mM Concentrations Of NaCl Research Articles

COMPARATIVE ANALYSIS OF EXPRESSION PROFILES OF ANTIPORTER ENCODING GENE (GhNHX1) UNDER DIFFERENT CONCENTRATIONS OF NaCl IN COTTON (Gossypium hirsutum L.)

Salt stress supresses the productivity of plants. One important way to mediate the harmful effects of Na+ in plants is the compartmentation of Na+ into vacuoles, which is mediated by NHX-like Na+/H+ antiporters. In this study, the expression level of GhNHX1 gene encoding antiporter was evaluated under 100 mM and 200 mM concentration of NaCl in 31 cotton genotypes. As a result of the ANOVA analysis, a significant differences was recorded in the expression level of the gene under 0 mM and 200 mM stress conditions. A decrease in the expression level of this gene was observed in highly sensitive varieties (Ganja-182 and Carisma) and both an increase and a decrease in tolerant varieties. Such diversity in tolerant varieties shows that the resistance of samples is controlled by separate dominant genes.

Physiological and Biochemical Characteristics and Response Patterns of Salinity Stress Responsive Genes (SSRGs) in Wild Quinoa (Chenopodium quinoa L.)

Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils. Quinoa, a protein-comprehensive cereal in the plant kingdom, is an exceptional crop in terms of salt stress tolerance level. It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms. In this study, the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution. The physiological, biochemical characteristics and agronomic traits were investigated, and the response patterns of three salt stress-responsive genes (SSRGs) in quinoa were determined by real-time PCR. The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl. Salt stress significantly induced expression of superoxide dismutase (SOD), peroxidase (POD), and particularly betaine aldehyde dehydrogenase (BADH). BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings, particularly at high NaCl concentrations, as it displayed upregulation until 24 h under 100 mM salt treatment. Moreover, it showed upregulation until 12 h under 250 mM salt stress. Taken together, these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa. Based on the expression level and prompt response induced by NaCl, we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development. Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth. Therefore, an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm, which is useful to the utilization of saline soils. Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.

Mineral nutrient composition in leaf and root tissues of fifteen polyembryonic mango genotypes, grown under varying levels of salinity

Mango (Mangifera indica L.) is a salt sensitive crop and its cultivation in salt affected area is declining day by day. There is a need to find out the rootstocks to sustain under saline conditions which can be used for commercial cultivation of superior cultivars through grafting. To achieve this, the present study was carried out to understand the salt tolerance and sensitive nature of fifteen polyembryonic mango rootstock seedlings (EC-95862, Bappakkai, Vellaikolamban, Nekkare, Turpentine, Muvandan, Kurukkan, Kensington, Olour, Manipur, Deorakhio, Vattam, Mylepelian, Sabre and Kitchener) which were exposed to 0 mM, 25 mM, 50 mM and 100 mM concentration of NaCl+CaCl2 (1:1) salt. The outcome of this study revealed that there was reduction in K+, Ca++, Mg++, Fe++ and Zn++ while the content of Cu++ and Mn++ in both leaf and root tissues were found to increase with gradual increase in salt concentration from 0 to 100 mM. The overall results of this study revealed that the salinity stress caused the alterations in mineral nutrient composition of polyembryonic mango genotypes. Among the fifteen genotypes the seedlings of Turpentine, Deorakhio, Olour and Bappakkai respond better in maintaining the mineral nutrient status in leaf and root tissues under higher level of salinity.

Effects of Salinity Stress on the Growth, Physiology, and Yield of Soybean (Glycine max (L.) Merrill)

This study was conducted to evaluate the salt tolerance ability of two soybean cultivars under salinity conditions using a selection of growth and physiological parameters. Three weeks after germination, plants began being treated with either a 100 mM concentration of NaCl in Hoagland solution or a non-salinity (0 mM NaCl) solution. The results showed that the plant height, number of leaves, leaf area index, and shoot and root biomasses were significantly reduced under salt conditions. A similar tendency was observed in several physiological parameters (SPAD, Fv/Fm). Since all the salt-treated plants of the D8 cultivar were dead after 40 days under the 100 mM NaCl treatment, the yield of D8 could not be obtained, while the treated plants of the D140 cultivar experienced a marked decrease in yield compared to the control plants. In this study, we identified that the D140 soybean cultivar had a better salt tolerance than the D8 soybean cultivar at a 100 mM NaCl concentration.

