Toxic Effects Of Salinity Research Articles

Nano-Management Approaches for Salt Tolerance in Plants under Field and In Vitro Conditions

Soil salinity is a serious global problem that threatens a high percentage of the global soils. Salinity stress can create ionic, oxidative, and osmotic stress, along with hormonal imbalances, in stressful plants. This kind of stress was investigated on agricultural productivity at different levels, starting in vitro (plant tissue culture), through hydroponics, pots, and field conditions. Several approaches were studied for managing salinity stress, including using traditional materials (e.g., gypsum, sulfur), organic amendments (e.g., compost, biochar, chitosan), and applied manufactured or engineered nanomaterials (NMs). Application of nanomaterials for ameliorating salinity stress has gained great attention due to their high efficiency, eco-friendliness, and non-toxicity, especially biological nanomaterials. The application of NMs did not only support growing stressful plants under salinity stress but also increased the yield of crops, provided an economically feasible nutrient management approach, and was environmentally robust for sustainable crop productivity. Nano-management of salinity may involve applying traditional nano-amendments, biological nanomaterials, nano-enabled nutrients, nano-organic amendments, derived smart nanostructures, and nano-tolerant plant cultivars. Producing different plant cultivars that are tolerant to salinity can be achieved using conventional breeding and plantomics technologies. In addition to the large-scale use of nanomaterials, there is an urgent need to address and treat nanotoxicity. This study aims to contribute to this growing area of research by exploring different approaches for nano-management of current practices under salinity stress under field and in vitro conditions. This study also raises many questions regarding the expected interaction between the toxic effects of salinity and NMs under such conditions. This includes whether this interaction acts positively or negatively on the cultivated plants and soil biological activity, or what regulatory ecotoxicity tests and protocols should be used in research.

Hydroponic and in vitro screening of wheat varieties for salt-tolerance

Salt-tolerant wheat cultivars are essential for sustainable wheat production and global food security. The present study aimed to establish a reliable screening protocol as well as successfully isolated the potential salt-tolerant wheat varieties by discerning morpho-physiological parameters with multivariate analysis. Seventeen wheat varieties were evaluated at 0, 12, 15 and 18 dSm-1 salinity levels in a hydroponic culture system at the seedling stage. Moreover, in vitro callusing responses of four selected varieties were determined to clarify the salt tolerance capability at 0, 9, 12 and 15 dSm-1 salt treatments. The seedling growth of most wheat varieties was highly interrupted and reduced by the toxic effects of salinity, however, some varieties such as BARI Gom-32, BARI Gom-33, BARI Gom-31, BARI Gom-30, and BARI Gom-28 showed the lowest reduction under all salinity stress conditions. The total salt tolerance index (TSTI) showed that the cultivar BARI Gom-33 was the most salt-tolerant followed by BARI Gom-32 and BARI Gom-30 whereas BARI Gom-25 was identified as the most sensitive. These results were strongly supported by the principal component analysis (PCA) and Ward’s Methods Euclidean based clustering. In vitro results revealed that the lowest reduction of callus induction was recorded in BARI Gom-33 which might show the greatest tolerance to salinity by improving morpho-physiological characteristics against salt stress. Therefore, the identified genotypes might be employed as donor parents to develop salt-tolerant and high-yielding cultivars in the wheat breeding programme.

Uncovering the Epigenetic Marks Involved in Mediating Salt Stress Tolerance in Plants.

The toxic effects of salinity on agricultural productivity necessitate development of salt stress tolerance in food crops in order to meet the escalating demands. Plants use sophisticated epigenetic systems to fine-tune their responses to environmental cues. Epigenetics is the study of heritable, covalent modifications of DNA and histone proteins that regulate gene expression without altering the underlying nucleotide sequence and consequently modify the phenotype. Epigenetic processes such as covalent changes in DNA, histone modification, histone variants, and certain non-coding RNAs (ncRNA) influence chromatin architecture to regulate its accessibility to the transcriptional machinery. Under salt stress conditions, there is a high frequency of hypermethylation at promoter located CpG sites. Salt stress results in the accumulation of active histones marks like H3K9K14Ac and H3K4me3 and the downfall of repressive histone marks such as H3K9me2 and H3K27me3 on salt-tolerance genes. Similarly, the H2A.Z variant of H2A histone is reported to be down regulated under salt stress conditions. A thorough understanding of the plasticity provided by epigenetic regulation enables a modern approach to genetic modification of salt-resistant cultivars. In this review, we summarize recent developments in understanding the epigenetic mechanisms, particularly those that may play a governing role in the designing of climate smart crops in response to salt stress.

