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1
Acuña, T. L. Botwright, and L. J. Wade. "Root penetration ability of wheat through thin wax-layers under drought and well-watered conditions." Australian Journal of Agricultural Research 56, no. 11 (2005): 1235. http://dx.doi.org/10.1071/ar05067.
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Sand over clay duplex soils and those compacted by heavy farm machinery restrict water infiltration and root growth because roots cannot penetrate hard soil. Under drought, restriction of roots to soil above the hard layer results in the early onset of plant water-deficit, unless roots can penetrate the hard layer to reach soil water and nutrients at depth. There is little to no information on the ability of roots of bread wheat (Triticum aestivum L.) to penetrate hardpans. Here we report on 3 experiments undertaken in a controlled environment in pots that validate and explore the use of thin Paraffin wax–Vaseline (WV) layers of different strengths to simulate a hardpan under contrasting water regimes. Seeds produced an average of 5 seminal roots, which all penetrated the low-impedance wax-layer (0.03WV), in such a way that seminal root dry matter (DM) was evenly distributed throughout the soil profile. The number and depth of penetrating seminal root axes declined as wax-layer strength increased, and a significant proportion of total length and DM of main seminal root axes was instead restricted to the 0–0.12-m soil layer above the wax layer. No roots penetrated the 0.60WV, which was equivalent to ~1.50 MPa penetrometer resistance. The distribution of seminal roots was less affected by water regime than nodal roots, which were severely reduced in number when drought was imposed at 14 days after sowing (DAS), compared with well-watered conditions. Growth of the seminal roots into soil beneath the wax-layer determined the pattern of stomatal conductance and volumetric soil water content (Jv) over the period of drought stress, as few nodal roots reached and penetrated the wax layer. Stomatal conductance declined suddenly at 19 days after the last irrigation, and partially recovered as water extraction increased in the 0.40–0.60-m soil depth. Reasons for this are discussed. The wax-layer technique requires validation for wheat in the field, but the technique offers promise for screening breeding lines for the ability to penetrate a hardpan.
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Kong, D. L., J. J. Wang, P. Kardol, H. F. Wu, H. Zeng, X. B. Deng, and Y. Deng. "Economic strategies of plant absorptive roots vary with root diameter." Biogeosciences 13, no. 2 (January 21, 2016): 415–24. http://dx.doi.org/10.5194/bg-13-415-2016.
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Abstract. Plant roots typically vary along a dominant ecological axis, the root economics spectrum, depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root economic strategies differ with increasing root diameter. To test this hypothesis, we used seven plant species (a fern, a conifer, and five angiosperms from south China) for which we separated absorptive roots into two categories: thin roots (thickness of root cortex plus epidermis < 247 µm) and thick roots. For each category, we analyzed a range of root traits related to resource acquisition and conservation, including root tissue density, different carbon (C), and nitrogen (N) fractions (i.e., extractive, acid-soluble, and acid-insoluble fractions) as well as root anatomical traits. The results showed significant relationships among root traits indicating an acquisition-conservation tradeoff for thin absorptive roots while no such trait relationships were found for thick absorptive roots. Similar results were found when reanalyzing data of a previous study including 96 plant species. The contrasting economic strategies between thin and thick absorptive roots, as revealed here, may provide a new perspective on our understanding of the root economics spectrum.
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Pinho, Luis Gustavo Nunes Dias, Gustavo Helder Vinholi, Tulio Kalife Coelho, Dimas João Rodrigues Neto, Daiane Cerutti Kopplin, and Anísio Lima Silva. "Evaluation of the fracture resistance of remaining thin-walled roots restored with different post systems." Journal of Research in Dentistry 1, no. 3 (September 1, 2013): 184. http://dx.doi.org/10.19177/jrd.v1e32013184-191.
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The purpose of this work was evaluating the fracture strength of bovine roots weakened experimentally, restored with two different techniques: internal reinforcement of root canal walls with composite resin and a cast metal post and core or anatomic post (glass fiber post associated with composite resin). Thirty bovine lower central incisive were selected and transversally sectioned, remaining 14 mm of root in order to approximate to the human maxillary central incisive. A sequence of standardized wear was used to weak the root until the walls remaining achieved from 0.5 to 0.7 mm of thickness at the cervical edge. Two groups were separated randomly (n=15) in order to test the roots reinforced with composite resin associated with cast metal post and core (CMP), or roots restored with composite resin associated to the glass fiber post (GFP). The test were applied in a Universal Test Machine (EMIC) with tangential compressive loading focused on the lingual face of core in an angle of 135° with the long axis of the tooth at a crosshead speed of 0.5 mm/min until failure occurred. The results showed that the fracture strength of remaining roots with weakened walls was influenced by the restorative technique, and the higher values of strength fractures were observed in the group of roots reinforced by composite resin associated with CMP (p<0.001) when compared to the group of roots restored with anatomic post.
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Kong, D., J. Wang, P. Kardol, H. Wu, H. Zeng, X. Deng, and Y. Deng. "The root economics spectrum: divergence of absorptive root strategies with root diameter." Biogeosciences Discussions 12, no. 15 (August 13, 2015): 13041–67. http://dx.doi.org/10.5194/bgd-12-13041-2015.
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Abstract. Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.
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Wu, Tien H., and Alex Watson. "In situ shear tests of soil blocks with roots." Canadian Geotechnical Journal 35, no. 4 (August 1, 1998): 579–90. http://dx.doi.org/10.1139/t98-027.
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In situ shear tests were performed on soil blocks that contained roots to study the contribution of roots to the shear strength in a case where the shear deformation is not constrained to a thin zone. The shearing resistance of the soil-root system, the tensile force in selected roots, and the deformation of the soil block were measured. The roots were exposed after the test and their positions were determined and used to estimate the initial positions. The root force and the shearing resistance of the soil-root system were estimated with known solutions and compared with measured root force and shearing resistance. None of the roots that passed through the shear zone failed in tension at the maximum displacement. As a consequence, the root resistance is much less than that found in a case where the failure surface is restricted to the boundary between a weak soil and a firm base and where roots are anchored in the firm base and fail in tension. Simplified procedures for estimating root forces are suggested for the case of a thick shear zone.Key words: in situ test, roots, shear strength, slope stability, soil reinforcement, soilroot interaction.
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De Micco, Veronica, and Giovanna Aronne. "Root structure of Rumex scutatus growing on slopes." IAWA Journal 31, no. 1 (2010): 13–28. http://dx.doi.org/10.1163/22941932-90000002.
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The effect of slope on root architecture and anatomy of Rumex scutatus L. was analysed in plants growing on slopes and on flat ground, on the flanks of Mt. Vesuvius. Roots of plants on steep slopes developed asymmetrically, with lateral roots growing upslope acting as tie-rods. In roots growing on flat ground, lignified xylem was limited to thin radial strips, surrounded by unlignified parenchyma cells filled with starch. A trend towards a larger lignified area was evident from plants growing on flat ground to those on steep slopes, as well as from taproots to tie-rod roots. The latter also showed larger vessels and a lower incidence of narrow vessels than taproots. Roots developing on steep slopes were characterised by high frequency of very-thick-walled, lignified fibres with long tips which accumulated both starch and phenolic compounds. Such fibres did not show lignified cell walls in roots growing on flat ground. Overall analysis showed that slope influences root architecture and anatomical traits, not only affecting mechanical properties but also water transport capacity.
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Bernier, Pierre Y., Gilles Robitaille, and Danny Rioux. "Estimating the mass density of fine roots of trees for minirhizotron-based estimates of productivity." Canadian Journal of Forest Research 35, no. 7 (July 1, 2005): 1708–13. http://dx.doi.org/10.1139/x05-099.
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Allocation of carbon for the production of fine roots is a significant component of the carbon budget within trees. Transformation of fine-root volumes or lengths as seen with minirhizotrons into fine-root mass per unit of horizontal area requires an estimate of the mass density or specific root length of fine roots for the species of interest. We obtained values of mass density of fine roots using three different sampling strategies on temperate and boreal forested sites. The strategies examined were (1) the use of bulk root samples from soil cores, (2) the use of individual roots from seedlings, and (3) the use of individual roots from soil cores. Our results show that the mass density of fine roots taken from seedlings is strongly dependent on root diameter, as shown by the strong drop in mass density with a decrease in diameter in all species examined. However, the dependency of mass density of individual fine roots extracted from soil cores on root diameter varies with the species mixture. Examination of thin cross-sections of roots using microscopy reveals that the proportion of xylem cell walls as a percentage of total cell walls also decreases strongly as root diameter diminishes for seedling fine roots, but that this relationship is not as clear in fine roots obtained from soil cores. We conclude that using the mass density from core fine roots may yield the best estimate of fine-root productivity when deriving such a value from the analysis of minirhizotron images. We also discuss some of the problems associated with the use of specific root length.
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Venzke Filho, Solismar de Paiva, Brigitte Josefine Feigl, Marisa de Cássia Piccolo, Lorival Fante Jr., Marcos Siqueira Neto, and Carlos Clemente Cerri. "Root systems and soil microbial biomass under no-tillage system." Scientia Agricola 61, no. 5 (October 2004): 529–37. http://dx.doi.org/10.1590/s0103-90162004000500011.
