Maintenance Of Water Balance Research Articles

A Study to Assess the Effectiveness of Video Assisted Teaching Programme on Knowledge, Attitude and Practice Regarding Renal Rehabilitation among Patients with Chronic Kidney Disease Who are Admitted in the Mamata General and Super Specialty Hospital, at Khammam, Telanagana

ABSTRACT Background: Kidneys are one of the vital organs in the human body. Kidneys perform vital functions like excretion of waste products, maintenance of water balance, thus maintaining the homeostasis. In addition, kidneys perform many other functions such as role in Homeostasis, Production of Erythrocyte, Endocrine function, Regulation of Blood Sugar and regulation of Blood Calcium level. Because the kidney performs a wide variety of functions, the effects of loss of renal function not only in kidney but also in other organ systems.Hemo dilaysis is used for clients with acute or irreversible renal failure and fluid and electrolyte imbalances. It is usually the treatment of choice when toxic agents, such as barbiturates after an over dose need to be removed quickly. The availability of the treatment for clients with end stage renal failure (ESRF) has become more prevalent. The population receiving hemo dilaysis now represents a wide cross-section of age rehabilitative potential of socio-economic status. Materials and Methods: For the present study, quantitative Evaluative Approach ,Pre – Experimental research design, one group pretest and one group post test design.The study was conducted in the Mamata General and super specialty Hospital at Khammam, Telangana. Results: The above table shows that the pre test mean knowledge score is 10.05 and standard deviation is 3.77 where as post test mean score is 18.02 and standard deviation is 3.36 and mean difference is 7.97, the paired ‘t’ test calculated value is 14.89, which is greater than table value with df value of 79at (p<0.05) level. Conclusion: The main study was conducted in Mamata general and super specialty hospital, at Khammam, Telanagana . The sample sizes 30. The sample was selected by using non probability of convenient sampling technique among those fulfill the criteria.

Potassium supply for improvement of cereals growth under drought: A review

AbstractPotassium (K) is an essential macronutrient that determines crop productivity and promotes crop growth under conditions of abiotic stress. In this review paper, peer‐reviewed publications (experimental data) dealing with the role of K administration in the control of cereals growth under drought stress are reviewed and analyzed. Most published research on the impact of K administration on cereals growth under drought focuses primarily on bread wheat (Triticum aestivum L.) and maize (Zea mays L.), along with barley (Hordeum vulgare L.), rice (Oryza sativa L.), pearl millet (Pennisetum glaucum L.), and sorghum (Sorghum bicolor L.). The beneficial effect of K on cereals growth under drought has been related to maintenance of water balance in the crops, increased activity of the antioxidant enzymes, increased synthesis of osmolytes, contribution to a low sodium (Na)/K ratio, extension of the grain filling period, and increase of the grain growth rate and weight. Moreover, K was suggested as a possible way for enhancing nitrogen use efficiency (e.g., bread wheat and sorghum). Nevertheless, the beneficial effect of foliar applied K in dried soil during grain filling differed among bread wheat cultivars, highlighting that the effect of K supply on grain weight may differ depending on application method, that is, administration through the soil or the foliage. Overall, K supply could be exploited as a tool for increasing cereal tolerance to drought, for example, by considering late administration of K through top dressing applications or foliar sprayings. Yet additional information is needed on the rate and the K form, along with the most suitable growth stage for application. Such information could help agronomists develop strategies for high‐quality cereal production in stressful environments.

ECR Spotlight – Nicolas Séon

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology during our centenary year but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Nicolas Séon is an author on ‘ Determination of water balance maintenance in Orcinus orca and Tursiops truncatus using oxygen isotopes’, published in JEB. Nicolas conducted the research described in this article while a PhD student in Dr Peggy Vincent, Dr Romain Amiot and Prof. Sylvain Charbonnier's lab at Centre de Recherche en Paléontologie - Paris (CR2P), France. He begins a post-doc in February 2024 in the lab of Dr Mia Wege and Prof. Trevor McIntyre at University of South Africa (UNISA)/University of Pretoria (UP), South Africa, investigating the ecology and physiology of extant and fossil marine vertebrates using isotope geochemistry.

ʟ-glutamic acid modulates antioxidant defense systems and nutrient homeostasis in lentil (Lens culinaris Medik.) under copper toxicity.

