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BackgroundSalinized soils negatively affect plant growth, so it has become necessary to use safe and eco-friendly methods to mitigate this stress. In a completely randomized design, a pot experiment was carried out to estimate the influence of the inoculation with endophytic bacterial isolates Azospirillum brasilense, Pseudomonas geniculata and their co-inoculation on growth and metabolic aspects of flax (Linum usitatissimum) plants that already grown in salinized soil.ResultsThe results observed that inoculation of salinity-stressed flax plants with the endophytes A. brasilense and P. geniculata (individually or in co-inoculation) increases almost growth characteristics (shoot and root lengths, fresh and dry weights as well as number of leaves). Moreover, contents of chlorophylls and carotenoids pigments, soluble sugars, proteins, free proline, total phenols, ascorbic acid, and potassium (K+) in flax plants grown in salinized soil were augmented because of the inoculation with A. brasilense and P. geniculata. Oppositely, there are significant decreases in free proline, malondialdehyde (MDA), hydrogen peroxide (H2O2), and sodium (Na+) contents. Regarding antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX), the inoculation with the tested endophytes led to significant enhancements in the activities of antioxidant enzymes in stressed flax plants.ConclusionsThe results of this work showed that the use of the endophytic bacterial isolates Azospirillum brasilense, Pseudomonas geniculata (individually or in co-inoculation) could be regarded as an uncommon new model to alleviate salinity stress, especially in salinized soils.

A pot experiment was designed and performed in a completely randomized block design (CRBD) to determine the main effect of two plant growth-promoting rhizobacteria (PGPR) and their co-inoculation on growth criteria and physio-biochemical attributes of canola plants (Brassica napus L.) plant grown in saline soil. The results showed that inoculation with two PGPR (Azotobacter chroococcum and/or Alcaligenes faecalis) energized the growth parameters and photosynthetic pigments of stressed plants. Moreover, soluble sugars’ and proteins’ contents were boosted due to the treatments mentioned above. Proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2) contents were markedly declined. At the same time, antioxidant enzymes, viz. superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase (POD), were augmented due to the inoculation with Azotobacter chroococcum and/or Alcaligenes faecalis. Regarding minerals’ uptake, there was a decline in sodium (Na) and an increase in nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) uptake due to the application of either individual or co-inoculation with the mentioned bacterial isolates. This study showed that co-inoculation with Azotobacter chroococcum and Alcaligenes faecalis was the most effective treatment and could be considered a premium tool used in facing environmental problems, especially saline soils.

Heavy metal contamination of the soil has grown in importance in recent years. It may reduce agricultural output and jeopardize the welfare of individuals by entering the food chain. The use of nanomaterials, such as copper-zinc (Cu-Zn) nanocomposites, has emerged as a potential strategy to alleviate lead (Pb) stress in plants. Chlorophyll content, biomass accumulation, root and shoot length, and other aspects of plant development were used to assess the impacts of these nanomaterials. Additionally, protein patterns and antioxidant isozyme analysis, including Antioxidant enzymes, were assessed to understand the mechanisms underlying the plant’s response to Cu-Zn exposure. The results suggest that after harvesting of the 35-day-old pea plant, signs of the plant’s amelioration from stress destruction included morphological traits, photosynthetic pigments, sugars, phenol content, protein levels, Pb accumulation, protein pattern, and isozymes analysis were performed. In stressed plants, measurements of growth parameters, physiological aspects, all showed severe declines. The study discovered that pea plants’ growth indices, chlorophyll content, and osmolytes were all improved by using foliar application of green-synthesis copper zinc (Cu-Zn) nanocomposites. Additionally, it lessened the negative effects of lead (Pb) stress on pea plants. Thus, Cu-Zn nanocomposites may be a viable approach to reducing heavy metal stress and enhancing pea plant crop growth and output.

