Effects of salt stress on root growth and nutrient absorption efficiency of different salt-tolerant summer maize varieties

In semiarid regions of the Mediterranean basin, water and salinity stresses restrict crop establishment. The effects of salt and water stress on seed germination and early embryo growth (radicle and shoot growth) were investigated in laboratory in two cultivars of sweet sorghum [Sorghum bicolor (L.) Moench] – cv. ‘90‐5‐2′ and cv. ‘Keller’ – to verify how these stresses may limit crop growth during the very early stages of growing season. Six water potentials (ψ) of the imbibition solution (from 0 to −1.0 MPa) in NaCl or polyethylene glycol (PEG) for salt and water stress tests, respectively, were studied. Daily germination was recorded, and radicle and shoot lengths and dry weights (DWs) were measured 2 days after initial germination. Seed germination was reduced (8–30% lower than control) by water stress at ψ <−0.6 MPa and was delayed (approx. +10 h) already at −0.4 MPa. Salt stress only prolonged germination time. Shoot and root growth was adversely affected by water stress (PEG), whereas the effect of salt stress was less relevant. Cv. ‘90‐5‐2’ was less sensitive than cv. ‘Keller’ to both stresses. These cultivars exhibited a greater sensitivity to abiotic stresses in terms of root and shoot growth; therefore, other parameters beside germination, such as early embryo growth rate, may help in evaluating sorghum lines for adaptation to semi‐arid areas.

The main purpose is to reveal the macroscopic effects of salt stress on oilseed rape, mainly the height effect of salt stress on oilseed rape, the effect of salt stress on the growth of oilseed rape roots, and the effect of salt stress on the overall weight of oilseed rape. In addition, there are also some explanations of the mechanisms by which the growth of oilseed rape is affected after being subjected to salt stress (relatively simple changes in chemical substance content, based on other papers), which do not include the data changes in chemical substance content in oilseed rape after being subjected to salt stress and the detailed pathways and methods by which oilseed rape responds to salt stress at the microscopic level.

Abiotic stresses are one of the major reasons for low crop productivity owing to the disturbances caused by them. Polyamines can be applied to mitigate the harmful effects of stress in plants. Nasturtium (Tropaeolum majus L.) is an ornamental, medicinal, and edible plant that is found in many countries. The objective of this work was to evaluate the effect of polyamines application and salt stress on the growth and leaf gas exchange of T. majus. The treatments to induce salt stress were as follows: 0 mM NaCl (no stress), 40 mM NaCl (moderate stress), 80 mM NaCl (severe stress), 40 mM NaCl + spermine (Spm), 40 mM NaCl + spermidine (Spd), 40 mM NaCl + putrescine (Put), 80 mM NaCl + Spm, 80 mM NaCl + Spd, and 80 mM NaCl + Put. Polyamines were applied every week for four weeks. The applications of Spd and Spm attenuated the harmful effects of moderate salt stress on plant height and leaf fresh mass. The application of Spm attenuated the harmful effects of moderate salt stress on stem diameter. The application of Spd attenuated the harmful effects of moderate salt stress on the number of buds, the stem fresh mass, and total fresh mass. The application of Spm attenuated the harmful effects of severe salt stress on stomatal conductance and transpiration rate and attenuated the harmful effects of moderate salt stress on stomatal conductance, net photosynthesis, and transpiration. The application of Spd attenuated the harmful effects of moderate salt stress on instantaneous water use efficiency and intrinsic water use efficiency. The applications of Spm and Spd application can attenuated the harmful effects of moderate salt stress on the growth and leaf gas exchange of nasturtium.

