Harmful Effects Of Salinity Stress Research Articles

Green synthesis of a dual-functional sulfur nanofertilizer to promote growth and enhance salt stress resilience in faba bean

BackgroundSalinity is a major abiotic stress, and the use of saline water in the agricultural sector will incur greater demand under the current and future climate changing scenarios. The objective of this study was to develop a dual-functional nanofertilizer capable of releasing a micronutrient that nourishes plant growth while enhancing salt stress resilience in faba bean (Vicia faba L.).ResultsMoringa oleifera leaf extract was used to synthesize sulfur nanoparticles (SNPs), which were applied as a foliar spray at different concentrations (0, 25, 50, and 100 mg/l) to mitigate the negative effects of salt stress (150 mM NaCl) on faba bean plants. The SNPs were characterized and found to be spherical in shape with an average size of 10.98 ± 2.91 nm. The results showed that salt stress had detrimental effects on the growth and photosynthetic performance (Fv/Fm) of faba bean compared with control, while foliar spraying with SNPs improved these parameters under salinity stress. SNPs application also increased the levels of osmolytes (soluble sugars, amino acids, proline, and glycine betaine) and nonenzymatic antioxidants, while reducing the levels of oxidative stress biomarkers (MDA and H2O2). Moreover, SNPs treatment under salinity stress stimulated the activity of antioxidant enzymes (ascorbate peroxidase (APX), and peroxidase (POD), polyphenol oxidase (PPO)) and upregulated the expression of stress-responsive genes: chlorophyll a-b binding protein of LHCII type 1-like (Lhcb1), ribulose bisphosphate carboxylase large chain-like (RbcL), cell wall invertase I (CWINV1), ornithine aminotransferase (OAT), and ethylene-responsive transcription factor 1 (ERF1), with the greatest upregulation observed at 50 mg/l SNPs.ConclusionOverall, foliar application of sulfur nanofertilizers in agriculture could improve productivity while minimizing the deleterious effects of salt stress on plants. Therefore, this study provides a strong foundation for future research focused on evaluating the replacement of conventional sulfur-containing fertilizers with their nanoforms to reduce the harmful effects of salinity stress and enhance the productivity of faba beans.

Effects of Salinity on ‘Fino 95’ Lemon Trees Inoculated with Arbuscular Mycorrhizal Fungi

An experiment was conducted with two-year-old ‘Fino 95’ lemon plants (Citrus limon Burm. f. cv. Fino) grafted on C. macrophylla (Citrus macrophylla Wester) to study the effects of salinity on plants inoculated with arbuscular mycorrhizal fungi (AMF). Half of the inoculated (+AM) and non-inoculated (−AM) plants were irrigated with half-strength Hoagland solution, and the remainder were inoculated with half-strength Hoagland solution + 30 mM NaCl. Ninety-eight days later, results showed that AMF had alleviated the negative effect of salinity on growth. Inoculation with AMF provided some protection against the damage that salinity caused on cellular membranes and improved the plant water status and turgor under saline conditions (Ψx and Π increased by 16% and 48%, respectively). The responses of mineral nutrition to salinity and AMF treatments were complex. P concentrations in the leaves and roots of +AM plants were lower than in those of −AM plants, but inoculation improved Ca2+ (by 20%), Mg2+ (24%), Fe2+ (21%), and Zn2+ (7%) nutrition in roots and also the Mg2+/Na+ ratio in leaves (33%), reducing the antagonistic effect of Na+ on Mg2+ nutrition in salt-treated plants. AMF could protect plants against salt stress through the maintenance of the gas exchange capacity and due to a better antioxidant response. All these positive effects of AMF contributed to mitigating the harmful effects of salinity stress on the plant growth performance of lemon trees grafted on C. macrophylla rootstock under salinity conditions.

