Epidermal Cell Size Research Articles

Plant adaptation or acclimation to rising CO2 ? Insight from first multigenerational RNA-Seq transcriptome.

Atmospheric carbon dioxide (CO2 ) directly determines the rate of plant photosynthesis and indirectly effects plant productivity and fitness and may therefore act as a selective pressure driving evolution, but evidence to support this contention is sparse. Using Plantago lanceolata L. seed collected from a naturally high CO2 spring and adjacent ambient CO2 control site, we investigated multigenerational response to future, elevated atmospheric CO2 . Plants were grown in either ambient or elevated CO2 (700μmolmol-1 ), enabling for the first time, characterization of the functional and population genomics of plant acclimation and adaptation to elevated CO2 . This revealed that spring and control plants differed significantly in phenotypic plasticity for traits underpinning fitness including above-ground biomass, leaf size, epidermal cell size and number and stomatal density and index. Gene expression responses to elevated CO2 (acclimation) were modest [33-131 genes differentially expressed (DE)], whilst those between control and spring plants (adaptation) were considerably larger (689-853 DE genes). In contrast, population genomic analysis showed that genetic differentiation between spring and control plants was close to zero, with no fixed differences, suggesting that plants are adapted to their native CO2 environment at the level of gene expression. An unusual phenotype of increased stomatal index in spring but not control plants in elevated CO2 correlated with altered expression of stomatal patterning genes between spring and control plants for three loci (YODA, CDKB1;1 and SCRM2) and between ambient and elevated CO2 for four loci (ER, YODA, MYB88 and BCA1). We propose that the two positive regulators of stomatal number (SCRM2) and CDKB1;1 when upregulated act as key controllers of stomatal adaptation to elevated CO2 . Combined with significant transcriptome reprogramming of photosynthetic and dark respiration and enhanced growth in spring plants, we have identified the potential basis of plant adaptation to high CO2 likely to occur over coming decades.

The Developmental Basis of Stomatal Density and Flux.

Equations for stomatal density and maximum theoretical stomatal conductance as functions of stomatal initiation rate, epidermal cell size, and stomatal size enable scaling from development to flux.

Increase in biomass and bioactive compounds in lettuce under various ratios of red to far-red LED light supplemented with blue LED light

The aim of this study was to analyze the growth and bioactive compounds of lettuce in response to far-red LED light supplemented with a combination of red and blue LED light. Sixteen-day-old red leaf lettuce seedlings were transplanted to a growth chamber equipped with red, blue, and far-red LEDs. After setting the ratio of blue (B) to red (R) LEDs to 2:8, the ratio of R to far-red (FR) LEDs was adjusted to 0.7, 1.2, 4.1, or 8.6 (B+R/FR 0.7, 1.2, 4.1, or 8.6). Additionally, plants were irradiated with combined B and R LEDs (B+R) and fluorescent lamps (control) for 24 days. Growth characteristics including cell division rate, epidermal cell density and thickness, and antioxidant phenolic compounds were measured. Supplementation with FR LED light improved shoot and root growth compared to plants under B+R and control treatment. B+R/FR 1.2 treatment resulted in the highest shoot fresh weight and leaf area on day 24 of treatment. Obvious activation of the G2M phase was not observed in plants under far-red treatment, and most far-red treatments besides B+R/FR 4.1 increased the epidermal cell size. Plants treated with B+R/FR ratios of only 0.7 and 1.2 had significantly higher total phenolic levels, antioxidant activity, chlorogenic acid contents, and caffeic acid contents per plant than the control. These results suggest that supplementing the existing visual light spectrum, such as red and blue light, with far-red LEDs improves lettuce growth and bioactive compound content in a closed-type plant production system.

In vivo reflectance-mode confocal microscopy assessments: impact of overweight on human skin microcirculation and histomorphology.

