Showing 60 results for Salinity
Volume 0, Issue 0 (1-2024)
Abstract
Salt stress is a serious environmental threat reducing crop yield. Hence, developing any breeding plan requires an understanding of the basic physiology and cell molecular genetic regulation under salinity stress. In this study, we evaluated the effectiveness of gene expression changes on ion homeostasis comprising salt overly sensitive (SOS1) and vacuolar Na+/H+ antiporter (NHX1) along with ion content measurement and proline content in the rice mutants at Rice Research Institute of Iran in 2018-2019. To survey these realities, tolerant mutant genotypes (em4hs290 and em4hs84) along with Hashemi parent cultivar, IR28 (sensitive), and FL478 (tolerant) seedlings were treated with 100 mM NaCl. Based on the results of growth indices, the seedling length of Hashemi cultivar and IR28 decreased considerably about 44.7%, and 44.2% reduction to that of the control, and the leaves progressively yellowed. Results showed that proline content and K+ and K+/Na+ ratio increased about ~2–3-fold higher in the tolerant genotypes than in the susceptible ones. Also, the overall amount of the OsNHX1 and SOS1 expression increased in tolerant genotypes compared to the susceptible ones. Accordingly, the compatible solute accumulation significantly advanced resulting in improvement of ionic homeostasis and probably suppresses the stress. Moreover, the variable pattern of gene expression in the two salt-tolerant mutants (em4hs290 and em4hs84) and Hashemi parent showed that the induced mutation could increase the salt-tolerant in mutant genotypes through ionic and osmotic homeostasis. Generally, these tolerant mutant genotypes could be applied to develop salt-tolerant varieties in rice breeding programs which can bring on production sustainability.
Volume 2, Issue 1 (9-2011)
Abstract
Abstract:
In recent years, extension of Artemia applications in aquaculture and decreasing of natural resource, lead many of related studies to the distribution of Artemia population and new resource assessment studies. Urmia Lake as one the biggest habitat for Artemia because of ecological variations in the regions in which of its differentiations in cyst biometry and Artemia, moreover some genetic variations suggested to have some several Artemia populations in the Lake. In this project Artemia cyst samples were collected from 5 ecological stations of the Lake Urmia. The cyst hatching and the nauplii breeding up to adult Artemia stage were done according to optimum conditions in laboratory. Growth rate and survival of larva in days of 3, 5, 7, 11, 15, 20 of rearing period were measured in feeding with a complex of Dunaliella tertiolecta and Lanzy PZ for a period of 20 days in 75 and 150 ppt. Data and its statistical analysis revealed that according to previously records the growth rate of the Artemia was influenced by increasing the salinity from 75 to 150 ppt survival and growth rate of Artemia have been influenced by water salinity (P<0.05) but increasing the salinity only in two population of Bari and Eslami led decreasing of survival. The produced cysts in two salinity showed that Artemia population can produce the cysts with different diameter and there were not any statistic correlations between the salinity and populations. The Dandrogarm of population statistic analysis emphasized that according to growth rate and survival parameters and among populations under this test there were 4 different populations of Artemia urmiana in which had interesting differentiations in growth rate and survival.
Keywords: Artemia, Survival, Growth rate, Salinity, Urmia Lake.
Reza Akrami, Hossein Chitsaz, Saheb Dashtian, Majid Razeghi Mansour,
Volume 2, Issue 3 (12-2013)
Abstract
Separate or combined effects of inulin and mannan oligosaccharide supplements on the growth, survival, body composition and salinity resistance of kutum roach (Rutilus frisii kutum) fry (410 ± 19 mg) were investigated for 45 days in 40-liter tanks containing 30 individuals. Fish were fed 7 to 12% body weight with a commercial diet (35% protein and 12% lipid) supplemented with 0 (control), 5 g kg-1 inulin, 5 g kg-1 MOS and 2.5 g kg-1 inulin + 2.5 g kg-1 MOS in a totally randomized design trial in triplicate. A general enhanced growth performance and feed efficiency were observed in fish fed on diet containing 5 g kg-1 MOS (p<0.05). There were no significant differences in survival rate among treatments (p>0.05). NO significant difference was observed in body composition, but protein and lipid contents in the whole body increased in fish fed with 5 g kg-1 MOS and control group. In general, the fish fed 5 g kg-1 MOS had the highest survival index after 48 hours exposed to salinity stress (15 ppt). Results showed 5 g kg-1 MOS could improve growth performance, survival and salinity stress resistance of kutum fry.
