Different Levels Of Salinity Research Articles

Study of interaction between salinity and charcoal rot diseases of melon (Macrophomina phaseolina) in Semnan and Garmsar

Charcoal rot diseases of melon caused by Macrophomina phaseolina is one of the most important diseases of melon occurring in regions with variable climate. Reduction of yield of melon by this disease has been reported up to 100% in some of Garmsar field. Salinity which can cause the important trouble in plant metabolism and nutrition is present in Semnan and Garmsar areas. Melon is susceptible to salinity stress, therefore salinity stress may increase the susceptibility of melon to M. phaseolina. Different levels of salinity including, 0, 10, 25, 50 and 75 Mmol NaCl/l with and without fungal pathogen on two current cultivars of melon (Ivaneki and Susski) were investigated at the field conditions in Semnan and Garmsar areas. A factorial analysis for completely randomized design was used in these experiments with three replications. At all experiments, significant differences were observed among the different levels of any factors investigated including, cultivars, salinity and fungal pathogen presence. Interactions between investigated factors were significant too. The factors investigated in these experiments, clearly suggested the occurrence of a wide effect of salinity stress on charcoal rot development on melon cultivars and showed the importance of salinity management for decrease of disease severity.

Production and quality of melon hybrid Mandacaru irrigated with different levels of salinity

Among the problems faced by the melon crop in the state of Rio Grande do Norte, northeastern Brazil, the effect of water and soil salinity is considered one of the key factors to limit fruit production and quality. The aim of this work was to study the effects of using irrigation waters with different salinity levels on yield and quality of fruits of the yellow melon hybrid Mandacaru. A randomized complete block design was used with five treatments (irrigation water salt concentrations: 0.54, 1.48, 2.02, 3.03, 3.9 dS m-1) and four replications. The effects of these concentrations were evaluated through, number of marketable fruits per plant, marketable and total fruit yield, average marketable fruit mass, soluble solids content and pulp firmness. Increment in water salinity level negatively influenced crop yield. The 3.9 dS m-1 salinity level caused yield losses of 20.31%, due to the reduction of fruit number per plant. The highest soluble solid content and the highest pulp firmness values were estimated to occur at salinity levels 2.09 and 3.5 dS m-1, respectively.

Foliar Application of Potassium Nitrate Affects the Growth and Nitrate Reductase Activity in Sunflower and Safflower Leaves under Salinity

Effect of foliar application of KNO3 on growth and the activity of nitrate reductase were studied in the leaves of sunflower (Helianthus annuus L.) and safflower (Carthamus tinctorius L.) plants growing under different levels of salinity. The seeds were sown in pots under non saline condition and saline water irrigation was started at three leaf stage after germination. Different concentration of saline water (i.e. 0.3% and 0.6%, equivalent to an EC of 4.8 and 8.6 dS/m respectively) were made by dissolving sea salt per litre of tap water. Nutrient solution of KNO3 was sprayed at the rate of 250 ppm. The concentration of Na+ and Cl- rapidly increased in the leaves of both the plants under salinity stress. In contrast the nitrate (NO3-) and soluble protein concentration were decreased with the increasing salinity. Salinity reduced leaf area, its fresh and dry weight per plant and also inhibited the activity of Nitrate reductase (NRA) enzyme. The application of KNO3 significantly reduced the increasing tendency of Na+ and Cl- and increased leaf area, its fresh and dry weight per plant, NO3- and soluble protein concentration and NR activity in leaves irrespective to the growth of plant under non saline or saline conditions.

