The rapidly growing industries have resulted in environmental changes, increase in sea level as well as soil and water salinity threatening the survival of many important crop species. Considering this urgency, our study was aimed at studying the effect of saltstress on different growth and biochemical parameters on Zea mays. We have found out that even though the plant is not affected visibly manifested by unaffected rather an increasing fresh and dry weights, the biochemical parameters like pigment and proteins are decreased. The soluble sugar content is increased owing to the increase in proline content, which is known to be increased under salinity stress. In conclusion, salinity is the most serious threat to agriculture and to the environment in many parts of the world and key molecular factors that can be used for genetic engineering of salt-tolerant plants.
Polyols, the polyhydric alcohols, are among the compatible solutes involved in osmoregula- tion and are thought to play a role in plant salt tolerance (Bohnert and Shen 1999). They exist in both acyclic and cyclic forms and are wide- ly distributed in the plant kingdom. The most common polyols in plants include acyclic forms, mannitol, glycerol, sorbitol, and cyclic (cyclitols) forms ononitol and pinitol. In general, they are thought to accumulate in the cytoplasm of some halophytes to overcome the osmotic disturbances caused by high concentrations of inorganic ions compartmentalized in vacuoles. Polyols make up a considerable percentage of all assimilated CO 2 as scavengers of stress-induced oxygen radicals (Bohnert et al. 1995). Mannitol, a sugar alcohol that may serve as a compatible solute to cope with saltstress, is synthesized via the action of a mannose-6-phosphate reductase (M6PR) in celery (Zhifang and Loescher 2003) and its accumula- tion increases when plants are exposed to low water potential. The accumulation is regulated by inhibition of competing pathways and decreased mannitol consumption and catabolism (Stoop et al. 1996). Studies using transgenic tobacco and Arabidopsis have shown improved growth of man-
cereals food are supplied by grain and dairy product. There are six cereals-rice, wheat, maize, barley, oats and rye are belong to the family Gramineae (Poaceace). Yield components and growth parameter also show differential responses to salinity stress. Shannon et al. (1994) had reported that the salinity often affects the timing of development. In wheat, sorghum and oat, ear emergence, anthesis and rye maturity is unaffected by salinity. Wheat is the most important stable crop in the world and its productivity in saline soils is considerably reduced due to improper nutrition of plants as well as osmotic and drought stress (Shannon, 1998). Rice is one of the main staple food in India and mostly for Asians people is susceptible to saltstress (Munns and Tester, 2008; Anbumalarmathi and Mehta, 2013 particularly during the early seedling stage (Li and Xu, 2007 Plants are sessile organisms and are directly exposed to environmental stress such as salinity, drought, low temperature (Munns and Termatt, 1986; Dadkhah, 2011
We then studied the localization of Rvs161p-GFP in the sphingolipid single fen1, sur4, sur2, sur1, ipt1, and lcb1-100 mutants; the last is a temperature-sensitive mutant impaired in the first step of sphingolipid biosynthesis (Fig. 1) that has been shown to be impaired in establishing DRMs (1). In sur2, sur1, and ipt1 deletants, the localization of Rvs161p was similar to what was seen in the wild-type strain (Fig. 7B), while Rvs161p- GFP was clearly mislocalized in the fen1 and sur4 deletants and in the lcb1-100 mutant. In the fen1 and sur4 mutants, cortical patches were still present but in a lower amount. No fluores- cence could be detected in the septa, while undefined struc- tures visible with Nomarski optics were stained (Fig. 7A). In the lcb1-100 mutant at the permissive temperature (26°C), cortical patches were present, but the septa were not stained, although the fluorescence increased in the mother bud neck area on the mother side. Importantly, when the lcb1-100 mu- FIG. 3. wsc1 mutant impaired for actin cytoskeleton depolarization following saltstress. (A) The wsc1 strain was grown and treated as described for Fig. 2. (B) Cells (⬇100) were classified and quantified according to their polarization state. Only cells with small buds were scored. Cells with actin patches concentrated in the small bud, with fewer than four patches in the mother cell, were classified as polarized cells (black bars). Cells with actin patches concentrated in the small bud but with more than four patches in the mother cell were classified as partially depolarized cells (grey bars). Cells with more actin patches in the mother cell than in the small bud were classified as totally depolarized cells (white bars).
