Chloride Salinity Research Articles

Hydrochemistry Differences and Causes of Tectonic Lakes and Glacial Lakes in Tibetan Plateau

The Tibetan Plateau has the largest lake cluster in China and in the world. In order to clarify the differences of lake hydrochemistry of Tibetan Plateau, water samples were collected from 32 lakes, including 22 tectonic lakes and 11 glacial lakes, along the Tibetan Plateau road, from September to October 2016. We detected and analyzed the major ion concentrations and characteristics of samples, and discuss the hydrochemistry type, controlling factors, and major ion sources of lake water. The results showed that, firstly, tectonic lake samples on the Tibetan Plateau have much higher physicochemical parameters and ion contents than glacial lakes, and Total Dissolved Solids (TDS) contents fluctuate from high to low latitudes. The variations of ion concentrations in the northern part of the Qiagui Co were more fluctuating and have two obvious peaks, while the variations in the southern part were moderate. The TDS of glacial lakes were low and leveling off in the upper and middle reaches of the basin, while higher and more variable in the lower reaches. Secondly, the tectonic lakes were mainly chloride saline lakes, with Na+ as the major cation, and SO42−, Cl− as the major anions. Glacial lakes were mainly carbonate and sulfate type lakes, Ca2+ and Mg2+ were the major cations, HCO3− was the major anion, and SO42− was the second. Thirdly, the hydrochemistry processes of the tectonic lakes were mainly controlled by evaporation-crystallization, and the ions mainly came from the evaporites of basin. Glacial lake water samples were mainly influenced by the weathering of basin rocks, with ion sources strongly influenced by the weathering of basin carbonates than evaporites, with calcite and dolomite being important sources of Ca2+, Mg2+, and HCO3−.

Anatomical Response of Atriplex Leaves under Different Levels of Sodium Chloride Salinity

Salinity causes physiological, morphological, and anatomical modifications in Mediterranean saltbush Atriplex halimus and giant saltbush Atriplex nummularia. Both species, which belong to Chenopodiaceae, are true xerophyte as shown from Kranz-anatomy and salt storage trichromes. Response of both species to salinity were differed according to genetic structures. Atriplex species leaves characteristic by presence of salt accumulating cells on upper and lower leaf epidermis, which have ecological significance. Increasing of salinity had negative effect on anatomical measurements of A. halimus leaves. However, low level of salinity had positive effect in A. nummularia leaves, but high level of had negative effect on leaves.

Methyl Jasmonate and Cytokinin Mitigate the Salinity-Induced Oxidative Injury in Wheat Seedlings

Application of methyl jasmonate (MeJA) has been shown to be effective in improving plant tolerance to various environmental stresses. Present research was conducted to explore the possible role of endogenous cytokinins (CK) in MeJA-mediated alleviation of oxidative stress in wheat plants (Triticum aestivum L.) subjected to sodium chloride salinity. We have compared the effects of 0.1 µM MeJA and 0.04 µM cytokinin 6-benzylaminopurine (BAP), both causing a twofold increase in the level of endogenous cytokinins, on the reactive oxygen species generation, antioxidant enzymes activities, levels of lipid peroxidation, and electrolytes leakage, as well as on the contents of proline and dehydrins under normal and salinity conditions. Salt stress significantly increased generation of superoxide anion and activity of both superoxide dismutase and peroxidase resulting in accelerated lipid peroxidation and electrolyte leakage and also elevated the contents of proline and dehydrins in wheat seedlings. Pretreatment with either MeJA or BAP reduced the salt-induced pro-oxidants/antioxidants imbalance as well as membrane damages. Meanwhile, both hormones promoted additional accumulation of proline and dehydrins under stress and enhanced the barrier properties of the cell walls in seedling roots by accelerating the lignin deposition. Similarity in the protective action of MeJA and cytokinin together with previous data on prevention of the decline in the cytokinin content in MeJA-pretreated salt-stressed wheat seedlings suggest the involvement of endogenous CK in MeJA-induced increase in salinity tolerance of wheat plants.