Copper (Cu), an essential micronutrient, can generate reactive oxygen species (ROS) at its supra-optimal level in living cells as a transition metal, thus producing oxidative stress in plants. Therefore, protecting plants from Cu-induced oxidative stress via the exogenous application of chemical substances, particularly L-glutamic acid (L-Glu), could be a viable strategy for mitigating the toxicity of Cu. The aim of our present study was to investigate how ʟ-Glu protects lentil seedlings from oxidative stress produced by toxic Cu and allows them to survive under Cu toxicity. The results exhibited that when lentil seedlings were exposed to excessive Cu, their growth was inhibited and their biomass decreased due to an increase in Cu accumulation and translocation to the root, shoot, and leaves. Exposure to toxic Cu also depleted photosynthetic pigments, imbalanced water content, and other essential nutrients, increased oxidative stress, and reduced enzymatic and non-enzymatic antioxidants. However, pre-treatment of ʟ-Glu improved the phenotypic appearance of lentil seedlings, which was distinctly evidenced by higher biomass production, maintenance of water balance, and an increase in photosynthetic pigments when exposed to toxic Cu. ʟ-Glu also protected the seedlings from Cu-induced oxidative stress by reducing the oxidative stress marker, specifically by the efficient action of enzymatic and non-enzymatic antioxidants, particularly ascorbate, catalase, monodehydroascorbate, and glutathione peroxidase and maintaining redox balance. Furthermore, ʟ-Glu assisted in maintaining the homeostasis of Cu and other nutrient in the roots, shoots, and leaves of lentil. Collectively, our results provide evidence of the mechanism of ʟ-Glu-mediated protective role in lentil against Cu toxicity, thus proposed as a potential chemical for managing Cu toxicity not only in lentil but also other plants.

Sialorrhea in the assessment and correction of water balance in a 2 month old baby in the ICU: a case report

INTRODUCTION: In some cases, saliva production (sialorrhea — hypersalivation) can be so significant that it needs to be monitored and accounted for in the assessment and maintenance of the patient's water balance. OBJECTIVE: Description of a clinical case of sialorrhea, which had a clinically significant manifestation in the assessment and maintenance of water balance in a 2-month-old child in the intensive care unit (ICU). MATERIALS AND METHODS: Baby, 2 month old, was treated in the ICU with a diagnosis: perinatal organic hypoxic-ischemic lesion of the central nervous system of a newborn, congenital pathology of the brain, respiratory failure III stage, convulsions of the newborn, neonatal coma. In the complex of specific therapy, he received enteral feeding, correction of water and nutritional status. RESULTS: On the first day of detection of sialorrhea, the level of salivation of 2.81 ml/kg/hour (the norm is 1.3 ml/kg/hour) exceeded the physiological values by more than 2 times. The excess of normal values of salivation persisted for the next two days, as well as on the 9th day of its control, which required taking into account the amount of fluid lost with saliva in the calculation of its daily requirement. No specific measures were required in the treatment of the patient to eliminate sialorrhea; within 14 days from the moment the fact of sialorrhea was established, the level of salivation returned to normal values. CONCLUSIONS: In assessing the cumulative factors that cause fluid loss in ICU patients, especially infants, it is also necessary to take into account the presence and intensity of salivation, which can manifest as sialorrhea, when calculating the volume and administration of infusion drugs.

Salinity Tolerance of Halophytic Grass Puccinellia nuttalliana Is Associated with Enhancement of Aquaporin-Mediated Water Transport by Sodium.