pratensis parentage, (3) four fescue phenotype like F. pabulare accessions with Lolium multiflorum × Festuca arundinacea parentage, and four ryegrass phenotype like F. pabulare accessions with Lolium multiflorum × Fes- tuca arundinacea parentage. Seeds from each acces- sion were germinated and grown in five replicates on 10 × 10 × 5 cm rock wool blocks and subjected to saltstress. The blocks were placed on tables that were inter- mittently flooded with water of the appropriate salt (NaCl) concentration and salt application was gradual. After 87 days establishment without salt, the plants were subjected to 0.5% NaCl for 28 days, then to 1.0% for 15 days, then to 1.5% for 34 days. Plant response to salt treatment was measured in terms of percentage of green leaves for each block with visual scoring. This phenotypic score was taken at three salt concentrations (0.5%, 1% and 1.5%). In order to ensure consistency, salt concentra- tion was determined in terms of electrical conductivity in the solution (EC) which is a recommended methodology in similar scenarios (Additional file 2: Fig S1) .
Different levels of saltstress varied significantly in terms of yield per plant of tomato (Table 1). The highest yield per plant (3.19 kg) was recorded from 0 dS m -1 Na, while the lowest yield (1.42 kg) was found from 8 dS m -1 Na. Most crops tolerate salinity up to a threshold level, above which yields decrease as salinity increases (Maas, 1986). Tomato yield were subjected to 75 and 150 mM NaCl stress in order to study the effect of saltstress on its antioxidant response and stress indicators by Slathia and Choudhary (2013). Rubio et al. (2009) found that total fruit yield was increased because the fruit weight was increased. NaCl to nutrient solution, significantly reduced fruit yield in terms of number of fruits per plant from 8.13 (control) to 3.83 (Lolaei, 2012). Different levels of calcium nitrate showed significant differences on yield per plant of tomato (Table 1). The highest yield per plant (2.89 kg) was recorded from 10 mM Ca, whereas the lowest yield (1.93 kg) was observed from 0 mM Ca. Hao and Papadopoulos (2004) reported that at 300 mg·L –1 Ca, total fruit yield increased linearly. Ahmad (2014) showed that exogenous application of silicon and potassium nitrate reduced sodium uptake, increased potassium and consequently improved seed yield. Howladar and Rady (2012) found that seed coating with calcium paste reduced the toxic effects of NaCl on plant growth and yield by increasing leaf pigments, ascorbic acid, proline contents and enzymatic activities.
decreased with increased salinity levels. When the salt treated plants were supplied with exogenous proline, they produced significant amount of grain and straw yields. Sodium content and uptake by plants were decreased with foliar application of proline. It can be concluded that saltstress in rice reduce to a significant extent due to the exogenous application of proline.
Abstract: Soybean seeds rapidly deteriorate or loss of viability and vigor, especially in stress conditions including by saline. This study was aimed to obtain the best seed viability and vigor of soybean treated by seed priming under saltstress. This study used a randomized completely block design with factorial pattern. First factor was the saline stress of NaCl concentration (C) which consisted of three levels (c0 = 0%, 0.5% = c1, c2 = 1%).Second factor was the treatment of seed priming (P) that consisted of 4 levels (p0 = hydropriming, p1 = osmopriming, p2 = matripriming, p3 = vitamin priming). The experiment was repeated three times. Data collected consisted of: germination capacity, germination rate, hypocotyl and epicotyl length, the weight of seedling, and the electrical conductivity. Data were analyzed by analysis of variance followed by Duncan's multiple range test at 5 percent. The results showed that osmopriming, matripriming, and vitamin priming improved total germination and germination rate of soybean seeds under salinity stress, while seed priming with hydropriming caused significantly the reduction of germination total and germination rate in salinity stress of 1 percent. Increased salinity stress from 0 to 1 percent caused a reduction in hypocotyl and epicotyl length, different with osmopriming, matripriming, and vitamin priming that produced hypocotyl and epicotyl longer than hydropriming. In all seed primings, increased salinity stress from 0 to 1 percent lowered the weight of seedlings, and most drastic reduction of seedling weight occurred in seeds treated with hydropriming. Among seed priming treatments, osmopriming, matripriming, and vitamin priming were more able to reduce membrane leakage compared to hydropriming as indicated by lower electrical conductivity rates contributing the increase in tolerance to saltstress and high in seed viability and vigor.