Hydrodynamic Pattern in Drying Saline Droplet with Suspended Nanoparticles

Evaporation of multicomponent droplets has gained much attention nowadays because of their complex flow fields and various deposition patterns. Here we observe strong flows in evaporating sodium chloride saline droplets with suspended alumina oxide nanoparticles. The evolution of flow pattern was studied by tracking the trajectories of particles and the velocity field was investigated with Particle Image Velocimetry analysis. The non-uniform evaporation rate along the droplet surface leads to a concentration gradient which induces the convection flow. During the evaporation process before crystallization happens, evolution of the flow can be divided into two regimes. In Regime I, a centrosymmetric convection recirculation is formed gradually. In Regime II, the convection recirculation migrates to the droplet edge and evolves into several small vortexes. At the late evaporation stage, crystallization could induce strong convection flows. It is shown that the flow tends to become more chaotic with a lower salt concentration.

NaCl and Na2SO4 Salinities Have Different Impact on Photosynthesis and Yield-Related Parameters in Rice (Oryza sativa L.)

To elucidate the comparative effect of chloride and sulfate salinities on photosynthesis and yield components in rice, plants of Oryza sativa (cv. I Kong Pao (salt-sensitive)) were exposed in nutrient solutions to 20 mM Na2SO4 or 40 mM NaCl (electrical conductivity of c.a. 4.30 dS m−1 for both solutions) from seedlings to maturity stage. Both types of salt induced a strong decrease in net photosynthesis (AN) at the seedling and tillering stages, while the intercellular CO2 concentrations (Ci) remained unaffected. Instantaneous transpiration (E) and stomatal conductance (gs) decreased at the tillering and seedling stages, respectively, only in plants exposed to NaCl. Chloride salinity also strongly decreased photosynthetic pigments, while no impact was detected in response to Na2SO4. All yield-related parameters were affected by salinities, but NaCl was significantly more deleterious than Na2SO4 for the mean number of tillers produced per plant, spikelets sterility and non-viable pollen percentage. In contrast, both types of salinity similarly impacted the percentage of fertile tillers and 1000-grain weight. At the grain level, more than 90% of toxic ions (Na+, excess of Cl− and S6+) accumulated in the hulls, thus preserving the internal part of the caryopses from toxic ion injuries.

STUDY OF COTTON VARIETIES 'RESISTANCE TO DROUGHT AND SALT

In this article, An-Bayaut-2, S-6524, Bukhara-102, Sultan, Navruz, Pakhtakor-1 and Andijan-37 varieties of cotton were introduced to the FC in the conditions of irrigated, saline, saline with sulfur chloride saline, grazing light gray soils of Syrdarya region. The volume of soil mass decreased by 0.01–0.02 g/cm3, the porosity of the soil increased by 0.2–0.8%, the water permeability of the soil increased by 2.8–14%, compared to 70–70–65%. Reduction to 5 m3/ha and reduction of salinity by 10-15%, cotton varieties to 70-270-65% in comparison with FC, 65-65-60% to 1.2-2.6 quintals of additional cotton yield, fiber length from quality indicators 0 , Fiber content up to 1–0.3%, fiber yield up to 0.2–0.9%, weight of 1000 seeds up to 0.2–0.5 g, wilt disease rate up to 2–3%, and different cotton in saline soils. Net profit from 40617-112785 soums per hectare and profitability when irrigating varieties with 70 nav70‒65% to 65‒65‒60% compared to FC The level is reported to be as high as 5.8–15%.

Chloride salinity in a chloride-sensitive plant: Focusing on photosynthesis, hormone synthesis and transduction in tobacco

