Excessive Water Loss Research Articles

Three novel quantitative trait loci for skin thickness in swine identified by linkage and genome-wide association studies.

Skin is the largest organ in the pig body and plays a key role in protecting the body against pathogens and excessive water loss. Deciphering the genetic basis of swine skin thickness would enrich our knowledge about the skin. To identify the loci for porcine skin thickness, we first performed a genome scan with 194 microsatellite markers in a White Duroc × Erhualian F2 intercross. We identified three genome-wide significant QTL on pig chromosomes (SSC) 4, 7 and 15 using linkage analysis. The most significant QTL was found on SSC7 with a small confidence interval of ~5 cM, explaining 23.9 percent of phenotypic variance. Further, we conducted a genome-wide association study (GWAS) using Illumina PorcineSNP60 Beadchips for the F2 pedigree and a population of Chinese Sutai pigs. We confirmed significant QTL in the F2 pedigree and replicated QTL on SSC15 in Chinese Sutai pigs. A meta-analysis of GWASs on both populations detected a genomic region associated with skin thickness on SSC4. GWAS results were generally consistent with QTL mapping. Identical-by-descent analysis defined QTL on SSC7 in a 683-kb region harboring an interesting candidate gene: HMGA1. On SSC15, the linkage disequilibrium analysis showed a haplotype block of 2.20 Mb that likely harbors the gene responsible for skin thickness. Our findings provide novel insights into the genetic basis of swine skin thickness, which would benefit further understanding of porcine skin function.

Secretion of von Willebrand factor by endothelial cells links sodium to hypercoagulability and thrombosis.

Hypercoagulability increases risk of thrombi that cause cardiovascular events. Here we identify plasma sodium concentration as a factor that modulates blood coagulability by affecting the production of von Willebrand factor (vWF), a key initiator of the clotting cascade. We find that elevation of salt over a range from the lower end of what is normal in blood to the level of severe hypernatremia reversibly increases vWF mRNA in endothelial cells in culture and the rate of vWF secretion from them. The high NaCl increases expression of tonicity-regulated transcription factor NFAT5 and its binding to promoter of vWF gene, suggesting involvement of hypertonic signaling in vWF up-regulation. To elevate NaCl in vivo, we modeled mild dehydration, subjecting mice to water restriction (WR) by feeding them with gel food containing 30% water. Such WR elevates blood sodium from 145.1 ± 0.5 to 150.2 ± 1.3 mmol/L and activates hypertonic signaling, evidenced from increased expression of NFAT5 in tissues. WR increases vWF mRNA in liver and lung and raises vWF protein in blood. Immunostaining of liver revealed increased production of vWF protein by endothelium and increased number of microthrombi inside capillaries. WR also increases blood level of D-dimer, indicative of ongoing coagulation and thrombolysis. Multivariate regression analysis of clinical data from the Atherosclerosis Risk in Communities Study demonstrated that serum sodium significantly contributes to prediction of plasma vWF and risk of stroke. The results indicate that elevation of extracellular sodium within the physiological range raises vWF sufficiently to increase coagulability and risk of thrombosis.

Arabidopsis DELLA and JAZ Proteins Bind the WD-Repeat/bHLH/MYB Complex to Modulate Gibberellin and Jasmonate Signaling Synergy

Integration of diverse environmental and endogenous signals to coordinately regulate growth, development, and defense is essential for plants to survive in their natural habitat. The hormonal signals gibberellin (GA) and jasmonate (JA) antagonistically and synergistically regulate diverse aspects of plant growth, development, and defense. GA and JA synergistically induce initiation of trichomes, which assist seed dispersal and act as barriers to protect plants against insect attack, pathogen infection, excessive water loss, and UV irradiation. However, the molecular mechanism underlying such synergism between GA and JA signaling remains unclear. In this study, we revealed a mechanism for GA and JA signaling synergy and identified a signaling complex of the GA pathway in regulation of trichome initiation. Molecular, biochemical, and genetic evidence showed that the WD-repeat/bHLH/MYB complex acts as a direct target of DELLAs in the GA pathway and that both DELLAs and JAZs interacted with the WD-repeat/bHLH/MYB complex to mediate synergism between GA and JA signaling in regulating trichome development. GA and JA induce degradation of DELLAs and JASMONATE ZIM-domain proteins to coordinately activate the WD-repeat/bHLH/MYB complex and synergistically and mutually dependently induce trichome initiation. This study provides deep insights into the molecular mechanisms for integration of different hormonal signals to synergistically regulate plant development.