Volume 3, Issue 1 (1-2001)
Abstract
Intra-specific variations in apex development of two salt-tolerant cultivars (Cross Rowshan
11 (CR) and Kharchia-65) and one salt-sensitive cultivar (Ghods) of spring wheat
(Triticum aestivum L.) grown in sand culture at selected levels of salinity (0, 100, 200, and
300 mol m-3 NaCl and CaCl2 in 5:1 molar ratio) were studied. To determine the apex
lengths and the number of spikelet primordia in the apex, the main shoot apex was dissected.
Results indicated that final spikelet number of wheat cultivars decreased with increasing
salinity. Cultivars showed different responses to a particular level of salinity.
Duration of spikelet development from double ridge to terminal spikelet, spikelet number
and apex length declined in the presence of salinity. Both shorter duration and reduced
rate of spikelet initiation were responsible for reduction in spikelet number in salt-treated
plants. Cultivar CR showed a better performance during spikelet initiation period and
produced relatively more spikelets under saline conditions than the others.
Volume 3, Issue 2 (4-2001)
Abstract
To use remote sensing data effectively, one must understand the spectral characteristics
of the particular features under investigations. To study the relationship between soil salinity
and soil reflectance, four MultiSpectral Scanners (MSS) and seven Thematic Mappers
(TM bands) over the Ardakan playa located on the Central Iranian Desert margins
were selected. In this study soil map, soil salinity observations, an interpolated soil salinity
map and 13 images in all, including 7 TM, 4 MSS and 2 Normalised Difference Vegetation
Indices (NDVI) images were used. After smoothing the imagery using a 3× 3 kernel, and
delineating the bare soil from vegetated areas, the correlation coefficients between soil salinity
(Electrical Conductivity) and related Digital Number (DN) values from TM and
MSS bands on different soil types, such as gypsiferons and saline soils, were calculated.
The results obtained demonstrate the trend of the correlation coefficients between soil salinity
and the related DN values of MSS and TM bands. Based on the results obtained, we
may conclude that the presence of gypsum in soil plays a significant role in lowering the
correlation coefficients between soil salinity and surface reflectance -further studies are
required to draw more general conclusions. From the results obtained we may also conclude
that the behavior of band 6 of TM on gypsiferous soil is completely different from
that on saline soil and, therefore, we may generally conclude that Landsat TM imagery
with six reflective bands, on the one hand, and the TM thermal band as complementary
information to the TM reflective bands, on the other hand, contained some useful information
that may play an important role in soil salinity studies and also the detection of
gypsiferous soils in desert areas.
Volume 3, Issue 4 (12-2015)
Abstract
Soil alkalinity and salinity are serious problems in arid and semi-arid regions, and therefore monitoring of soil pH and electrical conductivity (EC) is necessary in any region. The present study aimed to properly interpolate soil pH and EC as soil quality indices in a semi-arid mountainous area with annual precipitation of 342.4 mm. The study area is the Karimabad rangelands in Hamadan Province, western Iran. A total of 266 composite soil samples were collected from 0-25 cm soil depth in a systematic random design. Soil samples were processed for pH and EC analysis and then further used for interpolating based on the optimal interpolation method for the study area. The overall soil pH and EC ranged from 7.3-7.9 and 0.33-2.13 dS m-1, respectively, presenting the slightly alkalinity and salinity problem in the region. The results showed the accuracy of spatial prediction of interpolation methods, particularly inverse distance weighting and radius basis function. However, based on root mean square error, the radius basis function was the most appropriate interpolation method to predict spatial distribution of soil pH and EC of topsoil in the study area. While salinity and alkalinity were low, still monitoring these soil indices is highly recommended to prevent the salinization and alkalization in the study area.