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Some root parameters such as distribution, length, diameter and dry matter are inherent to plant species. Roots can influence microbial population during vegetative cycle through the rhizodeposits and, after senescence, integrating the soil organic matter pool. Since they represent labile substrates, especially regarding nitrogen, they can determine the rate of nutrient availability to the next crop cultivated under no-tillage (NT). The root systems of two crop species: maize (Zea mays L.) cultivar Cargill 909 and soybean [Glycine max (L.) Merr.] cultivar Embrapa 59, were compared in the field, and their influence on spatial distribution of the microbial C and N in a clayey-textured Typic Hapludox cultivated for 22 years under NT, at Tibagi, State of Paraná (PR), Brazil, was determined. Digital image processing and nail-plate techniques were used to evaluate 40 plots of a 80 ´ 50 ´ 3 cm soil profile. It was observed that 36% and 30% of the maize and soybeans roots, respectively, are concentrated in the 0 to 10 cm soil layer. The percent distribution of root dry matter was similar for both crops. The maize roots presented a total of 1,324 kg C ha-1 and 58 kg N ha-1, with higher root dry matter density and more roots in decomposition in the upper soil layer, decreasing with depth. The soybean roots (392 kg C ha-1 and 21 kg N ha-1) showed higher number of thinner roots and higher density per length unity compared to the maize. The maize roots enhanced microbial-C down to deeper soil layers than did the soybean roots. The microbial N presented a better correlation with the concentration of thin active roots and with roots in decomposition or in indefinite shape, possibly because of higher concentration of C and N easily assimilated by soil microorganisms.
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Kodrík, J., and M. Kodrík. "Root biomass of beech as a factor influencing the wind tree stability." Journal of Forest Science 48, No. 12 (May 22, 2019): 549–64. http://dx.doi.org/10.17221/11922-jfs.
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Beech is, thanks to its root system, in general considered to be a wind-resistant woody plant species. Nevertheless, the research on beech root systems has revealed that it is not possible to mechanically divide the woody plants into deep rooted and shallow rooted, because their root systems are modified according to various stand conditions. The root system shape, growth and development are mostly influenced by soil conditions and groundwater level. In the case of a high groundwater level beech root systems do not form tap roots and the lateral roots are rather thin and weak. Important factor for the tree static stability is number of roots with diameter 3–10 cm. The most important for the tree stability are roots with diameter over 10 cm. Wood-destroying fungi have strong negative impact on tree static stability. There are differences between beech below-ground biomass growing in soils rich in nutrients and poor in nutrients. The total below-ground biomass of the beech stands poor in nutrients is higher.
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Kıvanç, B. H., T. Alaçam, Ö. İ. A. Ulusoy, Ö. Genç, and G. Görgül. "Fracture resistance of thin-walled roots restored with different post systems." International Endodontic Journal 42, no. 11 (November 2009): 997–1003. http://dx.doi.org/10.1111/j.1365-2591.2009.01609.x.
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Zelko, Ivan, Alexander Lux, Thibault Sterckeman, Michal Martinka, Karin Kollárová, and Desana Lišková. "An easy method for cutting and fluorescent staining of thin roots." Annals of Botany 110, no. 2 (March 14, 2012): 475–78. http://dx.doi.org/10.1093/aob/mcs046.
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Park, Nam, Li Xiaohua, Romij Uddin, and Sang Park. "Phenolic compound production by different morphological phenotypes in hairy root cultures of Fagopyrum tataricum Gaertn." Archives of Biological Sciences 63, no. 1 (2011): 193–98. http://dx.doi.org/10.2298/abs1101193p.
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Hairy roots were obtained after inoculating sterile young stems of Fagopyrum tataricum with Agrobacterium rhizogenes R1000. The established roots displayed two morphological phenotypes when cultured on hormone-free medium containing Murashige-Skoog salts and vitamins. The thin phenotype had a higher growth rate than the thick phenotype. Further, the phenolic compound content of the thin phenotype was higher than that of the thick phenotype. In terms of their total dry weight, the thin phenotype produced an almost double amount of (-)-epigallocatechin as well as more than 51.5% caffeic acid, 65% chlorogenic acid, and 40% rutin compared to the thick phenotype after 21 days of culture. Therefore, selection of the optimal morphological phenotype of hairy roots of tartary buckwheat is an important factor for improved phenolic compound production.
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Richards, BG, and EL Greacen. "Mechanical stresses on an expanding cylindrical root analog in antigranulocytes media." Soil Research 24, no. 3 (1986): 393. http://dx.doi.org/10.1071/sr9860393.
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Previously published studies of the mechanical impedance of granular media to root growth have shown that the rate of elongation of barley roots was halved by a lateral cell pressure of 0.02 MPa, applied externally to the growing media. It was incorrectly assumed that this lateral pressure was always the pressure on the growing root. In this paper, the stress distribution around a growing root was modelled both theoretically and experimentally by a thin cylindrical rubber tube, which was expanded radially in two granular materials in a modified triaxial cell. The theoretical model which simulated the deformation of the granular material around the expanding rubber root analogue was controlled by the elastic stiffness parameters, bulk and shear modulus in the early stages and later, at larger diameters, by the plastic yield parameters, cohesion and friction angle. This theoretical stress-strain model was validated experimentally by the good agreement with the results obtained using the thin rubber tube in the two granular materials. Using the theoretical model with root diameters similar to those for barley roots, it predicted soil pressures on the 'root' surface of 0.2-0.3 MPa for lateral triaxial pressures of the order of 0.02 MPa. This result was similar to the predictions made using earlier analytical models. The model also predicts lower mechanical impedance for finer roots, and strongly suggests that cylindrical expansion of the root behind the tip is effective in relieving soil pressure ahead of the elongating root.
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Macko-Podgórni, Alicja, Katarzyna Stelmach, Kornelia Kwolek, Gabriela Machaj, Shelby Ellison, Douglas A. Senalik, Philipp W. Simon, and Dariusz Grzebelus. "Mining for Candidate Genes Controlling Secondary Growth of the Carrot Storage Root." International Journal of Molecular Sciences 21, no. 12 (June 15, 2020): 4263. http://dx.doi.org/10.3390/ijms21124263.
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Background: Diverse groups of carrot cultivars have been developed to meet consumer demands and industry needs. Varietal groups of the cultivated carrot are defined based on the shape of roots. However, little is known about the genetic basis of root shape determination. Methods: Here, we used 307 carrot plants from 103 open-pollinated cultivars for a genome wide association study to identify genomic regions associated with the storage root morphology. Results: A 180 kb-long region on carrot chromosome 1 explained 10% of the total observed phenotypic variance in the shoulder diameter. Within that region, DcDCAF1 and DcBTAF1 genes were proposed as candidates controlling secondary growth of the carrot storage root. Their expression profiles differed between the cultivated and the wild carrots, likely indicating that their elevated expression was required for the development of edible roots. They also showed higher expression at the secondary root growth stage in cultivars producing thick roots, as compared to those developing thin roots. Conclusions: We provided evidence for a likely involvement of DcDCAF1 and/or DcBTAF1 in the development of the carrot storage root and developed a genotyping assay facilitating the identification of variants in the region on carrot chromosome 1 associated with secondary growth of the carrot root.
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Gorrell, Richard M., Samuel W. Bingham, and Chester L. Foy. "Translocation and Fate of Dicamba, Picloram, and Triclopyr in Horsenettle,Solanum carolinense." Weed Science 36, no. 4 (July 1988): 447–52. http://dx.doi.org/10.1017/s0043174500075184.
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Greenhouse studies were conducted to determine the extent of translocation from the foliage to fleshy roots, the inherent toxicity, and the fate of radiolabeled and nonlabeled dicamba, picloram, and triclopyr in horsenettle. Roots of horsenettle acted as the major sink for photosynthate accumulation at the 0.2- to 0.5-bloom growth stages as determined by autoradiography. Dicamba, picloram, and triclopyr were translocated into the roots of horsenettle and accumulation continued for at least 16 days.14C associated with each herbicide found in the roots ranged from 1.3% at 4 days to 3.8% at 16 days. After 16 days, slightly more14C from plants treated with dicamba and triclopyr (3.8 and 3.6%) than picloram (3.0%) was translocated to roots. These compounds were metabolized slowly in the foliage and roots as determined by thin-layer chromatography (TLC) and autoradiography. In translocation studies with horsenettle shoots, picloram at 1.12 kg/ha killed the treated and untreated shoots and roots. Dicamba and triclopyr at the highest rates killed the treated shoots and partially destroyed the root system. Symptoms were noted on the untreated shoots, but full recovery occurred at 8 weeks. Since each of the herbicides was metabolized slowly and only slight differences in their translocation were observed, the relatively higher herbicidal effectiveness of picloram must be attributed to its greater inherent potency.
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Perelman, Adi, Naftali Lazarovitch, Jan Vanderborght, and Andreas Pohlmeier. "Quantitative imaging of sodium concentrations in soil-root systems using magnetic resonance imaging (MRI)." Plant and Soil 454, no. 1-2 (July 25, 2020): 171–85. http://dx.doi.org/10.1007/s11104-020-04628-8.
