recommended for management of P. hysterophorus. Likewise, insect Zygogramma bicolorata has proven successful in managing P. hysterophorus. Further, microorganisms like Alternaria alternata, Scerotiia sclerotiorum, Fusarium Pallidoroseum, Ralstonia solanacearum, Xanthomanas campestris are reported to infest P. hysterophorus. Use of chemical herbicides mainly glyphosate @ 2.5 kg a.i.ha-1,atrazine @ 2.6 kg a.i.ha-1,2,4-D amine @ 3 l/ ha-1, Paraquat 0.5 l/ ha-1 were proved effective in managing P. hysterophorus. No single option is suitable to control this invasive weed. Successful control of this weed can only be achieved by an integrated weed management approaches.
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Schlegel, Jürg, et Matthias Riesen. « Bracken fern (Pteridium aquilinum (L.) Kuhn) overgrowth on dry Alpine grassland impedes Red List Orthoptera but supports local orthopteran beta diversity ». Journal of Insect Conservation 25, no 4 (14 juin 2021) : 657–69. http://dx.doi.org/10.1007/s10841-021-00333-8.
Texte intégralRésumé :
Abstract The native bracken fern (Pteridium aquilinum (L.) Kuhn) has become increasingly invasive in abandoned or undergrazed Alpine grasslands. Bracken stands are generally assumed to be poor in species, but there is still very little information about the impact on the fauna. We recorded Orthoptera communities of 24 sample plots with varying bracken cover. Compared to plots with only sparse or medium bracken cover, species richness was highly significantly lower in densely overgrown plots, while the former two did not differ markedly. Multivariate ordination analyses revealed gradients with unequal orthopteran communities, showing distinct patterns of bracken cover clustering. Based on indicator values, 13 of 23 Orthoptera species turned out to be significantly or marginally significantly associated with a single bracken cover stratum or a combination of two strata, whereby all nine Red List species were primarily restricted to sparse or medium bracken cover. However, some generalist species were found to favor denser bracken stands, such as Tettigonia viridissima, contributing to the local Orthoptera beta diversity. Our data suggest that ongoing rotational sheep grazing with temporary paddocks is regarded as the most preferable management system. However, selected parts of the study area, which have only sparse vegetation and no pressure of bracken or scrub overgrowth, are recommended to be alternately left ungrazed for a few years to allow for the coexistence of different successional stages. Low-intensity bracken control measures, situationally by mowing or uprooting, are considered appropriate and should be pursued. Implications for insect conservation Even though most specialized and rare Orthoptera species in Western Europe tend to prefer sparsely vegetated areas, subareas with medium to even dense vegetation cover might promote certain generalist species, leading to a higher local species richness.
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Semeraro, Teodoro, Riccardo Buccolieri, Marzia Vergine, Luigi De Bellis, Andrea Luvisi, Rohinton Emmanuel et Norbert Marwan. « Analysis of Olive Grove Destruction by Xylella fastidiosa Bacterium on the Land Surface Temperature in Salento Detected Using Satellite Images ». Forests 12, no 9 (16 septembre 2021) : 1266. http://dx.doi.org/10.3390/f12091266.
Texte intégralRésumé :
Agricultural activity replaces natural vegetation with cultivated land and it is a major cause of local and global climate change. Highly specialized agricultural production leads to extensive monoculture farming with a low biodiversity that may cause low landscape resilience. This is the case on the Salento peninsula, in the Apulia Region of Italy, where the Xylella fastidiosa bacterium has caused the mass destruction of olive trees, many of them in monumental groves. The historical land cover that characterized the landscape is currently in a transition phase and can strongly affect climate conditions. This study aims to analyze how the destruction of olive groves by X. fastidiosa affects local climate change. Land surface temperature (LST) data detected by Landsat 8 and MODIS satellites are used as a proxies for microclimate mitigation ecosystem services linked to the evolution of the land cover. Moreover, recurrence quantification analysis was applied to the study of LST evolution. The results showed that olive groves are the least capable forest type for mitigating LST, but they are more capable than farmland, above all in the summer when the air temperature is the highest. The differences in the average LST from 2014 to 2020 between olive groves and farmland ranges from 2.8 °C to 0.8 °C. Furthermore, the recurrence analysis showed that X. fastidiosa was rapidly changing the LST of the olive groves into values to those of farmland, with a difference in LST reduced to less than a third from the time when the bacterium was identified in Apulia six years ago. The change generated by X. fastidiosa started in 2009 and showed more or less constant behavior after 2010 without substantial variation; therefore, this can serve as the index of a static situation, which can indicate non-recovery or non-transformation of the dying olive groves. Failure to restore the initial environmental conditions can be connected with the slow progress of the uprooting and replacing infected plants, probably due to attempts to save the historic aspect of the landscape by looking for solutions that avoid uprooting the diseased plants. This suggests that social-ecological systems have to be more responsive to phytosanitary epidemics and adapt to ecological processes, which cannot always be easily controlled, to produce more resilient landscapes and avoid unwanted transformations.