IntroductionSilicon (Si), the second most prevalent element in the earth, is not soluble enough for plants to absorb, despite being one of numerous helpful elements. Supplementing with silicon (Si) is seen to be one of the most promising ways to mitigate abiotic stressors like salt and drought. Legume crops are still underutilised, especially mung bean, an important crop in India, despite several research on the effects of salt and silicon stress on various crops.MethodsIn order to study the impact of exogenous application of Si concentrations on the growth and physiochemical, Photosynthetic efficiency, and antioxidative pathways of four mung bean cultivars—K1, Co6, Co7Gg, and Co8 exposed to two levels of salinity] [10 mM NaCl, 20mM NaCl and 5 mM of Si—a Pot experiment and field data were collected over the course of two growth seasons (2023–2024). The overall treatments given were in six combinations as: (i) -Si/-NaCl (control) (ii) -NaCl + Si (iii) 10mM NaCl/−Si (IV). 10 mM NaCl/+ Si (v) 20mM NaCl/-Si (vi) = 20mM NaCl/+Si Growth factors like biomass, plant length, height, and photosynthetic measurements were all lowered by salinity stress; however, these effects were lessened by silicon supplementation at a concentration of 5 mM sodium silicate.Results and discussionUnder salt stress, the presence of silicon boosted the production of photosynthetic proteins such Photosystem I, Photosystem II, and light harvesting complexes. In the mung bean, salinity stress also resulted in oxidative damage in the form of superoxide radical (O2−) and hydrogen peroxide (H2O2), which raised MDA (lipid peroxidation) and electrolyte leakage. On the other hand, 5 mM sodium silicate has the ability to scavenge free radicals, which lowers electrolyte loss and lipid peroxidation (MDA). Significant silica deposition in the leaf epidermis was associated with this, and in the end, this served as a mechanical barrier to lessen the harmful effects of salt stress. Our simulated investigations, which employed Si as a supplement, indicated that, of all the varieties used in this study, K1 and Co7Gg shown resilience to salt stress, but Co6 and Co8 showed sensitivity. Experiments conducted at the field level on yield and growth provided evidence for the study's findings that Si has a positive impact on salt stress. Si reduced the detrimental effects of salt stress and provided a basic idea for using Si as a fertilizer.

In this research, the effect of light and salt stress on bacteria that cause diarrhea, such as Shigella flexneri, EHEC O157:H7, and Salmonella Typhi, was studied. Light stress resulting from exposure to ultraviolet rays causes changes in the physiological and chemical composition of the cell, which leads to a reduction in the growth rate of bacteria, as bacterial density decreased by up to about 36.4% in Salmonella Typhi compared to the control group. In contrast, salt stress, represented by a 3% concentration of sodium chloride, shows a defensive effect of increasing biofilm formation; EHEC O157:H7 recorded a 100% increase in biofilm production as a cell protection mechanism, the effect of combined stress of light and salt on the movement of bacteria was also studied, showing that the movement of the three species decreased by a constant rate of up to 60% when exposed to double pressure. At the genetic level, the results showed an increase in the expression of some genes related to the stress response such as the rpoS gene and the stx toxin production gene, while a decrease was observed in the fliC movement gene, which indicates a shift in the cells' strategy towards strengthening defense mechanisms and conserving energy. Regarding the effect of salt stress, the expression of the osmY gene responsible for the osmotic response increased, with an increase in the ampC gene for antibiotic resistance and a decrease in the expression of the ipaH gene associated with plasmidic influence, the analyzes revealed that sensitivity to antibiotics changed, as the sensitivity of bacteria to ampicillin decreased compared to ciprofloxacin. Finally, microscopic studies showed shorter cell length under stress conditions compared to the control group. The study offers deep insight into the mechanisms of bacterial adaptation to changing environmental conditions, aiding in the development of innovative and effective infection prevention strategies.