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Abstract Aims Demonstrating the potential of MRI as a 3D, non-invasive and continuous measurement technique to map Na+ concentration distributions in soil and around roots. Methods Dissolved NaCl in soil and soil-plant systems was mapped by 3D 23Na-MRI. The lower limit of detectability in saturated and unsaturated porous media was evaluated, followed by evaporation experiments to test the quantification. Finally, Na+ enrichment around tomato roots, irrigated with saline solution under low/high transpiration rates (LT, HT), was imaged in parallel to the root system,. Results A spin echo pulse sequence allowed the quantitative mapping of the volume concentration of NaCl in sandy porous medium. Evaporation experiments showed slight enrichment in the top surface layer, plus uniform temporal enrichment in the deeper layers. In the tomato experiments, enrichment was more distinct under HT than under LT. Concentration-distance correlation curves revealed thin enrichment zones ranging a few mm around the roots. Conclusions MRI can map Na+ non-invasively in 3D at relevant concentrations for root activity. Visualizing water content, roots and Na+ on the same scale is possible, despite limitations of different scanning times and resolution. This opens a route for further quantitative investigations of salt enrichment processes in soil and soil-plant systems.
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Machado, Rosângela Paniago, Carolina de Andrade Lima Chaves, Fuad Jacob Abi Rached-Junior, Cassio José de Souza, Danielle Cristine Messias, and Yara Corrêa Silva-Sousa. "Effect of Light Sources on the Bond Strength of Resin Material to Thin-walled Roots." Brazilian Dental Journal 25, no. 3 (July 2014): 225–31. http://dx.doi.org/10.1590/0103-6440201302427.
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The aim of this study was to evaluate the bond strength to the dentin of an adhesive material used for root reinforcement light activated with different sources. Roots were divided into 4 groups (n=15) according to the light source used to activate the resin reinforcement: GI, non-weakened roots (control); GII, halogen light (H) 600 mW/cm2; GIII, LED 800 mW/cm2 and GIV, LED 1500 mW/cm2. The reinforcement was done with adhesive, composite resin and fiberglass posts. After 24 h, the specimens were sectioned and the first slice of each post region was used in the push out test in a universal testing machine with a crosshead speed of 0.5 mm/min. Failure modes of the debonded specimens were examined. Data (MPa) were analyzed by ANOVA and Holm-Sidak test (=0.05). The second slice from each region was analyzed by scanning electron microscopy (SEM). LED-1500 (4.69 ± 1.74) provided bond strength similar to the control group (5.05 ± 2.63) and statistically different from H-600 (1.96 ± 0.94) and LED-800 (2.75 ± 1.90), which were similar to each other (p<0.05). Cervical (4.16 ± 2.32) and middle (4.43 ± 2.32) regions showed higher bond strength than the apical (2.25 ± 1.50) (p<0.05). There was a prevalence of adhesive failures in H-600 and LED-800 and cohesive failures in LED-1500. SEM showed the formation of long, numerous and fine tags. It was concluded that LED-1500 provided higher bond strength of resin reinforcement to the dentin.
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Eliyahu, Avi, Zvi Duman, Sara Sherf, Olga Genin, Yuval Cinnamon, Mohamad Abu-Abied, Roy Weinstain, Arnon Dag, and Einat Sadot. "Vegetative propagation of elite Eucalyptus clones as food source for honeybees (Apis mellifera); adventitious roots versus callus formation." Israel Journal of Plant Sciences 67, no. 1-2 (February 25, 2020): 83–97. http://dx.doi.org/10.1163/22238980-20191112.
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Summer and autumn in Israel are highly arid with not enough plants in bloom offering nectar and pollen to support the local apiary. This leads to decline in colony health and honey production. To increase food sources for honeybees, we initiated a project to clone elite Eucalyptus trees exhibiting constant and rich blooming from late summer to early winter. We induced adventitious roots from cuttings of two mature Eucalyptus trees of which nectar production and honeybees’ attraction was measured: Eucalyptus brachyphylla and Eucalyptus x trabutii. During the rooting process, a high frequency of cylindrical callus formation instead of roots was obtained. To shed light on the inner anatomy of the callus chunks, we compared their cell organization and cell-wall composition to those of roots. Whereas in the root, cells were organized in circumferential symmetry, no symmetry was found in the callus. Instead, a more chaotic accumulation of meristematic-like cells with sporadic clusters of tracheary elements laid in different directions were observed. The outer cell layer of the callus often included swollen cells with thin cell walls. Most callus cells stained more strongly for cellulose and lignin than cells in the root meristem. In addition, specific antibodies to methylesterified and de-methylesterified pectin showed differential staining of callus vs. root cells indicating cell wall differences. Strikingly, roots were seen to differentiate from the chaotic cell organization of the callus, albeit at low rates. Further investigation of the cellular and molecular mechanisms underlying callus formation, are required.
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Vega-Frutis, Rocío, and Ana M. Hanan-Alipi. "Relationship between root traits and arbuscular mycorrhizal fungi in three species of weeds with different synanthropy index." Scientia Fungorum 51 (April 20, 2021): e1360. http://dx.doi.org/10.33885/sf.2021.51.1360.
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Background: Nutrient foraging strategies between thin and thick roots, including mycorrhizal symbionts are resource-costly, and therefore a trade-off could exist. These strategies can vary with the synanthropy index (degree to which a species associates with anthropogenic habitats), thus maximizing the benefits for the acquisition of soil resources.
Objectives: To quantify the arbuscular mycorrhizal colonization of Melampodium species with different synanthropy index, and to determine the correlations between arbuscular mycorrhizal colonization and the architectural and morphological root traits.
Methods: Roots of Melampodium divaricatum, M. perfoliatum and M. tepicense, with highest to lowest synanthropy index, respectively were collected. The root branching rate (RBR), total root length (TRL), diameter of first-order root, (FOR), root tissue density (RTD), specific root length (SRL), and arbuscular mycorrhizal colonization were quantified. Additionally, soil chemistry analyses were done.
Results and conclusion: Melampodium tepicense had lowest FOR, highest SRL and lowest arbuscular mycorrhizal colonization, whereas M. divaricatum and M. perfoliatum had the opposite values. Additionally, M. divaricatum and M. perfoliatum had higher TRL, RTD, and RBR, suggesting that both strategies, arbuscular mycorrhiza and fine roots, are used for acquisition of nutrients, independently of their phylogenetic relationship and soil nutrients.
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Pereira, Roberta Andressa, and Ana Claudia Rodrigues. "Morphoanatomy of the underground system of Androtrichum trigynum (Cyperaceae)." Rodriguésia 63, no. 2 (June 2012): 305–19. http://dx.doi.org/10.1590/s2175-78602012000200006.
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Androtrichum has only one species, A. trigynum (Spr.) Pfeiffer, occurring in coastal regions of the southwestern Atlantic coast. It presents an underground system consisting of rhizomes and adventitious roots. The rhizome is thickened, plagiotropic, sympodial, and floral scapes and roots arise from it. From the stem promeristem, the protoderm, procambium and ground meristem are differentiated. At the apex region, the intercalary meristem and primary thickening meristem (PTM) are observed. The adventitious roots originate from the PTM, and present root apex with closed organization. The young epidermis has papillose cells, and meristematic endoderm activity is observed. In a mature root, the outer cortex, or hypodermis, and the internal cortex can be identified. The endoderm presents radially elongated cells with thin walls and the pericycle is biseriate. The anatomical features observed in the present study are found in other species of Cyperaceae and some xeromorphic characters can be identified.
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Yin, Yuling, Shin Watanabe, and Hiroshi Ashihar. "Metabolic Fate of 14C-Labelled Nicotinamide and Adenine in Germinating Propagules of the Mangrove Bruguiera gymnorrhiza." Zeitschrift für Naturforschung C 67, no. 5-6 (June 1, 2012): 319–26. http://dx.doi.org/10.1515/znc-2012-5-612.
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We studied the metabolic fate of [carbonyl-14C]nicotinamide and [8-14C]adenine in segments taken from young and developing leaves, stem, hypocotyls, and roots of a shoot-root type emerging propagule of the mangrove plant Bruguiera gymnorrhiza. Thin-layer chromatography was used together with a bioimaging analyser system. During 4 h of incubation, incorporation of radioactivity from [carbonyl-14C]nicotinamide into NAD and trigonelline was found in all parts of the propagules; the highest incorporation rates into NAD and trigonelline were found in newly emerged stem and young leaves, respectively. Radioactivity from [8-14C]adenine was distributed mainly in the salvage products (adenine nucleotides and RNA), and incorporation was less in catabolites (allantoin, allantoic acid, and CO2). Adenine salvage activity was higher in young leaves and stem than in hypocotyls and roots. Over a short time, the effect of 500 mM NaCl on nicotinamide and adenine metabolism indicated that NaCl inhibits both salvage and degradation activities in roots
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Guasch-Vidal, B., J. Estévez, M. S. Dardanelli, M. E. Soria-Díaz, F. Fernández de Córdoba, C. I. A. Balog, H. Manyani, et al. "High NaCl Concentrations Induce the nod Genes of Rhizobium tropici CIAT899 in the Absence of Flavonoid Inducers." Molecular Plant-Microbe Interactions® 26, no. 4 (April 2013): 451–60. http://dx.doi.org/10.1094/mpmi-09-12-0213-r.