Chloride (Cl−) is a micronutrient and a beneficial ion for plant growth, but excess Cl− easily leads to Cl− salinity. As a species sensitive to Cl−, tobacco experiences serious damage when encountering excessive Cl−. However, the molecular mechanism by which excess Cl− delays plant growth and development remain largely unknown. In this study, physiological, biochemical and genetic responses were determined in tobacco plants exposed to 12 h, 24 h and 48 h of Cl− salinity. Compared with the control, Cl− salinity increased the content of Cl− and decreased the relative water content (RWC) in tobacco, which severely limited the photosynthetic capacity and reduced photosynthetic products, resulting in decreased levels of auxin (IAA) and gibberellin (GA3). In addition, tobacco increased the content of starch, total phenol and increased phenylalanine ammonia-lyase (PAL) activity in response to Cl− salinity. Multi-omics results revealed that a total of 15,445 genes and 1983 proteins were differentially abundant in response to Cl− salinity. Two metabolic pathways, phenylalanine metabolism and starch and sucrose metabolism, were specifically enriched in the transcriptomic and proteomic data, respectively. In addition, our conjoint analysis of RNA-Seq and proteomics data revealed that 734 differentially abundant genes/proteins were enriched mainly in plant hormone signal transduction, photosynthesis and photosynthesis-antenna protein pathways. Our work presented here not only provides new insights into the molecular response of tobacco to Cl− salinity but also offers important guidance for the improvement of Cl− sensitive crops.

The experience of polyhexanide usage as a part of wet environment in the treatment of limited burns

INTRODUCTION. The results of the treatment of patients with restrictive burns I-II degrees are presented in the article. The OBJECTIVE of the research was to establish the efficiency of the usage of polyhexanide included in wet environment in the treatment of burns I-II degrees. METHODS AND MATERIALS. The research was conducted in 2 groups of patients. In the first group (N=33), local treatment of hand wounds was performed in condition of wet environment created by isotonic solution of sodium chloride, in the second group (N=18) - with usage of polyhexanide as antiseptic and isotonic chloride saline solution. For evaluation of efficiency of the treatment, we studied the terms of the beginning of epithelialization of the wound surface, pain syndrome severity, microcirculation and conducted microbiological research of wound exudate. RESULTS. The appearance of the first signs of wound epithelialization after the beginnings of treatment was observed in 1.5 times in average sooner in the second group than in the first group. Pain syndrome was jugulated by the 3rd day in the first (research) group in 19 % of cases, in the second (control) group - in 46 % (p<0.05). In the second group, perfusion of tissues in the border area reduced, in the same time in the first group, it remained unchanged. The number of swabbing cases with Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae and Enterococcus faecalis increased in the first group by the 3rd day in contrast with the second group, where such cases was not noted or occurred significantly less often. CONCLUSION. The usage of polyhexanide as a part of wet environment promotes the reduction of wound surface swabbing level that allows to speed up the appearance of the first signs of wound epithelialization, reduces the severity of pain syndrome, and modeling of tissue microcirculation in periwound area.

Biological Activity of the Supramolecular Complex of Glycyrrhizic and Salicylic Acids

Supramolecular complexes of glycyrrhizic acid (GA) and salicylic acid (SA) in various mole ratios of 1:1, 2:1, 4:1, and 8:1 were prepared for the first time. Their IR and UV spectra indicated that a complex with SA did form. The supramolecular complex with a 2:1 ratio, which was called DAG-1, had the optimal molecular ratio of GA and SA for high biological activity. DAG-1 at a concentration of 10–7 M induced antioxidantenzyme (catalase, peroxidase, superoxide dismutase) activity and stimulated cotton growth and development under model chloride salinity conditions.

Arabidopsis thaliana Mutant with T-DNA Insertion in the Flot1 (At5g25250) Gene Promotor Possesses Increased Resistance to NaCl

Flotillin membrane proteins are involved in many cellular processes and physiological functions. However, these proteins’ participation in plant response to stresses remains poorly understood. In the present report, the possible involvement of flotillin Flot1 in Na+ and K+ homeostasis in cells under sodium chloride salinization of the medium was studied in Arabidopsis thaliana (L.) Heynh. For this purpose, the Flot1 gene transcription was analyzed in the roots and leaves of wild-type (WT) and flot1 mutant plants with a T-DNA insertion in the promoter using the quantitative Real Time-RT PCR (qRT-PCR). Along with this, a mutant phenotype was studied (growth characteristics, content of Na+ and K+ ions in organs, and ultrastructure of root cells) under normal conditions and in the presence of 100 mM NaCl in the culture medium. The mutation led to the activation of AtFlot1 expression, which was more noticeable in the roots during salinization. Under these conditions, the mutants had larger organ mass, lower Na+ content, and higher K+ content in organs than that of WT. The study of the ultrastructure of A. thaliana root cells in mutant plants showed more intensive formation of post-Golgi vesicles and multivesicular bodies (MVB) in the cytoplasm. In both mutant and WT plants, the presence of sodium chloride in the nutrient solution stimulated the formation of MVB and microvacuoles in the cytoplasm and fusion of the latters into larger structures. It is assumed that changes in the ultrastructure of root cells that are caused by mutation and salinization reflect the stimulation, respectively, of vesicular trafficking and biogenesis of vacuoles—processes involved in maintaining Na+ and K+ cell homeostasis.