Effects of melatonin on lettuce plant growth, antioxidant enzymes and photosynthetic pigments under salinity stress conditions

ABSTRACT Salinity is one of the most important abiotic stresses that significantly decreases the productivity of agricultural crops. Melatonin (MT) acts as an antioxidant and plays a vital role in overcoming oxidative damage. However, previous literature has not provided a clear understanding of the impact of MT on lettuce plants under salinity stress. So, we investigated the effect of exogenous MT at 0 μM, 50 μM, 100 μM and 150 μM on lettuce plants grown under salinity stress (0 mM NaCl, 50 mM NaCl and 100 mM NaCl) with respect to vegetative growth, photosynthetic pigments, relative water content (RWC), electrolyte leakage (EL), malondialdehyde (MDA), H2O2, O2 •- and antioxidants enzymes. Results showed that NaCl stress significantly decreased vegetative growth, RWC and photosynthetic pigments and in contrast enhanced dry matter, EL, MDA, H2O2, O2 •-, Na+, Cl-, peroxidase (POD), superoxide dismutase (SOD) and glutathione reductase (GR) of lettuce plants compared to non-salinized control. The results demonstrated that under salinity conditions, foliar applications of MT significantly alleviated the harmful effects of salinity and increased number of leaves, leaf area, fresh weight, chlorophyll (a), chlorophyll (b), total chlorophyll, carotenoids and RWC in comparison to untreated plants (control). Meanwhile, dry matter, MDA, H2O2, O2 •-, Na+, Cl-, POD, SOD and GR were significantly decreased compared to untreated lettuce plants. In this respect, spraying MT at 150 μM ranked the first, then 100 μM, compared to the lower concentration (50 μM). In conclusion, MT application can be used to alleviate harmful effects of salinity stress.

Impact of Calcium-Silicon nanoparticles on flower quality and biochemical characteristics of Lilium under salt stress

Lilium plants are one of the most important and widely distributed ornamental crops in the world. However, these plants are also susceptible to salinity, an environmental factor that is one of the main ones worldwide. Salinity negatively affects the development and productivity of plants, in addition to the fact that it can affect the quality of flowers in ornamental crops. The use of nanotechnology can be a useful tool to counteract the negative effects of salinity, since the application of nanoparticles can function as a biostimulant and induce positive responses against different types of abiotic stress. In the present study, the foliar application of two types and concentrations of calcium-silicon nanoparticles (Ca-Si NPs) (500 and 750 mg L−1) in lilium plants grown with or without stress and under saline stress (30 mM NaCl) was evaluated. The differences between both nanoparticles were the size and content of inorganic residues, where CaSi-1 had a size of 23.29 nm and a content of inorganic residues of 62.0 %, while CaSi-2 had a size of 15.29 nm and a content of inorganic residues of 87.0 %. The results showed that salinity affected the quality of the flowers, as well as the biochemical parameters of the plants. In contrast, the application of Ca-Si NPs induced positive effects on flower quality, improved flower size and fresh biomass. Under salt stress conditions, the application of Ca-Si NPs in lilium improved the biochemical parameters, increased the content of chlorophylls (up to 38.1 %), vitamin C (9.4 %), and antioxidant capacity (19.2-23.8 %) in the leaves. Regarding the stress indicators in the leaves, the hydrogen peroxide (H2O2) was not affected by salinity or by the Ca-Si NPs, while the malondialdehyde (MDA) increased by the application of the NPs, however, under saline stress there were no differences. In lilium flowers without salt stress, both H2O2 and MDA increased by the application of Ca-Si NPs, while under salt stress only MDA increased. The use of Ca-Si NPs can be an alternative to counteract the harmful effects of salinity stress in plants.

Selection of Salinity-Adapted Endorhizal Fungal Consortia from Two Inoculum Sources and Six Halophyte Plants.

Soil salinity is a limiting factor in crop productivity. Inoculating crops with microorganisms adapted to salt stress is an alternative to increasing plant salinity tolerance. Few studies have simultaneously propagated arbuscular mycorrhizal fungi (AMF) and dark septate fungi (DSF) using different sources of native inoculum from halophyte plants and evaluated their effectiveness. In alfalfa plants as trap culture, this study assessed the infectivity of 38 microbial consortia native from rhizosphere soil (19) or roots (19) from six halophyte plants, as well as their effectiveness in mitigating salinity stress. Inoculation with soil resulted in 26-56% colonization by AMF and 12-32% by DSF. Root inoculation produced 10-56% and 8-24% colonization by AMF and DSF, respectively. There was no difference in the number of spores of AMF produced with both inoculum types. The effective consortia were selected based on low Na but high P and K shoot concentrations that are variable and are relevant for plant nutrition and salt stress mitigation. This microbial consortia selection may be a novel and applicable model, which would allow the production of native microbial inoculants adapted to salinity to diminish the harmful effects of salinity stress in glycophyte plants in the context of sustainable agriculture.