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Evelpidou, Niki, Alexandros Petropoulos, Anna Karkani et Giannis Saitis. « Evidence of Coastal Changes in the West Coast of Naxos Island, Cyclades, Greece ». Journal of Marine Science and Engineering 9, no 12 (14 décembre 2021) : 1427. http://dx.doi.org/10.3390/jmse9121427.
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Coastal lagoons and dunes are of great ecological importance, not only for providing habitats for rare flora and fauna, but also for protecting coastal areas from rising sea levels and storms, etc. Even though these features are unique for sustainable development and are extremely important to the natural environment and economy, they are one of the most vulnerable and threatened ecosystems due to their small size. The western coasts of Naxos (central Aegean Sea) represent an example of such phenomena, with various wetlands bordered by low-lying sand dunes. The aim of our study is to assess the vulnerability and pressures of the western coasts of Naxos Isl. by taking into consideration both natural and anthropogenic factors. We used a variety of approaches for the environmental and geomorphological study of the coastal zone to achieve this goal, including: (a) study of aerial photography from 1960 until today, (b) systematic seasonal aerial monitoring by drone, since 2015, (c) use of DGPS for the mapping of the coastal zone and for obtaining detailed topographic sections, and (d) dune mapping. Our findings reveal the vulnerability of the western coasts of Naxos due to sea level rise, tectonic subsidence, and a variety of anthropogenic pressures, such as uncontrolled parking, vegetation uprooting, sand extractions, and heavy touristic traffic. Therefore, the protection of the sand dunes, their restoration where they have been eroded, the definition of a zone of control, and restriction of human activities must be a key priority.
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Montserrat-Martí, G., et D. Gómez-García. « Variación de los dominios forestal y herbáceo en el paisaje vegetal de la península Ibérica en los últimos 20.000 años. Importancia del efecto de los grandes herbívoros sobre la vegetación ». Cuadernos de Investigación Geográfica 45, no 1 (18 juin 2019) : 87. http://dx.doi.org/10.18172/cig.3659.
Texte intégralRésumé :
Mega-herbivores (body mass greater than 1000 kg) help structuring the plant landscape through consumption, breakage and uprooting of numerous woody plants, tending to transform wooded areas into grass, shrub and forest mosaics. These mosaics contribute to maintain a high biodiversity, since they enable the persistence of plants and animals of dense forests and treeless steppes, which alternated in the European landscapes following the glacial cycles of the Pleistocene. The disappearance of the mega-herbivores from the Iberian Peninsula at the end of the Pleistocene probably caused a cascade of ecological effects that remains unknown. We also do not know if the causes of their disappearance were natural or anthropogenic, and consequently it is not know if the plant landscapes that developed later, in the Holocene, have a natural or anthropogenic origin.The aim of this review is to explore in the scientific literature the hypothesis that the transformation of the natural landscape by humans began after their arrival in Europe through the intensive hunting of large herbivores, until their disappearance or extreme reduction. Consequently, the forest recovery of the end of the Pleistocene and beginning of the Holocene might have taken place without the containment that these animals would have exerted on woody vegetation in the previous interglacials. As a result, dense forests would spread over large territories reducing pastures and herbivores of open spaces, which were the sustenance of Homo sapiens in the Pleistocene. This limitation would force humans to change their diet to survive and, in a relatively short period of time, to adopt a new way of life-style based on livestock and agriculture.The results of the review do not allow us to support or reject the hypothesis raised, or even any of the most relevant issues arising from it. Some fundamental grounds of this hypothesis are currently debated, and are giving rise to contrasting interpretations.The most relevant ecological aspects found after the literature review are discussed, some ideas are proposed for their interpretation, and the limitations of the paleo-ecological information available in the literature to answer general questions such as those posed here, are emphasized.
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Kuuluvainen, Timo, et Raija Laiho. « Long-term forest utilization can decrease forest floor microhabitat diversity : evidence from boreal Fennoscandia ». Canadian Journal of Forest Research 34, no 2 (1 février 2004) : 303–9. http://dx.doi.org/10.1139/x03-159.