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The nodulation (nod) genes of Rhizobium tropici CIAT899 can be induced by very low concentrations (micromolar to nanomolar range) of several flavonoid molecules secreted by the roots of leguminous plants under a number of different conditions. Some of these conditions have been investigated and appear to have a great influence on the concentration and the number of different Nod factors, which can induce root nodule primordia and pseudonodules in several leguminous plant roots. In one such condition, we added up to 300 mM NaCl to the induction medium of R. tropici CIAT899 containing the nod gene inducer apigenin. At the higher concentrations of NaCl, larger amounts and more different Nod factors were produced than in the absence of extra NaCl. To our surprise, under control conditions (300 mM NaCl without apigenin), some Nod-factor-like spots were also observed on the thin-layer plates used to detect incorporation of radiolabeled glucosamine into newly synthesized Nod factors. This phenomenon was further investigated with thin-layer plates, fusions of nod genes to the lacZ gene, high-performance liquid chromatography, mass spectrometry, and the formation of pseudonodules on bean roots. Here, we report that, in the absence of flavonoid inducers, high concentrations of NaCl induced nod genes and the production of Nod factors.
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Wu, Xin, Anna T. T. Chan, Ya-Ming Chen, Kevin H. K. Yip, and Roger J. Smales. "Effectiveness and dentin bond strengths of two materials for reinforcing thin-walled roots." Dental Materials 23, no. 4 (April 2007): 479–85. http://dx.doi.org/10.1016/j.dental.2006.03.006.
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Clemente, E. P., C. E. G. R. Schaefer, R. F. Novais, J. H. Viana, and N. F. Barros. "Soil compaction around Eucalyptus grandis roots: a micromorphological study." Soil Research 43, no. 2 (2005): 139. http://dx.doi.org/10.1071/sr04069.
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This study aimed to evaluate the effects of Eucalyptus grandis root growth on localised soil compaction and fracturing. Undisturbed soil (Kandiustox) samples subjected to root growth pressure were used, employing 2 methods to study the phenomenon: (i) micromorphological analysis of thin sections of soil samples compacted by roots of 0.3, 0.9, 1.3, 2.8, 3.5, 6.4, 8.0, 9.0, and 10.2 cm diameter, carried out in the zone under direct root influence, up to 1 cm from the root–soil surface, compared with a reference area at a distance of 3 cm from the contact surface; (ii) a localised infiltration test to assess the time taken to infiltrate one drop of water into the surface of root-compacted soils, compared with the time taken in a reference sample without root compaction. The soil compaction was greater around root diameters >3.5 cm, and this effect was accompanied by reduced water infiltration in the soil surface at the root contact. Presence of chiseling fractures at an approximate 45° angle to the soil surface suggested helicoidal growth of the E. grandis root, causing both soil compression and shearing. At microscopic level the soil-root contact showed clay-oriented features, microfractures, fungi coatings, and micro-slickensides. The lower infiltration rate in the compacted soil–root surface is associated with both physical (compaction) and chemical (possibly hydrophobicity) mechanisms. The use of micromorphological techniques and image analysis allowed the observation and quantification of soil porosity in the vicinity of roots.
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Fyson, A., P. Kerr, J. N. A. Lott, and A. Oaks. "The structure of the rhizosphere of maize seedling roots, a cryogenic scanning electron microscopy study." Canadian Journal of Botany 66, no. 12 (December 1, 1988): 2431–35. http://dx.doi.org/10.1139/b88-330.
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The surface of primary roots of maize (Zea mays cv. W64A × 182E) seedlings grown in a field soil was examined after cryogenic preparation of samples for scanning electron microscopy. The very short preparation time of this method and the absence of fixation and drying procedures give excellent preservation of the spatial organization of the rhizosphere. As root hairs develop, they carry soil clear of the epidermal surface to form a distinct soil sheath layer. Root hairs remain turgid along the entire length of the primary root of the seedlings studied and are often distorted as a result of their growth around obstructing soil aggregates. The epidermal surface remains remarkably clean along the entire length of the root. Fractures of frozen roots reveal that the epidermis is covered by a thin layer that may be mucilage. Very few microorganisms are observed on the epidermal surface.
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Basu, Sautrik, and Timir Baran Jha. "In vitro Root Culture : An Alternative Source of Bioactives in the Rare Aphrodisiac Herb Chlorophytum borivilianum Sant et Fern." Plant Tissue Culture and Biotechnology 23, no. 2 (January 2, 2014): 133–46. http://dx.doi.org/10.3329/ptcb.v23i2.17505.
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Chlorophytum borivilianum is a rare, near-endemic high value root crop. The fasciculated roots of the plant have the potential to synthesize valuable bioactives having aphrodisiac, anti stress and immuno modulatory properties. The present investigation describes an alternative protocol for the development of a stable, fast growing, non-transformed root culture system in C. borivilianum and the simultaneous quantitative analysis of total steroidal saponins, amino acids and sugars. Liquid MS fortified with various concentrations and combinations of BA (0.44 - 8.8 µM), Kn (0.23 µM) and NAA (0.27 - 5.4 µM) was effectively used for the development of root culture system. High performance thin layer chromatography (HPTLC) was used for quantification and comparative analysis of bioactives from in vitro and in vivo grown tuberous roots. D. O. I. http://dx.doi.org/10.3329/ptcb.v23i2.17505 Plant Tissue Cult. & Biotech. 23(2): 133-146, 2013 (December)
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Parent, Sylvain, Marie-Josée Simard, Hubert Morin, and Christian Messier. "Establishment and dynamics of the balsam fir seedling bank in old forests of northeastern Quebec." Canadian Journal of Forest Research 33, no. 4 (April 1, 2003): 597–603. http://dx.doi.org/10.1139/x02-194.
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This study examines balsam fir (Abies balsamea (L.) Mill.) recruitment in old fir stands. Studying the regeneration of these stands is essential to understand the regeneration dynamic of the species in the absence of stand-destroying disturbances. The objectives were (1) to obtain substrateseedling associations for different age-classes and according to the presence or absence of adventitious roots; (2) to evaluate the contribution of the seed rain to seedling recruitment; (3) to re-examine age structures using the most appropriate method that minimizes estimation errors due to the presence of adventitious roots. A total of 90 quadrats (1 m2) were established along transects. In each quadrat, subtrates were characterized (type and topography) and their area was estimated. All balsam fir seedlings (<50 cm tall) present in the quadrats were located, harvested whole (root and shoot), and described (age, height, presence of adventitious roots, etc). Fir seedlings were strongly associated with woody mounds covered with thin mats of mixed mosses and Pleurozium shreberi (Bird.) Mitt. but negatively associated with flat topography particularly dominated by Hylocomium splendens (Hedw.) B.S.G. The presence of adventitious root is related to seedling age more than substrate type or topography. The age structure is in agreement with seed production and disturbance regime.
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Sugri, Issah, Bonaventure Kissinger Maalekuu, Eli Gaveh, Francis Kusi, and Salim Lamini. "Assessment of Low-cost Postharvest Techniques to Reduce Storage Losses in Sweet Potato." Sustainable Agriculture Research 9, no. 4 (August 10, 2020): 17. http://dx.doi.org/10.5539/sar.v9n4p17.
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Sweet potato is now classified among the high-priority crops targeted at reducing food insecurity and malnutrition in many countries. Despite this growing interest, high postharvest losses caused by poor handling, physiological weight loss, sprouting, weevil (Cylas spp.) damage and microbial decay remain a challenge. Decay losses due to tip rot and other pathogenic fungi are a challenge in Ghana. Incidence of tip rot, which is characterized by a dry decay at either or both ends of roots, is severe due to late harvesting of roots which are intended for storage. This study evaluated a series of postharvest techniques which can be integrated to extend shelf-life in small scale storage. These include harvest maturity, root tip coppicing, hot water treatment, honey waxing and sanitizing in postharvest chemicals. Tip coppicing significantly (P<0.001) reduced the incidence of tip rot across the varieties when stored for 8 weeks, but dipping roots in different oils did not significantly (P<0.05) reduce tip rot incidence. Decay losses in the control and hot water treated roots were similar during the first 4 weeks after storage, but later losses were significantly severe in hot water treated roots. The range of fungi genera identified in this study are generally fungal endophytes; often symptomless in roots but become pathogenic when conditions are favourable. Due to the root thin skin, mechanical injuries during harvesting and handling become infection pathways for such pathogens. Therefore, integration of best practices at each step of harvesting and postharvest handling operations can significantly minimize decay losses.
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Rafa, Asma, Mohamed Berrichi, and Ahmed Haddad. "Resilience aspects of woody plant species at the passage of fire: case of Quercus coccifera in Tlemcen Mountains (Algeria)." Lebanese Science Journal 21, no. 2 (December 27, 2020): 119–28. http://dx.doi.org/10.22453/lsj-021.2.119-128.
