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Roots are the hidden and most important part of plants. They serve as stabilizers and channels for uptaking water and nutrients and play a crucial role in the growth and development of plants. Here, two-dimensional image data were used to identify quantitative trait loci (QTL) controlling root traits in an interspecific mapping population derived from a cross between wild soybean 'PI366121' and cultivar 'Williams 82'. A total of 2830 single-nucleotide polymorphisms were used for genotyping, constructing genetic linkage maps, and analyzing QTLs. Forty-two QTLs were identified on twelve chromosomes, twelve of which were identified as major QTLs, with a phenotypic variation range of 36.12% to 39.11% and a logarithm of odds value range of 12.01 to 17.35. Two significant QTL regions for the average diameter, root volume, and link average diameter root traits were detected on chromosomes 3 and 13, and both wild and cultivated soybeans contributed positive alleles. Six candidate genes, Glyma.03G027500 (transketolase/glycoaldehyde transferase), Glyma.03G014500 (dehydrogenases), Glyma.13G341500 (leucine-rich repeat receptor-like protein kinase), Glyma.13G341400 (AGC kinase family protein), Glyma.13G331900 (60S ribosomal protein), and Glyma.13G333100 (aquaporin transporter) showed higher expression in root tissues based on publicly available transcriptome data. These results will help breeders improve soybean genetic components and enhance soybean root morphological traits using desirable alleles from wild soybeans.

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Rhizospheric based phosphorus (P) fertilizer management is necessary for crop production due to environmental concerns caused by the overuse of the broadcasting method and limited P reserves. This study proposes a comparison of P management that enhances P nutrition in Chilli (variety: Arka Khyati) through seedling root-dipping (SRD) in P-enriched slurry (SSP-amended; pH of 8.1), micro-dose placement (MDP; drill and place closer to plant root), and full dose (187.6 mg kg-1) placement by broadcasting (FD). In SRD, seedlings were dipped in five different P concentrations (50, 100, 200, 300, and 400 mg P2O5 kg-1) for varying durations (0, ½, 1, 2, 3, and 4 hours) and transplanted into pots (dipping in 0 mg P2O5 kg-1 consider as control), along with the MDP and FD treatments (total 33 treatments with 5 replications). [Seedlings dipped in 200, 300, and 400 mg P2O5 kg-1 died within a week after transplanting, thus were excluded from further analysis]. The amount of P received in MDP and FD were 21-90 times higher than P adhesion to seedling roots in SRD treatments. Root volume was in order SRD>MDP>FD. Seedlings dipped in 100 mg P2O5 kg-1 for 2 hours in SRD exhibited the highest biomass production, P-use and -recovery efficiency; and showed an increase of 52%, 178%, and 293% in FD, MDP, and SRD compared to the control respectively. It is recommended to use the SRD method with other P sources in reduced amount to maintain the native P pool in soil, and further multilocational trials are needed to validate.

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Purpose: Salinity is a main factor in decreasing seed germination, plant growth and yield. Salinity stress is a major problem for economic crops, as it can reduce crop yields and quality. Salinity stress occurs when the soil or water in which a crop is grown has a high salt content. Biochar improve plant growth and physiological traits under salt stress. The aim of the present study, the impact of biochar on growth, root morphological traits and physiological properties of alfalfa, amaranth and maize and soil enzyme activities under saline sands. Methods: We studied the impact of biochar on plant growth and the physiological properties of alfalfa, amaranth and maize under salt stress conditions. After 40 days, plant growth parameters (plant height, shoot and root fresh weights), root morphological traits and physiological properties were measured. Soil nutrients such as the P, K and total N contents in soil and soil enzyme activities were analyzed. Results: The results showed that the maize, alfalfa, and amaranth under biochar treatments significantly enhanced the plant height and root morphological traits over the control. The biochar on significantly increased the total root length, root diameter, and root volume. Compared to the control, the biochar significantly increased the chlorophyll a and b content, total chlorophyll and carotenoid content under salt stress. Furthermore, the biochar significantly increased enzyme activities of soil under salt stress in the three crops. Conclusions: Biochar treatments promote plant growth and physiological traits of alfalfa, amaranth, and maize under the salt stress condition. Overall, biochar is an effective way to mitigate salinity stress in crops. It can help to reduce the amount of salt in the soil, improve the soil structure, and increase the availability of essential nutrients, which can all help to improve crop yields.