Volume 4, Issue 1 (3-2016)
Abstract
Theeffect of salt stress on the pysiological and biochemical responses of the seedlings of eight Eucalyptus species viz. E. kingsmillii, E. tetragona, E. salubris, E. occidentali, E. microtheca, E. camaldulensis, E. globules and E. sargentii was analyzed. Four month-old seedlings grown in greenhouse were watered by five levels of salt solution (0, 50, 100, 150 and 200 mM of NaCl) in five replications with a factorial experimental design. The results indicated that salinity delayed and inhibited the seedlings’ growth after one month, and induced gradual decline in most of the criteria such as leaf area, relative water content and specific leaf area. Moreover, a significant reduction of chlorophyll a, b and total chlorophyll content was observed. Salinity stress raised the content of soluble sugars, proline and glycine betaine. Eucalyptus sargentii as the most tolerant species had the optimum growth up to 200 mM NaCl but E. globulus presented the most sensitive speciesto salinity stress. At 200 mM NaCl, proline and glycine beatine raised to 10.57 and 27 µg g-1 in the tolerant species (E. sargentii), respectively while proline in the sensitive species (E. globulus) dropped to 0.003 µg g-1. These results suggest that high tolerance of E. sargentii to salinity stress is closely related to lower specific leaf area and enhancement of compatible solutions such as proline, soluble sugar, glycine beatine. This would encourage the possibility of propagating E. sargentii in the southern coastal area of Iran. Furthermore, these results provided further biochemical support for the specific abiotic stress tolerance mechanism of Eucalyptus species.
Sajad Fatahi, , , , ,
Volume 4, Issue 2 (9-2015)
Abstract
The effect of different levels of betaine and tryptophan on growth and resistance to salinities in the Caspian roach was investigated. Fish (1.90 ± 0.04 g body weight) were divided into 9 groups (4 treatments groups containing betaine (0.5 and 1), tryptophan (0.25 and 0.5), betaine and tryptophan mixtures (0.25- 0.5, 0.25, -1, 0.5-0.5 and 0.5- 1), and control group). After recording the growth factors, the fish were exposed to salinities (12, 16 and 20 ppt) and clinical symptoms and mortality rate were recorded. No mortality occurred in 12 ppt salinity. At 16 ppt, the lowest mortality (16.66%) was recorded in the treatment containing 1% betaine and 0.5% tryptophan, while the highest mortalty (59.98%) occurred in the control group. At 20 ppt salinity, 100% mortality occurred within 6 hours in the control, while in the other treatments 100%-mortality occurred after 24 hours. Behavioral symptoms, such as jerky movements, ataxia, increased respiratory rate, were more prominent in higher salinities. Tryptophan did not reduce food consumption meaningfully. Increaesd food consumption as the result of betaine did not show significant effect on the fish growth rate.
Volume 5, Issue 1 (3-2017)
Abstract
Pedological criterion affecting desertification in alluvial fans was investigated, for which the map of units was prepared by crossing maps of land use, geology, slope classes and grid layer created by the extension of ET Geo-Wizards in ArcGIS 10.3. Three indices of salinity, erodibility, and permeability of soil were considered and classified. Weights of criteria and consistency ratio were calculated by the AHP method and ELECTRE I method was used to prioritize the options. After creating the weighted super matrix and calculating the concordance and discordance matrix, the difference between dominance and defeat values were calculated. The results showed that the difference in values obtained from AHP-ELECTRE I technique varied from -15 to 16. The alluvial fans were classified into three classes of I, III, and IV from the viewpoint of pedological criterion affecting desertification by using AHP-ELECTRE I technique. Results showed that 71.99% of the area was in the low desertification potential, while 2.19% and 25.82% were in the high and very high desertification potential, respectively.