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In this study, on the aspects of the resilience of woody species to the passage of fire, we wanted to test the alveolar specificity represented by the size of the pores of the secondary xylem of the root system in Quercus coccifera L., Pore size assessment is based on measuring 100 pores in cross sections, from the roots of 10 shrubs. The aim of this study is to explain how the roots can maintain their vitality after passing a fire and thus guarantee regeneration. In addition to the vigor of the root system of this species, the release of pyrolysis gases and the propagation of heat by conduction are provided by the porosity of the material. The results show that the pores are qualified as “fine” in the initial wood with an average diameter of 83.35 µm. In final wood, they are "very thin" with 42.30 µm in diameter. The absence of oxygen and the less porous structure delay the combustion cycle of the root system, the roots distant from the surface are thus protected from proliferation by heat conduction and thus guarantee regeneration.
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PAGARIYA, ASHISH SHANTILAL. "Pharmacognostical evaluation of Murraya roots." Journal of Drug Delivery and Therapeutics 9, no. 2 (March 15, 2019): 336–40. http://dx.doi.org/10.22270/jddt.v9i2.2570.
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Pharmacognostical evaluation is the first and foremost step to determine identity and assess the quality and purity of the crude drug. Murraya koenigii Spreng (Rutaceae), commonly known as Curry leaf plant or Mitha Neem in Hindi is a highly valued plant for its medicinal value and characteristic aroma. Leaves of the plants are extensively used as spice and condiment in India and other tropical countries.
Present research work includes study of macroscopic, microscopic study of the root include anatomy of the thin root, anatomy of the thick root and microscopy of the powdered root. Physiochemical studies were done by using WHO recommended parameters.
Photographs at different magnifications were taken with Nikon Labphot-2 microscopic unit.
These findings will be useful towards establishing pharmacognostical standards and preparation of monograph of the root of Murraya koenigii.
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Bauhus, Jürgen, and Christian Messier. "Soil exploitation strategies of fine roots in different tree species of the southern boreal forest of eastern Canada." Canadian Journal of Forest Research 29, no. 2 (February 1, 1999): 260–73. http://dx.doi.org/10.1139/x98-206.
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This study compared the ability of conifers (Abies balsamea (L.) Mill., Picea glauca (Moench) Voss) and deciduous trees (Populus tremuloides Michx., Betula papyrifera Marsh.) and shrubs and herbs to exploit soils in a southern boreal forest. Root samples were collected from undisturbed soil and ingrowth cores (disturbed soil) of aspen- and conifer-dominated plots. Total fine-root biomass was similar in aspen and conifer plots but length density was higher under aspen. The low root length density (0.7 cm·cm-3) of conifers suggests a dependency on mycorrhizal associations for effective nutrient uptake. Coniferous fine roots were thicker than in the other species. Root tip and internode lengths in deciduous trees showed little differences between undisturbed and disturbed soil, whereas these parameters increased substantially in conifers in disturbed soil. Root growth and architecture in disturbed soil indicated that conifers follow a conservative strategy of optimizing soil exploitation efficiency through the relatively slow development of coarse fine-root systems. In contrast, deciduous trees and understorey shrubs and herbs colonized favourable soil environments to a larger extent maintaining highly ramified thin fine roots to optimize the exploited soil volume. The different soil exploitation strategies may be as important as those differences reported for aboveground growth to explain the coexistence of these species.
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Stone, Audrey J., Steven W. Copp, and Marc P. Kaufman. "Role played by NaV 1.7 channels on thin-fiber muscle afferents in transmitting the exercise pressor reflex." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 309, no. 10 (November 15, 2015): R1301—R1308. http://dx.doi.org/10.1152/ajpregu.00246.2015.
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Voltage-gated sodium channels (NaV) 1.7 are highly expressed on the axons of somatic afferent neurons and are thought to play an important role in the signaling of inflammatory pain. NaV 1.7 channels are classified as tetrodotoxin (TTX)-sensitive, meaning that they are blocked by TTX concentrations of less than 300 nM. These findings prompted us to determine in decerebrated, unanesthetized rats, the role played by NaV 1.7 channels in the transmission of muscle afferent input evoking the exercise pressor reflex. We first showed that the exercise pressor reflex, which was evoked by static contraction of the triceps surae muscles, was reversibly attenuated by application of 50 nM TTX, but not 5 nM TTX, to the L4-L5 dorsal roots (control: 21 ± 1 mmHg, TTX: 8 ± 2 mmHg, recovery: 21 ± 3 mmHg; n = 6; P < 0.01). We next found that the peak pressor responses to contraction were significantly attenuated by dorsal root application of 100 nM Ssm6a, a compound that is a selective NaV 1.7 channel inhibitor. Removal of Ssm6a restored the reflex to its control level (control: 19 ± 3 mmHg, Ssm6a: 10 ± 1 mmHg, recovery: 19 ± 4 mmHg; n = 6; P < 0.05). Compound action potentials recorded from the L4 and L5 dorsal roots and evoked by single-pulse stimulation of the sciatic nerve showed that both TTX and Ssm6a attenuated input from group III, as well as group IV afferents. We conclude that NaV 1.7 channels play a role in the thin-fiber muscle afferent pathway evoking the exercise pressor reflex.
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Koike, S. T. "Black Root Rot Caused by Thielaviopsis basicola on Lettuce in California." Plant Disease 92, no. 9 (September 2008): 1368. http://dx.doi.org/10.1094/pdis-92-9-1368a.
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In 2005 and 2006, field-grown iceberg lettuce (Lactuca sativa) in California's coastal Salinas Valley (Monterey County) was affected by a previously unreported disease. Symptoms were observed on iceberg lettuce at the post-thin rosette stage (8 to 12 leaves). Plants were stunted and slightly chlorotic. Fine feeder roots had numerous, small (4 to 8 mm long), elongated, dark brown-to-black lesions. Larger secondary roots and taproots lacked lesions. No vascular discoloration was present. Isolations from root lesions consistently resulted in gray fungal colonies that formed catenulate, cylindrical, thin-walled, hyaline endoconidia and catenulate, subrectangular, thick-walled, dark aleuriospores. The fungus was identified as Thielaviopsis basicola (2). Conidial suspensions (5.0 × 105) of eight isolates from iceberg lettuce were used for pathogenicity tests. Iceberg cv. Ponderosa and romaine cv. Winchester were grown for 3 weeks in soilless peat moss rooting mix. Roots of 20 plants per cultivar were washed free of the rooting mix and soaked in conidial suspensions for 5 min. Plants were repotted and grown in a greenhouse. Control plant roots were soaked in sterile distilled water (SDW). After 3 weeks, inoculated iceberg exhibited slight chlorosis in comparison with control plants. Feeder roots of all iceberg plants inoculated with the eight isolates exhibited numerous black lesions and T. basicola was reisolated from these roots. Romaine lettuce, however, did not show any foliar symptoms. Small segments of roots had tan-to-light brown discoloration and T. basicola was occasionally reisolated (approximately 40% recovery). Roots of control iceberg and romaine showed no symptoms. Results were similar when this experiment was repeated. To explore the host range of T. basicola recovered from lettuce, two isolates were prepared and inoculated as described above onto 12 plants each of the following: iceberg lettuce (cv. Ponderosa), bean (cv. Blue Lake), broccoli (cv. Patriot), carrot (cv. Long Imperator #58), celery (cv. Conquistador), cotton (cv. Phy-72 Acala), cucumber (cv. Marketmore 76), green bunching onion (cv. Evergreen Bunching), parsley (cv. Moss Curled), pepper (cv. California Wonder 300 TMR), radish (cv. Champion), spinach (cvs. Bolero and Bossanova), and tomato (cv. Beefsteak). Control plant roots of all cultivars were soaked in SDW. After 4 weeks, only lettuce and bean roots had extensive brown-to-black lesions, from which the pathogen was consistently resiolated. Roots of cotton, pepper, spinach, and tomato had sections of light brown-to-orange discoloration; the pathogen was not consistently recovered from these sections. All other species and the control plants were symptomless. This experiment was repeated with similar results except that inoculated peppers were distinctly stunted compared with control plants. To my knowledge, this is the first report of black root rot caused by T. basicola on lettuce in California. Disease was limited to patches along edges of iceberg lettuce fields; disease incidence in these discrete patches reached as high as 35%. Affected plants continued to grow but remained stunted in relation to unaffected plants and were not harvested. Black root rot of lettuce has been reported in Australia (1); that report also showed that lettuce cultivars vary in susceptibility to T. basicola and isolates from lettuce were highly aggressive on bean but not on many other reported hosts of this pathogen. References: (1) R. G. O'Brien and R. D. Davis. Australas. Plant Pathol. 23:106, 1994. (2) C. V. Subramanian. No. 170 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1968.
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Brix, H., B. Lorenzen, J. T. Morris, H. H. Schierup, and B. K. Sorrell. "Effects of oxygen and nitrate on ammonium uptake kinetics and adenylate pools in Phalaris arundinacea L. and Glyceria maxima (Hartm.) Holmb." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 102 (1994): 333–42. http://dx.doi.org/10.1017/s0269727000014329.
