Showing 10 results for Salinity Stress
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 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 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.
Azin Fahim, Mohammad Reza Kalbassi, Abdolmohammad Abedian Kenari, Mohammad Sadegh Sabet,
Volume 11, Issue 4 (12-2022)
Abstract
The aim of this study is to investigate the changes in fatty acid composition in Nannochloropsis oculata microalgae under physicochemical stresses (light intensity and salinity). In this regard, the growth rate, the amount of chlorophyll and carotenoid, the approximate analysis and the profile of fatty acid changes of marine microalgae N. oculata under two mutual stresses of salinity (15, 25 and 40 g/l) and light intensity (Lux 1500 and Lux 10000) which at the end of the phase Logarithms were applied are examined. The results showed that according to the application of stresses after the completion of growth, there was no significant difference in the growth rate in different treatments (P>0.05). Also, despite the fact that the highest amount of lipid was obtained under the salinity treatment of 40 g/l and the light intensity of Lux 1500, the highest amount of saturated fatty acids (SFA) was obtained under the treatment of salinity of 15 g/l and the light intensity of 10000 Lux, the highest amount of monounsaturated fatty acids (MUFA) under 25 g/l treatment and 10000 Lux light intensity and the highest amount of polyunsaturated fatty acids (PUFA) under 15 g/l treatment and 10000 Lux light intensity were obtained after 4 days of stress. Considering the effectiveness of fatty acid compounds in N. oculata microalgae, by controlling the cultivation conditions, the maximum amount of desired fatty acids can be achieved in accordance with the desired goals.
Volume 15, Issue 4 (7-2013)
Abstract
To understand the effects of salinity stress on four different growth stages of sorghum, a greenhouse experiment with 10 treatments, considering all possible combinations of salinity stress and salt- free periods was carried out. The four growth stages for stress application included: emergence until growing point differentiation, growing point differentiation until half bloom, half bloom until soft dough, and soft dough until physiological maturity. Treatments were arranged based on randomized complete block design with 3 replications at the Research Greenhouse of theFerdowsiUniversityofMashhadin 2010-2011. Salinity stress during early growth and panicle differentiation declined the plant height and tiller number. The highest biological yield was obtained from the control treatment, but it was the lowest when plants were salinized throughout the growing season. When plants were stress-free at 2-3 early stages and then subjected to salt stress, reductions in total dry matter were remarkably less than those experienced when salinity was imposed in later growth stages, especially if salinity occurred at a late individual stage. Continuation of salt stress from emergence to both blooming and soft dough stages led to remarkably adverse effects on grain yield. The effect of salinity appears to be most effective on yield components that are growing or developing at the time the salt stress is imposed. The critical period of salinity stress for biological yield was more distinct than that of the grain yield. This indicates that sorghum is not sensitive to salinity at seed setting and seed filling periods.
Volume 18, Issue 2 (3-2016)
Abstract
Somatic embryos of Persian walnut were transformed with two strains of Agrobacterium tumefaciens i.e. LBA4404 and C58, and two plasmids, namely, pBI121 with nptII and gus genes for improving the transformation protocol, and p6u-ubi-FVTI plasmid containing the hpt and fld genes. The transformation frequency was 10%. PCR and RT-PCR analysis proved the presence and expression of the genes. The transgenic and non-transgenic somatic embryos of Persian walnut were exposed to four salinity levels (0, 50, 100, and 200 mM NaCl) and four osmotic stress (0, 1.5, 5, and 10% PEG) levels. After 20 days, the number of survived, secondary and cotyledonary somatic embryos, as well as fresh and dry weights of embryos were evaluated. In addition, the transgenic and non-transgenic regenerated plantlets with 3 leaves and 2.5 cm length were subjected to 200 mM NaCl. In both experiments, the main effects of fld-transformation and stress treatments on evaluated parameters were significant. Transgenic somatic embryos showed no significant differences at 0 and 200 mM NaCl and 0 and 1.5% PEG. Significant differences of transgenic vs. non-transgenic somatic embryos were observed at 50 and 100 mM NaCl and 5 and 10% PEG. Non-transgenic plantlets on medium containing 200 mM NaCl showed complete necrosis and died after 10 days, while transgenic lines continued growth until 45 days. Our results clearly showed that expression of fld gene increased stress tolerance in fld transformant lines of walnut, and also revealed that expression of this specific cyanobacterial protein may provide a powerful tool to improve tolerance to environmental stresses.