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ABSTRACT Objective: To develop a well-detailed and reproducible tooth segmentation method, when quantifying tooth volumetric measurements is needed. Material and Methods: This was an in vitro study in which lower incisors and canines of five patients were 3D reconstructed by means of an automatic segmentation with manual refinements process. All the images were obtained using a 0.3-mm voxel size CBCT imaging. The software utilized was the ITK-SNAP®. The primary outcomes were the intra-rater and inter-rater reliabilities and the respective measurement errors. Results: The intra-rater reliability was excellent, with a mean measurement error of 4.16%. The inter-rater reliability was good, with a mean measurement error of 7.11%. Accuracy assessment was not possible, as the assessed teeth were not extracted. Conclusions: Although the described method is reliable, tooth volumetric error measurements may become significant, depending on the assessed situation.

RESUMO Objetivo: Desenvolver um método de segmentação dentária bem detalhado e reprodutível, para quando for necessário quantificar as medidas volumétricas dos dentes. Material e Métodos: Esse foi um estudo in vitro no qual incisivos inferiores e caninos de cinco pacientes foram reconstruídos em 3D por meio de um processo de segmentação automática com refinamentos manuais. Todas as imagens de TCFC foram obtidas usando tamanho de voxel de 0,3 mm. O software utilizado foi o ITK-SNAP®. Os resultados primários foram as confiabilidades intra-avaliadores e interavaliadores e os respectivos erros de medição. Resultados: A confiabilidade intra-avaliador foi excelente, com erro médio de medição de 4,16%. A confiabilidade interavaliadores foi boa, com erro médio de medição de 7,11%. A avaliação da precisão não foi possível, pois os dentes avaliados não foram extraídos. Conclusões: Embora o método descrito seja confiável, os erros nas medições volumétricas dos dentes podem se tornar significativos, dependendo da situação avaliada.

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Silicon has been implicated as a factor affecting the degree of resistance to abiotic stresses in several plant species. However, the role of silicon in soybean (Glycine max) under water-limiting conditions is not yet fully understood. This study was conducted to evaluate the effects of silicon application on the vegetative growth of two soybean cultivars (Asgrow 5332 and Progeny 5333) grown under water-limiting conditions. Silicon was provided by adding silicate to the soil. Water-limiting treatments were imposed on plants at two vegetative growth stages for 20 days by irrigating with a reduced amount of water (66% or 33% of the required water). Silicate application enhanced plant height, leaf area, and total dry weight of soybean plants. Significant increases in root volumes were observed in both the silicate-treated cultivars compared to the control plants under water-limiting conditions (33% irrigation). Net photosynthesis and stomatal conductance were decreased, but the quantum efficiency of photosystem II (Fv'/Fm') did not change under the same irrigation condition, which indicates photosynthesis downregulation through stomatal limitation. Silicate-treated plants in both cultivars had higher water use efficiency as compared to control plants under water-limiting conditions (irrigated with 66% or 33% of required water). Under water-limiting conditions, the soil moisture content was significantly higher in pots containing silicate than in those without added silicate, suggesting that silicon application improves water holding capacity. Taken together, the results from this study indicate that silicon application can improve the vegetative growth of soybeans under low water conditions by increasing the water use efficiency of plants and enhancing the soil's ability to retain moisture.

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We investigated the influence of mature of oak trees of various dimensions on soil properties, acorn and oak seedling characteristics in semi-arid forests in western Iran. A total of 24 oak trees were selected in comparable site conditions according to three size categories: small trees (DBH< 20 cm), medium trees (DBH: 20-50 cm) and large trees (DBH> 50 cm). Soil properties, light availability below canopy, acorn dimensions and weight, various below- and above-ground seedling morphological traits were measured. Besides, a seedling quality index (SQI) was also produced as an integrative measure of the seedling response. We found an increasing light availability from small trees to large trees (1512-103 µmol m-2 s-1) and soil fertility was largely improved from small trees to large trees: soil organic carbon (1.33-2.2%), available phosphorus (12.9-18.1 ppm) and potassium (301.2-470.4 ppm). However, soil properties did not significantly differ between medium and large trees. In contrast, acorn weight and dimensions as well as many seedling traits, including the aerial and belowground biomass and the SQI, were the highest in the medium tree category. To fully explore the relationships among our large set of variables, we produced a partial least square path model which explained 72% of the variation of SQI across the three tree classes. To conclude, we identified a clear effect by mature trees which provided favourable conditions for seedling establishment, but that effect was mediated by tree size and optimal conditions were found below the canopy of medium trees.