Growth and Survival of Mangrove Seedlings under Different Levels of Salinity and Drought Stress

Water availability and salinity are determinants of growth, survival and establishment of mangrove species. This study aimed to compare the ability of the mangrove species to survive extreme water stress, and to determine differences in growth performance and biomass allocation between mangrove species grown in different water levels and saline conditions. Seedlings of Lumnitzera racemosa, Rhizophora apiculata, R. mucronata and Avicennia marina were used. A dry-down experiment was done to compare the ability of mangrove species from different zonations to survive drought stress by evaluating survival rates after re-watering consequent to drought exposure. The different mangrove species were grown at different water levels (dry, well-watered, flooded) and different salinity levels such as low (3-5 ppt), high (25-27 ppt) and pure seawater (32 ppt) to evaluate the growth performance and biomass allocation of the mangrove seedlings. L. racemosa was the most drought tolerant, followed by R. mucronata and A. marina while R. apiculata was the most drought sensitive. There is a possibility that A. marina may displace the current distribution of R. apiculata in the middle zone while the distribution of L. racemosa and R. mucronata in the landward and middle zone, respectively could be retained. The number of leaves of A. marina was significantly higher than R. apiculata and R. mucronata but was only comparable to that of L. racemosa across all salinity levels. L. racemosa was only significantly different from the two Rhizophora spp. under pure saline treatment. Root length of A. marina was significantly higher than R. apiculata but statistically similar to R. mucronata and L. racemosa. The capacity for root growth may allow roots to exploit water from dry soils and could correspond to the drought tolerance of A. marina, R. mucronata and L. racemosa. There was no significant effect of water and salinity stresses on the biomass allocation.

Life-history traits of the invasive fish Gambusia ­holbrooki in saline streams (SE Iberian Peninsula): Does salinity limit its invasive success?

Knowledge of the adaptive ability of the highly invasive fish Gambusia holbrooki to new habitats is essential for determining its invasion potential. Our main objective was to assess the life-history of G. holbrooki in saline streams by studying its abundance, size and age structure, growth and condition. Two populations inhabiting similar streams of different salinity in the southeastern Iberian Peninsula were monitored over a 2 yr period. In both populations, the life- history of the species was characterized by a short life span, a long recruitment period with a mas- sive emergence of young-of-the-year and fast growth of individuals during the first months of their lives. The species showed a less intense recruitment (6.9% of juveniles vs. 46.4% during the recruitment period) and an earlier end of the recruitment period (at least 2 mo) in the hypersaline system, although abundance, hepatic condition and female somatic condition were higher. In addition, temporary increases in salinity diminished population abundance, recruitment, and somatic and hepatic condition. Both populations showed similar seasonal abundance variation patterns, population structures, growth rates, and somatic and hepatic condition cycles. Other environmental factors independent of salinity could have influenced the differentiation in life- history of the species between populations, thus disguising direct relationships between salinity and life-history. However, the studied parameters show that G. holbrooki presents a great ability to adapt to lotic systems with high and different levels of salinity.

Effect of different levels of salinity on gill and kidney function in common carp Cyprinus carpio (Pisces: Cyprinidae)

Common carp is generally considered to be a stenohaline freshwater fish, but can tolerate a wide range of salinities and is therefore a good candidate for rearing in brackish water. The present study was undertaken to investigate the influence of environmental salinity on osmoregulatory mechanisms in the common carp (Cyprinus carpio). Seventy-five healthy adults of C. carpio were randomly divided into five groups kept in salinities of at least 3, 6, 9 and 12 g/l NaCl and a control (tap water) group. The salinity was gradually increased by 3 g/l daily, until the desired concentration for each group was reached. Then the urinary papilla was catheterized to allow urine collection. Urine was collected once daily for 14 days and after this period blood and gill tissue were sampled and plasma electrolytes and gill Na+–K+ ATPase activity were assayed. Plasma sodium and chloride significantly increased in response to increased environmental salinity (P≤0.05). Gill Na+–K+ ATPase activity had significantly increased in response to increased environmental salinity (P≤0.05). Our results showed that common carp can tolerate environmental salinities up to at least 12 g/l, but survival at salinities of at least 6 g/l and higher requires profound changes in function of gill and kidney as principal osmoregulatory organs.