In salt-sensitive plants, root hydraulic conductivity is severely inhibited by NaCl, rapidly leading to the loss of water balance. However, halophytic plants appear to effectively control plant water flow under salinity conditions. In this study, we tested the hypothesis that Na+ is the principal salt factor responsible for the enhancement of aquaporin-mediated water transport in the roots of halophytic grasses, and this enhancement plays a significant role in the maintenance of water balance, gas exchange, and the growth of halophytic plants exposed to salinity. We examined the effects of treatments with 150 mM of NaCl, KCl, and Na2SO4 to separate the factors that affect water relations and, consequently, physiological and growth responses in three related grass species varying in salt tolerance. The grasses included relatively salt-sensitive Poa pratensis, moderately salt-tolerant Poa juncifolia, and the salt-loving halophytic grass Puccinellia nuttalliana. Our study demonstrated that sustained growth, chlorophyll concentrations, gas exchange, and water transport in Puccinellia nuttalliana were associated with the presence of Na in the applied salt treatments. Contrary to the other examined grasses, the root cell hydraulic conductivity in Puccinellia nuttalliana was enhanced by the 150 mM NaCl and 150 mM Na2SO4 treatments. This enhancement was abolished by the 50 µM HgCl2 treatment, demonstrating that Na was the factor responsible for the increase in mercury-sensitive, aquaporin-mediated water transport. The observed increases in root Ca and K concentrations likely played a role in the transcriptional and (or) posttranslational regulation of aquaporins that enhanced root water transport capacity in Puccinellia nuttalliana. The study demonstrates that Na plays a key role in the aquaporin-mediated root water transport of the halophytic grass Puccinellia nuttalliana, contributing to its salinity tolerance.

Responses of tree growth and biomass production to nutrient addition in a semi-deciduous tropical forest in Africa.

Experimental evidence of nutrient limitations on primary productivity in Afrotropical forests is rare and globally underrepresented yet are crucial for understanding constraints to terrestrial carbon uptake. In an ecosystem-scale nutrient manipulation experiment, we assessed the early responses of tree growth rates among different tree sizes, taxonomic species, and at a community level in a humid tropical forest in Uganda. Following a full factorial design, we established 32 (eight treatments × four replicates) experimental plots of 40 × 40 m each. We added nitrogen (N), phosphorus (P), potassium (K), their combinations (NP, NK, PK, and NPK), and control at the rates of 125 kg N ha-1 year-1 , 50 kg P ha-1 year-1 and 50 kgK ha-1 year-1 , split into four equal applications, and measured stem growth of more than 15,000 trees with diameter at breast height (dbh) ≥1cm. After 2 years, the response of tree stem growth to nutrient additions was dependent on tree sizes, species and leaf habit but not community wide. First, tree stem growth increased under N additions, primarily among medium-sized trees (10-30 cm dbh), and in trees of Lasiodiscus mildbraedii in the second year of the experiment. Second, K limitation was evident in semi-deciduous trees, which increased stem growth by 46% in +K than -K treatments, following a strong, prolonged dry season during the first year of the experiment. This highlights the key role of K in stomatal regulation and maintenance of water balance in trees, particularly under water-stressed conditions. Third, the role of P in promoting tree growth and carbon accumulation rates in this forest on highly weathered soils was rather not pronounced; nonetheless, mortality among saplings (1-5cm dbh) was reduced by 30% in +P than in -P treatments. Although stem growth responses to nutrient interaction effects were positive or negative (likely depending on nutrient combinations and climate variability), our results underscore the fact that, in a highly diverse forest ecosystem, multiple nutrients and not one single nutrient regulate tree growth and aboveground carbon uptake due to varying nutrient requirements and acquisition strategies of different tree sizes, species, and leaf habits.

Habitat aridity as a determinant of the trade-off between water conservation and evaporative heat loss in bats.

The maintenance of water balance in arid environments might represent a formidable challenge for Chiroptera, since they have high surface-to-volume ratios. In deserts, bats conserve water, for example, using daily torpor, but they also might experience episodic heat bouts, when they may need to increase total evaporative water loss (TEWL) to thermoregulate. We hypothesized that in bats, habitat aridity and its variability determine a trade-off between water conservation and thermoregulation via evaporative means. To test this hypothesis, we collated data from the literature of 22 species of bats on TEWL, body temperature and resting metabolic rate, in torpor and euthermy. We also collected data on ambient temperature (Ta) and precipitation of the locations where bats were captured, calculated an aridity index, and built an index of variability of the environment. After correcting for phylogeny, we found that, as aridity and variability of the environment increased, bats had lower values of TEWL, but the rate at which TEWL increases with Ta was higher, supporting our hypothesis. These results suggest that at high Ta there is a trade-off between water conservation and evaporative heat loss in bats. The evolution of physiological mechanisms that allow water conservation and tolerance to conditions of high Ta without access to free water might thus be crucial to explain the distribution of desert bats.