干旱胁迫对黄土高原4种蒿属植物叶形态解剖学特征的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 干旱胁迫对黄土高原4种蒿属植物叶形态解剖学特征的影响 DOI: 10.5846/stxb201306301802 作者: 作者单位: 中国科学院教育部水土保持与生态环境研究中心,中国科学院水利部水土保持研究所,西北农林科技大学生命学院,中国科学院水利部水土保持研究所,西北农林科技大学生命学院 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院重要方向项目（KZCX2-YW-443）；中国科学院知识创新项目（KZCX2-XB2-05-01） Effect of drought on leaf anatomical characteristics of four Artemisia species in the Loess Plateau Author: Affiliation: Institute of soil and water conservation,CAS MWR,The college of life science,The north west agriculture and forest university,Institute of soil and water conservation,CAS MWR,The college of life science,The north west agriculture and forest university Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以黄土高原演替初期阶段的猪毛蒿（Artemisia scoparia Waldst. et Kit.）、茭蒿（Artemisia giraldii Pamp.）、铁杆蒿（Artemisia gmelinii Web. ex Stechm.）3种优势种和1种常见种黄花蒿（Artemisia annua Linn.）为供试材料，采用盆栽试验与称重控水法，将土壤含水量分别控制在田间最大持水量的75%（适宜水分对照）、55%（中度干旱）和35%（重度干旱），研究干旱胁迫对菊科蒿属植物叶片形态解剖学的影响，揭示植物叶片生态适应机制，为生态恢复过程中植被演替的规律提供理论依据。于植物营养生长末期选取代表性的叶片，分别采用电子扫描显微镜、电子透射显微镜和光学显微镜对叶表皮特征、亚细胞显微特征和组织结构进行观察。结果表明：干旱胁迫下，这4种植物表现为不同程度的叶片增厚、栅栏组织厚度、叶片紧实度和角质层厚度增加；3种旱生型植物猪毛蒿、茭蒿和铁杆蒿的叶片下表皮具有浓密的表皮毛，有利于防止水分过度蒸腾，而中生型黄花蒿叶片无此功能；铁杆蒿和黄花蒿上表皮毛稀少，不利于保水和防止强光照，干旱胁迫下依靠降低上表皮气孔密度和叶细胞叶绿体数目来适应环境；茭蒿和猪毛蒿叶绿体形态相似，具有较厚的基粒和浓密的基粒片层，强光下容易引起氧化损伤，猪毛蒿通过浓密的上表皮毛而茭蒿通过较强的抗氧化机制防止光能过剩，两者在重度干旱下均产生大量脂质体。4种蒿属植物中黄花蒿的叶片解剖学特征受到干旱的影响变化最大，铁杆蒿和猪毛蒿次之，茭蒿最弱，3种优势种的干旱适应性显著强于黄花蒿，干旱下叶片解剖学的结论与干旱耐受性指标结果一致。 Abstract:Leaf anatomical characteristics of 4 Artemisia species under drought conditions were investigated to reveal the drought-resistant strategies of vegetation at early stage of ecological succession in the Loess Plateau. Three dominant species as Artemisia scoparia Waldst. et Kit., Artemisia giraldii Pamp. and Artemisia gmelinii Web. ex Stechm. and one common specie, Artemisia annua Linn. during early succession in the Loess Plateau were selected to investigate the leaf anatomical adaptation of Artemisia to soil drought stresses. Pot experiment was adopted to control the soil water content. And 75%, 55% and 35% of field moisture capacity were set as control, moderate water stress and severe water stress, respectively. The latest mature leaves were freshly collected and fixed at the end of their vegetation growth period for SEM, TEM and the optical microscope. We analyzed the difference among leaf epidermis characteristics of the four Artemisia species according to the sub-cellular micro characteristic and the organizational anatomical structure. The results show that: the four Artemisia leaves have some kind of anatomy characteristics, as blade thickness, palisade tissue thickness, cutin layer thickness, ratio of palisade tissue thickness to sponge tissue thickness, tightness of leaf tissue structure were increased under drought conditions. Leaf epidermises of A. scoparia, A. giraldii and A. gmelinii have dense trichomes to prevent excessive water loss from evaporation; however A. annua has sparse trichomes. The upper epidermises of A. gmelinii and A. annua are sparse, which are not good for water conservation and to prevent highlight, the decrease of the stoma density and the number of chloroplast were conducted to adapt environment change. Similar chloroplast anatomy characteristics of thick grana and dense grana lamellae were observed in the leaf cells of A. scoparia and A. giraldii, which are easier to result in oxidative damage during photosynthetic process. To prevent the oxidative damage, the dense trichomes on upper epidermises of A. scoparia and outstanding antioxidant mechanisms of A. giraldii were conducted, and a large number of liposomes were also produced in the two species. The leaf anatomical characteristics influence of drought affected on the A. annua was the greatest between the four Artemisia species, and A. gmelinii and A. scopara were followed, the least affect was on Artemisia giraldii. The three dominant species had stronger ability to adapt to drought stress than the common species-Artemisia annua. The leaf anatomical characteristics and drought tolerance indexes of the 4 species represented similar comments of drought tolerance ability. 参考文献 相似文献 引证文献