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Aortic annuloplasty has demonstrated to be a protective factor in valve-sparing root replacement and aortic valve repair. Both reimplantation for aortic root aneurysms and external ring annuloplasty for isolated aortic regurgitation have demonstrated good long-term results. The aim of this anatomical study is to compare aortic reimplantation with Valsalva graft with aortic external ring annuloplasty in bicuspid aortic valves, analyzing their morphological features with CT scan. We selected 56 patients with bicuspid aortic valve who underwent reimplantation procedure with Valsalva graft or external ring annuloplasty; after propensity-matching, 2 homogeneous groups of 10 patients each were obtained. Through multiplanar ECG-gated CT-Scan reconstructions, pre- and postoperative, aortic annular, and valve geometrical characteristics were compared (diameters, perimeter, area and ellipticity index for the annulus; effective height, coaptation length and commissural height for the valve). Aortic root volume was also analyzed. Postoperative comparison of the two groups showed similar geometric features of the aortic annulus in terms of major and minor diameters, perimeter, area and ellipticity index. Analysis of valve's parameters showed similar results in terms of effective height and coaptation length (respectively 10.9 ± 2.1 mm and 7.5 ± 1.9 mm in External Ring group and 10.1 ± 2.0 mm and 7.6 ± 1.6 mm in the Reimplantation group). Both techniques achieve an efficient annuloplasty with similar anatomical results on bicuspid the aortic valves. The stability of these results needs to be confirmed by long-term clinical and echocardiographic follow-up.

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BACKGROUND: The aim of this study was to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. METHODS: Eighty human lower molars were selected and randomly divided into four groups (n = 20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentine volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05. RESULTS: There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P < 0.001). CONCLUSIONS: Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.

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Grasses have a segmental morphology. Compared to leaf development, data on root development at the phytomer level are scarce. Leaf appearance interval was recorded over time to allow inference about the age of segmental sites that later form roots. Hydroponically grown Lolium perenne cv. Aberdart tillers were studied in both spring and autumn in increasing and decreasing day length conditions, respectively, and dissected to define the development status of roots of known age on successive phytomers basipetally on the tiller axis. Over a 90-day observation period spring and autumn tillers produced 10.4 and 18.1 root bearing phytomers (Pr), respectively. Four stages of root development were identified: (0) main axis elongation (~0-10 days), (1) primary branching (~10-18 days), (2) secondary branching (~18-25 days), and (3) tertiary and quaternary branching without further increase in root dry weight. The individual spring roots achieved significantly greater dry weight (35%) than autumn roots, and a mechanism for seasonal shift in substrate supply to roots is proposed. Our data define a root turnover pattern likely also occurring in field swards and provide insight for modelling the turnover of grass root systems for developing nutrient efficient or stress tolerant ryegrass swards.

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Environmental conditions affect crop yield, and water deficit has been highlighted by the negative impact on soybean grain production. Radicial growth in greater volume and depth can be an alternative to minimize losses caused by a lack of water. Therefore, knowledge of how soybean roots behave before the chemical, physical, and biological attributes of the soil can help establish managements that benefit in-depth root growth. The objective was to evaluate the growth of soybean roots in response to chemical, physical, and biological variations in the soil, in different soil locations and depths. Six experiments were conducted in different locations. Soil samples were collected every 5 cm of soil up to 60 cm of soil depth for chemical, physical, and biological analysis. The roots were collected every 5 cm deep up to 45 cm deep from the ground. The six sites presented unsatisfactory values of pH and organic matter, and presented phosphorus, potassium, and calcium at high concentrations in the first centimeters of soil depth. The total porosity of the soil was above 0.50 m3 m-3, but the proportion of the volume of macropores, micropores, and cryptopores resulted in soils with resistance to penetration to the roots. Microbial biomass was higher on the soil surface when compared to deeper soil layers, however, the metabolic quotient was higher in soil depth, showing that microorganisms in depth have low ability to incorporate carbon into microbial biomass. Root growth occurred in a greater proportion in the first centimeters of soil-depth, possibly because the soil attributes that favor the root growth is concentrated on the soil surface.