Effect of salinity on physiological and biochemical attributes of different Brinjal (Solanum melongena L.) cultivars

Current study was conducted at The University of Haripur, to evaluate the effects of salinity on four brinjal cultivars Shamli, Black Nagina, Adventa 306 and Twinkle star. Experiment was laid out in CRD with two factors i.e. brinjal cultivars and salinity levels. Okra cultivars were subjected to four different levels of NaCl salinity i.e. control, 100mMol, 200mMol and 300mMol. Results revealed that brinjal cultivar Twinkle star exhibits maximum values of Fresh weight (59g) and Dry weight (8.79g), Plant height (50.66cm), Chlorophyll content (0.032mg/g), Proline content (165.08µg/g), and K+ ion concentration (54.8mg/g), under low to moderate salinity. Hence from this experiment it can be recommended that Twinkle star should be used under saline soil conditions in order to reduce toxic effects of salinity on growth of Brinjal plants. Keywords: Brinjal; Growth; Salinity; Solanum melongena L; Stress http://dx.doi.org/10.19045/bspab.2020.90234

Tissue-specific modulation of metabolism and nutrients acquisition through seed priming with sodium selenate confers salt tolerance in wheat

ABSTRACT The experiment was conducted to appraise whether exogenously applied selenium (Se) could alter nutrients acquisition and metabolism to mitigate the toxic effects of salinity in wheat. Seeds of two contrasting wheat (Triticum aestivum L.) cultivars (Auqab-2000 and Seher-2006) were pre-treated with different concentrations (0, 50, 100 µM) of sodium selenate for 12 h. The pots were irrigated with different NaCl concentrations (0 and 150 mM) applied through Hoagland’s nutrient solution before sowing. Salinity reduced fresh and dry mass and grain yield, but the exogenous Se restored the growth and increased grain yield. Further, salt stress decreased the concentrations of K+, Ca2+, P, N, Fe and Se while increased the concentration of Na+ and Cl‒ in the shoots and roots of wheat. The exogenous Se increased K+, Ca2+, N, Fe and Se concentrations while decreased Na+, Cl− and P, and thus mainly reversed the inhibitory effects of salinity on nutrients uptake. Further, exogenous Se increased the accumulation of proline and glycinebetaine under salinity. Overall, Se-priming proved an effective shotgun technique to mitigate the detrimental effects of salinity possibly through its beneficial effects on tissue-specific ion acquisition and accumulation of osmoprotectants in wheat.

Ocimum basilicum Leaf Extract Induces Salinity Stress Tolerance in Faba Bean Plants

THE PRESENT work investigated the possible protective role of aqueous Ocimum basilicum leaves extract (OLE) on Vicia faba plants irrigated with different leves of salinity (0.0, 50, 100 or 150 mM NaCl). The toxic effects of salinity on Vicia faba plants were assessed by determining oxidative stress such as lipid peroxidation. Furthermore, growth parameters, antioxidant enzymes activity [catalase (CAT), peroxidase (POD) and ascrobate peroxidase (APX)], organic solutes (soluble sugars, soluble proteins and proline) and ions content (Na+, K+, Ca2 and Mg2+) on Vicia faba plants grown under salinity stress in the presence or absence of aqueous extract of O. basilicum leaves were also measured. The obtained results revealed that salinity stress resulted in a significant increase in the activity of antioxidant enzymes, organic solutes, lipid peroxidation and ions content, which were associated with a significant reduction in growth parameters compared with control plants. OLE significantly alleviated the harmful effect of salinity on Vicia faba plants and increased the activity of antioxidant enzymes activity, osmolytes (soluble sugar and soluble protein), and ions content (K+, Ca2+ and Mg2+), which could be an induced defensive mechanism against salinity stress.