Volume 23, Issue 2 (3-2021)
Abstract
Ajowan is an important medicinal plant that grows mainly in arid and semi-arid regions of the world. To evaluate salinity tolerance of 25 Iranian ajowan ecotypes, three-step screening was conducted at germination, seedling, and adult plant growth stages using 0, 50, 100 and 150 mM of NaCl. The significant effects of salinity were observed at the three studied growth stages of ajowan ecotypes. Germination percentage, seed vigor, and biomass dry weight of investigated ecotypes decreased with the increase in NaCl levels. Different responses were observed among ajowan ecotypes in terms of activity of antioxidant enzymes of catalase and peroxidase, with the increasing salinity stress levels .Under the salinity stress, the proline content increased in the majority of the investigated ecotypes. Salinity stress had adverse effects on single plant seed yield and yield components. Results of the calculated correlation coefficient and path coefficient analysis showed that activity of catalase antioxidant enzyme and 1,000-seed weight were the most important characteristics that can be suggested as selection criteria for seed yield of ajowan under salinity stress conditions. The overall results suggest that nine Iranian ajowan ecotypes including Arak, Felaverjan, Ghoom, Hamedan, Karaj, Ghaen, Tehran, Yazd, and Shiraz were the salinity-tolerant ecotypes.
Volume 24, Issue 1 (1-2022)
Abstract
To study salinity tolerance of 15 basil accessions widely distributed across Iran, they were grown under two salt levels including control (no NaCl) and 40 mM NaCl (Hoagland nutrient solutions with EC of 1.1 and 5.5 dS m-1, respectively). The studied parameters included morphological characteristics and chlorophyll a fluorescence transient (OJIP) measurements. According to the results, the accessions were categorized into three clusters under the salt stress. Salinity had significant effects on morphological and growth parameters in all basil plants. Compared to the control, NaCl decreased plant height. The number of leaves in Khash, Zabol, and Orumiyeh accessions was more than the others. Both salt and accession caused a decrease up to 43% in leaf fresh weight, emphasizing the major role of accession when salinity was applied. Salinity influenced negatively the biomass yield in basil plants. These decreases varied from 19 to 45% depending on the accessions. Salt treatment of basil plants decreased photosystem II activity, as evaluated from chlorophyll fluorescence data. The parameters that were most affected by salt treatment were maximal quantum yield of PSII photochemistry (FV/FM) and calculated Performance Index (PIABS). Overall, among the studied basil accessions, genotype Ardabil had superior tolerance to salt stress. Furthermore, the most of accessions can be used for studying the mechanism of salinity tolerance in basil plant.
Volume 24, Issue 2 (3-2022)
Abstract
Soil salinity is one of the most important environmental constraints that reduce plant growth and productivity. This study aimed to investigate the effects of various NaCl concentrations on the physiological properties of grape cultivars. NaCl was added at three levels (0, 25, and 50 mM) to Murashige and Skoog medium under in vitro conditions to assess various effects on 21 grape cultivars. Effects of salinity stress were investigated on ascorbate peroxidase, catalase, and superoxide dismutase activities, as well as malondialdehyde, protein, proline, chlorophyll A and B contents, of all samples. The results showed that with an increase in salinity, the amount of antioxidant enzymes, proline content, and protein increased in cv. Rasha, suggesting that it was more tolerant than the other cultivars. Malondialdehyde and Electrolyte leakage accumulation also increased in all cultivars, but this increase was higher in salinity-sensitive cultivars, such as hybrids and wild cultivars than resistant cultivars. During salinity stress, chlorophyll content decreased, and the lowest decrease in chlorophyll content was recorded in cv. Rasha, compared to other cultivars. This research demonstrated that the resistance of cv. Rasha, H6 and H4 to salinity stress was due to its ability to adjust proline, protein content, and antioxidant enzymes.
Volume 26, Issue 2 (3-2024)
Abstract
Citrus is one of the most important fruits whose growth performance and production is significantly affected by environmental stresses. Abiotic stresses, such as salinity and alkaline pH, strikingly limit citrus growth and development. The aim of the present study was to investigate the effect of four NaCl concentrations (0, 30, 60, 90 mM) and two pH levels (6.5 and 8.2) on some of morphological, physiological, and biochemical parameters of two citrus rootstocks (Sour orange and Bakraei rootstocks). The experiment was conducted as factorial based on a completely randomized design with four replications, at the Faculty of Agriculture, Shahid Chamran University of Ahvaz, Iran. The results showed that the value of shoot dry weight, fresh and dry weight of roots, and transpiration were significantly decreased in both Bakraei and Sour orange rootstocks when receiving irrigation with 90 mM supplement of salinity at pH= 8.2. Proline and carbohydrates of citrus rootstocks were considerably increased by increasing the levels of salinity (90 mM NaCl) and alkaline stress (pH= 8.2) in each rootstock, at which condition the photosynthesis rate of Sour orange and Bakraei also declined by 34.77 and 50.80%, respectively. The activity of antioxidant enzymes such as peroxidase, catalase, and superoxide dismutase were increased by 57.42, 42.10, and 45.86% in Sour orange rootstock and 42.04, 26.78, and 37.92% in Bakraei rootstock, respectively. Overall, it can be concluded that the growth performance of Sour orange rootstock is more suitable than Bakraei to tolerate salt-alkali conditions.
