Impact Of Salt Stress Research Articles

Effects of salt stress on the fruit and yield quality of some selected tomato (<i>Lycopersicum esculentum</i> L.) varieties.

The growth, production, and nutritional characteristics of crops are impacted by abiotic factors such as salinity stress. The study aimed to assess the impact of salt stress on the fruit and yield characteristics of three distinct tomato cultivars, namely Rio, Dan syria, and UTC. Salt solutions with varying concentrations of NaCl were created by dissolving NaCl in deionized water. Four treatments were established, consisting of solutions with salt concentrations of 0g/L (control, without salt), 0.5g/L, 1.0g/L, and 1.5g/L. Each treatment was reproduced three times. The NaCl solutions were administered with a frequency of 7 days. The data in the study underwent Analysis of Variance (ANOVA). Rio outperformed the other varieties in terms of fruit quantity, fresh fruit weight, and fruit pericarp thickness under high salt stress, closely followed by UTC variety. The study also found that Dan syria performed better than the other varieties in terms of fresh and dry weight of shoot, as well as fresh weight of root, under mild and extreme salinity stress. However, Rio performed better than the other varieties in terms of dry weight of root under both mild and extreme salinity stress. The salt tolerance index of the Rio, UTC, and Dan Syria varieties under extreme salinity stress are 46.79%, 20.64%, and 34.70% respectively. This indicated that the Rio variety is the most salt-tolerant of the three types, with Dan Syria variety coming close.

Biohydrogen production from saline wastewater: An overview

The escalating global demand for sustainable energy has propelled the exploration of biohydrogen production with a promising avenue for simultaneously generating clean energy and managing waste effectively. This review mainly focuses on advances in sustainable biohydrogen production from saline wastewater, especially in a process that leverages the unique abilities of halotolerant and halophilic microorganisms adapted to high-salinity conditions. It provides an extensive understanding of various biohydrogen production methods, which are biophotolysis, photofermentation, dark fermentation, and microbial electrolysis. Additionally, this review elaborated on the enzymology of hydrogen production and the impact of salt stress, with a particular emphasis on the adaptive mechanisms of “salt-in” and “compatible solute” strategies. These adaptations are crucial for maintaining enzymatic activity and structural integrity under hypertonic conditions. Through a comprehensive examination of microbial pathways and strategies, this review aimed to furnish foundational insights that will drive future research and technological innovations in biohydrogen production.

Regulation of seed soaking with indole-3-butyric acid potassium salt (IBA-K) on rapeseed (Brassica napus L.) seedlings under NaCl stress

The growth and yield of rapeseed are significantly hampered by salt stress. Indole-3-butyric Acid Potassium Salt (IBA-K) has been found to alleviate the impact of salt stress on plant growth. However, the regulatory effect of IBA-K dipping on salt-stressed rapeseed remains unclear. To explore the implications of IBA-K on the growth and development of rapeseed during the seedling stage, we conducted potting experiments using the Huayouza 62 variety. Five different concentrations of IBA-K for seed soaking (0, 10, 20, 40, 80 mg·L− 1) were tested. The promotional impact of IBA-K on rapeseed demonstrated an initial increase followed by a decline, reaching a peak at 20 mg·L− 1. Therefore, 20 mg·L− 1 was determined as the optimal concentration for subsequent experiments. To further understand the mechanism of IBA-K’s action on salt-stressed rapeseed seedlings, we utilized the moderately salt-resistant cabbage rapeseed variety Huayouza 158R and the highly salt-resistant Huayouza 62 as specimens. The investigation focused on their response and repair mechanisms under 150 mmol·L− 1 NaCl stress. The findings demonstrated that compared with the sole NaCl stress, the 20 mg·L− 1 IBA-K seed soaking treatment under salt stress significantly enhanced the plant height, stem diameter, and leaf area of both rapeseed varieties. It also led to greater biomass accumulation, increased chlorophyll content, and improved photosynthetic efficiency in rapeseed. Furthermore, this treatment bolstered the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while significantly reducing the levels of electrolyte leakage (EL) and malondialdehyde (MDA). Consequently, it alleviated the membrane lipid peroxidation damage induced by NaCl stress, enhanced the accumulation of soluble proteins, maintained cellular osmotic pressure, and effectively mitigated the adverse effects of NaCl stress on rapeseed.