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Adenophora triphylla var. japonica Hara is a highly valued medicinal plant that is used to treat or prevent bronchitis, cough, cancer, and obesity. However, there has been no study on the production of Adenophora triphylla var. japonica Hara seedlings in a closed-type plant production system (CPPS). This study was conducted to examine the growth characteristics of Adenophora triphylla var. japonica Hara seedlings as affected by different growing media. The seeds were sown on a 128-cell plug tray filled with urethane sponges (US), LC grow foam (LC), rockwool (RW), or terra-plugs (TP). The seedlings were cultured for a duration of 54 days under temperature 25 ± 1°C, a photoperiod of 12/12 h (light/dark), and light intensity of 180 µmol·m-2·s-1 photosynthetic photon flux density provided by RB LEDs (red:blue = 8:2) in a closed-type plant production system (CPPS). The germination rate of Adenophora triphylla var. japonica Hara was significantly highest in the TP. Also, seedling shoot growth indicators of plant height, leaf length, leaf width, number of leaves, fresh weight (FW), and dry weight (DW) of the shoot, and leaf area were markedly the greatest in the TP and the lowest in the US. The SPAD (soil-plant analysis development) value was higher in the TP and US than in the LC or RW. In addition, the seedling root growth characteristics of total root length, root surface area, root volume, and number of root tips were significantly greatest in the TP. Moreover, the maximum root diameter, FW and DW of roots were the greatest in the TP. In conclusion, the results suggest that TP are viable for the growth development of Adenophora triphylla var. japonica Hara seedlings.

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Mandibular volume and tooth root volumes were shown to increase at different rates at locations containing the roots of the canine (C) and mesial and distal roots of the first molar (M1). Thirty-six dogs were included in this study. Data were generated using computed tomography at locations of the mandible involving the roots of the C and M1 teeth. Software was used to trace the external surface of the mandible, calculating the volume of the mandible at each location. Similar techniques were used to trace and calculate the volume of the C and M1 roots. Mandible volume, tooth root volume, and root percentage of mandible volume were analyzed and compared using the slopes of the best fit line. At the M1 mesial and distal roots, mandible volume ( P < .001) and root volume ( P < .001) were both noted to increase, with increasing weight at different rates. The rate of change in the root percentage by weight of M1 roots was not different ( P = .214). Each location demonstrated a different increasing rate of change for mandibular volume and increasing root volume. Results show that as patient's weight increases, the mandible and root volumes increase at different rates. Root percentage by volume at all three locations was noted to decrease by the same rate. Canine and M1 roots are proportionally larger than the supporting mandibular bone in smaller patients. Care should be taken to recommend periodontal disease prevention for owners of small dogs and consideration made when performing extractions or other surgery that may destabilize the mandible.

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OBJECTIVES: Purpose of the present study was to compare external root resorption (ERR) volumetrically in maxillary incisors induced by orthodontic treatment using self-ligating brackets (Damon Q, DQ) or conventional brackets (Titanium Orthos, TO) with the help of cone-beam computed tomography (CBCT). PATIENTS AND METHODS: A sample of 32 subjects, with Angle Class I malocclusion and anterior crowding of 4-10 mm, was divided randomly into two groups: a DQ group, in which self-ligating DQ brackets with Damon archwires were used; and a TO group, in which conventional TO brackets with large Orthos archwires were applied. The study was conducted using CBCT scans taken before (T1), and near the end (9 months after the initiation of treatment; T2) of the orthodontic treatment. The extent of ERR was determined volumetrically using Mimics software. Changes in root volume were evaluated by repeated-measures analysis of variance as well as by paired and independent t-tests. RESULTS: While significant differences were found between T1 and T2 for root volume in both groups (p < 0.05), there was no difference between the groups regarding the amount (mm3 or relative change) of ERR (p > 0.05). Maxillary central and lateral incisors showed similar volume loss (p > 0.05). Furthermore, the TO group showed a higher prevalence of palatinal and proximal slanted RR compared with the DQ group (p < 0.05). CONCLUSIONS: It is not possible to suggest superiority of one bracket system over the other only considering root resorption pattern or amount. Higher incidence of slanted RR found in patients treated with the TO system warrants further research to identify possible specific causes.