, Mahmoud Nafisi Bahabadi, , , ,
Volume 5, Issue 2 (9-2016)
Abstract
In the current study, the effect of fresh water and different salinities of 15, 35 and 50 ppt on growth, feeding, body composition, glucose and cortisol in Asian sea bass (Lates calcarifer); were investigated. 180 fingerlings with average weight of 34.36±0.41 gram in 12 circular fiberglass tanks with 300 liter volumes were administered. Feedinng was done to satiation twice a day for 30 days. At the end of the experiment, biometry carried out and plasma and carcass samples were collected for estimating blood biochemical parameters and whole body composition. The obtained results showed that freshwater treatment had a significant difference in growth and feeding performance with other treatments (p < 0.05). Also, the results of carcass analyze showed that freshwater treatment moisture percentage was significantly higher (72.07±0.11) compared to other treatments (p < 0.05). Glucose and cortisol value in 15 ppt treatment were significantly higher at 35, 50 ppt treatment and 35 ppt, freshwater treatment, respectively (p < 0.05). Overall, this study showed this species is able to tolerate changes in salinity in the surrounding medium from seawater to brackish water through a period of 30 days and successfully adapt to freshwater without showing mortality. But, it could not be a good case for culture in fresh water because of using high energy for osmoregulation in fresh water.
, , ,
Volume 5, Issue 3 (12-2016)
Abstract
In a randomly and factorially designed experiment, the interaction effects of dietary zeolite (0 and 2%) and three salinity levels (80, 130 and 180 ppt) on growth, survival, reproductive performance and total longevity of A. franciscana were determined (6 treatments in total). The experiment was carried in two stages: nauplius to maturity and maturity to death of all females. The results indicated that the total body length of Artemia fed with zeolite were not significantly different among treatments in the third week of rearing (P>0.05), except for nauplii fed zeolite in salinity 180 ppt. However, Artemia fed with zeolite in 80 ppt had a higher body length and furcal length compared with other treatments. Nauplii in all treatments reached sexual maturity within 17-23 days (P>0.05). Survival rate was far higher in groups fed with zeolite compared to unfed groups; the highest values were recorded in group fed with zeolite at the salinity 130 ppt (P<0.05). The reproductive period and total longevity of females decreased with increasing salinity, but this trend was not affected by diet type. Average offspring production in the groups fed with zeolite was in the range of 861-1160 offspring compared to unfed groups (604-741 offspring) (P<0.05). The encysted embryos percentage was different in the range of 20-35%. According to the results, the inclusion of 2% zeolite in salinity within 80-130 ppt were better for growth of the Artemia to maturity. Also, it is recommended to add zeolite in the Artemia diet with the increasing trend in salinity from 80 to 180 ppt for improving broodstock reproductive performance.
Volume 5, Issue 3 (9-2017)
Abstract
Background: Environmental stresses, especially salinity and drought, are effective on seed germination and growth.
Materials and Methods: After breaking seed dormancy by simultaneous use of leaching (48 hours) and gibberllic acid (1000 ppm), germination characteristics and seedling growth of Citrullus colocynthis from two ecotypes of Sistan-Baluchestan with six levels of drought (0, -0.3, -0.6, -0.9, -1.2, -1.5 Mpa) and salinity (0, 50, 100, 150, 200, 250 mM) were studied. This experiment was carried out in two different factorial experiments using completely randomized design with four replications. Statistical analysis was performed using version 18 of SPSS software and Factorial analysis of variance (general linear model) and mean comparisons were done using Duncan's multiple range test. Results: The results demonstrated that there were significant differences among different levels of drought and salinity in all measured traits (P<0.01) and a significant decrease in seed germination and seedling growth were observed with increasing levels of drought and salinity (P<0.01). The results revealed that there were significant interactions effect between ecotype and different levels of drought as well as salinity (P<0.01), so seed vigor of Zabol’ ecotype was higher than that of Saravan.