In the present study, we investigated the relationship between salt stress and nucleotide levels in the shoot ot Phaseolus vulgaris L. cv. Stringless Green Pod to determine if reduced growth was correlated with reduced nucleotide levels. Overall fresh weight of 25-d-old plants after having been on full salt treatment for 7 d was 33% lower compared with untreated plants. Shoot fresh weight decreased by 40% compared with 22% for the roots thus increasing the root to shoot ratio from 0-7 to 0-9. We examined young and juvenile leaves as well as mature leaves in order to compare growing tissue to fully enlarged tissue. To ascertain whether the effects of salt stress on nucleotide pools were more severe during the day than at night, we studied the combined effects of diurnal cycle and salt stress on these nucleotide pools. Salt treatment selectively affected certain nucleotide pools with the adenine nucleotides (AdN) being the most affected. We found large diurnal fluctuations of AdN pools in all leaves. During the day, AMP and ADP increased while ATP decreased. The sum, ATP + ADP, tended to remain constant and in mature leaves total AdN increased with AMP, an indication of net synthesis. At night, ATP increased in all leaves. However, salt stress prevented this night-time increase in mature leaves while enhancing it in juvenile and young leaves. In the daytime, salt stress caused a nearly 2-fold increase in AMP of young leaves and a large increase in the adenylate kinase mass action ratio (K). At night, the excess AMP disappeared with no change in total AdN. It is clear from these results that salt stress did not reduce shoot growth by depleting ATP in growing leaves. It did, however, reduce the ATP level of mature leaves and perhaps their ability to supply essential metabolites for growing regions.

A sand culture experiment assessed whether gibberellic acid(GA3) could alleviate the adverse effects of salt stress on thegrowth, ion accumulation and photosynthetic capacity of two spring wheatcultivars, Barani-83 (salt sensitive) and SARC-I (salt tolerant).Three-week-oldplants of both cultivars were exposed to 0, 100 and 200 molm−3 NaCl in Hoagland's nutrient solution. Threeweeks after the initiation of salt treatments, half of the plants of eachcultivar were sprayed overall with 100 mg L−1GA3 solution. Plants were harvested 3 weeks after theapplication of GA3. Fresh and dry weights of shoots and roots, plantheight and leaf area were decreased with increasing supply of salt, butgibberellic acid treatment caused a significant ameliorative effect on both thecultivars with respect to these growth attributes. However, GA3caused no significant change in grain yields but increased grain size in boththe cultivars. Saline growth medium caused a marked increase in theconcentrations of Na+ and Cl− in shoots androots of both the lines. However, with the application of GA3accumulation of Na+ and Cl− was enhanced inboth shoots and roots of both wheat lines, but more ions accumulated in saltsensitive Barani-83 than in salt tolerant SARC-1. Net CO2assimilation rate (A) of both wheat lines decreased consistently withincreasingsupply of NaCl, but application of GA3 alleviated the effect of saltstress on this variable in both the cultivars. However, the ameliorative effectof the hormone was more pronounced in Barani-83 than in SARC-1. Althoughwater-use efficiency (A/E = CO2assimilation/transpiration) and intrinsic water use efficiency(A/gs = CO2 assimilation/stomatalconductance) decreased significantly with increasing salt concentration of thegrowth medium in both the cultivars, GA3 was more effective inenhancing both the water-use attributes in Barani-83 than in SARC-1. Overall,GA3 treatment stimulated the vegetative growth of both cultivars ofwheat under salt stress, but it caused a slight reduction in grain yield.GA3 treatment enhanced the accumulation of Na+ andCl− in both shoots and roots of wheat plants under saltstress.It also caused a significant increase in photosynthetic capacity in both linesat the vegetative stage under both saline and non-saline media.

ABSTRACTSorghum [Sorghum bicolor (L.) Moench] is being explored in California as a multi-utility, water-use efficient crop, but water and salt stresses are common in the state’s San Joaquin Valley (SJV). Experiments were conducted to study the effect of water and salt stress on seed germination and the effect of salt stress on the early growth of a forage (SS405) and a grain (NK5418) sorghum hybrid. Solutions ranging from 0 to −5.56 MPa and 0 to 25 ds m−1 were prepared using polyethylene glycol and sodium chloride, respectively, and germination was evaluated in these solutions. Salinity tolerance at early growth stage was tested on plants irrigated with solutions ranging from 0 to 20 ds m−1. Plants were harvested 6 weeks after planting and their aboveground biomass was recorded. Chlorophyll content and stomatal conductance were also measured. Germination was reduced by 50% in SS405 and NK5418 at −2.5 MPa and −1.5 MPa, respectively, and by 50% in SS405 at 19.3 dS m−1, but NK5418 had 70% germination even at 25 dS m−1. Biomass of both hybrids was reduced by 50% at 16.8 dS m−1. Chlorophyll content and stomatal conductance of both hybrids was reduced by 50% at 10 dS m−1. Such studies may help in varietal selection of sorghum for cultivation in the SJV.