Some stress-induced epigenetic changes are likely to be maintained across mitotic divisions, and may allow plants to respond better to subsequent stress exposures. Through stable epigenetic modifications plants may become “primed” and develop a better tolerance to particular stress (Pieterse, 2012; Prime et al., 2006). Heritable effects accross generations have also been observed, where the offsping “inherit” stress-induced epigenetic changes acquired by the parental. Many studies have reported that stress-induced DNA methylation changes acquired by plants could be inherited across several generations under non-stresses conditions. For instance, Jiang et al., (2014) reported that majority of salt induced DMPs (~75%) were inherited across two non-stressed progeny. Surprisingly, I found that majority of methylation changes detected in stressed parental plants (stressed-PO plants) are erased in the untreated progenies (stressed-P1 and stressed-P2 progenies), suggesting that saltstress applied in my study only had transient effect on plants epigenome. Nevertheless, after 3 and 5 generations of constitutive saltstress treatment the P1- stressed progenies formed a sub-group in clustering analysis separated from P2- stressed progenies and control plants, suggesting that following multigenerational saltstress treatment a small fraction of stress-induced DNA methylation changes are inherited by non-stressed P1 progenies. These data are in accordance with my phenotype data, which shows increased tolerance in the P1 progeny only, thus indicating that acquired DNA methylation changes alter the response of plants to saltstress. Surprisingly, in the P2 progeny these DNA methylation changes are lost, which is associated with a reversion of plant’s tolerance to stress back to control
0.00158), serine-type endopeptidase inhibitor activity (P = 0.00211), and defense response (P = 0.00321) were detected both under salt-stress conditions and after Xoo inoculation (Fig. 7c–e; Additional file 13: Table S6, Add- itional file 14: Table S7). Accordingly, there were 404 and 1324 DEGs that were unique to responses to the saltstress and Xoo infection, respectively (Fig. 7c). The DEGs specifically detected under salt-stress conditions were as- sociated with oxidation–reduction process (FDR = 1.27E- 12), response to oxidative stress (FDR = 1.10E-07), fatty acid biosynthetic process (FDR = 7.74E-06), and response to stress (FDR = 9.33E-05). (Fig. 7f; Additional file 13: Table S6, Additional file 14: Table S7). Glucan, fatty acids (FAs), and FA-derivatives are important sources of reserve energy and essential components of cell organ- elles in plants. They also play significant roles in improv- ing stress tolerance in plants by participating in several defense-related pathways. The transcripts LOC_ Os03g01800, LOC_Os06g48200, LOC_Os07g36630, LOC_ Os09g25490, LOC_Os10g32980, and LOC_Os11g33270 are involved in glucan metabolic processes and were dif- ferentially regulated in this study. LOC_Os06g48200 and LOC_Os11g33270 were down-regulated in the WT plants in comparison with OsSAPK9-RNAi plants, while the other transcripts were up-regulated in the same comparison (Fig. 7g; Additional file 15: Table S8). There were also 16 DEGs associated with lipid metabolic pro- cesses that were up-regulated in the WT plants (Fig. 7 g; Additional file 15: Table S8). Of these processes, redox regulation, antioxidant defense, and ROS signaling are critical in realizing and fine-tuning metabolic activities. There were 43 DEGs associated with the oxidation–
as compatible solutes or osmolytes (Läuchli and Lüttge 2002). Many of these compatible solutes are N-containing compounds, such as amino acids and amides or betaines, hence the nitrogen metabolism is of central importance under stressful condi- tions (Läuchli and Lüttge 2002). It is significant to research the effects of saltstress on nitrogen metabolism in plants. It was well described that saltstress strongly affects nitrogen metabolism of plants (Parida and Das 2005, Munns and Tester 2008). In addition, high salt environments can break the ion homeostasis of plant cells, destroy the ionic balance, and affect the distributions of ion at cells, tissues, and whole plant levels (Niu et al. 1995). It is necessary to osmoregulate and re-establish the ion homeostasis in cells for plant
mechanisms that plants use to cope with detrimental effects of salinity stress ((Blumwald 2000); Zhu 2002; (Munns 2005; Ren et al. 2005; Munns and Tester 2008; Horie et al. 2009); Hauser et al. 2010). Correlations between the ploidy levels and morphological traits in wheat were significantly positive under saline conditions, showing that values of morphological traits increased with the number and types of genomes. Polyploidy was significantly associated with the species performance for all traits in the study, excluding the number of yellow leaves and shoots under saline conditions (Rauf et al. 2010). The expression of genes duplicated by polyploidy (termed homeologs) in cotton can be partitioned between the duplicates so that one copy is expressed and functions only in some organs, and the other copy is expressed only in other organs, indicative of subfunctionalization. These results suggest that the subfunctionalization of genes duplicated by polyploidy occurred in response to abiotic stress conditions. Partitioning of duplicate gene expression in response to environmental stress may lead to duplicate gene retention during subsequent evolution (Liu and Adam 2007). As several sources of improved Na + “exclusion” are now known to reside on different chromosomes in various genomes of species in the Triticeae, further studies are required to identify the underlying mechanisms controlling genes for the various traits that could act additively or even synergistically, which may enable substantial gains in salt tolerance (Colmer et al. 2006). The regulation mechanism is complicated in polyploid rice, and understanding how duplicated genes affect rice development under saltstress could be important for biological and agricultural applica- tions. The results of our work suggest that tetraploid rice has a better protective mechanism than diploid rice against salinity, in agreement with the results of earlier studies on the genome duplication effect in Citrus, Acanthophyllum spp., and other plants under saltstress (Saleh et al. 2008; Yildiz and Terzi 2008; Mouhaya et al. 2010). Several studies have indicated that the response of plant cells to high salt is con- trolled by multiple genes (Bartels and Sunkar 2005; Chinnusamy et al. 2005; Sahi et al. 2006). Polyploid rice was believed to improve the root adaptability to saltstress by regulating root growth and protective structure formation, subsequently decreasing Na + assimi- lation. Thus, exploring the significance of protection mechanisms in polyploid rice salt tolerance, including morphological barriers at the molecular, cellular, and whole plant level, is important to develop high-yielding, salt-tolerant polyploid cultivars.