Effect of seed priming on growth and physiological responses of chili pepper (Capsicum frutescens L.) under salinity stress

Increasing soil salinity in some agricultural areas due to global climate change is an obstacle in horticultural crop cultivation. Chili pepper (Capsicum frutescens L.) is an important horticultural crop that has high economic values but the extensive cultivation in saline land can reduce yields. Plant tolerance must be increased to be able to adapt in salinity stress conditions. One method that can be used is seed priming, which is pre-soaking the seeds to increase germination under unfavourable conditions. This study aimed to determine the effect of seed osmopriming using PEG 6000 on growth and physiological responses of chili pepper under salinity stress. The experimental design of this study included two factors: concentration of PEG 6000 (0, 12.5 and 25%) and salinity stress of 0, 2000, and 4000 ppm of NaCl. The observed parameters were 1) germination (percentage and rate of germination, germination synchronization); 2) growth (plant height; root length; dry weight of roots and shoot, number of fruits, fruit weight and capsaicin level); 3) physiological analysis (chlorophyll and proline levels). Seed osmopriming with 25% of PEG 6000 increased germination and plant growth of chili pepper under salinity stress conditions. Chlorophyll level increased while proline and capsaicin level decreased on osmopriming with 25% of PEG 6000. By studying the growth and physiological responses of chili pepper under salinity stress, the role of osmopriming in reducing the harmful effects of salinity stress can be determined.

Applied Selenium as a Powerful Antioxidant to Mitigate the Harmful Effects of Salinity Stress in Snap Bean Seedlings

Selenium (Se) plays several significant roles in regulating growth, development and plant responses to various abiotic stresses. However, its influence on sulfate transporters (SULTRS) and achieving the harmony with other salt-tolerance features is still limited in the previous literatures. This study elucidated the effect of Se supplementation (5, 10 and 20 µM) on salt-stressed (50 mM NaCl) snap bean seedlings. Generally, the results indicated that Se had dual effects on the salt stressed seedlings according to its concentration. At a low level (5 µM), plants demonstrated a significant improvement in shoot (13.8%) and root (22.8%) fresh weight, chlorophyll a (7.4%), chlorophyll b (14.7%), carotenoids (23.2%), leaf relative water content (RWC; 8.5%), proline (17.2%), total soluble sugars (34.3%), free amino acids (FAA; 18.4%), K (36.7%), Ca (33.4%), K/Na ratio (77.9%), superoxide dismutase (SOD; 18%), ascorbate peroxidase (APX;12.8%) and guaiacol peroxidase (G-POX; 27.1%) compared to the untreated plants. Meanwhile, most of these responses as well as sulfur (S), Se and catalase (CAT) were obviously decreased in parallel with increasing the applied Se up to 20 µM. The molecular study revealed that three membrane sulfate transporters (SULTR1, SULTR2 and SULTR 3) in the root and leaves and salinity responsive genes (SOS1, NHX1 and Osmotin) in leaves displayed different expression patterns under various Se treatments. Conclusively, Se at low doses can be beneficial in mitigating salinity-mediated damage and achieving the functioning homeostasis to tolerance features.

SALINITY STRESS EFFECTS ON PLANTS AND USE OF RHIZOBACTERIA: A REVIEW

Soil salinity is being recognized as a major threat to the agriculture and food production in the arid and semi-arid regions of the world. Accumulation of various salts creates osmotic imbalance and ionic toxicity in plants and makes crop production difficult. Plant system has developed certain adaptation strategies for tolerating the toxicity of the salts. The present review focuses on the various effects of salinity stress on physiological and biochemical aspects of plants and the role of rhizobacteria to mitigate the harmful effects of salinity stress. Induction of toxicity mechanism of salinity stress tolerance in plants along with the strategies needed to be adapted to make sustainable agriculture.