Chickpea response to saline water: Concurrence of ion homeostasis sustainment and antioxidative defense measures

Chickpea is a salt-sensitive staple crop that is widely produced in the arid and semi-arid regions, where water limitation is often coupled to high salt concentration of soil and irrigation water. In order to better understand comparative physiological, growth, and yresponses of three chickpea genotypes (namely Greet, Jam, and ILC-482), they were assessed under four NaCl concentrations of irrigation water (0, 25, 50, and 75 mM). The examined genotypes shared a same trend of dose-dependent increases in Na+, total soluble carbohydrates, proline, malondialdehyde, and H2O2 concentrations, Na+/K+, and increases in the activity of catalase and peroxidase enzymes. Though, chlorophyll and carotenoids concentrations, days to flowering, and root and shoot K+ concentration, shoot and root dry mass, seeds/plant, 100-seeds weight, and seed weight/plant were decreased with aggravation of salinity. Genotype ILC-482 tended to withstand the 50 and 75 mM concentrations of NaCl more notably, as evidenced by a greater catalase, ascorbate peroxidase, and peroxidase enzymes activities, tissue K+ concentration and seeds/plant, concomitant to smaller shoot Na+ concentration and Na+/K+, compared to the other chickpea genotypes. The greater level of salt tolerance in genotype ILC-482 was ascribed to the greater activities of the antioxidative enzymes and ability to maintain ion homeostasis, reflected in its smaller Na+/K+.

Arbuscular mycorrhizal fungus inocula from coastal sand dunes arrest olive cutting growth under salinity stress.

Cultivation of olive trees covers large coastal areas of land in Mediterranean regions, many of them characterized by low soil fertility and exposed to salinity and seasonal drought. In this frame, we developed mixed community inocula of arbuscular mycorrhizal fungi (AMF) derived from the extreme, seasonally arid environments of six Mediterranean sand dunes and evaluated their effects, in the form of community inocula, on rooted semi-woody olive tree cuttings (Olea europaea cv. Koroneiki). The plantlets were grown in the greenhouse for 10 months under 50 mM and 100 mM concentrations of NaCl, successively applied to induce osmotic stress. Inoculation had a positive effect on plant growth and nutrient uptake. However, the three best-performing inocula in early colonization and in plant growth enhancement also resulted in high plant sensitivity to high salinity, which was not observed for the other three inocula. This was expressed by decreased nutrient uptake and drastically lower plant growth, plant photosynthesis, and stomatal conductance (generally an over 50% reduction compared to no salinity application). Amplicon sequencing analysis of the olive plants under salinity stress showed that the AMF communities in the roots were clearly differentiated by inoculation treatment. We could not, however, consistently associate the plant responses observed under high salinity with specific shared AMF community membership or assembly attributes. The observed physiological overreaction to osmotic stress may be an adaptation trait, potentially brought about by host selection coupled to abiotic environmental filtering, in the harsh conditions from which the AMF inocula were derived. The overreaction may, however, be undesirable if conveyed to allochthonous plants at an agronomic level.

Effect salinity on germination percentage (%) and seed vigour index of rice (Oryza sativa L.)