Transcriptome and Metabolome Analyses Reveal Potential Salt Tolerance Mechanisms Contributing to Maintenance of Water Balance by the Halophytic Grass Puccinellia nuttalliana.

Elevated soil salinity exacerbated by human activities and global climate change poses serious threats to plant survival. Although halophytes provide many important clues concerning salt tolerance in plants, some unanswered questions remain to be addressed, including the processes of water and solute transport regulation. We performed high-throughput RNA-sequencing in roots and metabolome characterizations in roots and leaves of Puccinellia nuttalliana halophytic grass subjected to 0 (control) and 150 mM NaCl. In RNAseq, a total of 31 Gb clean bases generated were de novo assembled into 941,894 transcripts. The PIP2;2 and HKT1;5 transcript levels increased in response to the NaCl treatment implying their roles in water and ion homeostasis. Several transcription factors, including WRKY39, DEK3, HY5, and ABF2, were also overexpressed in response to NaCl. The metabolomic analysis revealed that proline and dopamine significantly increased due to the upregulation of the pathway genes under salt stress, likely contributing to salt tolerance mechanisms. Several phosphatidylcholines significantly increased in roots suggesting that the alterations of membrane lipid composition may be an important strategy in P. nuttalliana for maintaining cellular homeostasis and membrane integrity under salt stress. In leaves, the TCA cycle was enriched suggesting enhanced energy metabolism to cope with salt stress. Other features contributing to the ability of P. nuttalliana to survive under high salinity conditions include salt secretion by the salt glands and enhanced cell wall lignification of the root cells. While most of the reported transcriptomic, metabolomics, and structural alterations may have consequences to water balance maintenance by plants under salinity stress, the key processes that need to be further addressed include the role of the changes in the aquaporin gene expression profiles in the earlier reported enhancement of the aquaporin-mediated root water transport.

ВЛИЯНИЕ ШТАММА BACILLUS SUBTILIS НА СОДЕРЖАНИЕ АБСЦИЗОВОЙ КИСЛОТЫ У ДЕФИЦИТНОГО ПО ЭТОМУ ГОРМОНУ МУТАНТА ЯЧМЕНЯ И РАСТЕНИЙ ЕГО РОДИТЕЛЬСКОГО СОРТА

The ability to produce phytohormones and influence their metabolism in plants is an important property of rhizosphere bacteria that determines their plant growth promoting effect. Since abscisic acid (ABA) reduces stomatal conductance and increases the ability of tissues to conduct water, maintenance of water balance in lettuce plants on the background of activation of their growth was associated with the accumulation of ABA under the influence of bacteria. The aim of the study is to test the hypothesis that the growth-stimulating effect of bacteria on plants depends on their ability to synthesize the hormone ABA. The plants were grown on a light platform; seedlings were treated with a bacterial suspension simultaneously with planting. The ABA content, the relative water content, the chlorophyll content, the level of non-photochemical quenching, the leaf area and the weight of the shoots were measured. The level of transcripts of the HvNCED1, HvNCED2, and HvCYP707A1 genes responsible for ABA metabolism in barley was assessed using real-time PCR. Comparison of the ABA-deficient mutant of barley and plants of its wild type revealed the stimulation of the growth of plants of both genotypes upon bacterial treatment. The shoot mass and leaf area of the untreated mutant with bacteria were about 30 % less compared to Steptoe. The stimulating effect of bacteria was manifested in an increase in leaf area by 15 % in Steptoe and by 35 % in Az 34; shoot mass – by 18 % and 41 %, respectively. As a result, the phenotype difference between plants of two genotypes decreased. In the deficient mutant, the ABA level increased under the influence of Bacillus subtilis IB-22 more than twice. It was due to the ability of bacteria to produce ABA and reduce the activity of ABA degradation in barley plants. The results obtained in this study indicate that certain bacterial strains are able to increase the level of ABA in plants, compensating for the genetically determined deficiency of this hormone.