A Novel Plant Growth–Promoting Agent Mitigates Salt Toxicity in Barley (Hordeum vulgare L.) by Activating Photosynthetic, Antioxidant Defense, and Methylglyoxal Detoxification Machineries

Developing and applying a novel plant growth–promoting agent (PGPA; a micronutrient-amino acid chelated compound developed from autolysis yeast cells) in alleviating salt stress toxicity can be the best alternative option environmentally and economically. High-performance liquid chromatography (HPLC) showed that the assembled PGPA is rich in nucleobases than yeast extract (> 56-fold). This study, as a first investigation, was aimed to evaluate PGPA’s potential role in reducing oxidative injury induced by salt stress. Barley (Hordeum vulgare L. cv. Giza 123) plants were grown under non-saline or saline conditions (6.0 and 12.0 dS m−1) with and without PGPA foliar application. The PGPA application mitigated salt-induced oxidative stress by enhancing the activity of superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, glutathione peroxidase, and glutathione S-transferase, as well as the content of ascorbate, glutathione, proline, and glycinebetaine. Moreover, PGPA protected salt-stressed plants from the deleterious effects of methylglyoxal by up-regulating the glyoxalase enzymes activity. The PGPA alleviated membrane damage by decreasing reactive oxygen species (ROS) accumulation, lipid peroxidation, protein oxidation, electrolyte leakage, and NADP+ content. The protection of photosynthesis by PGPA was closely associated with the improved chlorophyll fluorescence parameters, leaf water content, membrane stability index, and NADPH content. The PGPA-treated plants also exhibited higher stomatal conductivity together with improved transpiration and photosynthetic rates under saline conditions. Overall, PGPA regulated the antioxidant machinery, glyoxalase system, and photosynthetic capacity, implying that it plays a critical role in salt stress mitigation. Therefore, it could be a useful agent to alleviate the harmful effects of salinity stress.

Titanium dioxide nanoparticle is involved in mitigating NaCl-induced Calendula officinalis L. by activation of antioxidant defense system and accumulation of osmolytes

This study is aimed at evaluating the effects of TiO2NPs on biochemical and physiological parameters of marigold (Calendula officinalis L.) under NaCl stress. Treatments included TiO2NPs applied as foliar spraying in three levels (50, 100, and 200 mgL−1), no foliar application as control, and different NaCl levels (0, 30, 60, and 90 mM) by adding NaCl to irrigation water. According to the results, the application of different concentrations of TiO2 had various effects on the studied parameters. The use of 100 mgL−1 TiO2NPs increased flavonoid content of the leaves (at 30 mM NaCl), cell membrane injury (with no salinity), CAT and SOD activities (at 90 mM NaCl), and PPO activity (at 60 mM NaCl). On the other hand, using 100 mgL−1 TiO2NPs under salinity stress decreased MDA and H2O2 contents. Moreover, using 200 mgL−1 TiO2NPs increased photosynthetic pigments content, total flavonoid content of flowers, total soluble sugar, carotenoid content of flowers, and RWC (at the treatment with no salinity), aboveground and underground biomasses (at 30 mM and 60 mM NaCl, respectively), phenolic content and antioxidant activity (at 30 mM NaCl), and APX activity (at 90 mM NaCl). In conclusion, the findings of the present study indicated that TiO2NPs could be a useful material to mitigate the harmful effects of salinity stress. Furthermore, the TiO2NPs spraying could have beneficial effects on osmotic adjustment, biochemical compound, non-enzymatic and enzymatic antioxidant activities, and growth of marigold under NaCl stress conditions.