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SynopsisWe studied the effects of oxygen (aerated versus O2 depleted ∼0.5 mg 1−1 O2) and nitrate (none versus 10 μmol 1−1) on the ammonium uptake kinetics and adenylate pools in two wetland plants differing in their degree of flood tolerance (Phalaris arundinacea L. and Glyceria maxima (Hartm.) Holmb.). The study was performed as a random block design in a growth chamber. The -uptake kinetics were estimated by using a computerised nonlinear parameter estimation procedure to fit the differential form of a modified Michaelis–Menten model to solution depletion curves. The uptake kinetics for differed between the two species: Vmax was significantly higher for P. arundinacea (24.7 to 29.6 μmol h−1 g−1 root dry weight) than for G. maxima (4.6–10.3 μmol h−1 g−1 root dry weight). The concentration at which uptake ceases (Cmin) was 0.2 to 0.5 μmol 1−1 for P. arundinacea and significant higher (1.1–2.7 μmol 1−1) for G. maxima.Km varied between 3.1 and 6.2 μmol 1−1 for P. arundinacea, and 1.6 and 3.0 μmol 1−1 for G. maxima. The different uptake kinetics of the two species reflect the different structure of their root systems: P. arundinacea has an extensive root system consisting of many thin roots whereas G. maxima has fewer but thicker roots. The uptake kinetics also suggest that P. arundinacea is adapted to growing at lower ambient concentrations than G. maxima. Oxygen had no consistent effect on uptake kinetics. However, the plants that had in the nutrient solution as well as had slightly higher Vmax values and lower Cmin and Km values than those without . Thus, both species were able to sustain their uptake characteristics at low external O2 concentrations, probably because of internal aeration through the air-space tissue of the plants. Nitrate deprivation also lowered the energy charge ratio and adenine nucleotide content in roots. The roots recovered quickly from deprivation once was resupplied. The stresses imposed by partially O2-depleted conditions and lack of nitrate were therefore relatively mild and reversible. It seems that the inherent aerenchyma development under aerated conditions in these species is sufficient to maintain adequate root oxygenation under partially O2-depleted conditions.
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Snyder, Robert H., Jonathan P. Lynch, Donald Kaufman, and Terry Schettini. "631 PB 487 ROOT ARCHITECTURAL RESPONSE OF BELL PEPPER TO SOIL AMENDMENTS." HortScience 29, no. 5 (May 1994): 522g—523. http://dx.doi.org/10.21273/hortsci.29.5.522g.
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Sustainable agricultural systems favor high organic amendments over chemical fertilizers for maintaining long-term soil fertility. To study root responses bell pepper was grown in soil treated with dairy compost, raw dairy manure, and a chemical fertilizer mix at Rodale Institute Research Center, Kutztown, Pa. Root crowns were excavated at 2-week intervals and total length determined from root subsamples by computer-based image analysis. Roots from compost amended plots displayed a simple branching pattern; a first order branch with short second order branches. Fertilizer stimulated a complex branching; short, thickened first and second order branches that supported long and thin third and fourth order roots. An intermediate form in the raw dairy plots yielded both simple and complex branching forms. All forms were dynamic within each treatment over time. Crown length averaged 250-300 m across treatments 6 weeks after transplanting. Raw dairy and fertilizer treatments decreased slightly in length by week 10, while compost remained constant. After heavy rainfall crown length increased to 400 m for compost and raw dairy, and to 750 m for the fertilizer treatment by week 13. Length for the fertilizer treatment dropped nearly 200 m by week 14. though an increase of 100-200 m occurred for compost and raw dairy treated roots respectively.
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Münch, Ch, T. Neu, P. Kuschk, and I. Röske. "The root surface as the definitive detail for microbial transformation processes in constructed wetlands – a biofilm characteristic." Water Science and Technology 56, no. 3 (August 1, 2007): 271–76. http://dx.doi.org/10.2166/wst.2007.527.
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It was the goal of the investigations to characterise the biofilm on the plant roots because of the demonstrable major role of these associated bacteria. The essential criteria for the research were to look at the structure of the microbial colonisation (pattern, density) and to determine properties of the rhizoplane biofilm such as thickness and structure. The root material from a hydroponic system, planted with Glyceria maxima and used for nitrogen removal, has been used for the investigations. Several properties of the bacteria became visible due to the application of specific dyes. The evaluation of the samples was performed by scanning confocal laser microscopy (CLSM). It was shown that the microbial colonisation of the root surface of Glyceria maxima was on an unexpected high level and seems to be related mainly to the permeability and therefore to the age of the plant roots. The thickness of the rhizoplane biofilm is remarkably thin; no inactive layers could be observed in contrast to biofilm growing on technical carrier material. Caused by the untypically two-sided supply with nutrients the whole biofilm is in interaction with the surroundings. This indicates the importance of the plant roots for the microbial transformation processes in wetlands and underlines the especialness of the root as carrier for microorganisms.
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MacLeod, W. J., and M. W. Sweetingham. "A root disease of Lupinus angustifolius caused by a new species of binucleate Rhizoctonia." Australian Journal of Agricultural Research 48, no. 1 (1997): 21. http://dx.doi.org/10.1071/a96021.
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A new root disease of narrow-leafed lupins that is common in the northern wheatbelt of Western Australia wa found to be caused by a slow-growing binucleate Rhizoctonia sp. with characteristically narrow hyphae (2–4 µm). The new root disease causes distinct patches of poor growth superficially similar to rhizoctonia bare patch. This root disease of lupins is widespread in the northern lupin-growing areas of Western Australia. The biological nature of the disorder was established by transfer of soil from a patch to a clean area and by treating patches using a soil fumigant (methyl bromide–chloropicrin). The thin binucleate Rhizoctonia sp. (TBR) was isolated directly from soil within, but not outside, patches by using a soil immersion plate technique. Lupins grown in pots inoculated with the TBR developed symptoms consistent with those seen on plants in patches in the field, and the fungus was re-isolated from the diseased roots. Field soil was inoculated with TBR, and in the following year, lupins were sown over the inoculated area and developed patches identical to the stunted patches occurring naturally. The fungus was re-isolated from diseased lupin roots taken from inoculated patches but not from diseased roots from outside patches.
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Noman, Omar M., Fahd A. Nasr, Ali S. Alqahtani, Mohammed Al-zharani, Mary Anne W. Cordero, Amal A. Alotaibi, Asmatanzeem Bepari, Saud Alarifi, and Ali Daoud. "Comparative study of antioxidant and anticancer activities and HPTLC quantification of rutin in white radish (Raphanus sativus L.) leaves and root extracts grown in Saudi Arabia." Open Chemistry 19, no. 1 (January 1, 2021): 408–16. http://dx.doi.org/10.1515/chem-2021-0042.
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Abstract The nutrient contents of Raphanus sativus L. (white radish) leaves (RSLs) and roots are known to have promising vital effects. We comparatively investigated the leaves and roots of R. sativus grown in Saudi Arabia to estimate the total phenol and flavonoid contents using the standard colorimetric methods. The antioxidant activity of RSLs and R. sativus roots (RSRs) were measured by 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. Both extracts’ cytotoxic activity was assessed by MTT assay against several human cancer cell lines (A549, HepG2, MDA-MB-231, and MCF-7). High-performance thin-layer chromatography was used to identify and quantify the biomarker compound rutin in both extracts. The total phenolic content in RSLs (125.3 mg of gallic acid equivalent [GAE]/g) was higher than that in roots (95.8 of GAE/g), whereas the flavonoid content (44.5 mg of quercetin equivalent [QE]/g) was almost double compared in RSR extract (24.4 of QE/g). Similarly, RSLs exhibited a higher antioxidative activity than RSRs in both DPPH (IC50 216.8 vs 359.7 µg/mL) and ABTS (IC50 326.7 vs 549 µg/mL) models. RSLs also demonstrated the highest antiproliferative efficiency against all cell lines, with IC50 values of 217–453 µg/mL. The reversed-phase-high-performance thin-layer chromatography results showed the presence of rutin (5.2 µg/mg) only in RSLs. Our study indicates RSLs as a promising source of bioactive compounds compared with roots.
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Jorgenson, Kimberly D., Peter F. Lee, and Nandakumar Kanavillil. "Ecological relationships of wild rice, Zizania spp. 11. Electron microscopy study of iron plaques on the roots of northern wild rice (Zizania palustris)." Botany 91, no. 3 (March 2013): 189–201. http://dx.doi.org/10.1139/cjb-2012-0198.
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The deposition, composition, and structure of iron plaques formed on the roots of northern wild rice (Zizania palustris L.) from five wetlands across Ontario, Canada, were examined through a scanning electron microscope and energy-dispersive X-ray analyzer. Iron was oxidized within the rhizosphere resulting in the precipitation of ferric hydroxide onto root surfaces, visible as an orange-brown plaque. The northern wild rice samples analyzed were found to form substantial iron root plaques in a variety of surface water and sediment chemistries. Iron plaques ranged structurally from thin to crust plaques (<1 μm to 14 μm thick) and were composed mainly of Fe, O, Al, and K. Iron plaque was found within and on root epidermal cells, occasionally filling epidermal cells and penetrating into the root cortex. Rounded grooves were observed in the plaque surface of two samples and were reasoned to have been caused by iron-reducing bacteria. Observations on the anatomy of northern wild rice roots are presented along with a model of iron plaque development.