Reflectance-mode confocal microscopy (RCM) enables in vivo assessment of the human skin. Impact of overweight on both human skin microcirculation and histomorphology has not been investigated in vivo. The purpose of this study is to evaluate both microcirculation and histomorphology in vivo in overweight. In 10 normotensive overweight nondiabetic individuals (OW-group, BMI 29.1 ± 2.7 kg/m(2)) and 10 age- and sex-matched healthy lean controls (CO-group, BMI 20.4 ± 1.9 kg/m(2)) the following parameters were evaluated using RCM: dermal blood cell flow (DBCF), density of dermal capillaries (DDC), epidermal thickness (ET), and epidermal cell size (ECS). DBCF was counted at 63.11 ± 4.14 cells/min in OW-group and at 51.06 ± 3.84 cells/min in CO-group (P < 0.05). DDC was reduced in OW-group (4.91 ± 0.39 capillaries/mm(2)) compared to the controls (6.02 ± 0.64 capillaries/mm(2), P < 0.05). Histometric evaluation of ET reveals thickening in OW-group compared to the CO-group (54.79 ± 4.25 μm versus 44.03 ± 3.11 μm, P < 0.05). ECS differed significantly (P < 0.05) in OW-group (821.3 ± 42.02 μm(2)) compared to the controls (772.6 ± 34.79 μm(2)). Inverse correlation of dermal capillary density and overweight point to reduced total tissue perfusion while positive related blood cell flow reveals vasodilatation. Increase of both ET and cell size indicates remodeling of cutaneous histomorphology, maybe as an early stage of adiposity-related skin condition.

Sucrose treatment enlarges petal cell size and increases vacuolar sugar concentrations in cut rose flowers

Treatment with sucrose promoted petal growth associated with flower opening in cut roses. We investigated the effect of sucrose treatment on cell size and subcellular concentration of soluble carbohydrates in petals of cut rose cv. Sonia flowers. Petals of sucrose-treated flowers, but not control flowers, markedly curved outward, resulting in complete reflection. Petal fresh weight (FW), petal area, and adaxial epidermal cell size in the control flowers increased with time, and treatment with sucrose accelerated this increase, indicating that sucrose promotes petal cell expansion. Glucose, fructose, sucrose, methyl glucoside, and xylose were detected in the petals. In the petals of control flowers, concentration of these carbohydrates, except fructose, decreased. Sucrose treatment markedly increased glucose and fructose concentrations in petals. Estimation of subcellular volumes based on transmission electron micrographs showed that volume of cell walls and vacuoles in the petals of control flowers increased in response to sucrose treatment. Sucrose treatment increased glucose and fructose concentrations in the vacuole and glucose, fructose, and xylose concentrations in the apoplast. We concluded that sucrose treatment increases glucose and fructose concentrations in the vacuole, which may reduce the osmotic potential of the symplast and increase water uptake leading to cell expansion during flower opening.

Modulation of miR156 to identify traits associated with vegetative phase change in tobacco (Nicotiana tabacum).

After germination, plants progress through juvenile and adult phases of vegetative development before entering the reproductive phase. The character and timing of these phases vary significantly between different plant species, which makes it difficult to know whether temporal variations in various vegetative traits represent the same, or different, developmental processes. miR156 has been shown to be the master regulator of vegetative development in plants. Overexpression of miR156 prolongs the juvenile phase of development, whereas knocking-down the level of miR156 promotes the adult phase of development. Therefore, artificial modulation of miR156 expression is expected to cause corresponding changes in vegetative-specific traits in different plant species, particularly in those showing no substantial difference in morphology during vegetative development. To identify specific traits associated with the juvenile-to-adult transition in tobacco, we examined the phenotype of transgenic tobacco plants with elevated or reduced levels of miR156. We found that leaf shape, the density of abaxial trichomes, the number of leaf veins, the number of stomata, the size and density of epidermal cells, patterns of epidermal cell staining, the content of chlorophyll and the rate of photosynthesis, are all affected by miR156. These newly identified miR156-regulated traits therefore can be used to distinguish between juvenile and adult phases of development in tobacco, and provide a starting point for future studies of vegetative phase change in the family Solanaceae.

Light Environment and Epidermal Cell Morphology in Grasses

Premise of research. Phytoliths (bio-opal) of grasses are preserved in the fossil record and constitute the best method to study grasses and grassland evolution in deep time. However, methods currently used to reconstruct habitat openness based on grass phytolith abundance are potentially biased because of the prolific production of phytoliths in grasses compared to other plants, both herbaceous and woody (ferns and dicots). On the basis of relationships observed in eudicot epidermal cells, we hypothesized that the shape (undulation) and size of epidermal cells (and phytoliths derived from them) will vary with irradiance. This variation could be used to develop a proxy for habitat openness in the fossil record.Methodology. We grew five species of grass under four irradiance levels and measured epidermal cell parameters, including undulation, area, length, and width, along with gross leaf morphology.Pivotal results. ANOVA statistical tests showed that with the exception of the shade-adapted Chusquea, the g...