This study compared the effects of salt (NaCl) stress on growth, photosynthesis and solute accumulation in seedlings of the three poplar (Populus bonatii) cultivars Populus × BaiLin-2 (BL-2), Populus × BaiLin-3 (BL-3), and Populus × Xjiajiali (XJJL). The results showed that BL-2 and BL-3 could not survive at a salinity level of 200 mM but XJJL grew well. The effect of moderate salt stress on leaf extension of the three cultivars was only slight. At a high level of salinity, however, NaCl clearly inhibited leaf extension of BL-2 and BL-3, whereas it did not affect that of XJJL, and the net photosynthetic rate (P N) in XJJL was much higher than those of BL-2 and BL-3. The lower P N of BL-2 and BL-3 might be associated with the high concentration of Na+ and/or Cl− accumulated in the leaves, which could be toxic in photosynthesis system. In summary, the greater salt-tolerance of XJJL compared with that of BL-2 and BL-3 might be explained by the higher P N and photosynthetic area, the lower Na+/K− ratio and Cl− in the leaf, and the greater accumulation of soluble sugars and SO4 2−.

Colombia is the main producer of cape gooseberry (Physalis peruviana L.), a plant known for its various consumption practices and medicinal properties. This plant is generally grown in eroded soils and is considered moderately tolerant to unfavorable conditions, such as nutrient-poor soils or high salt concentrations. Most studies conducted on this plant focus on fruit production and composition because it is the target product, but a small number of studies have been conducted to describe the effect of abiotic stress, e.g., salt stress, on growth and biochemical responses. In order to better understand the mechanism of inherent tolerance of this plant facing salt stress, the present study was conducted to determine the metabolic and growth differences of P. peruviana plants at three different BBCH-based growth substages, varying salt conditions. Hence, plants were independently treated with two NaCl solutions, and growth parameters and LC-ESI-MS-derived semi-quantitative levels of metabolites were then measured and compared between salt treatments per growth substage. A 90 mM NaCl treatment caused the greatest effect on plants, provoking low growth and particular metabolite variations. The treatment discrimination-driving feature classification suggested that glycosylated flavonols increased under 30 mM NaCl at 209 substages, withanolides decreased under 90 mM NaCl at 603 and 703 substages, and up-regulation of a free flavonol at all selected stages can be considered a salt stress response. Findings locate such response into a metabolic context and afford some insights into the plant response associated with antioxidant compound up-regulation.

In pea (Pisum sativum L.) plants the effect of short-term salt stress and recovery on growth, water relations and the activity of some antioxidant enzymes was studied. Leaf growth was interrupted by salt addition. However, during recovery, growth was restored, although there was a delay in returning to control levels. Salt stress brought about a decrease in osmotic potential and in stomatal conductance, but at 48 h and 24 h post-stress, respectively, both parameters recovered control values. In pea leaves, a linear increase in the Na+ concentration was observed in salt treated plants. In the recovered plants, a slight reduction in the Na+ concentration was observed, probably due to a dilution effect since the plant growth was restored and the total Na+ content was maintined in leaves after the stress period. A significant increase of SOD activity occurred after 48 h of stress and after 8 h of the recovery period (53% and 42%, respectively), and it reached control values at 24 h post-stress. APX activity did not change during the stress period, and after only 8 h post-stress it was increased by 48% with respect to control leaves. GR showed a 71% increase after 24 h of salt stress and also a significant increase was observed in the recovered plants. A strong increase of TBARS was observed after 8 h of stress (180% increase), but then a rapid decrease was observed during the stress period. Surprisingly, TBARS again increased at 8 h post-stress (78% increase), suggesting that plants could perceive the elimination of NaCl from the hydroponic cultures as another stress during the first hours of recovery. These results suggest that short-term NaCl stress produces reversible effects on growth, leaf water relations and on SOD and APX activities. This work also suggests that both during the first hours of imposition of stress and during the first hours of recovery an oxidative stress was produced.