English

The salinity of water and soil decreases the growth and yield of agricultural products. Salinity affects many physiological and morphological processes of plant by influencing soil solution osmotic potential and ion absorption and accumulation of minerals. To evaluate the effect of salinity on some physiological and morphological characteristics of the medicinal plant of Echium amoenum, an experiment was carried out with completely random design in four replications. In this study, the effect of different levels of salinity, including control (non-saline water), 3, 6, 9 and 12 dS m-1 from natural saline water was examined on root length, leaf area, dry weight of roots and shoots, also on the amount of absorption of salts Na+, K+, Cl-, Ca2+, Mg2+ and the ratio of Na+/K+ and Ca2+/Na+ in root and shoot of plants and proline and total soluble sugars of leaf in the vegetative growth stage in the greenhouses. Results indicated that the application of saline water reduces significantly all morphological traits under study. Also, as the salinity increased, the density of K+, Ca2+ and Mg2+ and the ratio of Na+/K+ and Ca2+/Na+ in root and shoot of E. amoenum declined. In contrast, by increasing salinity, Na+ and Cl-concentration in roots and shoots significantly increased. As the salinity increased, proline concentration and leaf total soluble sugars also increased significantly compared with the control. The results showed that the accumulation of proline and soluble sugars are good indicators of salinity tolerance. Results also suggest that the plant resists against salinity through osmotic adjustment and ion absorption and sharing within its cells. This process is essential for the survival of plants in saline conditions.   Key words: Salinity, Echium amoenum, vegetative growth, ion composition, proline, soluble sugars.

English

Salt stress is one of the most important abiotic stresses, and plays an important role in reducing the yield of crops worldwide. It is now recognized that tolerance to salinity is genetically and physiologically complex and also inherited quantitatively. Barley is a short-season, early maturing, diploid and self pollinating crop, thus it is an ideal model plant for genetic and physiological studies of salinity tolerance. In order to map the genes/QTLs for salinity tolerance in barley, 72 doubled-haploid lines derived from a cross between ‘Steptoe’ and ‘Morex’ were used in an experiment using a randomized complete factorial design with three replications. The phenotypic traits under study included: chlorophyll contents, chlorophyll fluorescence (Fo, Fv, Fv/Fm), proline and carbohydrate rates, relative water content (RWC) and dry and wet weight of plant. Analysis of variance results showed that there were significant differences among the lines and different levels of salinity for all the traits. The strongest correlation was observed between dry and wet weight of plant (r = 0.95**). QTL analysis was performed using the genetic linkage map derived from 327 RFLP molecular markers and QTL cartographer software with the composite interval mapping method. Phenotypic variations that were explained by these QTLs, ranged from 10.64 to 24.20. The highest and lowest phenotypic variances were related to chlorophyll content (Q3cls) and Fv/Fm (Q1fv/fms),respectively. LOD values ranged from 2.77 to 6.33. The highest LOD scores were attained for Fv/Fm on chromosome 2H. Physiological traits associated with salt tolerance in this population were mapped to chromosomes 1H, 2H, 5H and 7H.   Key words: Barley, QTL, salinity, stress, tolerance.

Salt tolerance and mycorrhization of Bacopa monneiri grown under sodium chloride saline conditions

Salinity of soil is a serious problem affecting plant growth and is increasing steadily in many parts of the world, particularly in arid and semi-arid areas. Arbuscular mycorrhiza (A M) is the most wide spread and significant mutualistic fungi having universal in their association including plants of agricultural and medicinal importance. A. mycorrhiza fungi have been shown to promote plant growth and salinity tolerance by various mechanisms.The effects of inoculation with two A. mycorrhizal fungi Glomus mosseae and Glomusintraradices have been investigated on B. monneiri, an important medicinal plant grown with five different levels of salinity (0.40, 80, 120 and 160 mM). Root colonization, leaf chlorophyll content and tolerance of the plants to salinity were determined. The results indicated that the A. mycorrhizal fungi could infect and colonize the roots effectively under high salinity levels and increased chlorophyll content. Dry mass production was significantly enhanced in the inoculated plants and the effect was more evident at the high salinity levels. More over, A. mycorrhizal colonization has increased Na+ and Cl- uptakeand reduced rhizosphere NaCl level significantly. A. mycorrhizal association significantly increased tolerance of plants to salinity and was found as an effective measure to enhance establishment of the plant and to decrease soil salinity. Key words: Arbuscular mycorrhiza, Glomus mosseae, Glomus intraradices, Bacopa monneiri, salt tolerance, proline.