Water relations in cut calla lily flowers maintained under different postharvest solutions

Abstract The use of chemicals in storage solutions has proved beneficial for the postharvest conservation of cut flowers. However, the effect of these solutions on the water relations of some species is still unknown. Therefore, the objective of the present investigation was to evaluate the water relations in calla lily flowers harvested at different stages and maintained under postharvest solutions with different chemicals. The flower stems were harvested in two stages of spathe opening: the early stage (cartridge) and the 1/3 flower opening stage. The flower stems were dipped in solutions with water (control), 100 mg L-1 sodium hypochlorite (NaClO), 100 mg L-1 aluminum sulfate [Al2(SO4)3], 200 mg L-1 8-hydroxyquinoline (8-HQ) and 10 mg L-1 silver nitrate (AgNO3). Over 9 days, the floral stems were kept in a room at 21 ± 2 °C and 75% ± 5% relative humidity and evaluated for changes in the pH of the solution and the water absorption, transpiration and commercial quality of the cut flowers. The addition of conservation substances to the storage solution induced spathe opening at both harvest stages and promoted water absorption by the stems, thus increasing the efficiency of flower hydration. The water balance maintenance was best for stems stored in water and storage solutions with Al2(SO4)3.

Ecophysiological steps of marine adaptation in extant and extinct non-avian tetrapods.

Marine reptiles and mammals are phylogenetically so distant from each other that their marine adaptations are rarely compared directly. We reviewed ecophysiological features in extant non-avian marine tetrapods representing 31 marine colonizations to test whether there is a common pattern across higher taxonomic groups, such as mammals and reptiles. Marine adaptations in tetrapods can be roughly divided into aquatic and haline adaptations, each of which seems to follow a sequence of three steps. In combination, these six categories exhibit five steps of marine adaptation that apply across all clades except snakes: Step M1, incipient use of marine resources; Step M2, direct feeding in the saline sea; Step M3, water balance maintenance without terrestrial fresh water; Step M4, minimized terrestrial travel and loss of terrestrial feeding; and Step M5, loss of terrestrial thermoregulation and fur/plumage. Acquisition of viviparity is not included because there is no known case where viviparity evolved after a tetrapod lineage colonized the sea. A similar sequence is found in snakes but with the haline adaptation step (Step M3) lagging behind aquatic adaptation (haline adaptation is Step S5 in snakes), most likely because their unique method of water balance maintenance requires a supply of fresh water. The same constraint may limit the maximum body size of fully marine snakes. Steps M4 and M5 in all taxa except snakes are associated with skeletal adaptations that are mechanistically linked to relevant ecophysiological features, allowing assessment of marine adaptation steps in some fossil marine tetrapods. We identified four fossil clades containing members that reached Step M5 outside of stem whales, pinnipeds, sea cows and sea turtles, namely Eosauropterygia, Ichthyosauromorpha, Mosasauroidea, and Thalattosuchia, while five other clades reached Step M4: Saurosphargidae, Placodontia, Dinocephalosaurus, Desmostylia, and Odontochelys. Clades reaching Steps M4 and M5, both extant and extinct, appear to have higher species diversity than those only reaching Steps M1 to M3, while the total number of clades is higher for the earlier steps. This suggests that marine colonizers only diversified greatly after they minimized their use of terrestrial resources, with many lineages not reaching these advanced steps. Historical patterns suggest that a clade does not advance to Steps M4 and M5 unless these steps are reached early in the evolution of the clade. Intermediate forms before a clade reached Steps M4 and M5 tend to become extinct without leaving extant descendants or fossil evidence. This makes it difficult to reconstruct the evolutionary history of marine adaptation in many clades. Clades that reached Steps M4 and M5 tend to last longer than other marine tetrapod clades, sometimes for more than 100 million years.

Polyamine homeostasis modulates plasma membrane- and tonoplast-associated aquaporin expression in etiolated salt-stressed sunflower (Helianthus annuus L.) seedlings.