Effect of saltstress on seedlings protective enzyme activities. The level of the antioxidant enzymes SOD, POD, and CAT may determine the sensitivity of plants to lipid peroxidation (Kanazawa et al. 2000). In our study, with increasing salinity levels, activities of the antioxidative enzymes of SOD, POD, and CAT were enhanced by salts treat- ment of Periploca sepium Bunge seedlings, but CAT activity decreased at 200 mmol/L NaCl saltstress (Figure 3), indicating that the ability of these antioxidant enzymes to eliminate ROS is limited. The activity of enzymes of POD and CAT is higher than that of SOD at 200 mmol/L NaCl, which sug- gests that POD and CAT provide a better defense mechanism against saltstress-induced oxidative damage in Periploca sepium Bunge seedlings. The results are similar to Yeonghoo et al. (2004).
Saltstress is one of the vital stresses consequential in decrease the yield and component of various crops including wheat (Triticum aestivum L.). Current practical was conducted to determine best variety of wheat (T. aestivum L.) for Charsadda under saline condition. The consequence caused by saltstress on the biochemical constituent (moisture, ash, crude fiber, crude fat, carbohydrates and protein) of five different varieties of wheat seeds grown under high artificial NaCl stress. During time period of sowing-harvesting different doses of NaCl were given to the plant. Result of approximate analysis showed reduction in moisture, ash, crude fiber and fat contents with increase in NaCl stress, while protein and carbohydrates contents increased with increase in salinity. On the base of percentage difference between control and 58g (higher concentration) Sahar and Siran varieties were less effected by NaCl stress in 4 out of 6 constituent even at 58g (higher concentration) as compare to the Ta-Habib , galaxy 2013 and Janbaz.
Many investigators have reported retardation in growth of seedlings at high salinity (Bernstein, 1962; Garg and Gupta, 1997; Ramoliya and Pandey, 2003). However, plant species differ in their sensitivity or tolerance to salts (Brady and Weil, 1996). There are many different types of salts and almost an equally diverse set of mechanisms of avoidance or tolerance. In addition, organs, tissues and cells at different developmental stages of plants exhibit varying degrees of tolerance to environmental conditions (Munns, 1993; Ashraf, 1994). It is reported that soil salinity suppresses shoot growth more than the root growth (Ramoliya and Pandey, 2003; Maas and Hoffman, 1977). However, fewer studies on the effect of soil salinity on root growth have been conducted (Garg and Gupta, 1997). The high salt content lowers osmotic potential of soil water and consequently the availability of soil water to plants. In saline soil, salt induced water deficit is one of the major constraints for plant growth. As soils dry down soil salinity is exacerbated. Frequent droughts are a regular phenomenon in saline deserts. In addition, many nutrient interactions in salt-stressed plants can occur which may have important consequences for growth. Internal concentrations of major nutrients and their uptake have been frequently studied (e.g. Maas and Grieve, 1987; Cramer et al., 1989), but the relationship between micro- nutrient concentrations and soil salinity is rather complex and remains poorly understood (Tozlu et al., 2000). Zandi (2010) studying Suaeda vermiculata and Atriplex leucoclada pointed to the direct relationship between salinity and proline. Panahi et al. (2012) studied Salsola responses to saltstress and concluded that proline and soluble sugars were significantly affected by salinity levels and increased with salinity increase and the rate of growth parameters increased with an increase in moderate salinity while in high salinity levels caused all growth characteristics decline. Daoud et al. (2013) studied the salt response of halophytes (like Sporobolus spicatus, Spartina alterniflora, Batis maritime and etc.) and stated that maximum growth occurred in low and moderate salinities (25 and 50% seawater). Brakez et al. (2013) studied the performance of Chenopodium quinoa under saltstress and reported that maximum biomass was registered in 20% seawater treatment (low salinity level). Tawfik et al. (2013) studied saline land improvement through testing Leptochloa fusca and Sporobolus virginicus and concluded that increasing soil salinity significantly increased soluble carbohydrates and proline concentration in the plant tissues.