Early diagnosis of water deficiency is essential to mitigate salt stress injury in plants. The effects of salt stress during the fruit growth stage on stem and fruit diameters of Japanese persimmon trees (Diospyrus kaki Thunb.) were measured by a micromorphometric technique under greenhouse conditions. This technique is less cumbersome and more precise in comparison to measurement of water potential in a small pressure chamber. The effect of stress was measured on photosynthetic rate, pre-dawn water potential, stomatal conductance, transpiration and Na+ and K+ contents of the stem and leaves. Salt stress was imposed by irrigating the plants with NaCl solution. Stem and fruit diameters of the plants given the control treatment started to decrease around 0600 h and reached a minimum at 1400 h. Salt stress did not change the diurnal pattern of response in stem and fruit diameter dynamics, but decreased the amplitude of the circadian rhythm by influencing both declining and recovery phases. The effect of salt stress on stem diameter appeared after 1 d of treatment, and on the third day in the fruit. Salt stress also reduced water potential, photosynthesis, transpiration and stomatal conductance, and increased concentrations of Na and K in the plant parts. Most of these effects were expressed after a lag period of 5 d of salt application. Utilization of micromorphometric techniques for early diagnosis of water deficiency in salt-prone environments is recommended based on results of this study.

The salinity of soils and water for irrigation is a limitation that influences the productivity of crops that has increased worldwide and af fects the morphology and physiology of plants since it causes osmotic stress and ionic toxicity and impairs the absorption of water and nutrients. The ef fect of salt stress on some morphological and physiological traits in Coccoloba uvifera (L.) L. (sea grape) seedlings from dif ferent origins was evaluated and the traits whose behavior under salt stress could be used as an ef fective criterion of tolerance to salinity were determined. A completely randomized design experiment with ten repetitions was performed. The factors under study were salinity (0, 5, 15, and 25 dS m-1), which was maintained for a period of sixteen weeks, and the second factor was the origin of the plant material. The salinity level and the seedlings’ origin significantly influenced the morphological and physiological variables controlled. However, it is necessary to carry out in situ experiments to obtain more information related to the mechanisms used by sea grape to tolerate salinity conditions, because in the consulted sources no research focused on evaluating the ef fect of salinity and the origin on the morphology and physiology of C. uvifera seedlings in Cuba has been found. The results of the research provide preliminary information to understand the negative ef fect of salt stress on this type of plant. The behavior of some controlled traits under salt stress can be used as an ef fective criterion of tolerance to salinity.

Effects of drought and salt stresses on growth characteristics of euhalophyte Suaeda salsa in coastal wetlands

Aims: This research has as objective to evaluate the effect of NaCl salt stress on African eggplant plant growth and to determine the implication of the accumulation of Na+, proline and soluble sugars and the reduction of K+ in the detrimental effect of NaCl in the growth of this plant species.
 Study Design: The experiment was laid out in a Completely Randomized Design (CRD) having five treatments and three replications.
 Place and Duration of Study: The experiment was carried out in screening house under natural conditions at the International Institute of Tropical Agriculture, Commune of Abomey-Calavi. Republic of Benin from June to august 2022.
 Methodology: Five NaCI concentrations (0, 30, 60, 90 and 120 mM) were used to irrigate four weeks old plants for two weeks. Plant growth, sodium (Na), potassium (K), proline, and soluble sugars contents of leaves and roots were determined at the end of the experiment.
 Results: Salt stress induced a significant reduction (P = .001) in shoot and root growth from 30 : 60 or 90 mM NaCI according to the growth parameter but had no impact on shoot water content. Leaf and roots Na+ contents significantly increased (P = .001) under salt stress whereas K+ content deoreased significantly (P = .05) only in root. Na change was observed for proline and soluble sugars contents in both leaf and root.
 Conclusion: Salt stress reduces the growth of plants of African eggplant due mainly to Na+ ion toxicity. The ionic selectivity ratio (K+/ Na+) rather than the K+ ion content plays an important role in the response of plants of African eggplant to salt stress. Proline and soluble sugars accumulation appeared not to intervene.