Present investigation was conducted during Kharif 2017-18 in laboratory, at experimental study Department of Crop Physiology, Narendra Deva University of Agriculture and technology, Kumarganj Faizabad (U.P.). Soil salinity has become a severe threat to ensure food security, salinity-imposed limitations on plant growth. At the present, salinity level stimulates many of the metabolic processes involved in phases (2nd, 4th, 6th, 8th and 10th day) of germination, resulting in an improved performance of germination and higher. Experiment was laid out in complete randomized design (CRD) with three replication on six genotypes of rice crop i.e. tolerant- CSR-36, CSR-43, Usar Dhan-3 and Susceptible- Swarna Sub-1, IR-28, Pusa-44. Present investigation was carried to study the effect of salinity with 0, 50 and 100 mM concentration of NaCl on germination. The exposure of rice varieties to increasing concentration of NaCl had significantly increased germination (%), seed vigour index. It is evident from the result that concentration with NaCl significantly improved the germination and enzymatic activities of rice genotypes. The concentration are effective in increasing the germination percent, Seed vigour index, radicle length, plumule length, and enzymatic activities like α- amylase, catalase and carbohydrates biochemical parameters like proline accumulation, in all varieties under normal as well as under laboratory condition. The concentration with NaCl 0, 50 and 100 mM influences the germination and biochemical changes under normal as well as under anaerobic condition and might be useful in mitigating the adverse effect of laboratory condition or helpful in increasing the yield and yield attributes in all the varieties. Thus, it may be recommended that salinity level with concentration (0, 50 and 100 mM) of NaCl is the most desirable for mitigating the adverse effect of salinity.

Self-Sustainable, self-healable, Load Bearable and Moldable stimuli responsive ionogel for the Selective Removal of Anionic Dyes from aqueous medium

Among the tested strategies to remove the toxic dyes from the aquatic environment, absorption is widely preferred owing to its ease of formation, lower cost and modulating ability of the absorbents used. Designing advance absorbents that offer higher absorptivity, selectivity, reusability, moldability and high pre-concentration factor for the analyst is a challenging task yet to be achieved. Herein, we had designed new age low molecular weight gelator from prototypical molecular gelators, an ionic liquid based gelator; 1-n-hexadecyloxy-carbonylmethylpyridinium bromide (C16EPyrBr) that exhibited unusual, unprecedented stimuli responsive reversible transition from opaque to transparent ionogel due to the change in the gel microstructure from lamellar for the opaque ionogel to cylindrical for the transparent ionogel. Small angle neutron scattering and scanning and scanning electron microscopy measurements characterized the microstructure and morphology of the ionogel respectively. Although having lower molecular weight based, the ionogel show excellent tolerance against the salinity (1500 mM concentration of NaCl), offer good mechanical strength and have self-healing, self-sustaining, and load bearing characteristics. The ionogel could be loaded in apparatus like dialysis membrane and syringe with 99% removal efficiency and can selectively remove the anionic dye, methyl orange from the aqueous medium even after 20 cycles. As a final thought, the low molecular weight ionic liquid based gelator could be a promising alternative to the traditional anionic dye absorbents.

The effect of NaCl on some physiological and biochemical parameters in Triticum aestivum L. genotypes

Effects of salinity caused by different concentrations of NaCl (100 and 200 mM) have been studied in two genotypes of Triticum aestivum L. (salt tolerant Saratovskaya-29 and salt sensitive Gyrmyzygul-1) with contrasting salt tolerance. Stress caused by salinity influenced differently on the content of photosynthetic pigments (chlorophyll a, b and carotenoids) in 14 to 16-day-old seedlings. In plants exposed to 100 mM NaCl an increase in quantity of photosynthetic pigments was observed in leaves, while 200 mM concentration of NaCl caused a reduction of the pigment content in leaves. A slightly higher amount of photosynthetic pigments were observed in the salt tolerant genotype Saratovskaya-29 at 200 mM NaCl. Lipid peroxidation level was higher in the sensitive Gyrmyzygul-1 genotype compared with tolerant Saratovskaya-29. It was found that, salinity stress caused an accumulation of soluble sugars and secondary metabolites—phenolic compounds. The amounts of soluble sugars and phenolic compounds were high in the salt sensitive genotype exposed to salt stress.

Sodium-chloride-induced effects on the expression profile of human periodontal ligament fibroblasts with focus on simulated orthodontic tooth movement.