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Imhof, Stephan. "Subterranean structures and mycotrophy of the achlorophyllous Triuris hyalina (Triuridaceae)." Canadian Journal of Botany 76, no. 12 (December 1, 1998): 2011–19. http://dx.doi.org/10.1139/b98-168.
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Triuris hyalina Miers, an unusual achlorophyllous plant, was investigated for subterranean morphology, root anatomy, and mycotrophy. Stems with scale leaves extend subterraneously to a depth of 15 cm. Pairs of adventitious roots develop at the scale leaves and clumps of apparently radiating roots, formed by accumulations of side shoot and scale leaf developments, occur. Roots consist of epidermis, short cell exodermis, three distinct layers of cortex parenchyma, endodermis, and an extremely reduced central cylinder with one or two central tracheidal xylem elements. The fungus associated with T. hyalina roots exhibits thick-walled, 6-9 µm thick, aseptate external hyphae. It penetrates the epidermis by developing appressoria and enters the cortex solely through the short cells of the exodermis. In the cortex cells, the aseptate hyphae start to coil. In the outer cortex layer, hyphae are thin, frequently branched, and most densely coiled. In the middle cortex layer they are thicker and less densely coiled, and mostly appear degenerated to clumps of amorphous fungal material. The inner cortex layer rarely becomes colonized. Vesicles occur in the outer and the middle cortex layers. This mycorrhizal pattern is interpreted as an adaption to attain a sustainable use from the endophyte. It is suggested that the mycorrhiza in Triuris hyalina be interpreted as a type of arbuscular mycorrhiza (AM). Implications for systematics and ecology are discussed.Key words: Triuris, Triuridaceae, root structure, anatomy, arbuscular mycorrhiza, myco-heterotrophy.
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Teixeira da Silva, Jaime, Maria Maddalena Altamura, and Judit Dobránszki. "The Untapped Potential Of Plant Thin Cell Layers." Journal of Horticultural Research 23, no. 2 (December 1, 2015): 127–31. http://dx.doi.org/10.2478/johr-2015-0024.
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Abstract Thin cell layers (TCLs), which contain a small number of cells or tissues, are explants excised from different organs (stems, leaves, roots, inflorescences, flowers, cotyledons, hypocotyls/epicotyls, and embryos). After almost 45 years of research, this culture system has been used for several monocotyledonous and dicotyledonous plants of commercial importance, and for model plants. The limited amount of cells in a TCL is of paramount importance because marker molecules/genes of differentiation can be easily localized in situ in the target/responsive cells. Thus, the use of TCLs has allowed, and continues to allow, for the expansion of knowledge in plant research in a practical and applied manner into the fields of tissue culture and micropropagation, cell and organ genetics, molecular biology, biochemistry, and development. Starting from a brief historical background, the actual and potential uses of the TCL system are briefly reviewed.
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Batista, Michelli Fernandes, Ismar Sebastião Moscheta, Carlos Moacir Bonato, Marcelo Augusto Batista, Odair José Garcia de Almeida, and Tadeu Takeyoshi Inoue. "Aluminum in corn plants: influence on growth and morpho-anatomy of root and leaf." Revista Brasileira de Ciência do Solo 37, no. 1 (February 2013): 177–87. http://dx.doi.org/10.1590/s0100-06832013000100018.
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Aluminum (Al) toxicity is one of the most limiting factors for productivity. This research was carried out to assess the influence of Al nutrient solution on plant height, dry weight and morphoanatomical alterations in corn (Zea mays L.) roots and leaves. The experiment was conducted in a greenhouse with five treatments consisting of Al doses (0, 25, 75, 150, and 300 µmol L-1) and six replications. The solutions were constantly aerated, and the pH was initially adjusted to 4.3. The shoot dry matter, root dry matter and plant height decreased significantly with increasing Al concentrations. Compared to the control plants, it was observed that the root growth of corn plants in Al solutions was inhibited, there were fewer lateral roots and the development of the root system reduced. The leaf anatomy of plants grown in solutions containing 75 and 300 µmol L-1 Al differed in few aspects from the control plants. The leaf sheaths of the plants exposed to Al had a uniseriate epidermis coated with a thin cuticle layer, and the cells of both the epidermis and the cortex were less developed. In the vascular bundle, the metaxylem and protoxylem had no secondary walls, and the diameter of both was much smaller than of the control plants.
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Berlin, J., I. N. Kuzovkina, C. Rügenhagen, L. Fecker, U. Commandeur, and V. Wray. "Hairy Root Cultures of Peganum harmala II. Characterization of Cell Lines and Effect of Culture Conditions on the Accumulation of ß-Carboline Alkaloids and Serotonin." Zeitschrift für Naturforschung C 47, no. 3-4 (April 1, 1992): 222–30. http://dx.doi.org/10.1515/znc-1992-3-410.
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Abstract Hairy root cultures of Peganum harmala established by genetic transformation with Agrobacterium rhizogenes wild type strains A4, 15834 or carrying the binary vector pLTCgus 1, respectively, were analyzed with respect to their tryptophan-derived metabolites. Beside the previously detected β-carboline alkaloids harmine, harmol, harmaline and harmalol all hairy root cultures were found to contain the β-carboline glucoside ruine and serotonin. The appearance of the root cultures and the levels of β-carboline alkaloids were greatly affected by the nitrogen source of the medium. In the presence of higher levels of ammonium ions (as in MS medium) the roots were short and thick, while in B50 medium (low ammonium) they were thin and long. Ammonium ions had a negative effect on the levels of β-carbolines. The best root cultures accumulated on B50 1.5-2% β-carbolines on a dry mass basis and in the presence of 6% sucrose ca. 10 mg β-carbolines/L x d were formed. In the presence of phytohorm ones root cultures were converted into low producing suspension cultures, from which the highly productive roots were reinduced on phytohormone-free medium.
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Vegapareddy, M., G. M. Richter, and K. W. T. Goulding. "Using digital image analysis to quantify the architectural parameters of roots grown in thin rhizotrons." Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology 144, no. 2 (June 2010): 499–506. http://dx.doi.org/10.1080/11263501003732324.
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Gahoonia, Tara Singh, and Niels Erik Nielsen. "A method to study zhizosphere processes in thin soil layers of different proximity to roots." Plant and Soil 135, no. 1 (August 1991): 143–46. http://dx.doi.org/10.1007/bf00014787.
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Khangura, R. K., and D. W. Wright. "First Report of Club Root Caused by Plasmodiophora brassicae on Canola in Australia." Plant Disease 96, no. 7 (July 2012): 1075. http://dx.doi.org/10.1094/pdis-11-11-1006-pdn.
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In 2009, a disease survey was conducted in 97 commercial canola (Brassica napus L.) fields in Western Australia by the Department of Agriculture and Food, Western Australia (DAFWA). In about 20% of the fields from the northern agricultural region of Western Australia, small patches were observed where canola plants showed symptoms of stunting and wilting. These plants were collected and roots of affected plants were washed thoroughly and examined for the presence of root disease. Small galls and clublike structures were observed on the secondary roots and sometimes on the main root of the affected plants. Examination of thin free hand sections from the root galls revealed that several cortical cells were enlarged and full of resting spores. The diameter of resting spores ranged between 2.5 and 3.0 μm. Plasmodia and zoosporangia were also observed in the root hairs. The identity of Plasmodiophora brassicae Woronin was confirmed by PCR using a modified method of Cao et al. 2007 (1). DNA from spores and slices of the galls of 14 different samples were extracted using DNeasy plant mini kit (QIAGEN Australia) as per manufacturer's instructions. Samples were disrupted by placing them into MPBIO tube A and placed in the Fast Prep machine at speed of 6 ms–1 for 40 s. This was repeated twice. The species-specific primers TC1F (5′-GTGGTCGAACTTCATTAAATTTGGGCTCTT-3′)/TC1R (5′-TTCACCTACGGAACGTATATGTGCATGTGA-3′) and TC2F (5′-AAACAACGAGTCAGCTTGAATGCTAGTGTG-3′)/TC2R (5′-CTTTAGTTGTGTTTCGGCTAGGATGGTTCG-3′) were used (1). The primers TC1F and TC1R failed to produce a PCR product of 548-bp size but using the primers TC2F and TC2R the PCR reaction resulted in a 519- bp fragment. Seven out of 14 samples gave positive results for P. brassicae with primers TC2F and TC2R. This indicates that the P. brassicae pathotype from Western Australia may be different than the one found in Alberta, Canada. However, pathotypes of P. brassicae from brassica vegetables from Australia have been found similar to the populations of P. brassicae present in the United States (2). Pathogenicity of P. brassicae was tested by dipping roots of five 10-day-old canola plants var. Cobbler in a spore suspension (1 × 106 resting spores/ml). Roots of five control plants were dipped in sterile water. Five weeks after inoculation, small galls were observed on the roots of three inoculated plants and the control plants remained symptomless. Resting spores were recovered from the galls developed on the roots of affected plants. Presence of P. brassicae in the affected roots was further confirmed by PCR using the method described above. To our knowledge, this is the first report of club root of canola in Australia. Club root is reported from vegetable brassicas and white mustard (Sinapis alba L.) in Australia. Club root has become a serious disease of canola in Canada since its detection in Alberta in 2006 (3). The resting spores of the fungus can survive for several years in soil, and therefore, this disease could pose a significant threat to canola production in Western Australia. References: (1) Cao et al. Plant Dis. 91:80, 2007. (2) Donald et al. Ann. App. Biol. 148:239, 2006. (3) S. Streklov et al. Can. J. Plant Pathol. 28:467, 2006.