Ethanolamine affects physiological responses of salt-treated jute plants

ABSTRACTHigh soil salinity decreases growth, photosynthetic activity, productivity and causes nutrient imbalance in plants. The important biogenic ethanolamine (EA), a natural compound found in plant cells, exerts a protective effect against unfavorable environments. This study evaluated the efficacy of foliar applied EA (150 µM) in reducing effects of salt applied at 200 mM NaCl, equivalent to 20 dS·m−1, in jute (Corchorus olitorius L.), a green leafy vegetable. Plants grown at 20 dS·m−1 NaCl had decreased growth, less photosynthetic pigments contents, photosynthetic activity (14CO2 fixation), nucleic acids, total protein, and levels of N, P, and K. Foliar application of EA increased these parameters compared to the untreated control and salt-treated plants. Salt-treated plants had increased transpiration, antioxidant and nonantioxidant enzyme activities, and H2O2, malondialdehyde, free proline content, and Na+ and Cl− levels, compared to untreated controls and plants treated with EA. Exogenous application of EA to foliage appears to ameliorate toxic effects of salinity by improving the antioxidant system, ionic balance, and 14CO2 assimilation of jute. It appears that EA application can help plants cope with high salinity via induction of tolerance mechanisms.

Fruit yield and survival of five commercial strawberry cultivars under field cultivation and salinity stress

Abstract Strawberry is one of the most salt-sensitive horticultural crops, and important to the economies of both United States and California, the highest producer country and state, respectively. Thus, the increasing salinity (electrical conductivity) of irrigation water (ECiw) in semiarid areas of the world is a growing concern to strawberry growers. We evaluated five commercial cultivars under the ECiw of 0.7 (control), 1.0, 1.5, and 2.5 dS m−1, under field conditions for 240 days. Increased ECiw increased Cl− in all tissues, while Na+ only increased in roots and petioles. Thus, toxic effects of salinity in leaves were attributed to Cl−, not Na+. All cultivars maintained sufficient levels of both macro and micronutrients in shoots without competition between Na+ and K+, or Ca2+ or between Cl− and NO3−. All cultivars had decreased fruit production, even when ECiw increased to 1.0 dS m−1. Although ‘Albion’ and ‘San Andreas’ had the least fruit yield at control salinity, ‘Albion’ was the cultivar with the least mean relative reduction in fruit yield, marketable fruit size, shoot + root biomass, and survival at ECiw = 2.5 dS m−1, and thus the most salt tolerant. Regarding absolute yield, ‘Monterey’ was the highest fruit producer under salinity. All cultivars maintained fruit total soluble sugars (Brix%) across salinity levels with ‘Albion’, ‘Monterey’, and ‘Benicia’ having the highest values (11–13% Brix) regardless of salinity. ‘Albion’ and ‘San Andreas’ were the best at maintaining commercial fruit size under salinity. ‘Albion’, ‘Benicia’, and ‘Monterey’ had higher fruit yields at ECiw = 2.5 dS m−1 than ‘Ventana’ and ‘San Andreas’ and can enable farmers to produce strawberries with irrigation water ECiw up to 1.5 dS m−1, although with some fruit yield loss. Results indicate that these newer commercial cultivars are more salt-tolerant than cultivars previously tested, and with enough variability in salt tolerance to improve selection for irrigation water salinity with ECiw >1.0 dS m−1.

Salicylic Acid Enhances Growth and Productivity in Cabbage (Brassica oleracea var. Capitata L.) Grown Under Saline Condition

Introduction: This experiment was set up to investigate the beneficial effect of salicylic acid to reduce the harmful consequence of salinity on cabbage productivity where Salt stress severely limits plant growth, development and yield.Methods: We had grown cabbage plants under different levels of NaCl salinity (0, 4, 8 dS m -1) alone or supplemented with foliar spray of different concentrations of salicylic acid (SA, 0, 0.25 and 0.5 mM). This experiment was laid out in a randomized complete block design with three replications. Collected all data were statistically analyzed following the analysis of variance (ANOVA) technique using MSTAT-C program and the mean differences were adjudged by least significant difference (LSD) test at 5% level of significance.Results: Results showed that, higher concentrated salt treated plants give the significant lower growth and head yield. Plant growth as well as yield of cabbage such as heads thickness, diameter and weight were decreased with increased level of salinity such as 8 dS m-1 compared with other treatment. While, foliar application of SA increased growth and yield also hindered stress induced growth and production inhibition. The improvement in plant height, leaf number, leaf length and breadth, foliage coverage, number of root and weight, head thickness, diameter and weight were increased with increased concentration of SA and higher value were recorded from 0.50 mM SA. Conclusions: It can be concluded that SA improve the plant defense system to resist the toxic effect of salinity.

Effects of salt stress imposed during two growth phases on cauliflower production and quality.