Increased salt (NaCl) consumption triggers chronic diseases such as hypertension or osteopenia. Its impact on orthodontic tooth movement and periodontitis, however, has not been investigated, although both processes are related to the immune system, with periodontal ligament fibroblasts (PDLFs) playing a key mediating role. Here, we investigated the impact of NaCl on the expression pattern of PDLFs in a model of simulated compressive orthodontic strain. Periodontal ligament fibroblasts were preincubated for 24h with additional 0 or 40mM NaCl and concurrently treated for another 48h with or without compressive strain of 2gcm-2 . We analyzed the expression of genes and proteins involved in orthodontic tooth movement by reverse transcriptionquantitative polymerase chain reaction (RT-qPCR), ELISA, and immunoblot. Co-culture experiments were performed to observe PDLF-mediated osteoclastogenesis. A higher (40mM) concentration of NaCl in the culture medium resulted in increased secretion of prostaglandin, expression of alkaline phosphatase, and expression of genes involved in extracellular matrix remodeling, but decreased compression-induced expression of the interleukin-6 (IL6) gene. The 40mM concentration of NaCl also enhanced receptor activator of nuclear factor kappa-B ligand (RANKL) but reduced that of osteoprotegerin (OPG), resulting in upregulated PDLF-mediated osteoclastogenesis. A high NaCl concentration in the periodontal ligament, corresponding to a high-salt diet in vivo, may influence orthodontic tooth movement and periodontitis through increased secretion of prostaglandins by PDLFs and upregulated PDLF-mediated osteoclastogenesis, possibly accelerating orthodontic tooth movement and propagating periodontitis and periodontal bone loss.

The effect of various NaCl concentrations on morphophysiological properties of bread wheat sprouts (Triticum aestivum L.)

Aim. The effects of various NaCl concentrations on germination energy, germination percentage of seeds and morpho-physiological indices of seedlings have been determined in bread wheat (Triticum aestivum L.) varieties. Methods. Wheat seeds were germinated at 0, 100, 150, 200 mM concentrations of NaCl using the roll method. Rezults. The delay of the growth of seedlings and root system was observed with increasing salt concentrations in all samples. The effect of various salt concentrations on separate varieties was diifferent. Conclusions. The highest indices of the development of coleoptiles and root system and the highest amount of chlorophyll were detected at 150 and 200 mM concentrations of NaCl in the Mirbashir-128 variety. The Bezostaya and Nurlu-99 varieties manifested medium tolerance, while the Sheki-1 variety was relatively less tolerant.
 Keywords: NaCl, wheat varieties, germination energy, germination percentage, chlorophyll.

Salicylic Acid (SA) Induced Alterations in Growth, Biochemical Attributes and Antioxidant Enzyme Activity in Faba Bean (Vicia faba L.) Seedlings under NaCl Toxicity

In the present study we tried to evaluate the effect of salicylic acid (SA) in alleviating the negative effects of salinity stress. NaCl stress (50 and 100 mM) declines the shoot and root length and maximum decrease was observed at 100 mM concentration of NaCl. Similarly shoot dry weight decreased by 57.14% and root dry weight by 67.24% with 100 mM NaCl stress. The pigments and leaf relative water content (LRWC) were also observed to decline with increase in NaCl concentration. However, supplementation of SA to NaCl stressed seedlings showed enhanced length and dry weight of shoot and root. The pigment and LRWC also increased by the application of SA in the present study. NaCl stress also enhanced proline and glycine betaine (GB) by 3.01 and 2.04 folds, respectively; further enhancement was recorded by the application of SA. Hydrogen peroxide (H2O2) and malondialdehyde (MDA) content also showed rise in accumulation, however, seedlings treated with SA and NaCl (100 mM + SA) declines the H2O2 accumulation to 1.90 from 2.45 folds and MDA to 1.69 from 2.34 folds over the control. Antioxidants were observed to increase with NaCl concentration and further increase was recorded by the application of SA. Indoleacetic acid (IAA) and indole butyric acid (IBA) decreased by 36.60 and 44.16%, respectively, and ABA increased by 750% with 100 mM NaCl. Addition of SA to NaCl stressed seedlings enhanced the IAA and IBA and decreased the ABA concentration to appreciable level. NaCl is also responsible for the higher accumulation of Na+ and Na+/K+ ratio and decreased uptake of Ca2+ and K+. Supplementation of SA decreased the Na+ accumulation and enhanced the uptake of Ca2+ and K+ in NaCl stressed seedlings. In conclusion, SA supplementation mitigates the negative effects of NaCl toxicity in faba bean seedlings through the modulation of different osmoprotectants, antioxidants and nutrients uptake.