Micropropagation of <i>Artocarpus lakoocha</i> Roxb (Monkey jack) through Shoot Bud Culture

The Lakoocha ( Artocarpus lakoocha Roxb . ), popularly known as “monkey jack”, is called as ‘ barhal’ in India, belongs to family Moraceae and comprises of many species of woody trees. The present study was aimed to develop a micropropagation protocol for Lakoocha towards commercial mass production of planting material which permits rapid and easy multiplication rates, outwits genotype barriers, offers opportunities for continuous availability of genuine planting material with economic viability. We report here a prototype system of micropropagated plantlets of Lakoocha through shoot bud culture within 6 months catering to those parameters of commercial mass multiplication. Nodal explant with an axillary bud used as explant; showed in vitro bud induction within 7.33days in MS+BAP 13.33+IAA 2.28+GA 3 0.57 µM. The maximum shoot multiplication (6.66 shoots/explant) was observed in MS medium supplemented with BAP 13.33 +IAA 1.14 µM. The microshoots were maintained in MS basal medium (BAP 0.89 µM) supplemented with Casein Hydrolysate 100 mg/l and then subsequently rooted in ½ MS medium supplemented with IBA 9.85+BAP0.89 µM+Activated charcoal 500 mg/l which resulted in 88.16% rooting. The in vitro rooted plants were primary hardened on autoclaved Sand : Soil : Peat moss (1:1:2) drenched with ½ strength MS nutrients in plastic cups covered with transparent polyethylene bags to prevent excess water loss for 3 weeks in growth room at 25±2 0 C and then transferred to shade net house (50% shade 70%±5% RH) for secondary hardening. All plants showed 88.33% survival during acclimatization. The plants that were field established showed > 85% survivability, which is under further evaluation for fruiting and quality characters.