Effect of magnetic field on growth and yield of barley treated with different salinity levels

Even though water treatment can be based on several techniques, one new promising process is applying magnetic treatment to water, which can alleviate salinity stress and improve crop productivity. Using magnetic technology in agriculture is considered non-conventional, economical, and eco-friendly. Moreover, it can improve soil and water properties, which in turn can enhance crop and water productivity whether in normal conditions or under salinity stress. The objective of our study is to quantify the impact of the application of this technique on the growth and productivity of barley under different levels of salinity stress. The experiment included two factors: (i) water treatments (i.e., magnetized water; water after pathing through static magnetic unit, 0.5 inch diameter, 0.35 T and non-magnetized water) and (ii) five levels of salinity stress (320, 2000, 4000, 6000, and 8000 ppm). Results indicated that irrigation barley plants with magnetized saline water reduced the harmful effect of salinity stress where the grain yield (g pot−1) increased by 14.75, 14.32, 16.06, 12.97, and 15.85% under 320, 2000, 4000, 6000, and 8000 ppm salinity levels, respectively compared to the irrigated plants with non-magnetized water of the same salinity level. Similar trends were recorded in all tested parameters. The overall results show that magnetized saline irrigation water, even at high salinity, increases barley growth parameters as well as photosynthetic pigments, resulting in an increase in grain yield compared to irrigation with non-magnetized saline water.

Use of plant growth-promoting bacteria to enhance salinity stress in soybean (Glycine max L.) plants.

The effects of three rhizobacterial isolates namely Pseudomonas fluorescens (M1), Pseudomonas putida (M2) and Bacillus subtilis (M3) were examined to enhance growth and chemical components such as chlorophyll and proline of three cultivars of soybean (Glycine max L.) under two levels of salinity stress (S1 = 200 mM and S2 = 400 mM of NaCl salt). Several morphological and physiological parameters were investigated. The highest mean values of final germination percent (FGP) were registered in cultivar Crawford (95%) followed by Giza111 cultivar (93%) in the presence of P. fluorescens, while, FGP of Clark was 85%. Mean germination time was decreased by the application of P. fluorescens or P. putida in both salt stressed and unstressed traits. All growth parameters were significantly decreased by salinity treatments, particularly at S2. A significant increase in stem length and shoot fresh weight was recorded in plants treated with P. fluorescens. This enhancing trend was followed by the application of P. putida then B. subtilis. Chlorophyll contents and plant soluble proteins were decreased, while proline content was increased as compared with control treatment. Results showed that the salt tolerant cultivar, Crawford, may have a better tolerance strategy against oxidative damages by increasing antioxidant enzymes activities under high salinity stress. These results suggest that salt induced oxidative stress in soybean is generally counteracted by enzymatic defense systems stimulated under harsh conditions. Our results showed that inoculation with plant growth-promoting rhizobacterial (PGPR) alleviated the harmful effects of salinity stress on soybean cultivars. The diversity in the phylogenetic relationship and in the level of genetic among cultivars was assessed by SDS-PAGE and RAPD markers. Among the polymorphism bands, only few were found to be useful as positive or negative markers associated with salt stress. The maximum number of bands (17) was recorded in Crawford, while the minimum number of bands (11) was recorded in Clark. Therefore, the ISSR can be used to identify alleles associated with the salt stress in soybean germplasm.

Effect of Ascorbic Acid and Zinc on the Productivity of Sunflower (Helianthus annuus L.) under Saline Stress Conditions

SALTINESS is the most restricting factor for agriculture in arid and semi-arid regions, addition to zinc is deposited in forms not accessible to plants in calcareous soils. During the 2018 and 2019 seasons, two field experiments were conducted at the Desert Research Center, Agriculture Experimental Station at Ras-Sudr, South Sinai Governorate, Egypt. The impact of seed priming by soaking seeds in ascorbic acid at 0, 100, 200, and 300mg ASC/L and the soil application of zinc at the rates of 0, 3, 6, 12, and 24kg zinc sulfate/ha (ZnSO4) on sunflower yields and its attributes were studied. The results reported that plant height, head diameter, number of seeds/head, seed weight/head, seed index, biological, seed and oil yields, and seed oil content responded considerably to ascorbic acid (ASC) in both seasons. In this connection, sunflower seeds soaked in 200mg ASC/L was the potency practice compared to other treatments in both years. ZnSO4 significantly affected all the aforementioned traits in both seasons. In this regard, adding 12kg ZnSO4 ha-1 gave the highest values for all the studied parameters, except for plant height, which recorded the highest value of 143.2 and 131.2 cm at 24kg ZnSO4 ha-1, respectively as compared to non-ZnSO4 application in both seasons. The outcomes of this study suggest that soaking sunflower seeds in 200mg/L ASC alongside ZnSO4 fertilization at a rate of 12kg/ha could be used to alleviate the harmful effects of salinity stress and increase the sunflower yields.