Cultivation of cauliflower is diffused in Mediterranean areas where water salinity results in the need to identify alternative irrigation sources or management strategies. Using saline water during two growth phases (from transplanting to visible appearance of inflorescence or from appearance of inflorescence to head harvest), the present study aimed to identify the growth period that is more suitable for irrigation with low quality water in relation to cauliflower production and quality. Salinity affected cauliflower growth mainly when imposed in the first growth phase. The growth reduction depended mainly on ion-specific effects, although slight nutrient imbalances as a result of Na+ and Cl- antagonisms were observed. The use of non-saline water in the first or second growth period reduced both the osmotic and toxic effects of salinity. When salinity was applied during inflorescence growth, yield was reduced because of a restriction of water accumulation in the head. The results of the present study demonstrate the possibility of producing marketable cauliflower heads under conditions of salinity by timing the application of the best quality water during the first growth phase to improve fruit quality and during the second phase to reduce the negative effects of salinity on yield. © 2016 Society of Chemical Industry.

Grapevine recovery from saline irrigation was incomplete after four seasons of non-saline irrigation

Crop exposure to salinity can be episodic. The effects on the crop are the sum of those manifest whilst stress establishes, persists and abates. This paper reports on the response of grapevines during stress abatement. It follows from Stevens et al. (2011a) which reported on the response over three consecutive seasons of Colombard vines (Vitis vinifera) on Ramsey rootstock (Vitis champinii) to irrigation with saline water (ECi 3.5dS/m) during specific growth stages, and with non-saline water (ECi 0.5dS/m) during the rest of the season. Over the next four seasons all vines were irrigated with non-saline water (ECi 0.4dS/m). The current paper characterises recovery during this period using key traits including growth, yield and concentrations of Na+ and Cl− in root and leaf lamina. By harvest in the second season following cessation of saline irrigation, the soil salinity and leaf lamina Na+ and Cl− concentrations in previously salinised vines had fallen below the levels associated with salinity-induced yield loss. Maximum yield loss of 22% averaged over the four seasons was higher than the maximum of 15% during saline irrigation. Yield losses were associated with loss of berry weight. Following cessation of saline irrigation, a reduction in bunch numbers caused an additional yield loss. A reduction in pruning weights did not emerge until after saline irrigation ceased. Salinity's sting can be in its tail. Losses of yield, bunch number and pruning weight were independent of season, whilst those in berry weights diminished over the four seasons. In the last two seasons, yield loss could not be attributed to osmotic or toxic effects of salinity. Another unidentified effect of salinity was stressing the vines.

Interactions between Ca, Mg, Na and K: alleviation of toxicity in saline solutions

Saline soils limit plant production worldwide through osmotic stress, specific-ion toxicities, and nutritional imbalances. The ability of Ca2+ and K+ to alleviate toxicities of Na+ and Mg2+ was examined using 89 treatments in short-term (48 h) solution culture studies for cowpea (Vigna unguiculata (L.) Walp.) roots. Root elongation was related to ionic activities at the outer surface of the root plasma membrane. The addition of K+ was found to alleviate the toxic effects of Na+, and supplemental Ca2+ improved growth further in these partially-alleviated solutions where K+ was present. Therefore, Na+ appears to interfere with K+ metabolism, and Ca2+ reduces this interference. Interestingly, the ability of Ca2+ to improve K-alleviation of Na+ toxicity is non-specific, with Mg2+ having a similar effect. In contrast, the addition of Ca2+ to Na-toxic solutions in the absence of K+ did not improve growth, suggesting that Ca2+ does not directly reduce Na+ toxicity in these short-term studies (for example, by reducing Na+ uptake) when supplied at non-deficient levels. Finally, K+ did not alleviate Mg2+ toxicity, suggesting that Mg2+ is toxic by a different mechanism to Na+. Examination of how the toxic effects of salinity are alleviated provides clues as to the underlying mechanisms by which growth is reduced.

Is osmotic potential a more appropriate property than electrical conductivity for evaluating whole-plant response to salinity?