Pore water freezing characteristic in saline soils based on pore size distribution

Pore water freezing point and unfrozen water content heavily depend on the properties of ion solutions, ice–liquid interface energy, and pore radius and are essential for analyzing the thermal and mechanical behavior of saline soils in cold regions. This paper focuses on the analyses of pore water freezing characteristics and estimation of the unfrozen water content in saline soils. Based on the thermodynamic principles, a general equation based on the chemical potential was used to describe water freezing in chloride saline soils and derive analytical models for predicting the freezing point and unfrozen water content. Meanwhile, the initial freezing point and unfrozen water content data were obtained by cooling experiments and nuclear magnetic resonance tests, respectively, for validating the proposed analytical models. The results show that the freezing point of saline soils is closely related to water activity, pore size, and unfrozen water content. Specifically, the freezing point decreases with decreasing water activity, pore size, and unfrozen water content. Furthermore, pore water freezing is mainly determined by the solution properties for pores larger than 0.2 μm. For pores smaller than 0.2 μm, however, the effect of pore size on water freezing should be considered. Experimental data provide validation of the analytical models for saline silty clay. Additionally, the proposed models are also shown to provide improved prediction of unfrozen water content for nonsaline silty clay.

SCREENING OF POWDERY MILDEW RESISTANT BARLEY ACCESSIONS FROM ETHIOPIA FOR TOLERANCE TO ABIOTIC STRESSORS

Background. Analyzing the adaptive potential of cultivated barley with the aim of using new genotypes selected and developed in the process of work is a priority trend in scientific research. The Ethiopian barleys adapted to a variety of soil and climate conditions are characterized by many valuable biological and agronomic traits. Of particular value are genotypes that combine resistance to harmful organisms and environmental stressors.Materials and methods. The collection accessions of Ethiopian barley possessing powdery mildew resistance were studied for tolerance to adverse edaphic factors (chloride salinity and high content of toxic aluminum ions in the soil). Resistance to abiotic stressors was assessed in laboratory experiments. In the study of salt tolerance, a ‘roll-based’ assessment technique was used, which takes into account the inhibition of root growth under salt (NaCl) stress conditions, compared with the reference conditions without salinization. Aluminum sensitivity of barley accessions was diagnosed in the early stages of plant development using the root test.Results and conclusions. A polymorphism of Ethiopian barleys for resistance to adverse edaphic factors was revealed. Twentyone new sources of barley resistance to toxic aluminum ions were identified, of which accessions k-8552 and k-22933 were classified as highly resistant. Accessions k-17554, k-19975, k-20029, k-20048, k-22752, k-23450 and k-25009 proved resistant to soil salinization. Barley accessions k-17554, k-22752 and k-25009 were characterized by complex resistance to powdery mildew, toxic aluminum ions, and chloride soil salinity.

Influence of salinization on seeds germination of the fodder semi-shrub of the eastern saltwort (Salsola orientalis S.G. Gmel.)