Toxic effect of NaCl on ion metabolism, antioxidative enzymes and gene expression of perennial ryegrass

Two-month old seedlings of perennial ryegrass ( Lolium perenne L.) were subjected to four different levels of salinity for 7 days. The NaCl treatments reduced turf quality and normalized transpiration rates. Both chlorophyll (Chl) a and Chl b contents decreased in the grass exposed to 255 mM relative to the control. An increase in the lipid peroxidationin was observed. The activity of leaf superoxide dismutase increased while, peroxidase and catalase activities decreased in response to NaCl treatments. The expression of Chl Cu/ZnSOD, Cyt Cu/ZnSOD, FeSOD, CAT, POD, GPX and GR was up-regulated for NaCl-treated grass. Salt stress increased accumulation of Na + and decreased K +/Na + ratio, Mg 2+ and P content in both shoots and roots of perennial ryegrass. The findings of this study suggest that salt stress may cause toxicity to perennial ryegrass through oxidative injury and damage to Chl and cell membrane integrity.

Contribution of Glomus intraradices inoculation to nutrient acquisition and mitigation of ionic imbalance in NaCl-stressed Trigonella foenum-graecum

The study aimed to investigate the effects of an AM fungus (Glomus intraradices Schenck and Smith) on mineral acquisition in fenugreek (Trigonella foenum-graecum) plants under different levels of salinity. Mycorrhizal (M) and non-mycorrhizal (NM) fenugreek plants were subjected to four levels of NaCl salinity (0, 50, 100, and 200 mM NaCl). Plant tissues were analyzed for different mineral nutrients. Leaf senescence (chlorophyll concentration and membrane permeability) and lipid peroxidation were also assessed. Under salt stress, M plants showed better growth, lower leaf senescence, and decreased lipid peroxidation as compared to NM plants. Salt stress adversely affected root nodulation and uptake of NPK. This effect was attenuated in mycorrhizal plants. Presence of the AM fungus prevented excess uptake of Na(+) with increase in NaCl in the soil. It also imparted a regulatory effect on the translocation of Na(+) ions to shoots thereby maintaining lower Na(+) shoot:root ratios as compared to NM plants. Mycorrhizal colonization helped the host plant to overcome Na(+)-induced Ca(2+) and K(+) deficiencies. M plants maintained favorable K(+):Na(+), Ca(2+):Na(+), and Ca(2+):Mg(2+) ratios in their tissues. Concentrations of Cu, Fe, and Zn(2+) decreased with increase in intensity of salinity stress. However, at each NaCl level, M plants had higher concentration of Cu, Fe, Mn(2+), and Zn(2+) as compared to NM plants. M plants showed reduced electrolyte leakage in leaves as compared to NM plants. The study suggests that AM fungi contribute to alleviation of salt stress by mitigation of NaCl-induced ionic imbalance thus maintaining a favorable nutrient profile and integrity of the plasma membrane.

Saline stress tolerance partly matches with habitat preference in ground‐living wolf spiders