De Novo Transcriptome Characterization, Gene Expression Profiling and Ionic Responses of Nitraria sibirica Pall. under Salt Stress

Nitraria sibirica Pall., a typical halophyte of great ecological value, is widely distributed in desert, saline, and coastal saline-alkali environments. Consequently, researching the salt tolerance mechanism of N. sibirica Pall. has great significance to the cultivation and utilization of salt-tolerant plants. In this research, RNA-seq, digital gene expression (DGE), and high flux element analysis technologies were used to investigate the molecular and physiological mechanisms related to salt tolerance of N. sibirica Pall. Integrative analysis and de novo transcriptome assembly generated 137,421 unigenes. In total, 58,340 and 34,033 unigenes were annotated with gene ontology (GO) terms and mapped in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. Three differentially expressed genes (DEGs) libraries were subsequently constructed from the leaves of N. sibirica Pall. seedlings under different treatments: control (CK), light short-term salt stress (CL2), and heavy long-term salt stress (CL6). Eight hundred and twenty-six, and 224 differentially expressed genes were identified in CL2 and CL6 compared to CK, respectively. Finally, ionomic analysis of N. sibirica Pall. seedlings treated with 0, 100, 200 or 300 mM concentrations of NaCl for one day showed that the uptake and distribution of Ca, Cu, Fe, Mg and K in different organs of N. sibirica Pall. were significantly affected by salt stress. Our findings have identified potential genes involved in salt tolerance and in the reference transcriptome and have revealed the salt tolerance mechanism in N. sibirica Pall. These findings will provide further insight into the molecular and physiological mechanisms related to salt stress in N. sibirica Pall. and in other halophytes.

Effects of iron nanoparticles on Mentha piperita L. under salinity stress

The progress of nanotechnology presents many nanoparticles that are important in medicine, agriculture and industry. Quickly and entirely absorbed by plants, nano-compounds and remedy their nutrient deficiency and satisfy this need. Iron oxide nanoparticles with suitable surface chemistry can be used as a rich source of iron for plants due to its gradual release of Fe in a wide pH range (pH 3 to 11). The present study investigated the impact of iron oxide nanoparticles (Fe2O3NPs in 0, 10, 20 and 30 µM concentrations) on physiological parameters of peppermint (Mentha piperita) under salt stress (0, 50, 100 and 150 mM concentrations of NaCl). Fe2O3NPs caused increases in leaf fresh weight and dry weight, phosphorus, potassium, iron, zinc, and calcium contents of the peppermint under salinity stress but did not have an effect on the sodium element. 30 µM concentration of Fe2O3NP was more impressive. Lipid peroxidation and proline contents of the peppermint under salinity decreased significantly by applying Fe2O3NPs. The maximum activities of total antioxidant enzymes (I %), catalase, superoxide dismutase, and guailcol peroxidase were observed in plants treated with 150 mM of NaCl, but application of Fe2O3NPs declined these antioxidant activities. The results suggest that the appropriate concentration of iron nanoparticles could be used for stress resistance of the peppermint.

English

In Tunisia, more particularly in semiarid and arid areas, the drought accentuated by the surface evaporation of water lead to gradual increase in salinity of the soil which a major hurdal in development of vegetation. In these highly salted ecosystems, some plants are growing naturally; however, various species show different tolerance levels to salinity during their development. Seed germination is the stage which is most susceptible to this abiotic constraint. The aim of this study is to investigate the influence of increasing NaCl concentrations from 0 to 200 mM on the germination behavior of some halophytic plants species (Acacia cyanophylla, Acacia ampliceps, Medicago arborea, Hedysarum carnosum, Casuarina glauca and Ceratonia siliqua) whose seeds, were collected from Tunisian stands. The germination is evaluated through the daily and the cumulated rates of germination, the corrected seed germination rate and the recovery rate. The effect of salt stress revealed that the elevation of NaCl concentration induces a reduction of germination capacity as good as germination speed. In this setting, 200 mM concentrations of NaCl constitute a physiological limit of germination for all studied species. However, the interspecific variability is relatively important. According to the principal component analysis (PCA), seeds of C. glauca were the most salt tolerant, followed by M. arborea. Seeds of A. ampliceps were the least salt tolerant. The increase of the recovery rate with high salinity supposed that the latter has an osmotic reversible effect and not a toxic irreversible one on the studied species seeds.   Key words: Halophytes, salt stress, germination, Tunisia.