Eastern saltwort (Salsola orientalis S. G. Gmel.) belongs to the goosefoot family (Chenopodiaceae Vent.), the genus Salsola L., a semi-shrub with 25-70 cm high with fleshy leaves. It is distributed on saline sandy loam and stony soils from plains to low mountains. It is widely used to restore productivity of degraded natural pastures in arid regions of Russia and Central Asia countries. It is characterized by good palatability, nutritional value, exceptional resistance to salt stress, drought and other adverse environmental conditions. The objective of the study is to find out the effect of different salt concentrations on the germination of eastern saltwort seeds. The influence of various types of salinization on the germination of eastern saltwort seeds in concentrations was tested (0.2; 0.4; 0.6; 0.8; 1.0; 1.2; 1.4; 1.6; 1.8 and 2.0% to the absolutely dry mass of sand): chloride, sulphate, sulphate-chloride, chloride-sulphate, control – sand moistened with distilled water. With chloride salinization at concentrations of 0.2-0.4%, the germination energy and germination of eastern saltwort seeds decreased slightly, and at concentrations of 1.2-1.4%, germination stopped. Sulfate salinization was the least toxic. With all types of salinization, with an increase in the salt concentration, the sowing – germination period is delayed and the process of germination of eastern saltwort seeds is expanded. Although eastern saltwort is a true halophyte, its seeds germinate better on a nonsaline substrate.

ВЛИЯНИЕ НАНОСЕЛЕНА НА СОДЕРЖАНИЕ ИОНОВ K+, Na+ И Cl- В ПРОРОСТКАХ ПШЕНИЦЫ В УСЛОВИЯХ КОМБИНИРОВАННОГО ДЕЙСТВИЯ ЗАСОЛЕНИЯ И ЗАСУХИ

Soil salinization is one of the most important problems for agriculture. In most cases, the effect of salinization is manifested in conjunction with water deficiency, reinforcing each other. One of the most dangerous types of salinization is sodium chloride, in which both sodium and chlorine ions have a damaging effect on plants. The physiological processes taking place under stressful conditions with the participation of enzymes and antioxidants are closely related to each other. The content of some enzymes is significantly affected by selenium. The least toxic and bioavailable is selenium in the form of nanoparticles stabilized by natural biologically active substances. The aim of the work was to study the effect of the tread action of the original water-soluble composition of nanosalen stabilized with sodium alginate on the content of K+, Na+ and Cl— ions in wheat seedlings under the combined effects of salinization and drought. The objects of study were winter wheat seeds (Triticum aestivum L.) and a water-soluble composition of selenium nanoparticles. Wheat seeds were soaked for 4 hours in a solution of selenium nanocomposition at a concentration of 10.0; 20.0 and 30.0 mg/l. The control was seeds soaked in distilled water. Plants were grown for 10 days under controlled conditions in a climatic chamber in vessels with a capacity of 1.0 L., a 16-hour photoperiod, a temperature of 25/20 °C (day / night) and a relative humidity of 60±5 %. Well washed river sand was used as a substrate. On day 10, the mass of raw and dry matter and the content of K+, Na+ and Cl— ions in the leaves and roots, as well as on the water content of the leaf tissues and the relative water content (RWC) were determined. For the first time, a study was made of the protective effect of selenium nanocomposite on the content of K+, Na+ and Cl— in leaves and roots, as well as their relationship with the water status of leaves in wheat seedlings under the combined effect of chloride salinity and drought. The action of nanoselen increases the absorption of K+ ions by both roots and leaves. In this case, the absorption of Na+ ions are significantly reduced. The protective effect of nanoselen is also manifested in maintaining a high-water status.

EVALUATION OF MORPHOLOGICAL AND BIOCHEMICAL RESISTANCE PARAMETERS TO CHLORIDE SALINATION IN DIFFERENT WHEAT GENOTYPES

Determining salt tolerance potential in wheat is one of the most important problems in breeding practice for areas with primary and secondary salinity. Presence of large areas of saline soils results in inhibition of growth, development and stability in obtaining high yields of agricultural plants. Therefore, there is a need for a comprehensive studying and improving of diagnostic methods during early growth stages. Different genotypes of wheat Triticum aestivum Host. and Triticum durum Desf. were used to identify salt tolerance markers. Both morphometric and some biochemical indicators of wheat varieties were used as salt tolerance markers. At this stage, it was shown that a comprehensive description of wheat varieties is needed to assess resistance of wheat varieties to chloride salinity.