Effect of nanoparticle on growth, biochemical and anatomical characteristics of moringa plant (Moringa oleifera L.) under salinity stress condition

Two pot experiments were carried out at the Experimental Farm of the Agricultural Botany Department, Faculty of Agriculture, Al-Azhar University (Assiut branch), Assiut, Egypt, during two successive seasons of 2018 and 2019. The main aim of this study was to find out the effect of both of foliar application with some growth promoters (using nanotechnology) i.e., zinc, iron, copper oxide nanoparticles at 50, 100 and 150 mgl-1 of each and silica nanoparticles at 20, 40 and 60 mgl-1 as well as salinity stress level of irrigation water at 9000 mgl-1 individually and their interactions on growth, biochemical and anatomical characteristics of Moringa oliefera L. plant. The results showed that individually salinity stress level of irrigation water at 9000 mgl-1 decreased all studied vegetative growth parameters of moringa plant i.e., plant height (cm), stem diameter (cm), leaves number plant-1, leaf area plant-1 as well as root, stem and leaves dry weights plant-1 compared with the control. The same trend was obtained in photosynthetic pigments content (total chlorophyll) as well as the studied anatomical characteristics of root section (i.e., root diameter of V.C and length of xylem arch), stem section (i.e., stem diameter, O of V.C, length of V.B in the stem) and Leaf blade section (i.e., upper epidermis thickness, lower epidermis thickness and mesophyll tissue for leaflet) at 50 days of Moringa oliefera leaves compared with unstressed plant. On other hand, salinity stress level at 9000 mgl-1 resulted in increasing antioxidant activity as well as total phenolic contents at 60 days of Moringa oliefera leaves compared with unstressed plant. Data also indicated that the individually foliar application treatments with Zinc, Iron, Copper oxide nanoparticles at 50, 100, 150 of each and Silica at 20, 40, 60 mgl-1 nanoparticles increased studied vegetative growth as well as anatomical characteristics, chemical compositions, photosynthetic pigments (total chlorophyll), antioxidants activity and total phenolic contents of moringa plant compared with the control treatment. In this respect, Silica nanoparticles at 60 mgl-1 followed by zinc and iron oxide at 150 mgl-1 nanoparticles of each were the most effective treatments, respectively. Finally , Based on these results, it could be concluded that the foliar application with nanoparticles gave the highest Valois of morphological, chemical compositions and anatomical characteristics its that reduce the harmful effects of salinity stress of Moringa oliefera L. plant specially at silica 60 mgl-1,. Data recorded that this results using it under the same field conditions (Assiut governorate, Egypt).

Growth and biochemical responses of sorghum genotypes to nitrogen fertilizer under salinity stress conditions

This study was carried out to assess the efficiency of nitrogen (N) fertilizer in mitigating the harmful effects of salinity stress on growth and biochemical traits in sorghum genotypes. The experiment was conducted as a factorial trial based on the completely randomized design with four replications under the greenhouse conditions. The factors included four sorghum genotypes (KDFGS1, KDFGS23, KDFGS29 lines, and KFS2 cultivar), two salinity levels (3 and 12 dS m−1) and three nitrogen levels (0, 75 and 150 mg N kg−1soil). The results showed that application of nitrogen fertilizer increased photosynthetic pigments and K+/Na+ ratio in leaf sheath and root. Also, nitrogen dramatically decreased malondialdehyde (MDA) content. This was an indication of the reduced detrimental effects of salinity stress found in all genotypes. In addition, it was found that upon 150 mg N kg−1 treatments, proline (Pro) and antioxidant enzymes markedly decreased in all sorghum genotypes. The highest impact of nitrogen fertilizer for reducing the negative effect of salinity stress was observed in KFS2 (known as tolerant genotype). Due to the highest Pro accumulation in KDFGS23 (known as sensitive genotype), it did not appear to be a suitable criterion for the selection of the tolerant lines/cultivars. In general, the results suggested that using a reasonable N fertilizer level could be used as an efficient tool to improve the growth of the sorghum genotypes subjected to salinity stress and this effect was more pronounced in the tolerant genotype.