Salt stress adversely affects plants by causing osmotic and ionic imbalance. Cellular osmotic adjustment occurs by modulation of water fluxes. Polyamines (PAs) are often advocated to be involved in osmoregulation during stressful conditions, and thus, they serve as potential "osmolytes." Aquaporins (AQPs), the water-transporting channels, are expected to play crucial roles in osmoregulation. Present investigations on etiolated sunflower seedlings demonstrate a possible correlation between PA homeostasis and maintenance of water balance, as a function of modulation of the abundance of two major AQP subfamilies: PIP2 (plasma membrane intrinsic protein 2) and TIP1 (tonoplast intrinsic protein 1). Salt stress (120 mM NaCl) restricts growth of sunflower seedlings and induces reduction in relative water content (RWC). This accompanies enhanced abundance of PIP2s and TIP1s in seedling roots and that of TIP1s in cotyledons, as revealed by Western blot analysis of AQP isoforms and also their imaging by confocal laser scanning microscopy (CLSM). Raising seedlings in the presence of 500 μM of DFMA (DL-α-difluoromethylarginine) or DFMO (DL-α-difluoromethylornithine), which are potent inhibitors of PA biosynthesis enzymes (arginine decarboxylase (ADC) and ornithine decarboxylase (ODC), respectively), significantly promotes root extension, irrespective of NaCl stress, and results in further lowering of salt-induced reduction in RWC in roots and cotyledons. This correlates with enhanced accumulation of both PIP2s and TIP1s in seedling roots, but not in cotyledons. Present work, therefore, implicates PA homeostasis in the maintenance of water status of sunflower seedlings, possibly via regulation of abundance and distribution of AQP isoforms associated with the plasma membrane and tonoplast.

АHТРОПОГЕННАЯ ТРАНСФОРМАЦИЯ ГОРНО-ЛЕСНЫХ ПОЧВ В СЕВЕРО-ВОСТОЧНОЙ ЧАСТИ МАЛОГО КАВКАЗА (НА ПРИМЕРЕ БАССЕЙНА р. БАБАДЖАН)

Our planet needs the rational use of forest resources and forest soils in order to combat erosion and preserve the biosenosis. Soils provide the basis for the growth of trees and woodlands, and are an essential component of forests and forest ecosystems, as they are involved in the regulation of such important processes as the absorption of nutrients, their decomposition and maintenance of water balance. By reducing the risk of soil erosion and the threat of landslides and avalanches, the sustainable use of forest resources greatly contributes to the functioning of the systems responsible for maintaining the planet’s clean water supply, as well as a balanced water cycle. In the soil environment, trees develop root systems and in turn, forest trees and vegetation in general are an important factor in protecting the soil cover. The authors have examined the natural and anthropogenic degradation of brown mountain-forest soils under a beech forest, brown mountain-forest soils under hornbeam and oak forests in the north-eastern part of the Lesser Caucasus in the Babadjan river basin. The erosional relief of the studied region is represented by highly dissected low mountains, middle mountains and mountain basins, which are rather densely indented by mountain rivers. In conditions of such a relief, soils are well developed in dry low mountains and in the humid part of the middle mountains. To clarify the effect of soil properties on the growth and development of tree species in forest communities of the study area, soil sections were laid. The influence at altitudes of 950-1800 m above sea level, the slope of the relief, the exposure of slopes, the composition of the forest cover, the lithological composition of the parent rocks, the physic-chemical composition of the soil and other factors on the intensity of the degradation process in different ecosystems have been studied

Phenotypic plasticity but no adaptive divergence in cuticular hydrocarbons and desiccation resistance among translocated populations of dung beetles

Translocated populations must adapt to their new environment to survive. A key aspect of survival for insects is the maintenance of water balance. It is thought that insects can adapt to dry environments by adjusting their cuticular hydrocarbon (CHC) profile to reduce water loss, though there is limited empirical support for this, and studies generally focus on other roles of CHCs, such as chemical communication. We tested for phenotypic adaptation in introduced populations of the Mediterranean dung beetle Onthophagus taurus, which have become established along a climatic gradient from dry northern to wet southern locations in southwestern Australia. We compared CHC profiles and desiccation resistance between northern and southern populations of the species. To quantify desiccation resistance, we measured both the rate of weight loss and time until death in beetles incubated at 35 °C. We tested for associations between these measures of desiccation resistance and CHC profiles, which were obtained through gas chromatography mass spectrometry. The abundance of CHCs was positively associated with desiccation resistance, and individuals that underwent the desiccation treatment produced a greater quantity of several CHC compounds indicating their ability to plastically adjust their CHC profile in response to desiccation stress. However, northern populations did not produce more CHCs than southern populations, and southern populations were better able to tolerate desiccation. Our results suggest that CHCs are an important component of desiccation resistance in O. taurus. However, the lack of evidence for local adaptation to the drier northern climate suggests there may be constraints to increasing desiccation resistance, and demonstrates the importance of considering local environmental conditions before translocating populations to new locations.