Ultrastructural Reorganization of Chloroplasts during Plant Adaptation to Abiotic Stress Factors

This review presents a comparative analysis of the literature and the authors’ data on the ultrastructural reorganization of plant chloroplasts adapting to abiotic factors of different nature—low temperature (factor of a physical nature) and chloride salinity (factor of a chemical nature). All ultrastructural changes in chloroplasts are considered in close relationship to the physiological, biochemical, and functional adaptive changes of the photosynthetic apparatus (PSA). The review discusses the adaptive value and emphasizes the nonspecific nature of ultrastructural transformations occurring in plant chloroplasts under abiotic stress. A separate section considers the effect of metal nanoparticles on the PSA and the nanoparticle-aided modeling of the PSA responses to stresses.

Spatial distribution of nutrients and morpho-physiological indicators of salinity tolerance among five olive cultivars - The use of relative nutrient concentration as an efficient tolerance index

Olive is the most important fruit tree species grown in Mediterranean basin, where many times it grows under saline conditions, due to irrigation with low quality water. Olive response to salinity is cultivar dependent and the evaluation of native genotypes is an important tool in finding tolerant genetic material. For this reason, five Greek olive cultivars, i.e. “Koroneiki”, “Gaidourelia”, “Lefkolia Serron”, “N-K Gigas” and “Throumbolia”, were evaluated regarding their tolerance to sodium chloride salinity (0, 50, 100 and 200 mM). All cultivars exhibited a significant reduction of growth, while the most severe symptoms were found in “Gaidourelia” while “Lefkolia Serron” presented the least symptoms. The latter exhibited the lowest sodium concentration in the leaves and the highest in the roots. Both potassium to sodium and calcium to sodium ratios were high in “Gaidourelia” leaves and stems, suggesting that the use of nutrient concentration for comparison of olive tolerance among cultivars could lead to erroneous results. The best indicator proved to be the determination of nutrient relative concentration compared to corresponding cultivar’s control, as “Gaidourelia” exhibited the highest sodium relative concentration as well as the lowest nutrient ratios, revealing its inability to restrain sodium in the root level.

Индикаторные признаки адаптации субтропических древесных растений на основе комплексных исследований

For the Lower Volga region with difficult soil and climatic conditions, forecasts bear an increase in the length of the growing season, an increase in heat, and a softer winters. This indicates the need for studies of subtropical plants for an objective assessment of the identification of mechanisms for their adaptation and prospects for creating protective forest plantations in sparsely wooded regions. Theoretical and practical interest for the Volgograd region is a valuable fruit, medicinal, forest reclamation and ornamental shrub (unabi) plant Zizyphus jujuba Mill. (family Rhamnaceae). The purpose of the research is to study the ecological and physiological features of subtropical woody plants of Zizyphus jujuba and to identify indicator signs of their adaptation in the Volgograd region. The objects of research were the varietal plants of the unabi (Ta-yang-zao, Southerner - large-fruited, Druzhba, Phenicia - medium-fruited, Sochi, Temryuk - small-fruited). They are tested in the Volgograd region for the first time, obtained from the FSBI (city of Sochi) and are cultivated in FSBI FNTS Agroecology RAS (Volgograd region, Russia). The soils of the experimental plot (50 ° 4´-50 ° 5´N and 45 ° 22´-45 ° 23´E) are characterized by a low humus content (from 0.57 to 1.15%). It was revealed that the study area (Volgograd region) is characterized by a small amount of precipitation, low temperatures in winter, high temperatures in summer, droughts of high and medium intensity. The amplitude of the absolute maxima and minima varies from seventy-eight (dry steppe) to ninety degrees Celsius (semi-desert). It has been established that the agroclimatic resources of natural distribution areas differ from the introduction points of Zizyphus jujuba Mill. to culture. Different levels of morphological variability, as well as water availability, lead to a change in the ability to expend and retain water, to a lack of moisture in the leaves of Z.jujuba. The insignificant effect of drought on the state of the aboveground plant organs during the arid periods was observed in medium-sized and large-fruited varieties. Young, non-lignified shoots are damaged (at an air temperature of about 40 ° C and a decrease in air humidity of up to 10%). A decrease in leaf turgor was observed with water deficit indicators of 28.3-35.8%. Water deficiency decreases by 6-10% with increasing age, which is due to increased adaptation and regulation of water balance. According to the indicators of the relative electrolyte yield, groups were determined according to the degree of drought resistance: low - Southerner, Ta-Yan-Zao (4.23-4.71), medium - Finik, Friendship (3.10-3.61) and high - Temryuk, Sochi (1.64-1.99). Ecological tolerance of various organisms to low temperatures is quite specific. Evaluation of different varieties of Zizyphus jujuba under light-brown soils showed that the adaptation of plants to low temperatures increases with increasing age. In small varieties with an increase in age, the damage is minor. Based on the vegetation experience, the limits of ecological tolerance of small-fruited forms of Zizyphus jujuba to chloride salinity were established, which makes it possible to predict their successful cultivation on soils with a chlorine ion content of 0.1%. Thus, complex ecological and physiological studies of the adaptive capacity of subtropical plants Zizyphus jujuba revealed indicator signs that allow to evaluate and predict the degree of adaptation depending on the variety and the response to stress factors specific to the conditions of the Lower Volga region.