Symbiotic plant-fungi interaction is a promising approach to alleviate salt stress in plants. Moreover, endophytic fungi are well known to promote the growth of various crop plants. Herein, seven fungal endophytes were screened for salt tolerance; the results revealed that Aspergillus ochraceus showed a great potentiality in terms of salt tolerance, up to 200 g L−1. The indole acetic acid (IAA) production antioxidant capacity and antifungal activity of A. ochraceus were evaluated, in vitro, under two levels of seawater stress, 15 and 30% (v/v; seawater/distilled water). The results illustrated that A. ochraceus could produce about 146 and 176 µg mL−1 IAA in 15 and 30% seawater, respectively. The yield of IAA by A. ochraceus at 30% seawater was significantly higher at all tryptophan concentrations, as compared with that at 15% seawater. Moreover, the antioxidant activity of ethyl acetate extract of A. ochraceus (1000 µg mL−1) at 15 and 30% seawater was 95.83 ± 1.25 and 98.33 ± 0.57%, respectively. Crude extracts of A. ochraceus obtained at 15 and 30% seawater exhibited significant antifungal activity against F. oxysporum, compared to distilled water. The irrigation of barley plants with seawater (15 and 30%) caused notable declines in most morphological indices, pigments, sugars, proteins, and yield characteristics, while increasing the contents of proline, malondialdehyde, and hydrogen peroxide and the activities of antioxidant enzymes. On the other hand, the application of A. ochraceus mitigated the harmful effects of seawater on the growth and physiology of barley plants. Therefore, this study suggests that the endophytic fungus A. ochraceus MT089958 could be applied as a strategy for mitigating the stress imposed by seawater irrigation in barley plants and, therefore, improving crop growth and productivity.

In this study, the anti-stress capabilities of the foliar application of chitosan, dissolved in four different organic acids (acetic acid, ascorbic acid, citric acid and malic acid) have been investigated on tomato (Solanum lycopersicum L.) plants under salinity stress (100 mM NaCl). Morphological traits, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress, minerals, antioxidant enzymes activity, isozymes and protein patterns were tested for potential tolerance of tomato plants growing under salinity stress. Salinity stress was caused a reduction in growth parameters, photosynthetic pigments, soluble sugars, soluble proteins and potassium (K+) content. However, the contents of proline, ascorbic acid, total phenol, malondialdehyde (MDA), hydrogen peroxide (H2O2), sodium (Na+) and antioxidant enzyme activity were increased in tomato plants grown under saline conditions. Chitosan treatments in any of the non-stressed plants showed improvements in morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Besides, the harmful impacts of salinity on tomato plants have also been reduced by lowering MDA, H2O2 and Na+ levels. Chitosan treatments in either non-stressed or stressed plants showed different responses in number and density of peroxidase (POD), polyphenol oxidase (PPO) and superoxide dismutase (SOD) isozymes. NaCl stress led to the diminishing of protein bands with different molecular weights, while they were produced again in response to chitosan foliar application. These responses were varied according to the type of solvent acid. It could be suggested that foliar application of chitosan, especially that dissolved in ascorbic or citric acid, could be commercially used for the stimulation of tomato plants grown under salinity stress.

Potato plants can be infected by different bacterial diseases, among them, the potato brown rot disease, caused by Ralstonia solanacearum . The novelty of the present research is to assess the potential impact of the synthesized copper oxide NPs (CuO NPs)-streptomycin nano-drug synthesized by gamma irradiation for inducing the systemic resistance against potato brown rot disease. CuO NPs-streptomycin was completely-characterized by UV–Vis., XRD, FTIR, HRTEM, SEM, and EDX elemental analysis. In the greenhouse experiment, the efficiency of CuO NPs was tested after three times of application. Disease index percent, phytochemicals, and metabolic indicators of resistance (as a response to induction of systemic resistance) were investigated. Our results indicated that treatment with CuO NPs during planting was more effective for increasing the protection percent by 55.8% and reducing the disease severity by 37.5% in the infected potato plants. CuO NPs-streptomycin increased not only the photosynthetic pigments but also the osmolytes contents. The highest reduction in malondialdehyde (44.89%) and hydrogen peroxide (32.9%) contents was achieved in the case of potato plants treated one week after planting. Therefore, it suggested applying CuO NPs-streptomycin in controlling plant disease since they are cost-effective and eco-friendly.

A pot experiment was carried out to study the ameliorative role of foliar application of an extract of the halophyte Arthrocnemum macrostachyum (A. macrostachyum) on soybean (Glycin max L.) plants grown under salinity stress (0, 75, and 150 mM NaCl). Growth traits, content of photosynthetic pigments, osmolytes, ascorbic acid and total phenol, oxidative damage, and proteins pattern were determined. Growth parameters of soybean plants grown under both saline regimes (75 and 150 mM NaCl) were reduced except for the response to the foliar application of A. macrostachyum extract in either stressed or non-stressed plants. Foliar application of A. macrostachyum extract reinforced the photosynthetic pigment, soluble sugars, and soluble proteins content. Besides, it also minimized the negative impacts of salinity on soybean plants by decreasing the content of malondialdehyde (MDA) and hydrogen peroxide (H2O2). The results herein showed that the plant water extract and their interactions in the two NaCl levels increased the proline, total free amino acids, total phenols, and ascorbic acid content. Protein patterns in soybean leaves indicated protein expression suppression in soybean plants irrigated with 150 mM NaCl. The magnitude of suppression caused by the saline level was enhanced by using A. macrostachyum extract. The findings of this study indicate that the use of an extract of the halophyte A. macrostachyum can be considered as an unconventional and novel tool in the mitigation of salinity stress.