Proper Sizing of Infiltration Trenches Using Closed-Form Analytical Equations

Infiltration trenches in urban areas are mainly used for the purposes of water balance maintenance and water quality improvement. To ensure that a high enough fraction of runoff from a contributing catchment is infiltrated, trenches are usually sized to provide enough storage capacity so that runoff from a design storm of certain depth can be temporarily stored and infiltrated. Since it is difficult to quantify the actual long-term average runoff reduction ratio provided by individual trenches, their exact long-term average performances are often unknown. In this study, the closed-form analytical equations derived and verified previously for the estimation of the long-term average trench performance are applied in the practical design analysis of infiltration trenches following the detailed design guidelines of Atlanta, Georgia and New Durham, New Hampshire, U.S.. The results demonstrate that the conventional design storm-based design procedure cannot always ensure uniform trench performances because of different site soil and infiltration conditions. Use of the analytical equations (also known as the analytical stormwater models) can facilitate more accurate and consistent design of infiltration trenches because the effects of soil type, trench footprint dimensions, drain time and infiltration conditions on trench performance are all taken into consideration. The analytical equations are recommended as a convenient tool for the proper sizing of infiltration trenches so that a uniform long-term average performance can be achieved for all individual cases.

Characterization of Na+ exclusion mechanism in rice under saline-alkaline stress conditions

This study was designed to elucidate the physiological responses of two rice genotypes to different pH levels under high saline stress. A salt-tolerant cultivar, FL478, and a salt-sensitive cultivar, IR29, were exposed to saline-alkaline solutions supplemented with 50 mM Na at pH 9 (severe), pH 8 (moderate), and pH 7 (mild) for three weeks. The results indicated that FL478 is relatively saline-alkaline tolerant compared to IR29, and this was evident from its higher dry mass production, lower Na+ concentration in the leaf blades, and maintenance of water balance under both mild and moderate saline-alkaline stress conditions. In both cultivars, Na+ concentrations in the leaf blades were considerably higher at pH 8 than at pH 7, indicating that high alkaline stress promoted Na+ accumulation under highly saline conditions. FL478 plants had lower Na+/K+ ratios in leaf blades and leaf sheaths than IR29 plants under saline-alkaline stress at both pH 7 and pH 8. To understand the mechanisms behind the difference in saline-alkaline tolerance between the two rice genotypes, transcript levels of the genes encoding Na+ transport proteins were analyzed. In response to mild and moderate saline-alkaline stress conditions, salt-tolerant FL478 had highly induced expression of the OsHKT1;5 gene in the roots, corresponding to lower Na+ accumulation in the leaf blades. Induction of high expression of the OsSOS1 gene in the roots of FL478 implied that Na may be effectively exported from cytosols to apoplasts in the roots resulting in sequestration of Na+ to outside of the roots and loading Na+ in xylem transpiration stream. On the other hand, the salt-sensitive IR29 had lower expression of the genes related to Na+ transporters, such as the OsHKT1;5 gene and the OsSOS1 gene, in the roots, leading to higher Na+ accumulation in the shoots. Expression of the determinant genes for alkaline tolerance, such as K+ and Fe acquisition and acidification of the rhizosphere was highly induced in FL478, but not in IR29. Thus, molecular analysis suggested that genes encoding Na+ transport proteins are involved in regulating Na+ transport under saline-alkaline stress in both salt-tolerant and salt-sensitive rice cultivars, and this is useful information for improving saline-alkaline tolerance traits of rice in the future.

Identification of candidate genes related to salt tolerance of the secretohalophyte Atriplex canescens by transcriptomic analysis