Adaptive reactions of wheat seedlings differentiating varieties under hyperthermia

When creating varieties, adapted to temperature stress factors, it is necessary to carry out diagnostics of their resistance to stress factors. Diagnostic methods should have high differentiating ability in reliably distinguishing the resistance of closely related objects, such as varieties from the same crop or plants from the same variety population. To ensure the differentiating ability of the method, the assessment of resistance diagnostics towards stress factors should be conducted with the same strength of stress load and modes of stress factors that would enable to range varieties. In model laboratory vegetation experiments, the adaptive reactions of 10-day-old seedlings of three varieties of spring wheat were assessed according to changes in growth rates, wet and dry biomass, and permeability of cell membranes of seedlings under hyperthermia (warming the seeds) with the purpose of identifying the temperature that differentiates varieties. The seedlings were grown in roll culture on tap water in a climate chamber with preset parameters of microclimate. Before that, the seeds were pre-heated in hot water in thermostat at temperatures of 30, 43 и 54°C. The seedlings of control variety were cultivated in the same conditions without warming the seeds. The formation of adaptive reaction to hyperthermia of seeds differed across varieties of seedlings of spring wheat varieties Novosibirskaya 18, Novosibirskaya 44 and Omskaya 18. Adaptation of varieties to similar temperature factors formed in different ways, which can be explained by hereditary nature of plants. According to the results of the research, the maximum values of variation coeffi cient of biophysical and biometric indicators of seedlings was identifi ed at the temperature of 43°C. This is the differentiating temperature in assessment of wheat crop varieties adaptation to the increased temperature. This temperature was applied in experiments to study the reaction of wheat varieties to separate and joint effects of chloride salinity, seed infection with common root rot and hyperthermia.

Effects of Sodium Chloride Salinity on Water Relations and Ion Accumulation in Two Mungbean Varieties Differing in Salinity Tolerance

Salt tolerance in relation to water status and plant nutrients of two mungbean varieties, BARImung 2 (salinity sensitive) and BUmung 2 (salinity tolerant) was evaluated. The seeds were grown in pots and treated with NaCl levels of 0 (control), 100 and 200 mM. Different parameters related to water relations as well as mineral nutritients were measured. The exudation rate and relative water content were decreased but water saturation deficit was increased by salinity in both the varieties. In BARImung 2 plants, the exudation rate and relative water content were lower but water saturation deficit was higher than those in BUmung 2 at both 100 and 200 mM NaCl levels. Salinity also influenced the accumulation of Na, K, Ca and Mg in leaves, stems and roots of the two said mungbean varieties. Sodium accumulation was inceseased in all the plant-parts of both the varieties in the order of stem > root > leaf but in BUmung 2 the accumulation was lower than that of BARImung 2 except in root. Potassium accumulation deceresed in all parts of both the mungbean varieties but that was lower in BUmung 2 than that of BARImung 2. The contents of Ca and Mg in all the plant-parts increased more in BUmung 2 than those of BARImung 2 with the increase of salinity levels. All these results indicated that high salt tolerance in BUmung 2 was associated with its better water status, more or less uniform mineral nutrient (Ca and Mg) distribution in different plantparts than that in BARImung 2.
 Asiat. Soc. Bangladesh, Sci. 45(1): 45-54, June 2019