Microscale modeling of coupled water transport and mechanical deformation of fruit tissue during dehydration

Water loss of fruit typically results in fruit tissue deformation and consequent quality loss. To better understand the mechanism of water loss, a model of water transport between cells and intercellular spaces coupled with cell deformation was developed. Pear (Pyrus communis L. cv. Conference) was chosen as a model system as this fruit suffers from shriveling with excessive water loss. A 2D geometric model of cortex tissue was obtained by a virtual fruit tissue generator that is based on cell growth modeling. The transport of water in the intercellular space, the cell wall network and cytoplasm was predicted using transport laws using the chemical potential as the driving force for water exchange between different microstructural compartments. The different water transport properties of the microstructural components were obtained experimentally or from literature. An equivalent microscale model that incorporates the dynamics of mechanical deformation of the cellular structure was implemented. The model predicted the apparent tissue conductivity of pear cortex tissue to be 9.42±0.40×10−15kgm−1s−1Pa−1, in the same range as those measured experimentally. The largest gradients in water content were observed across the cell walls and cell membranes. A sensitivity analysis of membrane permeability and elastic modulus of the wall on the water transport properties and deformation showed that the membrane permeability has the largest influence. The model can be improved further by taking into account 3-D connectivity of cells and intercellular pore spaces. It will then become feasible to evaluate measures to reduce water loss of fruit during storage and distribution using the microscale model in a multiscale modeling framework.

Management of Hyponatremia in the ICU

Hyponatremia is common in critical care units. Avoidance of neurologic injury requires a clear understanding of why the serum sodium (Na) concentration falls and why it rises, how the brain responds to a changing serum Na concentration, and what the goals of therapy should be. A 4 to 6 mEq/L increase in serum Na concentration is sufficient to treat life-threatening cerebral edema caused by acute hyponatremia. In chronic (> 48 h), severe (< 120 mEq/L) hyponatremia, correction by > 8 to 10 mEq/L/d risks iatrogenic osmotic demyelination syndrome (ODS); therefore, a 4 to 6 mEq/L daily increase in serum Na concentration should be the goal in most patients. With the possible exception of hyponatremia caused by heart failure or hepatic cirrhosis, a rapid initial increase in serum Na for severe symptoms and avoidance of overcorrection are best achieved with 3% saline given in either a peripheral or central vein. Inadvertent overcorrection can be avoided in high-risk patients with chronic hyponatremia by administration of desmopressin to prevent excessive urinary water losses. In patients with hyponatremia with oliguric kidney failure, controlled correction can be achieved with modified hemodialysis or continuous renal replacement therapies. ODS is potentially reversible, even in severely affected patients who are quadriplegic, unresponsive, and ventilator dependent. Supportive care should be offered several weeks before concluding that the condition is hopeless.

Evapotranspiration and Its Energy Exchange in Alpine Meadow Ecosystem on the Qinghai-Tibetan Plateau

To understand the water and energy exchange on the Qinghai-Tibetan Plateau, we explored the characteristics of evapotranspiration (ET) and energy fluxes from 2002 to 2005 over a Kobresia meadow ecosystem using the eddy covariance method. The ratio of annual ET to precipitation (P) of meadow ecosystem was about 60%, but varied greatly with the change of season from summer to winter. The annual ET/P in meadow was lower than that in shrub, steppe and wetland ecosystems of this plateau. The incident solar radiation (Rs) received by the meadow was obviously higher than that of lowland in the same latitude; however the ratio of net radiation (Rn) to Rs with average annual value of 0.44 was significantly lower than that in the same latitude. The average annual ET was about 390 mm for 2002-2005, of which more than 80% occurred in growing season from May to September. The energy consumed on the ET was about 44% of net radiation in growing season, which was lower than that of shrub, steppe and wetland on this plateau. This study demonstrates that the Kobresia meadow may prevent the excessive water loss through evapotranspiration from the ecosystem into the atmosphere in comparison to the shrub, steppe and wetland ecosystems of the Qinghai-Tibetan Plateau.

Integration of thermal and osmotic regulation of water homeostasis: the role of TRPV channels.