Salinity interacts with many physiological functions and therefore probably influences the distribution of terrestrial fauna in tidal flooded salt marshes. The present study tests the hypothesis that the physiological tolerance of stenotopic wolf spiders for saline conditions at least partially determines their occurrence throughout salt‐marsh and nonsaline habitats. The duration of survival of three stenotopic wolf spider species (Araneae: Lycosidae) with different habitat preferences is compared in a controlled laboratory experiment. The forest‐dwellingPardosa saltans, the salt‐marsh residentPardosa purbeckensisand its sister species the inland‐livingPardosa agrestisare exposed to experimental conditions with different levels of salinity. Individuals (45 males and 20–45 females per treatment) are placed in individual air‐tight boxes filled with water‐saturated sand. Three levels of salinity are tested: nonsaline (0‰), medium saline (33–35‰) and highly saline (66–70‰). Contents of carbon, hydrogen and nitrogen and the molar ration carbon/nitrogen remain constant over time and do not differ among salinity treatments, indicating that starvation effects on survival, if any, are similar for all treatments. Conversely, body water significantly decreases over time and differs among salinity treatments, in accordance with patterns of survival. Conforming to their habitat preference, the survival ofP. saltansandP. agrestisdecreases quickly under highly saline conditions.Pardosa purbeckensis, however, has a high survival under both saline and nonsaline conditions. The duration of survival of females is significantly lower than that of males ofP. saltansandP. purbeckensis. Durations of survival of ground‐living wolf spiders exposed to salinity partly match their habitat distribution but do not explain the restriction of salt‐marsh species to saline habitats.

Effect of mycorrhizal inoculation on growth, nitrogen fixation, and nutrient uptake in Cicer arietinum (L.) under salt stress

Most legumes in natural conditions form a symbiosis with arbuscular mycorrhizal (AM) fungi. AM fungi in saline soils have been reported to improve salinity tolerance and growth in plants. In the present study, interaction between mycorrhizal fungus, Glomus mosseae, and salinity stress in relation to plant growth, nitrogen fixation, and nutrient accumulation was evaluated in Cicer arietinum (L.) (chickpea). Two genotypes of chickpea (Pusa-329, salt tolerant, and Pusa-240, salt sensitive) were compared under different levels of salinity with and without mycorrhizal inoculations. Salt stress resulted in a noticeable decline in shoot and root dry matter accumulation, resulting in a decline in the shoot-to-root ratio (SRR) in all plants. However, Pusa-329 was found to be more tolerant to salinity than Pusa-240. AM plants exhibited better growth and biomass accumulation under stressed as well as unstressed conditions. Mycorrhizal infection (MI) was reduced with increasing salinity levels, but the mycorrhizal dependency (MD) increased, which was more evident in Pusa-240. Salinity resulted in a marked decline in the nodule dry weights, whereas a surge in the nodule number was recorded. Nitrogenase activity was reduced with increasing salt concentrations. AM plants had considerably higher nodule numbers, dry weights, and nitrogenase activity under both saline and nonsaline environments. Pusa-329 had a comparatively lower Na^+ concentration and higher K^+ and Ca^{2+} concentrations than Pusa-240. Although nitrogen (N) and phosphorus (P) contents declined with increasing salinity, Pusa-329 had higher levels of N and P as compared with Pusa-240. Plants inoculated with Glomus mosseae had better plant growth and nitrogen fixation under salt stress.

FAO-56 methodology for the stress coefficient evaluation under saline environment conditions: Validation on potato and broad bean crops

Abstract This study aims at validating the methodology proposed by Allen et al. (1998) to calculate the stress coefficient Ks (ratio between actual and maximal evapotranspiration) under saline environment conditions not affected by soil water shortage. Validation was performed in Mediterranean region (Bari, southern Italy) on two crops: a winter crop (broad bean) and a spring crop (potato) grown in lysimeters, on clay and loam soils, having different levels of salinity. Preliminary observations were carried out to verify that the conditions established by Allen et al. (1998) for applying this Ks calculation methodology were fulfilled. The measured Ks values showed an evolution during the growing cycle. Ks values were close to 1 after emergence, and decreased at the end of the growing cycle. Contrarily, the calculated Ks values showed steady values during the whole crop cycle, being lower than the measured Ks. Only at the end of the crop cycle the calculated Ks values approached those measured. The various causes of differences between measured and calculated values of Ks are analyzed in this study. The observed differences between calculated and measured values of Ks led to an underestimation of calculated actual evapotranspiration (AET), at different stages in the crop growing cycle, by an average of 12%. The analysis of seasonal evapotranspiration as a function of soil salinity allows for a modulation of this mean value. The underestimation was quite negligible (close to 4%), if the average value of ECe during the crop cycle was close or lower than 3 dS m−1. On the contrary, the underestimation in evapotranspiration was close to 20% when the ECe raised up to 6 dS m−1. An underestimation of calculated AET in saline environment conditions, by the methodology proposed by Allen et al. (1998) , causes the appearance of an additional water stress, mainly when soil salinity, increases due to the combined effect of soil water shortage and water quality. Different solutions are proposed to improve the calculation of AET in this condition.