BackgroundAtriplex canescens is a typical C4 secretohalophyte with salt bladders on the leaves. Accumulating excessive Na+ in tissues and salt bladders, maintaining intracellular K+ homeostasis and increasing leaf organic solutes are crucial for A. canescens survival in harsh saline environments, and enhanced photosynthetic activity and water balance promote its adaptation to salt. However, the molecular basis for these physiological mechanisms is poorly understood. Four-week-old A. canescens seedlings were treated with 100 mM NaCl for 6 and 24 h, and differentially expressed genes in leaves and roots were identified, respectively, with Illumina sequencing.ResultsIn A. canescens treated with 100 mM NaCl, the transcripts of genes encoding transporters/channels for important nutrient elements, which affect growth under salinity, significantly increased, and genes involved in exclusion, uptake and vacuolar compartmentalization of Na+ in leaves might play vital roles in Na+ accumulation in salt bladders. Moreover, NaCl treatment upregulated the transcripts of key genes related to leaf organic osmolytes synthesis, which are conducive to osmotic adjustment. Correspondingly, aquaporin-encoding genes in leaves showed increased transcripts under NaCl treatment, which might facilitate water balance maintenance of A. canescens seedlings in a low water potential condition. Additionally, the transcripts of many genes involved in photosynthetic electron transport and the C4 pathway was rapidly induced, while other genes related to chlorophyll biosynthesis, electron transport and C3 carbon fixation were later upregulated by 100 mM NaCl.ConclusionsWe identified many important candidate genes involved in the primary physiological mechanisms of A. canescens salt tolerance. This study provides excellent gene resources for genetic improvement of salt tolerance of important crops and forages.

Comparative analysis of abscisic acid levels and expression of abscisic acid-related genes in Scots pine and Norway spruce seedlings under water deficit

Abscisic acid (ABA) is one of the main participants in the regulation of plant responses to water deficiency. Knowledge of the ABA signal transduction pathways in gymnosperms is rather limited, especially in comparison with those in angiosperms. Seedlings of Scots pine and Norway spruce are known for their contrasting behaviour strategies under water deficit. To characterize the possible role of ABA in these differences, ABA dynamics were investigated under conditions of water deficit in seedlings of these two species. The content of ABA and its catabolites was followed in the roots and needles of seedlings of Pinus sylvestris and Picea abies under conditions of polyethylene glycol (PEG)-induced water deficiency (−0.15 and −0.5 MPa) for 10 days. The expression of the main genes for ABA-biosynthetic enzymes was also analysed. ABA showed more pronounced stress-dependent dynamics in pine roots than in spruce roots, whereas in needles, the response was greater for spruce than pine. The ABA increase during drought was mainly due to de novo synthesis and the shift in the balance between ABA synthesis and catabolism towards synthesis. The ABA-glucosyl ester did not serve as a reserve for the release of free ABA under water deficiency. The expression levels of the main ABA biosynthetic genes showed a weak or no correlation with changes in ABA content under water stress, i.e., the ABA content in the seedlings of both species was not directly linked to the transcript levels of the main ABA biosynthetic genes. Less-pronounced stress-induced changes in ABA in pine needles than in spruce needles may be related to pine seedlings having a less conservative strategy of growth and maintenance of water balance under water deficit.

Transcriptome analysis reveals dynamic changes in the salt stress response in Salix

Soil salinization is a serious ecological problem worldwide and information regarding the salt tolerance mechanisms of Salix is scarce. To elucidate the dynamic changes in the molecular mechanisms of Salix under salt stress, we generated gene expression profiles and examined changes in the expression of those genes. RNA-Seq was used to produce six cDNA libraries constructed from the leaves of Salix × jiangsuensis CL ‘J2345’ treated with NaCl for 0, 2, 6, 12, 24 and 48 h. In total, 249 million clean reads were assembled into 12,739 unigenes, all of which were clustered into 10 profiles based on their temporal expression patterns. KEGG analysis revealed that as an early defense response, the biosynthesis pathways of cutin, suberin and wax, which are involved in cell wall structure, were activated beginning at 2 h. The expression of secondary metabolism genes, including those involved in the phenylpropanoid, flavonoid, stilbenoid, diarylheptanoid and gingerol pathways, peaked at 6 h and 24 h; the upregulated genes were mainly involved in plant hormone pathways and beta-alanine, galactose and betalain metabolism. We identified roles of key phytohormones and found ETH to be the major signaling molecule activating TFs at 12 h; ETH, ABA, IAA and SA were the key molecules at 24 h. Moreover, we found that the upregulated genes were associated with elevated levels of amino acids, sucrose, inositol, stress proteins and ROS-scavenging enzymes, contributing to the maintenance of water balance. This research constitutes the first detailed analysis of salt stress-related mechanisms in Salix and identifies potential targets for genetic manipulation to improve yields.