Maintenance of body water homeostasis is critical for preventing hyperthermia, because evaporative cooling is the most efficient means of dissipating excess body heat. Water homeostasis is achieved by regulation of water intake and water loss by the kidneys. The former is achieved by sensations of thirst that motivate water acquisition, whereas the latter is regulated by the antidiuretic action of vasopressin. Vasopressin secretion and thirst are stimulated by increases in the osmolality of the extracellular fluid as well as decreases in blood pressure and/or blood volume, signals that are precipitated by water depletion associated with the excess evaporative water loss required to prevent hyperthermia. In addition, they are stimulated by increases in body temperature. The sites and molecular mechanisms involved in integrating thermal and osmotic regulation of thirst and vasopressin secretion are reviewed here with a focus on the role of the thermal and mechanosensitive transient receptor potential-vanilloid (TRPV) family of ion channels.

Salt Poisoning as a Cause of Morbidity and Mortality in Neonatal Dairy Calves

Salt Poisoning as a Cause of Morbidity and Mortality in Neonatal Dairy Calves

Skin penetration enhancers

The skin has evolved to prevent excessive water loss from the internal organs and to limit the ability of xenobiotics and hazardous substances to enter the body. Notwithstanding this barrier function, a number of strategies have been developed by scientists to deliver drugs to and through the skin. The aim of this review is to consider the various types of chemical penetration enhancers (CPEs) which have been investigated in the scientific literature. Potential pathways for CPEs to exert their action are examined with reference to the physical chemistry of passive skin transport. The emphasis is on those studies which have focussed on human and porcine skin because of the limitations associated with skin permeation data collated from other species. Where known, the mechanisms of action of these compounds are also discussed. Examples of enhancers used in commercial topical and transdermal formulations are provided. It is proposed that overall the effects of CPEs on the skin barrier may best be explained by a Diffusion-Partition-Solubility theory. Finally, some of the limitations of studies in the literature are considered and the importance of monitoring the fate of the penetration enhancer as well as the active is highlighted.

Pathogenetic rationale for the use of skin care products in patients suffering from atopic dermatitis

Filaggrin is a key protein participating in the differentiation of epidermal cells, which prevents any excessive transepidermal water loss and contributes to the maintenance of skin barrier properties. Mutations in the filaggrin gene (FLG) are among the most important factors predisposing to the development of atopy. Today correct skin care comprising the use of moisturizing and softening products forms an integral part of the therapy for patients with atopic dermatitis and an important component of measures aimed at the reduction of the number of exacerbations and extension of the remission.

Tight junction dysfunction in the stratum granulosum leads to aberrant stratum corneum barrier function in claudin-1-deficient mice

BackgroundTight junctions (TJs) contribute to the epithelial barrier function by preventing leakage of solutes through the intercellular space. In the skin, TJs occur in the stratum granulosum (SG), where claudin-1 and claudin-4 are expressed as adhesion molecules of TJs. Claudin-1-deficient (Cldn1−/−) mice die within one day of birth accompanied by excessive transepidermal water loss, indicating a critical role of TJs in the epidermal barrier function. However, it has been debated whether the impaired TJ function in the SG also affects the stratum corneum (SC) barrier function or whether it results in skin barrier defects despite a normal SC barrier. ObjectiveTo clarify whether the impaired TJ function affects the SC barrier function in Cldn1−/− mice. MethodsThe morphology, barrier function and biochemical characteristic of the SC were compared between Cldn1−/− and Cldn1+/+ mice. ResultsScanning electron microscopy demonstrated abnormally wrinkled and rough corneocytes in Cldn1−/− mice. Notably, the X-gal tracer easily permeated into the Cldn1−/− SC, and water evaporation through isolated Cldn1−/− SC sheets was significantly higher than that through Cldn1+/+ SC sheets. Furthermore, the ceramide composition of the SC lipids and filaggrin processing were altered in Cldn1−/− mice. ConclusionCldn1−/− mice exhibited the abnormal SC formation and SC barrier defects. These findings demonstrate for the first time that TJs in the SG play crucial roles in the complete SC formation and SC barrier function.