Increased size of epidermal cells in Syringa josikaea Jacq. smaller leaf side as an adaptive mechanism for reducing its asymmetry

Comparative study of quantitative anatomy of the epidermis in Syringa josikaea Jacq. leaf halves of different width was conducted in order to analyze the possible mechanism of formation of the value of fluctuating leaf asymmetry. A regular decrease in the density of main epidermal cells in the smaller leaf half compared with the bigger one was traced during leaf ontogeny. Stomatal index was equal in different-sized leaf halves. Adaptive response was found in fully formed leaves; it was aimed at reducing leaf blade fluctuating asymmetry by 23% on average and consisted of compensatory growth--further elongation of main epidermal cells in the smaller half of the leaf. It was concluded that the level of fluctuating leaf asymmetry in Hungary lilac is mainly due to a lower rate of cell division, as well as due to their greater elongation in the smaller half of adult leaf compared with the bigger half.

Comparative morphology and anatomy of Backebergia militaris (Echinocereeae–Cactaceae) cephalium

The morphology and anatomy of the Backebergia militaris cephalium is characterized in comparison with its vegetative branch and with apical and lateral cephalia of other species. Our working hypothesis was that the B. militaris cephalium is more similar to the apical or lateral cephalia of other taxa than to its own vegetative branch. Our results revealed that the differences between the vegetative branch and the cephalium are primarily morphological: there is a change in the phyllotaxy, there are no interareolar spaces, making the ribs indistinguishable and abundant trichomes and bristles are produced in the areoles. In addition, a comparison between the vegetative branch and the cephalium shows differences in the epidermal cell size, thickness of the hypodermis and abundance of cortical bundles and mucilage cells. Unlike Melocactus intortus apical cephalia, B. militaris retains stomata in the epidermis and chlorenchyma, allowing the cephalium near the apical meristem to perform photosynthesis. The development of periderm in each areole after flowering and fruiting is a distinctive and defining feature of lateral and apical cephalia. In addition to early periderm development, the necrosis of cortical and pith parenchyma and fibers in secondary xylem and phloem in B. militaris distinguishes it from other cephalia described to date.

Fine mapping of a palea defective 1 (pd1), a locus associated with palea and stamen development in rice.

KEY MESSAGE : pd1, a genetic factor in a 69 kb region between RM11239 and RM11245 on rice chromosome 1, controls stamen number and palea development. Spikelets are important organs that store photosynthetic products in rice. Spikelet development directly affects grain yield and rice quality. Here, we report a palea defective (pd1) mutant identified from selfing progenies of indica cv. 93-11 after (60)Co γ ray treatment. pd1 mutant flowers only had four stamens (wild-type has six), but pollen fertility was not affected. Compared with 93-11 palea, pd1 mutant palea showed smaller and flatter leaf, which caused the lemma to bend excessively inward. pd1 mutants had only 46% seed setting rate and 21.6 g 1000-grain weight, which led to two-thirds loss of grain yield. Scanning electron microscope analysis revealed that pd1 mutants had reduced epidermal cell size and reduced numbers of fibrous sclerenchyma cells in both palea and lemma. To analyze the genetic factors involved, we crossed pd1 mutants with three japonica cultivars and generated F1 and F2 populations. The F1 phenotype and F2 segregation ratio indicated that a recessive gene controlled the mutant traits. Using the F2 population, we found that pd1 mapped between the simple sequence repeat markers RM11236 and RM11280 on rice chromosome 1. From a segregating population of 2836 plants, 77 recombinants were screened by RM11236 and RM11280. High-resolution linkage analysis narrowed the pd1 locus to a 69 kb region between RM11239 and RM11245 that contained 10 open reading frames (ORFs). Sequence alignment and quantitative real-time PCR expression analysis of these ORFs between 93-11 and pd1 mutant plants found no unequivocal evidence to identify the pd1 gene.