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There is high uncertainty in the contribution of land-use change to anthropogenic climate change, especially pertaining to below-ground carbon loss resulting from conversion of primary-to-secondary forest. Soil organic carbon (SOC) and coarse roots are concentrated close to tree trunks, a region usually unmeasured during soil carbon sampling. Soil carbon estimates and their variation with land-use change have not been correspondingly adjusted. Our aim was to deduce allometric equations that will allow improvement of SOC estimates and tree trunk carbon estimates, for primary forest stands that include large trees in rugged terrain. Terrestrial digital photography, photogrammetry and GIS software were used to produce 3D models of the buttresses, roots and humus mounds of large trees in primary forests dominated by Eucalyptus regnans in Tasmania. Models of 29, in situ eucalypts were made and analysed. 3D models of example eucalypt roots, logging debris, rainforest tree species, fallen trees, branches, root and trunk slices, and soil profiles were also derived. Measurements in 2D, from earlier work, of three buttress 'logs' were added to the data set. The 3D models had high spatial resolution. The modelling allowed checking and correction of field measurements. Tree anatomical detail was formulated, such as buttress shape, humus volume, root volume in the under-sampled zone and trunk hollow area. The allometric relationships developed link diameter at breast height and ground slope, to SOC and tree trunk carbon, the latter including a correction for senescence. These formulae can be applied to stand-level carbon accounting. The formulae allow the typically measured, inter-tree SOC to be corrected for not sampling near large trees. The 3D models developed are irreplaceable, being for increasingly rare, large trees, and they could be useful to other scientific endeavours.

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This study was carried out to assess the effect of Bacillus pumilus on the roots of four cruciferous vegetables with different root structures in regard to enhancement of 137Cs bioavailability in contaminated rhizosphere soil. Results revealed that B. pumilus inoculation did not enhance the plant biomass of vegetables, although it increased root volume and root surface areas of all vegetables except turnip. The pH changes due to rhizosphere acidification by B. pumilus inoculation and root exudation did not affect the bioavailability of 137Cs. However, concentrations of 137Cs in plant tissues and soil-to-plant transfer values increased as a result of the larger root volume and root surface area of vegetables due to inoculation. Moreover, leafy vegetables, which possessed larger root volume and root surface areas, had a higher 137Cs transfer value than root vegetables.

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The objective of this study was to evaluate root restriction as a tool to increase volume utilization efficiency in spaceflight crop production systems. Bell pepper plants (Capsicum annuum cv. California Wonder) were grown under restricted rooting volume conditions in controlled environment chambers. The rooting volume was restricted to 500ml and 60ml in a preliminary trial, and 1500ml (large), 500ml (medium), and 250ml (small) for a full fruiting trial. To reduce the possible confounding effects of water and nutrient restrictions, care was taken to ensure an even and consistent soil moisture throughout the study, with plants being watered/fertilized several times daily with a low concentration soluble fertilizer solution. Root restriction resulted in a general reduction in biomass production, height, leaf area, and transpiration rate; however, the fruit production was not significantly reduced in the root restricted plants under the employed environmental and horticultural conditions. There was a 21% reduction in total height and a 23% reduction in overall crown diameter between the large and small pot size in the fruiting study. Data from the fruiting trial were used to estimate potential volume utilization efficiency improvements for edible biomass in a fixed production volume. For fixed lighting and rooting hardware situations, the majority of improvement from root restriction was in the reduction of canopy area per plant, while height reductions could also improve volume utilization efficiency in high stacked or vertical agricultural systems.

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ABSTRACT Zinc (Zn) participates of numerous metabolic processes in plants. However, it can become toxic to plants in excessive concentrations in the soil. Pfaffia glomerata is a Brazilian medicinal species that has stood out because of its numerous chemical and functional properties, mainly by the triterpene saponins and ecdysteroids accumulated in its roots. This study aimed to evaluate the effects of zinc excess on many root morphological parameters of Pfaffia glomerata. A 4 x 3 factorial design was employed in a completely randomized scheme with 3 replicates. The treatments consisted of four concentrations of Zn (2, 100, 200, and 300 µM) and three accessions of P. glomerata (BRA, GD, and JB) grown in a hydroponic system for 7 and 14 days. Differences in root morphology and dry mass production were observed among the three accessions in response to excessive Zn. Some growth parameters of GD accession increased with the addition of Zn, ranging from 36 to 79 µM. However, the GD and JB accessions presented reduction in dry mass production, root area, length, and volume with increasing Zn levels. The BRA accession, which had the lowest growth among accessions, presented chlorotic leaves. The shoot/root dry mass ratio and root diameter increased linearly for BRA and GD accessions at 7 days. Based on the evaluated parameters, we observed the following order of Zn excess tolerance in P. glomerata accessions: GD> JB> BRA.