Texte intégralRésumé :
Forest floor microhabitat diversity was studied in old Pinus sylvestris L. dominated forest sites in two regions within the middle boreal vegetation zone in Fennoscandia: in 50 managed forest sites in the Häme region in southwestern Finland and in 45 natural or old selectively logged forest sites in the KuhmoViena region in northeastern Finland and northwestern Russia. The forests in the Häme region are characterized by a long history of forest utilization, while the forests in the KuhmoViena region can be regarded as natural or near natural. The managed forest sites in Häme had significantly lower forest floor microhabitat diversity compared with natural and near-natural forests. Microhabitats that were significantly more scarce in managed versus natural and near-natural forest sites included humps, depressions, decayed wood, and vicinity of decayed wood. On the other hand, even ground was significantly more abundant in managed forest compared with natural and near-natural forest. Microhabitat availability was also reflected in the occurrence of tree saplings growing in different microhabitats. The results suggest that long-term forest utilization has decreased forest floor microhabitat diversity. This has occurred because of a decreased amount of fallen deadwood and, possibly, lack of soil disturbances because of fewer uprootings caused by falling trees.
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Rekah, Y., D. Shtienberg et J. Katan. « Role of the Shrub Tamarix nilotica in Dissemination of Fusarium oxysporum f. sp. radicis-lycopersici ». Plant Disease 85, no 7 (juillet 2001) : 735–39. http://dx.doi.org/10.1094/pdis.2001.85.7.735.
Texte intégralRésumé :
The saltcedar shrub Tamarix nilotica grows as a weed in the Arava region of Israel. This weed is commonly found in cultivated fields naturally infested with Fusarium oxysporum f. sp. radicis-lycopersici, the causal agent of tomato crown and root rot. Young bushes, 20 to 40 cm tall, were randomly uprooted from different fields. The roots were cut into segments which were placed on Fusarium-selective medium. Although the plants did not show any symptoms of disease, the roots of the shrub were colonized by the pathogen. The incidence of infected saltcedar plants and level of root colonization by F. oxysporum f. sp. radicis-lycopersici decreased with increasing distance of the sampling location from a tomato field infected with crown and root rot. F. oxysporum f. sp. radicis-lycopersici was also isolated from chaff of inflorescence samples taken from mature T. nilotica shrubs. Identity of the pathogen isolates obtained from T. nilotica roots and chaff samples was verified by pathogenicity and vegetative compatibility tests. Roots of T. nilotica plants sown under greenhouse conditions in soil naturally infested with F. oxysporum f. sp. radicis-lycopersici became colonized by the pathogen. Uprooting and removing saltcedar plants throughout the season from fields not cultivated with tomatoes lowered the inoculum density of F. oxysporum f. sp. radicis-lycopersici in the soil from 611 to 6 and from 176 to 10 CFU/g of soil in the 1998-99 and 1999-2000 growing seasons, respectively. These results demonstrate that T. nilotica may contribute to the buildup of the pathogen populations in the absence of a susceptible host. Colonization of saltcedar by F. oxysporum f. sp. radicis-lycopersici is an additional mechanism for survival of this pathogen in the fields and for dissemination through the spread of infested seed or chaff of T. nilotica.
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Caponi, Francesco, David F. Vetsch et Annunziato Siviglia. « A model study of the combined effect of above and below ground plant traits on the ecomorphodynamics of gravel bars ». Scientific Reports 10, no 1 (13 octobre 2020). http://dx.doi.org/10.1038/s41598-020-74106-9.
Texte intégralRésumé :
Abstract Both above- and below-ground plant traits are known to modulate feedbacks between vegetation and river morphodynamic processes. However, how they collectively influence vegetation establishment on gravel bars remains less clear. Here we develop a numerical model that couples above- and below-ground vegetation dynamics with hydromorphological processes. The model dynamically links plant growth rate to water table fluctuations and includes plant mortality by uprooting and burial. We considered a realistic hydrological regime and used the model to simulate the coevolution of alternate gravel bars and vegetation that displays trade-offs in investment of above- and below-ground biomass. We found that a balanced plant growth above- and below-ground facilitates vegetation to establish on steady, stable bars, because it allows plants to develop traits that maximise growth performance during low flow periods and thus survival during floods. Regardless of the growth strategy, vegetation could not establish on migrating bars because of large plant loss by uprooting during floods. These findings add on previous studies suggesting that morphodynamic processes play a key role on determining plant trait distributions and highlight the importance of including the dynamics of both above- and below-ground plant traits for predicting shifts between bare and vegetated states in river bars.
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Satoshi, Nakada, Haga Hiroki, Iwaki Maho, Mabuchi Kohji et Takamura Noriko. « High-resolution flow simulation in Typhoon 21, 2018 : massive loss of submerged macrophytes in Lake Biwa ». Progress in Earth and Planetary Science 8, no 1 (16 août 2021). http://dx.doi.org/10.1186/s40645-021-00440-9.