Differentiation and adaptive radiation of amphibious gobies (Gobiidae: Oxudercinae) in semi‐terrestrial habitats

During several surveys made in the region of the lower Fly River and delta, Papua New Guinea, nine species of oxudercine gobies (Gobiidae: Oxudercinae) were recorded: Boleophthalmus caeruleomaculatus, Oxuderces wirzi, Periophthalmodon freycineti, Periophthalmus darwini, Periophthalmus novaeguineaensis, Periophthalmus takita, Periophthalmus weberi, Scartelaos histophorus and Zappa confluentus. An exploratory multivariate analysis of their habitat conditions discriminated five guilds, differentially distributed in habitats with different quantities of environmental water and three guilds corresponding to different levels of salinity. A partial correspondence between phylogenetic and ecological categories suggested the presence of parallel adaptive radiations within different genera. In particular, the species found in the most terrestrial habitats (P. weberi) was also found in the widest range of conditions, suggesting that colonization of extreme semi-terrestrial and freshwater habitats by this species was facilitated by eurytypy. It is proposed that these findings provide insight into convergent adaptations for the vertebrate eco-evolutionary transition from sea to land.

Salinity Effects on Germination of Forage Sorghumes

Abstract: To investigate the effects of osmotic stress on forage sorghum (Sorghum bicolor L. Moench) varieties at critical stage of seed germination, i.e., at which salinization is initiated. A study was conducted at the Seed Technology Laboratory at University of Putra Malaysia (UPM- lab.) from October to November 2007. Two forage sorghum varieties (Speedfeed and KFS4) were evaluated in the salinity levels of 0, 5, 10, 15 dS m-1. The experimental design was Completely Random Design (CRD), which was based on factorial with 3 replications. In the experiment, seeds were germinated in covered, sterilized, disposable Petri dishes. Three parameters, namely germination percentage, germination rate, germination index and coefficient velocity of germination were estimated. The results of this study showed that different levels of salinity had significantly affected the germination percentage, germination rate germination index. In addition, a significant difference (1%) was also found in the germination percentage between the two varieties. Meanwhile, the mean comparison of the treatments showed that the germination percentage in distilled water (S1) was the highest (92.5%) and salinity dS m-1 (S4) had the lowest germination percentage. The maximum germination rate (35.58) and germination index (391.67) were retrieved from EC 0 and with the increasing salinity, these parameters were decreased. The evaluation of the two varieties showed that KFS4 (V1) had a higher germination percentage (82.91%) than the speed feed (72.5%). Consequently, the seed germination of KFS4 was better than the speed feed (in salty water and non-stress conditions). In other words, salt stress had been found to delay germination of both varieties.

Primary Nutritional Content of Bio-Flocs Cultured with Different Organic Carbon Sources and Salinity

Application of bio-flocs technology (BFT) in aquaculture offers a solution to avoid environmental impact of high nutrient discharges and to reduce the use of artificial feed. In BFT, excess of nutrients in aquaculture systems are converted into microbial biomass, which can be consumed by the cultured animals as a food source. In this experiment, upconcentrated pond water obtained from the drum filter of a freshwater tilapia farm was used for bio-flocs reactors. Two carbon sources, sugar and glycerol, were used as the first variable, and two different levels of salinity, 0 and 30 ppt, were used as the second variable. Bio-flocs with glycerol as a carbon source had higher total n-6 PUFAs (19.1 ± 2.1 and 22.3 ± 8.6 mg/g DW at 0 and 30 ppt, respectively) than that of glucose (4.0 ± 0.1 and 12.6 ± 2.5 mg/g DW at 0 and 30 ppt). However, there was no effect of carbon source or salinity on crude protein, lipid, and total n-3 PUFAs contents of the bio-flocs.