Metapontum Forest Reserve is an area that was estab- lished since 1934 and plays an important role in the landscape hosting to a large and diverse groups not only of plant species, but also animals, that found in this area an ideal habitat for their survival. Our study was aimed to characterizing the responses of d’Aleppo pine to NaCl stress at proteome level. It is particularly important un- derstand how plants acquire stress tolerances due to their sessile nature. The proteins in pine needle leaves that were identified as being affected by saltstress include proteins involved in photosynthesis (down-regulated), defense and protein folding (up-regulated). This protein pattern is more visible as we approach the sea, due to increased soil salinity. Taken together these results sug- gest that exposure to high concentrations of salt causes gross up-regulation of the defense-related proteins in pine neddle leaves, which is possibly the reason of ability to protect cells against saltstress.
The alleviative effect of salicylic acid (SA) on growth and physiological parameters of two wheat verities under saltstress was studied at greenhouse condition in 2016. The experimental treatments were arranged as factorial based on a RCBD with 4 replications. Salinity stress comprised of three levels of control, 4 and 8 dS/m and the salicylic acid treatments were control (without salicylic acid) and 1 mM salicylic acid application. The experiment was carried out on two varieties of wheat (Tabasi, salinity sensitive and Arvand, salinity tolerant). The results indicated that salinity stress especially in 8 dS/m had inhibitory effect on plant height, spike length, grain number per plant, grain weight per plant, chlorophyll content, and relative water content. Salinity stress enhanced the proline content in wheat varieties, especially in sensitive variety. Foliar application of SA mitigated the adverse salinity impacts on the growth characteristics, chlorophyll, proline, and relative water content. SA spraying increased plant height by 24.3% and 7%, spike length by 20.1% and 6.6%, and relative water content by 5.2% and 2% in Tabasi and Arvand varieties, respectively.Maximum total chlorophyll content (0.82 mgg -1 FW) was achieved in Arvand variety in control treatment while sprayed by SA. Based on the results of this study, spraying SA on sensitive wheat varieties will warrant much better growth and development under salinity stress.
The experimental design consisted of 36 treatments replicated three times in a split plot design, with salinity as main factor and line as sub factor. Twelve sunflower lines namely R2, R27, R29, R41, R43, R50, R56, B11, B15, B25, B109 and B353 were subjected to three NaCl concentrations (0, 100 and 200 mM) (Heidar et al., 2011). Seeds were sterilized with sodium hypochlorite and germinated in petri dishes and seven day old seedling of uniform size were transferred into large sand tanks housed within an environmentally controlled greenhouse (15 h daily light, 600-800 µmol m -2 s -1 photosynthetic photon flux density (PPFD), thermo period 25±5 °C day\night, and relative humidity 45\60% day\night). The tanks were sub irrigated and flushed four times daily with a modified Hoagland nutrient solution. NaCl stress was imposed 7 days after the seedlings were transferred (Heidar et al., 2011). Thirty day after imposing saltstress, plants were harvested for growth measurement. After separation of shoots, the roots were carefully removed from the sand and washed with distilled water to remove any additional salt surface contamination and dried on absorbing paper, then, the height, fresh and dry weight was measured. Leaf area was recorded using a leaf area meter (Heidar et al., 2011).
accompanied by an increase in water-use-efficiency. The concentration of Na in the leaves and roots was significantly reduced by Si, while root K and leaf Ca concentrations were higher in Si-treated plants under saltstress compared with –Si ones. The activity of antioxidative enzymes increased under saltstress and Si application caused a further increase, being significant for superoxide dismutase (SOD). Saltstress induced membrane damage, as was indicated by a higher malondialdehyde (MDA) concentration. In Si-supplemented plants, however, the MDA amount did not increase under saltstress. The results indicated that the Si- mediated alleviation of saltstress in pistachio plants is related to higher photosynthesis and water-use efficiency, a reduction of Na uptake and transport, and the stimulation of the plant’s antioxidative defence capacity.