RESUMO O zinco (Zn) participa de numerosos processos metabólicos nas plantas. No entanto, em concentrações excessivas no solo pode tornar-se tóxico para os vegetais. Pfaffia glomerata é uma espécie medicinal brasileira que tem se destacado devido as suas inúmeras propriedades químicas e funcionais, devido principalmente às saponinas triterpênicas e ecdisteróides acumuladas em suas raízes. O objetivo do presente trabalho foi avaliar os efeitos do excesso de Zn sobre vários parâmetros morfológicos radiculares de Pfaffia glomerata. O delineamento experimental utilizado foi o inteiramente casualizado com três repetições, dispostos em um arranjo fatorial (4 x 3). Os tratamentos consistiram em quatro níveis de Zn (2, 100, 200 e 300µM) e três acessos (BRA, GD e JB) de P. glomerata cultivados em sistema hidropônico em casa de vegetação por 7 e 14 dias. Diferenças na morfologia radicular e na produção de material seca foram observadas entre os três acessos em resposta ao excesso de Zn. Alguns parâmetros de crescimento do acesso GD aumentaram sob a adição de Zn variando entre 36 e 79 µM. No entanto, os acessos GD e JB apresentaram redução na matéria seca, bem como na área de superfície, comprimento e volume radicular com o aumento dos níveis de Zn. O acesso BRA, que teve o menor crescimento entre os acessos, apresentou folhas cloróticas. A razão entre matéria seca da parte aérea e raízes e o diâmetro radicular aumentou linearmente para os acessos BRA e GD aos 7 dias de cultivo. Baseando-se nos parâmetros avaliados foi observada a seguinte ordem de tolerância ao excesso de Zn: GD> JB> BRA.

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OBJECTIVE: To investigate the amount of the cementum layer formed over the rat's dental root surfaces by daily application of low-level laser therapy (LLLT) for 2 weeks. METHODS: Twelve female Sprague-Dawley (SD) rats were divided into two groups: six rats received daily LLLT (Ga-Al-As, 830 nm), and six rats received no treatment (control). The treatment lasted 2 weeks. In vivo Micro-CT imaging analyzed the root's hard tissue volumetric changes. The cementum thickness was evaluated histologically. RESULTS: Total cementum thicknesses in the LLLT group increased significantly (p = 0.015) compared to the control group. This significant increase in the cementum thickness, verified histologically, was not detectable during in vivo Micro-CT imaging, which showed no significant difference between the groups regarding the root hard tissues volumetric changes over the 2-week evaluation period. CONCLUSION: Two weeks of daily application of LLLT significantly increased rat's dental root cementum thickness as determined histologically. However, in vivo Micro-CT imaging failed to accurately reveal this cementum growth as it was not possible to differentiate dentinal changes.

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OBJECTIVE: The aim of this study was to determine how physical and morphological properties affect the fracture resistance of roots, and which criteria are important for root specimen standardization in fracture resistance studies. MATERIALS AND METHODS: Seventy-five freshly extracted human canine teeth were selected. Crowns were sectioned from the cement-enamel junction and the root lengths were set at 16 mm. Then they were prepared up to ProTaper F3 file. Each root was numbered and data were obtained by measuring mesiodistal and buccolingual dimensions, volume, weight, and density. Tests for fracture strength were performed using an Instron Testing Machine (Instron Corp. MA, USA). The force was applied axially, angled at 45 degrees with a constant speed of 1 mm/min. For each sample, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically using linear regression analysis. RESULTS: Volume and weight of the roots had more effect than mesiodistal or buccolingual dimensions on root fracture resistance. CONCLUSIONS: In root fracture resistance studies, volume or weight of the roots must be standardized when distributing roots to groups.

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In Mediterranean regions drought is the major factor limiting spring barley and durum wheat grain yields. This study aimed to compare spring barley and durum wheat root and shoot responses to drought and quantify relationships between root traits and water uptake under terminal drought. One spring barley (Hordeum vulgare L. cv. Rum) and two durum wheat Mediterranean cultivars (Triticum turgidum L. var durum cvs Hourani and Karim) were examined in soil-column experiments under well watered and drought conditions. Root system architecture traits, water uptake, and plant growth were measured. Barley aerial biomass and grain yields were higher than for durum wheat cultivars in well watered conditions. Drought decreased grain yield more for barley (47%) than durum wheat (30%, Hourani). Root-to-shoot dry matter ratio increased for durum wheat under drought but not for barley, and root weight increased for wheat in response to drought but decreased for barley. The critical root length density (RLD) and root volume density (RVD) for 90% available water capture for wheat were similar to (cv. Hourani) or lower than (cv. Karim) for barley depending on wheat cultivar. For both species, RVD accounted for a slightly higher proportion of phenotypic variation in water uptake under drought than RLD.

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