Osmotic diuresis-induced hypernatremia: better explained by solute-free water clearance or electrolyte-free water clearance?

Hypernatremia may result from inadequate water intake, excessive water loss or a combination of the two. Osmotic diuresis leads to losses of both solute and water. The relationship between solute and water losses determines the resulting changes in serum osmolality and sodium concentration. Total solute loss is routinely higher than loss of water in osmotic diuresis. Theoretically, then, decreases in serum osmolality (and serum sodium concentration) should follow. In clinical situations of osmotic diuresis, however, reduction in osmolality can take place, but not reduction in serum sodium concentration. It is of note that serum sodium concentration changes are related to urinary losses of sodium and potassium but not to the loss of total solute. In osmotic diuresis, the combined loss of sodium and potassium per liter of urine is lower than the concurrent serum sodium level. Consequently, hypernatremia can ensue. A patient who presented with osmotic diuresis and hypernatremia is described here. In this patient, we have shown that electrolyte-free water clearance is a better index of the effect of osmotic diuresis on serum sodium concentration than the classic solute-free water clearance.

Neonatal Skin and Chlorhexidine: A Burning Experience

Despite the lack of safety data, chlorhexidine gluconate (CHG) is an antiseptic with broadspectrum coverage often used in neonatal intensive care units (NICUs). Adverse skin reactions, most commonly burns, have been reported after the use of CHG. Preserving skin integrity in preterm infants is vital in the prevention of sepsis, excessive water loss, hypothermia, and renal failure. This is a case report of two incidents of significant skin burning in extremely low birth weight (ELBW) infants who were treated with CHG for the purposes of umbilical cord sterilization prior to umbilical line placement. This case report of burns associated with CHG in one infant weighing 610 g at birth and a second infant weighing 600 g at birth. CHG does have a strong association with causing skin burns in the ELBW population; however, wiping the solution off of the skin seems to reduce injury.

Comparison of runoff characteristics of two adjacent basins in a tropical rainforest using a modified hydrologic cycle model with outflow

We propose a new runoff model including an outflow process that was applied to two adjacent basins (CL, TL) located in Lambir Hills National Park in north-central Sarawak, Malaysia. Rainfall, runoff, topography, and soil layer thickness were observed. About 19% of annual runoff was observed in the CL basin (21.97 ha), whereas about 46% was observed in the TL basin (23.25 ha). It was inferred that the CL basin has an outflow because of low base flow, small runoff peak, and excessive water loss. By incorporating the outflow process into the HYdrological CYcle MODEL, good agreement between the data generated by the model and that observed was shown, with the exception of the data from the rainless period. Then, the fitting parameters for each basin were exchanged, except for the outflow parameter, and the characteristics of each basin were compared by calculating virtual runoff. As a result, the low base flow of the CL basin was estimated by the movement of the rainwater that escaped from the basin as deep percolation or lateral flow (11% of rainfall). The potential of the CL basin for mitigating flood and drought appeared to be higher than that of the TL basin. This is consistent with the topographic characteristics of the CL basin, which has a gentler slope than the TL basin. Copyright © 2012 John Wiley & Sons, Ltd.

Imaging Mass Spectrometry Visualizes Ceramides and the Pathogenesis of Dorfman-Chanarin Syndrome Due to Ceramide Metabolic Abnormality in the Skin

Imaging mass spectrometry (IMS) is a useful cutting edge technology used to investigate the distribution of biomolecules such as drugs and metabolites, as well as to identify molecular species in tissues and cells without labeling. To protect against excess water loss that is essential for survival in a terrestrial environment, mammalian skin possesses a competent permeability barrier in the stratum corneum (SC), the outermost layer of the epidermis. The key lipids constituting this barrier in the SC are the ceramides (Cers) comprising of a heterogeneous molecular species. Alterations in Cer composition have been reported in several skin diseases that display abnormalities in the epidermal permeability barrier function. Not only the amounts of different Cers, but also their localizations are critical for the barrier function. We have employed our new imaging system, capable of high-lateral-resolution IMS with an atmospheric-pressure ionization source, to directly visualize the distribution of Cers. Moreover, we show an ichthyotic disease pathogenesis due to abnormal Cer metabolism in Dorfman–Chanarin syndrome, a neutral lipid storage disorder with ichthyosis in human skin, demonstrating that IMS is a novel diagnostic approach for assessing lipid abnormalities in clinical setting, as well as for investigating physiological roles of lipids in cells/tissues.