Discussion and Conclusions: This species has acceptable germination at -0.6 Mpa droughts and 50 mM salinity. These issues must be considered in its intense planting in Sistan-Baluchestan province and using of Zabol’ ecotype seed is recommended.
Volume 6, Issue 3 (2-2004)
Abstract
Salinity is the primary water quality concern in irrigated agriculture. An Electrical Conductivity (EC) meter and a hydrometer are two possible methods for measurement of irrigation water salinity. The conductivity meter method is based on measuring the amount of electrical current that a fluid will support. Although it is the most widely used method, the instrumentation is rather expensive and in some instances may require sample dilution. The hydrometer method is based on measuring the density of the fluid. The main objectives of this study were to compare these two methods and, based on hydrometer method, develop empirical models for prediction of EC, sodium adsorption ratio (SAR), and the principle ion concentrations in the irrigation waters of Yazd Province, Iran. The electrical conductivity, temperature, and density of 206 water samples from wells across Yazd Province were measured. Temperature correction factors for adjusting the hydrometer reading to 25 oC were determined. The correlation between EC and hydrometer readings was high (R2 = 0.97). Although the empirical model developed for prediction of EC slightly underpredicted the measured values, it is still accurate enough for practical purposes. Hydrometer readings were also highly correlated with the principle ions and SAR. The salt type also affected the hydrometer readings. Magnesium sulfate solution had the highest density among the major salt types present in irrigation waters. Finally, a chart was developed for rough estimations of EC, sodium and chlorine concentrations in irrigation waters of Yazd Province, Iran.
Volume 7, Issue 1 (6-2016)
Abstract
CO2 biosequestration by using algae is one of the promising and environmentally friend methods. The present study aimed at investigating the ability of Spirulina platensis in terms of growth and carbon dioxide fixation under different salinity levels and also variety of CO2 concentration. To this purpose, analysis of growth parameters including biomass productivity, specific growth rate and carbon fixation rate during the 8-day periods by maintaining the same conditions, under 3 salinity levels (3, 1500 and 34000 µs/cm) and four CO2 concentration (0.03%, 2%, 5% and 10%) were performed. this test have been performed in flat plate reactors by using pure stock of Spirulina platensis culturing in Zarrouk's medium . in all cultures, microalgae showed the highest specific growth rate during the first four days, as 0.35, 0.23, 0.24 and 0.24 d-1 in natural water, respectively. The highest carbon fixation rate and biomass production of Spirulina platensis were related to natural water (the city of birjand) under 10% CO2 concentration( 0.49 and 0.98 gL-1 d-1) that is followd by pure water of 0.45, 0.09 gL-1 d-1 and artificial sea water of 0.42 and 0.84 gL-1 d-1 respectively.the growth rate was lower in artificial sea water because of high salinity.
Volume 8, Issue 2 (4-2006)
Abstract
Use of saline water for irrigation has shown considerable promise. However, its effect on the solubility and bioavailability of native soil nutrients is not well understood. This study was conducted to evaluate the effects of salinity on the behavior of zinc(Zn) in calcareous soils. The soil samples with different physiochemical properties were collected from four locations in Khorasan province (Iran). The factorial experiment was carried out as a completely randomized design on soils with four levels of water salinity (0, 37.5, 75 and 150 mole m-3 prepared with the same equivalents of NaCl and CaCl2) and four reaction times (0, 10, 20, and 30 days) with three replications. DTPA-extractable Zn was measured in the incubated soil samples after the given reaction times. Different chemical forms of Zn were characterized after 30 days using the sequential extraction procedure. DTPA-extractable Zn increased by 1 to 6.3% with the increasing levels of salinity, and decreased from 8.7 to 3.9% by increasing the reaction time significantly (P<0.05). The determination of Zn compounds by the sequential extraction procedure revealed significantly different forms of Zn with the average amounts in the following order: (KNO3+H2O)-Zn(soluble+exchangeable forms) < NaOH-Zn(organic form) < EDTA-Zn (carbonate form) << HNO3 -Zn (residual). Salinity affected various forms of Zn i.e. soluble + exchangeable, organic and residual. Increasing soil salinity level increased the KNO3+H2O extractable Zn by 20 to 80% and the NaOH extractable form by 8.6 to 43%. DTPA-Zn was significantly correlated with the NaOH extractable form (r=0.98 P<0.05) and with the (KNO3+H2O)-Zn, (r=0.94 P<0.05). It was concluded that increasing salinity redistributed HNO3-extracted Zn (residual) to the KNO3+H2O extractable (soluble + exchangeable) and NaOH extractable (organic) forms of Zn.