Salinity Stress Mitigation Using Encapsulated Biofertilizers for Sustainable Agriculture

The harmful effect of salinity stress on crops needs to be mitigated. Therefore, the application of microbial inoculum in combination with nanomaterials and methyl salicylate was investigated. Initially, different seeds were exposed to salinity levels treated with variable microbial treatments using different modes of applications. The microbial treatments included application of cyanobacterial strain Cyanothece sp. and the rhizobacterium Enterobacter cloacae, alone or in combination with one another, and a final treatment using combined microbial inoculum supplied with methyl salicylate. Later, different nanomaterials were used, namely, graphene, graphene oxide, and carbon nanotubes in combination with biofertilizers on the highest salinity level. The nanomaterial with microbial treatment and methyl salicylate were applied partly as a mixture in soil and partly as capsules. Results showed that salinity stress had a drastic inhibitory effect on growth parameters, especially at −5 MPa level. Nonetheless, the microbial treatments significantly alleviated the deleterious effect of salinity stress, especially when combined with methyl salicylate. When the nanomaterials were added to biofertilizers at highest salinity level, the inhibitory effect of salinity was mostly alleviated. Smart use of synergistic biofertilizers alongside the right nanomaterial, both encapsulated and in soil, would allow for mitigation and alleviation of inhibitory effect of salinity.

Impact of glutathione on enhancing sunflower growth and biochemical aspects and yield to alleviate salinity stress

The effect of presoaking sunflower seeds with various concentrations of glutathione under salt stress on growth, some biochemical aspects and yield attributes were evaluated. A greenhouse pot experiment was carried out through two consecutive successive seasons. Irrigation sunflower plants with various concentrations (0, 3000 and 6000 mg L −1 ) of saline water caused gradual decreases in growth indices, photosynthetic pigments as chlorophyll (a, b) and carotenoids, some minerals (nitrogen, phosphorus, potassium and magnesium). Yield attributes, oil% and protein % of the yielded seeds of sunflower plant were decreased significantly by different salinity levels. While, free amino acids, proline, total soluble sugars, hydrogen peroxide and lipid peroxidation were increased under salinity conditions. Moreover salinity stress increased some antioxidant enzymes and sodium contents. Soaking of seeds with the various concentrations of glutathione (20, 40 and 60 mg L −1 ) could alleviate the harmful effects of salinity stress via increasing growth indices, photosynthetic pigments, osmolytes (free amino acid, proline and total soluble sugars), the studied antioxidant enzymes and minerals contents as well as, yield attributes quantity and quality of sunflower plant. Meanwhile decreased significantly hydrogen peroxide, lipid peroxidation and sodium element of sunflower plant grown under salinity stress. In conclusion, soaking sunflower seeds in different concentrations of glutathione improve growth indices and different biochemical aspects and yield quantity and quality not only under normal irrigation water but also under different salinity levels. Glutathione exogenous treatment with 40 mg L −1 was the most effective treatment enhancing the above mentioned characters. • Salinity stress results in reduction in plant growth and biochemical alterations. • Glutathione (GSH) mitigate the adverse effect of salinity stress on growth and oxidative stress. • The effective dose of GSH application to enhance the plant stress tolerance. • The differences in fatty acid compositions of sunflower oil under treatments. • Rising the efficiency of plant yield quantity and quality.