Glycogen, not dehydration or lipids, limits winter survival of side-blotched lizards (Uta stansburiana)

Climate change is causing winters to become milder (less cold and shorter). Recent studies of overwintering ectotherms have suggested that warmer winters increase metabolism and decrease winter survival and subsequent fecundity. Energetic constraints (insufficient energy stores) have been hypothesized as the cause of winter mortality but have not been tested explicitly. Thus, alternative sources of mortality, such as winter dehydration, cannot be ruled out. By employing an experimental design that compared the energetics and water content of lizards that died naturally during laboratory winter with those that survived up to the same point but were then sacrificed, we attempt to distinguish among multiple possible causes of mortality. We test the hypothesis that mortality is caused by insufficient energy stores in the liver, abdominal fat bodies, tail or carcass or through excessive water loss. We found that lizards that died naturally had marginally greater mass loss, lower water content, and less liver glycogen remaining than living animals sampled at the same time. Periodically moistening air during winter reduced water loss, but this did not affect survival, calling into question dehydration as a cause of death. Rather, our results implicate energy limitations in the form of liver glycogen, but not lipids, as the primary cause of mortality in overwintering lizards. When viewed through a lens of changing climates, our results suggest that if milder winters increase the metabolic rate of overwintering ectotherms, individuals may experience greater energetic demands. Increased energy use during winter may subsequently limit individual survival and possibly even impact population persistence.

Microstructural differences in Agave atrovirens Karw leaves and pine by age effect

We evaluated the effects of the leaves, “pine” or “head” (plants without leaves) age of Agave atrovirens on the epidermal, parenchyma and fibrillar microstructure as possible maturity indicators, since plant age is a determinant factor of the concentration of inulin. Samples were taken from three, six and nine year-old plants, and observations were made with scanning electronic microscopy (SEM) and light microscopy (LM). The results showed that the isolated cuticular membrane (ICM) microstructure in the agave plant changes considerably with the age, becoming harder and allowing the mature plant to avoid excessive water loss, on the other hand, the increased size of the suprastomal cavity makes the respiration process more efficient in older plants. The agaves present the three main types of calcium oxalate crystals reported for monocotyledons (druses, raphides and styloids). The plant age is an important factor in the identification of calcium oxalate crystals because it is only in six year-old plant that all three types were identified. However, the druses are present only in the cuticular membrane (CM), while the styloids and raphides are distributed on the parenchyma and chlorenchyma. The fibrillar structures in agave are modified with age such thatagave can support severe hydric stress and the storage of soluble carbohydrates. Key words: Crystals, calcium oxalate, fibrillar, druses, raphides, styloids.

Digital photogrametry in investigation of application membranes on the surfaces of cementitious materials

Purpose The purpose of this work is to demonstrate usage of the photogrametry in construction, testing and monitoring of structures. Method The method of photogrametry is based on capturing digital shots of the cementitious surface covered with a membrane preventing water loss from concrete either by single shot or time-lapse method. By converting the pictures into gray scale and analyzing the brightness either of the whole surface or any differential area, we are able to calculate an evenness of the membrane application, a prediction of water loss from cementitious material, humidity underneath the membrane, and the areas of the structure most likely weakened due to excessive water loss. Results & Discussion We analyzed the effectiveness of concrete curing by application of a membrane (paraffin–based) on the surface of fresh concrete while studying loss of water depending on boundary conditions of the exposure to the ambient environment. The results in the picture help to refine the data and show this is a means of curing works up to 70%.