Elicitation Based Enhancement of Secondary Metabolites in Rauwolfia serpentina and Solanum khasianum Hairy Root Cultures.

Background:Rauwolfia serpentina and Solanum khasianum are well-known medicinally important plants contained important alkaloids in their different parts. Elicitation of these alkaloids is important because of associated pharmaceutical properties. Targeted metabolites were ajmaline and ajmalicine in R. serpentina; solasodine and α-solanine in S. khasianum.Objective:Enhancement of secondary metabolites through biotic and abiotic elicitors in hairy root cultures of R. serpentina and S. khasianum.Materials and Methods:In this report, hairy root cultures of these two plants were established through Agrobacterium rhizogenes mediated transformation by optimizing various parameters as age of explants, duration of preculture, and co-cultivation period. NaCl was used as abiotic elicitors in these two plants. Cellulase from Aspergillus niger was used as biotic elicitor in S. khasianum and mannan from Saccharomyces cerevisiae was used in R. serpentina.Results:First time we have reported the effect of biotic and abiotic elicitors on the production of important metabolites in hairy root cultures of these two plants. Ajmalicine production was stimulated up to 14.8-fold at 100 mM concentration of NaCl after 1 week of treatment. Ajmaline concentration was also increased 2.9-fold at 100 mg/l dose of mannan after 1 week. Solasodine content was enhanced up to 4.0-fold and 3.6-fold at 100 mM and 200 mM NaCl, respectively, after 6 days of treatments.Conclusion:This study explored the potential of the elicitation strategy in A. rhizogenes transformed cell cultures and this potential further used for commercial production of these pharmaceutically important secondary metabolites.SUMMARY Hairy roots of Rauwolfia serpentina were subjected to salt (abiotic stress) and mannan (biotic stress) treatment for 1 week. Ajmaline and ajmalicine secondary metabolites were quantified before and after stress treatmentAjmalicine yield was enhanced up to 14.8-fold at 100 mM concentration of NaCl. Ajmaline content was also stimulated 2.9-fold at 100 mg/l dose of mannan after 1 weekHairy roots of Solanum khasianum were treated with cellulase (biotic elicitor) and salt (abiotic stress)Solasodine content was improved up to 4.0-fold and 3.6-fold at 100 mM and 200 mM NaCl, respectively, after 6.days of treatmentsThe α-solanine content increased to 1.6-fold after 24 h of treatment at 100 μg/mL cellulase concentration. Abbreviations used: MS medium: Murashige and Skoog medium, B5 medium: Gamborg B5 medium, OD: Optical Density, NaCl: Sodium Chloride.

Ultrastructural changes in potato ( Solanum tuberosum ) under NaCl mediated salinity stress in vitro

Histological analysis was employed to investigate the way potato plants (Solanum tuberosum cv. Draga and Spunta) face salinity stress. Different concentrations of NaCl (50, 100, 150, 200 and 250 mM) were used on potato plantlets growing in vitro to simulate salinity stress condition. Potato plants treated with 50 and 100 mM concentrations of NaCl went into the osmotic stage, and responded with changes: the flavone naringin was created and accumulated in the cells of the aerial parts, and a different of trichome was observed, in addition to the original types, in potato plants treated with concentration 100 mM. This new of trichome appeared similar to B trichomes therefore they were called type B-like trichomes. While no substance was exudated from these trichomes in cv. Draga, the trichomes, in cv. Spunta, green droplets were noted on the glandular vesicle. Furthermore, the non glandular trichomes had some swollen stem cells, and branched ones were also observed. Thanks to these new trichomes, the plants had increased leaf pubescence.