Volume 8, Issue 3 (7-2006)
Abstract
This study investigated intra-specific variation in the growth parameters and dry mat-ter partitioning of sugar beet cultivars at different levels of salinity (0, 50, 150, 250 and 350 mM NaCl + CaCl2 in 5:1 molar ratio) using four cvs, one British (Madison) and three Iranian cvs (7233-P12, 7233-P21 and 7233-P29). The plants were grown in a controlled greenhouse environment for about 18 weeks. Although growth parameters such as leaf area and dry matter accumulation were stimulated or unaffected at a low level of salinity (50 mM), higher salt concentrations significantly decreased all growth traits. At a high level of salinity, cv P29 showed a significantly higher leaf area and total dry matter than others at 16 weeks of salt treatment. Pre-dawn leaf-water potential (ΨL) and shoot water content (SWC) were decreased by salinity. Cvs Madison and P12 had significantly lower ΨL (more negative) and shoot water content at high levels of salt treatment (250 and 350 mM), while P29 and P21 showed higher ΨL (less negative) and shoot water content at the same salt concentrations. Analysis of ion accumulation revealed that Na+ and Cl- contents were greatly increased in leaves under saline conditions. However, salt tolerant P29 had lower Na+ and Cl- concentrations than other cvs at high levels of salinity. The root dry matter of sugar beet cvs at the lowest and the highest salt concentrations reduced by 23.3% and 89.8%, respectively compared to the non-stressed plants, while shoot dry mat-ter decreased by 1.1% and 77% at the same salt concentrations, respectively, after 16 weeks of salt treatment. The pattern of dry matter partitioning to different parts of the plant was changed by salt stress and the dry matter allocated to the storage roots was re-duced by 6% and 18% at the lowest and the highest salt concentrations, respectively, at 16 weeks after salinisation.
Volume 8, Issue 3 (7-2020)
Abstract
Aims: High salt accumulation has severe adverse effects on soil characteristics. Humic acid can improve the soil structure, soil microbial communities, and absorption and maintenance of mineral nutrients. The aim of the present study was to determine the effects of humic acid on some physicochemical and biological soil properties in soils under salt stress.
Materials & Methods: The experiment was conducted as a factorial based on RCBD design with four replications. The first factor included humic acid in five levels (zero, 10, 20, 30, and 40mg kg-1 soil). The second factor was salinity stress in five levels (0, 25, 50, 75, and 100mM NaCl). The sampling was carried out in two stages, before and after harvest.
Findings: The results showed that S1H5 treatment had the lowest soil electrical conductivity (EC), soil reaction (pH), bulk density, and population of actinomycetes with average values of 0.26dS m-1, 6.21, 1.12g cm-3, and 516cell g-1 of soil and had the highest fungal and bacterial population with an average of 1525000 and 137500000cell g-1 of soil, respectively.
Conclusion: Salt stress has a significant effect on physicochemical and biological soil properties except for the population of actinomyces that their activity was better, at a high level of salinity stress, it had adverse effects on other properties. Although using humic acid improved soil properties. According to the results, using humic acid can be a good solution to reduce the adverse effects of salt stress.