Arabidopsis EDT1/HDG11 improves drought and salt tolerance in cotton and poplar and increases cotton yield in the field

Drought and salinity are two major environmental factors limiting crop production worldwide. Improvement of drought and salt tolerance of crops with transgenic approach is an effective strategy to meet the demand of the ever-growing world population. Arabidopsis ENHANCED DROUGHT TOLERANCE1/HOMEODOMAIN GLABROUS11 (AtEDT1/HDG11), a homeodomain-START transcription factor, has been demonstrated to significantly improve drought tolerance in Arabidopsis, tobacco, tall fescue and rice. Here we report that AtHDG11 also confers drought and salt tolerance in upland cotton (Gossypium hirsutum) and woody plant poplar (Populus tomentosa Carr.). Our results showed that both the transgenic cotton and poplar exhibited significantly enhanced tolerance to drought and salt stress with well-developed root system. In the leaves of the transgenic cotton plants, proline content, soluble sugar content and activities of reactive oxygen species-scavenging enzymes were significantly increased after drought and salt stress compared with wild type. Leaf stomatal density was significantly reduced, whereas stomatal and leaf epidermal cell size were significantly increased in both the transgenic cotton and poplar plants. More importantly, the transgenic cotton showed significantly improved drought tolerance and better agronomic performance with higher cotton yield in the field both under normal and drought conditions. These results demonstrate that AtHDG11 is not only a promising candidate for crops improvement but also for woody plants.

Cell size versus body size in geophilomorph centipedes.

Variation in animal body size is the result of a complex interplay between variation in cell number and cell size, but the latter has seldom been considered in wide-ranging comparative studies, although distinct patterns of variation have been described in the evolution of different lineages. We investigated the correlation between epidermal cell size and body size in a sample of 29 geophilomorph centipede species, representative of a wide range of body sizes, from 6mm dwarf species to gigantic species more than 200mm long, exploiting the marks of epidermal cells on the overlying cuticle in the form of micro-sculptures called scutes. We found conspicuous and significant variation in average scute area, both between suprageneric taxa and between genera, while the within-species range of variation is comparatively small. This supports the view that the average epidermal cell size is to some extent taxon specific. However, regression analyses show that neither body size nor the number of leg-bearing segments explain this variation, which suggests that cell size is not an usual target of change for body size evolution in this group of arthropods, although there is evidence of its correlation with other morphological variables, like cuticle thickness. Scute sizes of miniaturized geophilomorph species are well within the range of the lineage to which the species belong, suggesting recent evolutionary transitions to smaller body size.

Estimation of genetic mechanism of stomatal traits influencing grain yield in hexaploid wheat (Triticum aestivum L.)

Efforts to improve wheat plant have been made at various plant characters. Yield component breeding and modification of the plant architecture offer possibilities to develop more efficient breeding systems for increased grain yield. A 6 × 6 diallel experiment was conducted to determine the genetic mechanism of stomatal traits influencing grain yield in hexaploid wheat. Graphical representation indicated the over-dominant type of gene action for 1000-seed weight, seed yield per plant, leaf venation, stomatal size, epidermal cell size and stomatal frequency suggesting that selection would be difficult in early segregating generation. Hence heterosis breeding may useful for genetic improvement for these traits. Non allelic interactions were found to be absent for all traits. The genotype Aas-11 contained maximum dominant genes for epidermal cell size while genotype 9515 for 1000grain weight and seed yield per plant. The genotype 9516 possessed maximum dominant genes for leaf venation. Whereas, genotype Iqbal-2000 carried maximum dominant genes for stomata size.

Volume, water content, epidermal cell area, and XTH5 expression in growing grains of wheat across ploidy levels

The cellular expansion of maternal tissues has been suggested as strongly associated to grain volume determination in wheat and is therefore a key process to understand potential grain weight determination. The dynamics of grain growth in seed size-contrasting diploid, tetraploid and hexaploid genotypes of wheat were evaluated to explore the relationships between the final grain weight and: a) grain volume, b) water content, c) epidermal pericarp cell size and d) the rate of cell area (area per cell) increase. The assessment of cell expansion was reinforced by the study of the expression of the XTH5 gene in pericarp tissues, as this gene codifies a cell wall-remodeling agent. Differences in grain weight across ploidies and experiments (greenhouse and field evaluations) were attributable to the grain-filling rate (ANOVA p<0.05; R2=0.91 and R2=0.98, respectively), with no significant effect of grain filling duration. Strong correlations were found between final dry matter of grain and both volume (R2=0.98; p<0.01) and stabilized water content (R2=0.99; p<0.01) of grains across genotypes. The epidermal cell area was positively correlated with the final grain volume (R2=0.71; p<0.05) and with the grain-stabilized water content (R2= 0.72; p<0.05). The increases in grain volume and grain elongation were accompanied by epidermal cell enlargement during grain growth across the genotypes. Also, at each ploidy, the rate of cell area increase was greater in the heavier grain genotype, which showed faster dry matter accumulation (p<0.05). The XTH5 gene was expressed during the high-rate water accumulation phase with a significant decrease (p<0.05) at 320 - 350°Cd after anthesis, shortly before the grain water content leveled off. This work provides new evidence for the relevance of pericarp cell size in the regulation of grain volume and the potential grain weight of wheat.