Germination and Seedling Growth of <i>Zea mays</i> L. under Different Levels of Sodium Chloride Stress

Salt stress is one of the most severe environmental factors that reduces and limits growth and development of plants. Abiotic stresses such as heavy metals, salinity, drought, temperature, UV-radiation, ozone causes drastic yield reduction in most of the crops. Especially salt stress affects around 20 of NaCl on germination and seedling growth of Zea mays L. Seeds of Zea mays were germinated in glass Petri- 100 × 15 mm diameter lined with blotting paper. Ten seeds were placed in each petri-dish. Petridishes were irrigated with 25, 50, 75, 100, 125, 150, 175 and 200 mM concentrations of NaCl. A control was moistened with ten milliliters of distilled water. The germination percentage, water absorption of the seeds, water uptake percentage and the growth parameters were observed. The results obtained showed that the inhibition of the germination percentage, germination rate, water uptake, growth and biomass accumulation of the seedlings were observed to decrease with increasing NaCl concentrations. At the highest level of stress both plumule and radical decreased significantly. The salt stress decreased seed germination, biomass and growth of maize seedlings due to ion toxicity, decrease osmotic potential and oxidative stress

Germination and Seedling Growth of <i>Zea mays</i> L. under Different Levels of Sodium Chloride Stress

Salt stress is one of the most severe environmental factors that reduces and limits growth and development of plants. Abiotic stresses such as heavy metals, salinity, drought, temperature, UV-radiation, ozone causes drastic yield reduction in most of the crops. Especially salt stress affects around 20 of NaCl on germination and seedling growth of Zea mays L. Seeds of Zea mays were germinated in glass Petri- 100 × 15 mm diameter lined with blotting paper. Ten seeds were placed in each petri-dish. Petridishes were irrigated with 25, 50, 75, 100, 125, 150, 175 and 200 mM concentrations of NaCl. A control was moistened with ten milliliters of distilled water. The germination percentage, water absorption of the seeds, water uptake percentage and the growth parameters were observed. The results obtained showed that the inhibition of the germination percentage, germination rate, water uptake, growth and biomass accumulation of the seedlings were observed to decrease with increasing NaCl concentrations. At the highest level of stress both plumule and radical decreased significantly. The salt stress decreased seed germination, biomass and growth of maize seedlings due to ion toxicity, decrease osmotic potential and oxidative stress

Molecular Mechanisms, Thermodynamics, and Dissociation Kinetics of Knob-Hole Interactions in Fibrin

Polymerization of fibrin, the primary structural protein of blood clots and thrombi, occurs through binding of knobs 'A' and 'B' in the central nodule of fibrin monomer to complementary holes 'a' and 'b' in the γ- and β-nodules, respectively, of another monomer. We characterized the A:a and B:b knob-hole interactions under varying solution conditions using molecular dynamics simulations of the structural models of fibrin(ogen) fragment D complexed with synthetic peptides GPRP (knob 'A' mimetic) and GHRP (knob 'B' mimetic). The strength of A:a and B:b knob-hole complexes was roughly equal, decreasing with pulling force; however, the dissociation kinetics were sensitive to variations in acidity (pH 5-7) and temperature (T = 25-37 °C). There were similar structural changes in holes 'a' and 'b' during forced dissociation of the knob-hole complexes: elongation of loop I, stretching of the interior region, and translocation of the moveable flap. The disruption of the knob-hole interactions was not an "all-or-none" transition as it occurred through distinct two-step or single step pathways with or without intermediate states. The knob-hole bonds were stronger, tighter, and more brittle at pH 7 than at pH 5. The B:b knob-hole bonds were weaker, looser, and more compliant than the A:a knob-hole bonds at pH 7 but stronger, tighter, and less compliant at pH 5. Surprisingly, the knob-hole bonds were stronger, not weaker, at elevated temperature (T = 37 °C) compared with T = 25 °C due to the helix-to-coil transition in loop I that helps stabilize the bonds. These results provide detailed qualitative and quantitative characteristics underlying the most significant non-covalent interactions involved in fibrin polymerization.