Studies of whole-plant or crop responses to salinity often focus on yield or growth reduction in terms of solution ion concentration or electrical conductivity. The response functions describing salt stress may be better presented in terms of solution osmotic potential. We looked at the effect of increasing concentrations of NaCl and CaCl 2, either alone or in equinormal combination, on three different plant species: bean ( Phaseolus vulgaris L.), corn ( Zea mays L.) and melon ( Cucumis melo L.). Corn and melon were found to be relatively tolerant and beans more sensitive to salinity. When yield response was related to the electrical charge concentration of the salts, i.e. salinity was expressed in units of mequiv. L −1 or electrical conductivity, the stress effects of Na and Ca appeared to be of different magnitudes: plant growth was more sensitive to excess Na than to excess Ca and the effect of combined Na and Ca was intermediate. The effects of the two salts were, however, indistinguishable when salinity was expressed in terms of osmotic potential of the water. For all three species, the response curves of yield as a function of level of equipotential solutions of NaCl, CaCl 2 or combinations of the two salts practically overlapped. Presentation and interpretation of the whole-plant salinity response in terms of osmotic potential would be beneficial in attempts to differentiate between the osmotic and toxic effects of salinity, in normalizing data sets and in increasing their relevance in practical applications.

Salt tolerance and avoidance mechanisms at germination of annual pasture legumes: importance for adaptation to saline environments

Mechanisms for tolerance and avoidance of salinity at germination were examined in five self-regenerating annual pasture legumes of Mediterranean origin (Medicago polymorpha, Melilotus siculus, Trifolium subterraneum, T. michelianum and T. tomentosum). The maximum NaCl concentrations, for which no reduction in germination percentage occurred, were 300 mM for M. siculus, 240 mM for M. polymorpha and 120 mM for T. michelianum, T. subterraneum and T. tomentosum. Following 21 days exposure to 300 mM NaCl, imbibed seeds of T. subterraneum showed reduced germinability upon transfer to non-saline solution, whereas those of the four other species recovered full germinability. Following exposure to 600 mM NaCl, however, only T. michelianum and Melilotus siculus had some degree of recovery, with 38% and 31% germinability, respectively. Na+ in imbibed seed tissues of all species increased markedly with increasing NaCl concentration, while K+ decreased in all but Melilotus siculus. Seed coat impermeability (‘hard seeds’) acted as protection against the toxic effects of salinity. Melilotus siculus, Medicago polymorpha and T. tomentosum showed a delay in hard-seed breakdown (‘seed softening’) over the summer–autumn period, compared to T. subterraneum and T. michelianum, which acts to defer germination until soil surface salinity levels are likely to be lower. These three species also had higher levels of residual hard seeds. The results from this study support field observations that Melilotus siculus and Medicago polymorpha are the best adapted annual pasture legumes for highly saline soils in southern Australia, T. tomentosum and T. michelianum have some adaptation to moderately and mildly saline soils, respectively, whereas T. subterraneum has no adaptive traits for even mildly saline environments. A model for annual legume germination on saline land in southern Australia is also presented.

The use of freshwater and saltwater animals to distinguish between the toxic effects of salinity and contaminants in irrigation drain water

AbstractIrrigation drain waters entering Stillwater Wildlife Management Area (SWMA) in south‐western Nevada contain elevated levels of salinity and several inorganic contaminants (As, B, Cu, Li, Mo, and Sr). Mortalities of fish and waterfowl at the management area are believed to be associated with the poor water quality of the drains. The objective of the present study was to use fresh‐water and saltwater animals to distinguish between the toxic effects of salinity and contaminants in effluent samples collected from irrigation drain waters. Static acute effluent tests were conducted with water collected from four sites at SWMA. Animals acclimated or cultured in fresh water (fathead minnows, Pimephales promelas; amphipods, Hyalella azteca; cladocerans, Daphnia magna) and salt water (striped bass, Morone saxatilis; amphipods, Hyalella azteca; and cladocerans, Daphnia magna) were used to separate toxic effects of salinity from the effects of inorganic contaminants in the drain water. One drain water (TJ drain, salinity 19 parts per thousand (grams per liter), osmolality 503 mmol/kg, hardness 3,780 mg/L as CaCO3) was toxic only to freshwater animals and saltwater cultured daphnids; water from a receiving pond (Pintail Bay, salinity 23 g/L, osmolality 542 mmol/kg, hardness 830 mg/L as CaCO3) was toxic to both freshwater and saltwater animals. Acute tests conducted with reconstituted waters representative of the Pintail Bay sample indicated that atypical ion ratios were toxic to striped bass and amphipods, even without the addition of inorganic contaminants. However, the addition of inorganic contaminants representative of the Pintail Bay sample increased the toxicity of this reconstituted water. These findings indicate that the toxicity of the TJ drain sample was related mainly to elevated salinity and that the toxicity of the Pintail Bay sample was a function of inorganic contamination and atypical ion ratios in combination with elevated salinity.