Studies on the foliar epidermal tissues of three species of Digitaria Haller in Jos, Plateau state Nigeria

Foliar epidermal studies were carried out on Digitaria iburua Stapf, Digitaria exilis Stapf and Digitaria barbinodis Henr. with the aim of determining the patterns of variation in their epidermal characteristics and assessing the value of leaf epidermal characters in the identification of these culturally important species. Micro hairs, silica bodies, short cells, anticlinal wall pattern, epidermal cell shape and stomata index were diagonistic characters. While micro hairs were distributed on the surfaces of Digitaria exilis and Digitaria barbinodi, they were absent in Digitaria iburua. Short cells were present on the surfaces of Digitaria iburua and Digitaria barbinodis but absent on Digitaria exilis. Stomata index was smallest in Digitaria barbinodis distinguishing it from the other two species. The epidermal cell shape varied from rectangular to polygonal while the anticlinal wall pattern varied from straight to wavy in the three species. Other useful characters for distinguishing the species are epidermal cell size, stomata size and stomata number.Keywords: Digitaria iburua, microhairs, foliar, silica bodies, Digitaria exilis

Variation in Pharmacognostic Characters and Polyphenolic Contents among Four Species of Medicinal Plants from the Genus Spermacoce (Rubiaceae).

Spermacoce hispida L. is one of the important medicinal plants used in traditional systems of medicine. It is observed that, several times it is difficult to differentiate the plant from the other allied species from the same genus, Spermacoce, especially, when they are in drug form. Therefore, the present study aims to document the differences in the pharmacognostic characters, preliminary phytochemical analysis and polyphenolic contents from the leaves of four species belonging to the genus Spermacoce, viz. S. hispida L., S. mauritiana O. Gideon, S. stricta L. and S. ocymoides Burm. Transverse section passing through the midrib with lamina on either sides, epidermal characters, leaf constants, organoleptic characters, physicochemical analysis, extractive values and preliminary phytochemical analysis were carried out for all these species. Total phenolic content by Folin-Ciocalteu method and total flavonoids by AlCl3 method were also estimated from the leaves of all these species. The results indicated that S. hispida can be clearly differentiated from the other selected species on the basis of size and number of epidermal cells, size of trichomes, leaf constants, physicochemical analysis and extractive values. However, it is also found that S. hispida possess total phenolic content at 6.88±0.34 mg CAE/g and 9.17±0.46 mg TAE/g. Total flavonoids was at 5.98±0.30 mg QE/g. The study will provide information with respect to identification and differentiation amongst selected species of genus Spermacoce.

Myosin Vb mediated plasma membrane homeostasis regulates peridermal cell size and maintains tissue homeostasis in the zebrafish epidermis.

The epidermis is a stratified epithelium, which forms a barrier to maintain the internal milieu in metazoans. Being the outermost tissue, growth of the epidermis has to be strictly coordinated with the growth of the embryo. The key parameters that determine tissue growth are cell number and cell size. So far, it has remained unclear how the size of epidermal cells is maintained and whether it contributes towards epidermal homeostasis. We have used genetic analysis in combination with cellular imaging to show that zebrafish goosepimples/myosin Vb regulates plasma membrane homeostasis and is involved in maintenance of cell size in the periderm, the outermost epidermal layer. The decrease in peridermal cell size in Myosin Vb deficient embryos is compensated by an increase in cell number whereas decrease in cell number results in the expansion of peridermal cells, which requires myosin Vb (myoVb) function. Inhibition of cell proliferation as well as cell size expansion results in increased lethality in larval stages suggesting that this two-way compensatory mechanism is essential for growing larvae. Our analyses unravel the importance of Myosin Vb dependent cell size regulation in epidermal homeostasis and demonstrate that the epidermis has the ability to maintain a dynamic balance between cell size and cell number.