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AbstractThe global activities of typhoons and hurricanes are gradually changing, and these storms can drastically affect lake ecosystems through the recession of submerged macrophytes that regulate the water quality in lakes. Using an echosounder, we captured the short-term, massive loss of submerged macrophytes attributed to the abnormal fluctuation of the water level induced by the approach of a catastrophic super typhoon in the southern basin of Lake Biwa, Japan. This paper investigates the physical processes responsible for the loss of vegetation using a high-resolution circulation model in Lake Biwa as a pilot study area. The circulation model was coupled with dynamical models of the fluid force and erosion acting on the vegetation. Our simulation successfully reproduced the water level fluctuation and high-speed current (torrent) generated by the typhoon gale. The simulated results demonstrated that the fluid force driven by the gale-induced torrent uprooted submerged macrophytes during the typhoon approach and that this fluid force (rather than erosion) caused the outflow of vegetation. As a result, this uprooting attributed to the fluid force induced the massive loss of submerged macrophytes in a large area of the southern basin, which might have increased primary production and reduced the stock of fish such as bluegill in the lake. Our model can estimate the reduction in the macrophyte height within the range of − 1.3 to − 0.4 m, suggesting that fluid forces greater than the time-averaged value (1.24 × 10−4 N) were available. Flow speeds of approximately 0.8 m/s might be the critical value that induces the fluid force acting on the uprooting of the submerged macrophytes. Our approach is practical for evaluating changes in lake environments attributed to the massive outflow of submerged macrophytes under various climate change scenarios.
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Khanina, L. G., M. V. Bobrovsky et I. V. Zhmaylov. « VEGETATION DIVERSITY ON THE MICROSITES CAUSED BY TREE UPROOTING DURING A CATASTROPHIC WINDTHROW IN TEMPERATE BROADLEAVED FORESTS ». Russian Journal of Ecosystem Ecology 4, no 3 (2019). http://dx.doi.org/10.21685/2500-0578-2019-3-1.
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ATES, Fadime, Alper DARDENİZ, Mehmet Ali GÜNDOĞDU, Tolga SARIYER et Esra ŞAHİN. « Amerikan Asma Anaç Kalemlerinin Köklenme ve Vejetatif Gelişimi Üzerine Farklı Söküm Tarihlerinin Etkisi ». Türk Tarım ve Doğa Bilimleri Dergisi, 18 août 2022. http://dx.doi.org/10.30910/turkjans.1080339.
Texte intégralRésumé :
This study was conducted in the years 2013 and 2014 to determine rooting and vegetative development parameters of different American grapevine rootstock (‘5BB’, ‘110R’, ‘140Ru’, ‘1613C’, ‘1103P’ and ‘41B’) scions uprooted in different dates. Present findings revealed that hard and insufficient rooting problems especially of ‘140Ru’, ‘41B’ and ‘110R’ American grapevine rootstock scions were resulted from genetic characteristics and insufficient number of days between uprooting and planting dates. Significant increases were observed in rooting ratio (%), number of roots (roots/scion), root fresh weight (g scion–1), root scale (0–4), shoot length (cm), number of nodes (leaves) (nodes/scion), shoot fresh weight (g scion–1), scion weight (g) and shooting ratio (%) of American grapevine rootstock scions with the increasing number of days between uprooting and planting dates.
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Dhiman, Nisha, Anil Kumar, Dinesh Kumar et Amita Bhattacharya. « De novo transcriptome analysis of the critically endangered alpine Himalayan herb Nardostachys jatamansi reveals the biosynthesis pathway genes of tissue-specific secondary metabolites ». Scientific Reports 10, no 1 (14 octobre 2020). http://dx.doi.org/10.1038/s41598-020-74049-1.
Texte intégralRésumé :
Abstract The study is the first report on de novo transcriptome analysis of Nardostachys jatamansi, a critically endangered medicinal plant of alpine Himalayas. Illumina GAIIx sequencing of plants collected during end of vegetative growth (August) yielded 48,411 unigenes. 74.45% of these were annotated using UNIPROT. GO enrichment analysis, KEGG pathways and PPI network indicated simultaneous utilization of leaf photosynthates for flowering, rhizome fortification, stress response and tissue-specific secondary metabolites biosynthesis. Among the secondary metabolite biosynthesis genes, terpenoids were predominant. UPLC-PDA analysis of in vitro plants revealed temperature-dependent, tissue-specific differential distribution of various phenolics. Thus, as compared to 25 °C, the phenolic contents of both leaves (gallic acid and rutin) and roots (p-coumaric acid and cinnamic acid) were higher at 15 °C. These phenolics accounted for the therapeutic properties reported in the plant. In qRT-PCR of in vitro plants, secondary metabolite biosynthesis pathway genes showed higher expression at 15 °C and 14 h/10 h photoperiod (conditions representing end of vegetative growth period). This provided cues for in vitro modulation of identified secondary metabolites. Such modulation of secondary metabolites in in vitro systems can eliminate the need for uprooting N. jatamansi from wild. Hence, the study is a step towards effective conservation of the plant.