Effect of Gypsum, K-Humate and Plant Growth Promoting Bacteria on Improvement of Soil Properties and Productivity of Wheat and Maize Irrigated by Saline Water

Because of water shortage in North Nile Delta, Egypt, some farmers have to irrigate their crops by saline water. So, soils and/or plants are preferred to be treated by some amendments to alleviate the hazardous effects of salt stress. Two field experiments were conducted at Sakha Agric. Res. Station Farm, Kafr Elsheikh Gov., Egypt, to study the effect of gypsum (50, 75 and 100% of gypsum requirement, 8.2 t ha-1), K-humate (5 and 10 kg ha-1) and inoculation with plant growth-promoting-rhizobacteria (PGPR), (108-109 colony, ml-1) on soil properties and productivity of wheat (2018/19) and maize (2019) irrigated by saline water (0.7 and 2.43 dSm-1). The results revealed that plant height, grain filling, grain and straw yields of wheat and maize were negatively affected by irrigation water salinity. Also, irrigation water salinity clearly affected soil ECe and ESP, while it slightly affected soil bulk density and total porosity. Also, soil ECe, ESP, bulk density and total porosity were slightly affected by application of gypsum, K-humate and PGPR. The biomass yield, plant height and grain filling in both crops were positively affected by gypsum application, whereas it alleviated the adverse effects of salinity on crop growth. Also, K-humate with PGPR positively affected the crop yield and its attributes. The bio amendments alleviated the harmful effects of salinity stress on both crops. Finally, 100% gypsum combined with higher rate of K-humate and PGPR treatments was more effective treatment on plant growth and alleviated the harmful effects of salinity stress on plant growth.

Effect of irrigation with saline water on ion homeostasis and forage dry yield in Alfalfa ecotypes application of high salty water for Alfalfa plants irrigation

Salinity stress is a brutal environmental stress which decreases the yield production of plants. Questions rise on which of the ionic stress or lack of water has deleterious effects on plants forage dry yield. Also, questions remain on whether the K+ reduction or Na+ accumulation is more important in forage dry yield reduction under salinity stress. The present experiment was conducted to answer the above questions in four alfalfa ecotypes. To do so, 6-7 weeks seedlings were irrigated with high salty water (EC=20dS m-1) and RWC, MSI, height, forage dry yield, Na+ and K+ were measured 1, 3, 6, 10, and 16 days after the salt shock. The results showed that one day after irrigation with saline water, all measured traits changed adversely. Salinity stress by decreasing K+ and increasing Na+ content reduced the growth of alfalfa plants. RWC reduction was less than K+ reduction or Na+ accumulation, so ionic stress had more deleterious effects on forage dry yield of alfalfa plants. Root cells had a higher content of K+ and Na+ ions compared with leaves, hence, they had a major defensive role against salinity stress. The K+/Na+ ratio reduction in saline condition was the main element for decreasing plant forage dry yield. The application of high salty water for irrigation of alfalfa plants is possible if there is a good subsoil drainage system to remove the leached saline water regularly from the soil. It is also suggested that foliar application of potassium may be ameliorate harmful effects of salinity stress in plant growth.

Priming of Silybum marianum (L.) Gaertn seeds with H2O2 and magnetic field ameliorates seawater stress

Silybum marianum (L.) Gaertn is an important medicinal plant and has been used as a traditional medicine for diseases of the liver and biliary tract. The effects of seed priming by H2O2 (Haloprimig) and magnetic field (Magnetopriming, MF) on the impacts of seawater concentration were tested using S. marianum at the vegetative stage. These plant species accumulate flavonoids especially slimarine that is used in liver treatment. Some soaked S. marianum seeds were subjected to 0.18 T MF for different time durations (0, 10, 20 and 30 min) and other seeds were soaked in different concentrations of H2O2 (0, 80,160 and 240μM) for 8h. H2O2 priming increased growth and development under water irrigation more than under sea water stress. Moreover, our results uncovered statistical evidence that the priming seeds with H2O2 and MF increased the tolerance of S. marianum to salinity. In summary, we provide clear evidence that seawater stress caused a highly significant reduction in the growth parameters and stimulation in proline and phenolic compounds. It was concluded that, application of H2O2 and MF of S. marianum could scavenge or alleviate the harmful effects of salinity stress at early seedling stage and alleviate the oxidative damage leading to improvements in physiological attributes for the plant growth under sea water stress.