Caracterização da anatomia foliar de cafeeiros arábica em diferentes períodos sazonais

Drought is among the hindering factors for coffee plant growth and yield. This study aimed to analyze the anatomy of leaves grown during the rainy and dry seasons in nine Coffea arabica L. plants, previously described as tolerant or sensitive to water deficit, in order to identify structural features of drought tolerance. We measured the size and density of stomata and epidermal cells, the thickness of epidermis and mesophyll, the diameter of petiole and midrib, the thickness of phloem and xylem in the midrib and petiole, and the diameter and frequency of elements of xylem vessels. Differences observed between the leaf structure of coffee plants evaluated and the leaf growth conditions (rainy and dry seasons) indicated that there is a favorable anatomical plasticity regarding drought conditions. Thicker palisade parenchyma and total limbo, larger radii of phloem and xylem in the petiole and midrib were considered as favorable structural features to cope with water scarcity and they could be used as criteria to select drought-resistant cultivars. The following coffee plants were considered as more adapted to drought: Geisha, Semperlorens, BA 10, IAC H 8105-7, IAC H 8421-2, and the cultivar Catuai Vermelho IAC 81.

Prepenetration and Penetration of Colletotrichum gloeosporioides into Guava Fruit (Psidium guajava L.): Effects of Temperature, Wetness Period and Fruit Age

AbstractIn this study, we determined the influences of temperature, wetness period and guava fruit age on infection caused by Colletotrichum gloeosporioides. Optimal temperatures in vitro for germination, appressoria formation and melanization were 22.7, 20.6 and 23°C, respectively. In vivo, the optimal temperatures for germination and appressoria formation were 22.5 and 23°C, respectively. Values for germination, appressoria formation and melanization were higher as the wetness period increased. There was no difference in conidial germination and appressorial formation on fruit of different ages. On the surface of 10‐, 35‐ and 60‐day‐old fruit, despite the high percentage of appressorial formation, there was no development of the penetration peg. Penetration pegs were only observed on the 85‐ and 110‐day‐old fruit. Thickness of the cuticle, size and architecture of epidermal and parenchymal cells, as well as the content of phenolic compounds changed as the fruit ripened.

Effect of varied summer deficit irrigation on components of olive fruit growth and development

The timing, duration, and intensity of summer water restrictions differentially affect overall olive fruit growth and production, based on the underlying fruit developmental processes. For that, the fruit component and tissue morphogenetic response to different irrigation strategies during summer was examined in a hedgerow olive orchard cv. Arbequina. Control trees (CON) were irrigated to maintain the root zone close to field capacity throughout fruit growth. From budburst to 4 weeks after full bloom (WAFB) (Period 1) and from 14 WAFB to harvest (at 23 WAFB) (Period 4) trees of all treatments were irrigated as CON. Two severe water deficit treatments were applied during summer by irrigating 30% CON from 4 to 9 WAFB (Period 2) in DI-P2 or from 9 to 14 WAFB (Period 3) in DI-P3. Moderate water deficit was applied in Periods 2 and 3 by irrigating 50% CON in DI-P2&3. Growth and development of the fruit and its component tissues (exocarp, mesocarp and endocarp), fruit composition, mesocarp cell area and cell number, and epidermal characteristics at the end of each period were evaluated. Water deficits significantly reduced fruit volume at the time when they were applied. Mesocarp size was more sensitive to water deficit than endocarp size and showed a high recovery capacity after rewatering. Although the majority of cells were developed in Period 1, a substantial number of mesocarp cells were also formed later. While mesocarp cell number was unaffected by water reduction in any of the deficit periods, cell size was highly affected but with high recoverability. Endocarp size was reduced when water restriction was applied in DI-P2 and its effect continued until harvest. Fruit oil content at harvest was not significantly affected by the applied water restrictions, whereas water was the fruit component which most responded to both the increases and decreases in irrigation. Cuticle thickness, epidermal cell size and number at harvest appeared to respond to both irrigation regime and fruit expansion pressures.