Attributes of irrigated rice and soil solution as affected by salinity levels of the water layer

In the State of Rio Grande do Sul, Brazil, flooded rice fields using Patos Lagoon as the source of water for irrigation are subject to be damaged by salinity, since this source is bound to the sea on its southern end. The sensitivity of rice is variable during plant development, being higher in the seedling and reproductive periods. However, there is not enough information about the behavior of plants under salt stress during the course of its development, especially in the vegetative stage. This study evaluated the effect of different levels of salinity of irrigation water on the salinity of soil solution over time and on some plant attributes, during the vegetative stage of rice. The study was conducted in a greenhouse, where seeds of the variety IRGA 424 were sown in pots and irrigated with water with electrical conductivity (ECi) levels of: 0.3, 0.75, 1.5, 3.0 and 4.5 dS m-1; from the tillering initiation (V4) until the panicle initiation (PI). The evaluations made were the electrical conductiviy of soil solution (ECe), the dry biomass of plants and stems, tillering, height and the transpiration of plants. The ECe increased with the ECi over time, and was determined by water transpiration flux in pots. The ECe values at the end of the experiment were high and, in most cases, higher than the critical values for flooded rice. The growth attributes of rice were negatively affected from ECi of 2.0 dS m-1 and ECe of 4.0 dS m-1.

Impact of salt stress on five varieties of Wheat(<i>Triticum aestivum</i> L.) cultivars under laboratory condition

The impact of salt stress under different salinity level (0,25,50,75,100,125,150 mM NaCl ) onfive varieties of Wheat viz., HOW-234, HD-2689, RAJ-4101, RAJ-4123, and HD-2045 was conducted. The data showed that different level of salinity significantly affected the growth attributes by reducing root and shoot length for salinity below 125mM. Fresh weight and dry weight of root and shoot were reduced significantly with subsequent treatment. Regarding germination maximum germination was found in variety HD2689 in all thetreatments and maximum inhibition was found to be in case of HOW234 variety at 150mM salinity level. Regarding biochemical analysis the sugar, proline content increased with increasing salinity level where as proteincontent decreased in the physiologically active leaves of different treatments for all the varieties of wheat

Improving emergence and early seedling growth of two cool season grasses affected by seed priming under saline conditions

Soil salinity threatens initial stages of emergence and early seedling growth in cool season grasses, although it may be tolerant in its adult stages. Today, seed priming has been known as an effective technique for improving seed germination, seedling vigor, and emergence rate and seedling establishment under different environmental stresses. A pot experiment was conducted to evaluate osmopriming effects in ameliorating emergence rate (ER) and final emergence percentage (FEP), seedling growth, Na+ and K+ accumulated in shoot at early growth stages of two cool season grasses including tall wheat grass (Agropyron elongatum Host.) and bulbous barley (Hordeum bulbosum L.) when seeds were imbibed with CaCl2, -1.5 MPa, and NaCl, -1 MPa for a duration of 2 and 5 days respectively, in response to seven salinity concentrations of NaCl (0, 50, 100, 150, 200, 250 and 300 mM) under greenhouse conditions. With increasing salinity levels, ER and FEP and seedling growth were significantly decreased in both grasses for primed and non-primed (control) seeds (p 0.05) but for non-primed seeds increasing the accumulation of Na+ in shoot, led to significant decline (r= -0.62, P< 0.01) of shoot dry weight. The results suggest that seed priming could significantly improve the threshold value especially for FEPin both grasses under different levels of salinity. Also, it seems that seed priming could better improve root and shoot growth at early seedling growth stage perhaps by decreasing toxicity of Na+ concentration and adjusting Na+ and K+ ratio under saline conditions. Key words: Early seedling growth, emergence rate, seed priming, salinity stress, cool-season grasses.