Volume 8, Issue 3 (7-2020)
Abstract
Aims: Allelopathy and salinity stresses are known as major abiotic factors which limits the growth and production of plants. Environmental stresses such as salinity and allelopathy can affect the growth and establishment of rangeland species; however the interaction of such environmental stress and inter-plant competition (i.e., allelopathic effects) associated with arbuscular mycorrhiza rarely understood. Therefore, this study aimed to investigate the effect of arbuscular mycorrhiza on physiological traits and nutrient uptake of Poa bulbosa L. under the influence of allelopathy and salinity stress.
Materials & Methods: A factorial experiment was designed with a completely randomized design with three replications. Factors include allelopathy extracted by Artemisia persica Boiss root (treat vs. control), salinity (control, 1, 4, and 8mmol/kg NaCl) and mycorrhizal fungi (mixed and unmixed). The experiment was set up in Malayer University greenhouse in a completely randomized design with factorial layout and 3 replications.
Findings: The stem and root of the studied plant species were higher than those found in non-inoculated treatments at low salinity and allelopathy treatments (p<0.05). Also, in severe stress conditions, mycorrhizal dependency was significantly higher (50.87). Proline content does not show variation under all studied treatments (p<0.05). Chlorophyll content decreased significantly with increasing salinity and allelopathy, but in the presence of mycorrhizal fungi, the rate of reduction was significantly lower and mycorrhizal fungi increased chlorophyll well. Plant nitrogen and phosphorus contents also coincided with the mycorrhizal fungi, showing the highest yield (3.7% and 2.6g kg-1 for total nitrogen and phosphorus respectively).
Conclusion: The growth, establishment and physiological properties of the Poa bulbosa L. are improved under the influence of mycorrhizal application. Thus, the use of mycorrhizal fungi can be a useful biological method to reduce the destructive effects of environmental stresses such as salinity and allelopathy.
Volume 8, Issue 34 (12-2011)
Abstract
High concentrations of salt in beach water and some industrial wastewaters resulted in an increase in water salinity, which causes difficulties in wastewater treatment. In this research, the effect of salt concentration (up to 30000 mg/L) on the treatment efficiency rates of saline wastewater in lab- scale batch conditions of Sequencing Batch Reactors (SBR) and Moving Bed Biofilm Reactor (MBBR) were investigated.
The results indicated that at low concentration of salinity (0.5%) the removal rate of 94% in both MBBR and SBR has been achieved but in high concentration (3%) the efficiency of SBR (90%) was more than MBBR (83%). On the other hand attached growth in SBR has more potential to remove salinity. The rate of COD removal was 78 and 85 percent in MBBR and SBR, respectively. In the investigation of shock effect in salinity concentration of 50000 mg/L, the salinity removal efficiencies in MBBR and SBR has decreased to 56 and 68 percent respectively that has been reached to the previous level after 28 days.
Volume 9, Issue 1 (12-2020)
Abstract
One critical environmental stress that limits plant production and development is salinity stress. Recently it has been shown that application of plant growth-promoting rhizobacteria (PGPR) can alleviate the deleterious effects of environmental stresses. Present study aimed to evaluate the effects of some bacterial strains on proline, sugar, total phenolic compounds (TPC), Phenylalanine ammonia lyase (PAL), photosynthetic pigments and antioxidant activities (guaiacol peroxidase, polyphenol oxidase and superoxide dismutase) of cucumber plants under salinity stress. A completely randomized design was applied with a factorial arrangement of two factors: salinity at three levels (0, 50 and 100 mM) and Pseudomonas fluorescens and Bacillus subtilis strains, with three replications. The results showed that cucumber plants that were inoculated with Pseudomonas and Bacillus strains possessed noticeable variations in proline, sugar, TPC, PAL and enzymes activity compared to un-inoculated control. These results suggest that use of these bacterial strains overcame harmful effect of salinity by accumulation of proline, TPC, sugar, PAL activity and enzymes activity that can be considered as a suitable method to manage salinity stress.