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Böckenhoff, A., and F. M. W. Grundler. "Studies on the nutrient uptake by the beet cyst nematode Heterodera schachtii by in situ microinjection of fluorescent probes into the feeding structures in Arabidopsis thaliana." Parasitology 109, no. 2 (August 1994): 249–55. http://dx.doi.org/10.1017/s003118200007637x.
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SUMMARYA method was developed, which enables substances to be injected into the feeding structure (syncytium) established by Heterodera schachtii in roots of Arabidopsis thaliana. The technique was used to study the uptake of nutrients by the feeding nematode. The fluorescent dye lucifer yellow CH (LYCH) and fluorescence-labelled dextrans of different molecular weights were injected into the thin and translucent roots of A. thaliana. Such roots are a feature of this plant and they provide optimal conditions for microinjection. Injected LYCH was taken up by feeding juveniles and adults, indicated by the staining of the alimentary duct and the digestive system. Fluorescent dextrans of 3, 10 and 20 kDa but not of 40 and 70 kDa were ingested, suggesting that molecules of a maximum Stokes radius of 3·2 to 4·4 nm are taken up. It is likely that the feeding tube, forming the interface between the plant cytosol and the nematode's digestive system, is responsible for this size exclusion effect. The injected fluorescent substances were not detected in plant cells adjacent to the syncytium or in the root vascular elements. Injections into parts of roots which were infested by several nematodes revealed that feeding H. schachtii individuals may share one syncytium.
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Kim, Min Jin, Ji-Soo Song, Young-Jae Kim, Jung-Wook Kim, Ki-Taeg Jang, and Hong-Keun Hyun. "Clinical Considerations for Dental Management of Children with Molar-Root Incisor Malformations." Journal of Clinical Pediatric Dentistry 44, no. 1 (January 1, 2020): 55–59. http://dx.doi.org/10.17796/1053-4625-44.1.10.
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Molar root-incisor malformation (MRIM) or molar-incisor malformation (MIM) is a new type of dental anomaly characterized by dysplastic roots of permanent first molars, occasionally second primary molars, and the crowns of maxillary central incisors. MRIM involving permanent first molars and second primary molars is characterized by normal crowns with short, thin, and narrow roots, whereas MRIM involving permanent maxillary central incisors exhibits constrictions of the crown in the cervical area. In the first case, we extracted the affected first permanent molars at the optimal timing to minimize space deficiencies and induce space closure. In addition, composite resin restorations were performed on the anterior central incisors. In the second case, a mandibular lingual arch was used to stabilize the affected teeth in order to mitigate discomfort by reducing rotational biting forces.
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Uzbek, I. Kh. "Some properties of man-made Dnieper Steppe ecosystems." Fundamental and Applied Soil Science 16, no. 3-4 (October 8, 2015): 60–67. http://dx.doi.org/10.15421/041518.
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Physico-chemical and hydrogeological properties of technogenic ecotope landscapes are unique in the world. Their development has created a new, completely unexplored problem of recultivation of disturbed lands. The ecological and biological evaluation of ecotypes is the leading place because it is the basis of targeted restoration of fertility of such anthropogenic tumors. As tests for the development of waste quarry sectors in the long-term stationary trials there were tested 23 species of higher plants. In the steppe of Ukraine the greatest ecological and biological according to technogenic ecotopes showed alfalfa and sainfoin. They are plant-dominants, accumulate large quantities of biomass, creating pockets of concentrations of elements in soil fertility, improve the sanitary conditions of the surrounding area. The nature translocational process in higher plants was identified. It completely depends on their biological features and is the creation of their root systems with the same structure and therefore their distribution in the thickness of elafotopos who are able to provide plants with nutrients and to produce the maximum possible efficiency in data soil-ecological conditions. Alfalfa and sainfoin showed great ecological plasticity of root systems. On the poverty of ecotopes batteries they reacted by increasing the surface and length of roots. It is established that the saturation of ecotopes roots is directly proportional to their mass, and the surface root system and its length are values associated with root mass. With the depth of the absorbing working surface root systems increases. The mathematical model of calculation of the ecological and biological characteristics of root systems of plants and progressive framework method of selection of soil monoliths with roots. After washing, the roots are reported to air-dry state and are distributed through the thickness of 4 factions: more than 5 mm, 5–1, 1–0,5 and less than 0.5 mm. This allows you to get an idea about the structure of the root system and its distribution in the thickness of ecotopes, as well as to determine the portion of the roots through which the greatest absorption of water and food items. The features of the development of the underground part of plants that is the basis for the development of practical methods of influence on ecotopia. For example, alfalfa is useful for sodding slope plots dump pits or eroded fields, and sainfoin – to create water-stable structural units. It is shown that the qualitative indicators of ecotopes strictly determine the morphology and aboveground and underground parts, as well as the number and weight of nodules in legumes. In the thickness of ecotopes man-made landscapes is the basis for the creation of primary consorting relations are root systems of perennial leguminous grasses. They determine the structure of microbial cenosis and regulate the number of microorganisms. Adaptation of perennial legumes and soil microorganisms to the variability of environmental conditions in the deep ecotypes reflects their close interaction with the factors of this unique environment. Overburden, the unconsolidated rocks have a high stimulatory effect on the development of microorganisms. In 10–15 years after the removal of the "day" the surface sets up a pool of microorganisms and is manifested microbiological profile, the pattern of which reflects the diversity of ecotopia. There was determined the intensity of decomposition of roots in a layer of technogenic ecotopes landscapes. It falls in the direction from the zonal soil to gray-green clay. For the year transformed to 80 % of the roots of alfalfa and to 66 % in winter wheat. First of all the thin roots of the legumes were destroyed in the spring. It was shown increased sidorovskaya role of kulturpflanzen, especially species of alfalfa and sainfoin. They are plant-dominants and create pockets of concentration of the soil platoro-Diya. Soil formation begins with the surface, gradually spreading to the lower layers of ecotopes.
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Udalova, O. R., L. M. Anikina, G. V. Mirskaya, P. Yu Kononchuk, and G. G. Panova. "Low-volume and thin-layer panoponics in intensive artificial-light culture of cucumber: basics and results of application." Vegetable crops of Russia, no. 2 (May 19, 2021): 39–44. http://dx.doi.org/10.18619/2072-9146-2021-2-39-44.
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Relevance. The year-round provision of the population of our country with fresh vegetable products remainsis relevant. The creation and widespread implementation of high-tech automated phytotechnological complexes based on innovative technologies for growing plants in intensive light culture, including the development of new-generation root-dwelling environments, low-volume and thin-layer analogs of soil and systems for providing plants with water and mineral nutrition elements, is one of the promising ways to solve this problem.The purpose. Assessment of the influence of root environment conditions on the production process of cucumber plants in intensive light culture is the aim of our work.Methods. The research was carried out under controlled conditions of intensive artificial-light culture, when growing a hybrid of cucumber Tristan F1 by using of low-volume and thin-layer analogs of soil with the supply of a nutrient solution to the plant roots through a slit capillary and by drip irrigation with the use of plant growing light equipment developed at Agrophysical Institute.Results. Evaluation of the influence of the conditions of the root environment - alow-volume analogue of the soil based on high-moor peat – agrophyte and a thin-layer analog of the soil based on a clay suspension with a feed of nutrient solution through a slit capillary, on the production process of cucumber plants showed that in comparison with the control – a low-volume analog of the soil-agrophyte with a feed of nutrient solution by drip irrigation, there is growth acceleration of the cucumber hybrid Tristan F1 in the form of a positive trend and reliable values; as well as a significant increase in the number of fruits by 38-43%, the weight of fruits by 52-53% from the plant; an increase in the accumulation of raw by 38-40% and dry weight by 27-32% by cucumber leaves; an increase in the leaf surface area by 38-40%, leaf water content by 7.3- 9.6%; a significant or positive trend increase in the content of calcium in cucumber fruits by 18-29%, magnesium by 20-29%, iron by 5-16%, vitamin C by 17-23%, while the content of heavy metals and nitrates does not exceed exceeded the MPC in all variants. Methods of growing plants on low-volume and thin - layer analogs of soil with the supply of a nutrient solution to the roots through a slit capillary can be recommended for any cultivation facilities in conditions of intensive light culture.