Climate changes have a direct impact on agricultural lands through their impact on the rate of water levels in the oceans and seas, which leads to a decrease in the amount of water used in agriculture, and therefore the use of alternative sources of irrigation such as wastewater and overcoming its harmful effect on plants was one of the solutions to face this problem. In the present study, the impacts of the synthesized selenium nanoparticles (Se NPs) alone or in combination with glycine betaine and proline treatments on the growth, physiological, and yield attributes of wastewater irrigated carrot plants are investigated. Furthermore, to evaluate heavy metals uptake and accumulation in edible plant parts. The usage of wastewater to carrot plants significantly increased free proline contents, total phenols, superoxide dismutase, catalase, peroxidase, polyphenol oxidase, Malondialdehyde (MDA), and hydrogen peroxide (H 2 O 2 ) throughout the two growth stages. While total soluble carbohydrate and soluble protein content in carrot shoots and roots were significantly reduced. Moreover, the concentrations of nickel (Ni), cadmium (Cd), lead (Pb), and cobalt (Co) in carrot plants were considerably higher than the recommended limits set by international organizations. Application of selenium nanoparticles alone or in combination with glycine betaine and proline reduced the contents of Ni, Cd, Pb, and Co; free proline; total phenols; superoxide dismutase; catalase; peroxidase; polyphenol oxidase; Malondialdehyde (MDA) and Hydrogen peroxide (H 2 O 2 ) in carrot plants. However, morphological aspects, photosynthetic pigments, soluble carbohydrates, soluble protein, total phenol, and β-Carotene were enhanced in response to Se NPs application. As an outcome, this research revealed that Se NPs combined with glycine betaine and proline can be used as a strategy to minimize heavy metal stress caused by wastewater irrigation in carrot plants, consequently enhancing crop productivity and growth.

Climate changes and stresses negatively affected the physiological processes inside plant cells, which led to a clear imbalance in the global diet. In both irrigated and non-irrigated areas, salinity is one of the principal abiotic factors influencing plant growth and production, especially in crop plants. The present experiment was designed to evaluate two types of foliar feeding as anti-salt stress by measuring stress tolerant and antioxidant levels. Foliar feedings, Gluamin Cu, and Ascophyllum nodosum (WeGrow Special) were used as therabutic nutrients and stress raisers on plants irrigated with saline solution (150 mmol) and others irrigated with tap water. After 70 days of plant life, morphological characteristics, plant pigments, osmosis levels, phenols, and antioxidant enzyme activity were measured as indicators of plant recovery from stress damage. Measurements of vegetative growth, photosynthesis, sugars, and protein content decreased significantly in stressed plants. On the contrary, the level of proline, phenol, malondialdehyde, hydrogen peroxide, and sodium (Na + ) and the activity of antioxidant enzymes increased compared to non-stressed plants. The beneficial impacts of the foliar feedings (Gluamin Cu and WeGrow Special) have been broadened to increase all growth parameters, photosynthetic pigments, proline, phenol, and enzyme activities, in both unstressed and stressed plants in comparison to control. Interestingly, the harmful impact of salinity on tomato plants was significantly decreased and it can be evident from reduced MDA and H 2 O 2 levels. The results indicated that Gluamin Cu at a concentration of 3 cm L −1 foliar was the best treatment in increasing shoot length by 18.75%, root length by 51.8%, number of leaves by 31.5%, chlorophyll A by 98.9% and chlorophyll B by 47.6%, proline 12.6%, peroxidase by 39.6%, polyphenol oxidase by 14.29%, super oxide dismutase by 16.4%, and catalase by 54.9% in stressed plants compared to the stressed control. These results indicated that the use of any of the foliar nutrients (Gluamin Cu and WeGrow Special) considered to raise the salt stress in the plant and improve its morphological characteristics and metabolic processes inside the cells, and thus it can be used and applied commercially as environmentally friendly anti-salt stress.