Physicochemical and Color Changes During Fruit Ripening in Pepper Species (C. annuum L., C. baccatum L., and C. chinense Jacq.) Exposed to Salt Stress

This study examines the impact of salt stress on the physicochemical and color characteristics of three pepper species (Capsicum annuum L., Capsicum baccatum L., and Capsicum chinense Jacq.) at different ripening periods. Peppers were exposed to 0 mM, 50 mM, and 100 mM NaCl during the green, breaking, and red ripening periods. The results showed that salt stress significantly influenced moisture content, total ash, pH, titratable acidity, water activity, and color parameters. C. chinense had the highest moisture content and water activity, while C. annuum demonstrated a higher total ash content and pigment density (ASTA value). As fruits ripened, moisture content decreased, and total ash content increased. Salt stress caused reductions in water activity, pH, and titratable acidity, with high salt concentrations leading to increased water loss and a decline in fruit quality. Furthermore, salt stress reduced color parameters and ASTA values, indicating suppressed carotenoid pigment synthesis. The study highlights the importance of developing salt-tolerant pepper varieties, as salt stress negatively impacts the physiological and biochemical quality of peppers. These findings suggest that appropriate agronomic strategies and careful environmental monitoring are essential for sustainable pepper production, particularly in areas with saline soils. The results provide valuable insights into the mechanisms through which salt stress affects pepper fruit quality and suggest avenues for improving crop resilience.

Can exogenous application of putrescine and priming modulate salinity stress in Camelina sativa L?

High salinity in soil significantly reduces growth and productivity; however, employing priming techniques and foliar spraying of putrescine can serve as an impressive method to reduce the impact of salt stress in saline soil. The current investigation intends to explore the effected of foliar spraying and priming methods on the growth, physiological, biochemical characteristics, and seed chemical compositions of salt-stressed Camelina sativa L. crop. A pot test was set up in a randomized complete block design by a factorial scheme with four replications. The experiment involved three factors: 1) salinity stress (0, 60, and 90 mM(, 2) priming techniques (no priming, hydro-priming, putrescine-priming (50 μmol L − 1), and 3) foliar application of putrescine at concentrations of 0, 100, and 200 μmol L−1. Camelina plants subjected to salinity stress showed decreased growth and performance, which correlated with lower chlorophyll levels, reduced photosynthesis maximum quantum efficiency, potassium concentration, and total soluble sugars and proline content. This decline was associated with increased lipid peroxidation (malondialdehyde content), sodium concentration, and electrical leakage, leading to diminished antioxidant enzyme activities. In contrast, under salt stress (60 mM), priming with putrescine led to an increase in grain yield (45 %), chlorophyll content (43 %), shoot length (54 %), maximum quantum efficiency (16 %), Superoxide dismutase (49 %), Catalase (58 %), Ascorbate peroxidase (47 %), linoleic acid (20 %), linolenic acid (38 %), oleic acid (27 %), eicosanoic acid (13 %) and shoot K+ ion (50 %) compared with non-treated plants. The application of 100 μmol L−1 putrescine through foliar application elicited the efficiency of camelina plants with increasing proline content, total soluble sugars, and antioxidant enzyme activities against salinity stress. In addition, the putrescine-priming method could improve photosynthetic efficiency and antioxidant enzyme activity under salt stress levels. Overall, our results supply an important outlook for the use of foliar putrescine spraying and putrescine-priming in modulating salinity tolerance in camelina crops.

Revisiting the role of light signaling in plant responses to salt stress

Abstract As one of the grave environmental hazards, soil salinization seriously limits crop productivity, growth and development. When plants are exposed to salt stress, they suffer a sequence of damage mainly caused by osmotic stress, ion toxicity and subsequently oxidative stress. As sessile organisms, plants have developed many physiological and biochemical strategies to mitigate the impact of salt stress. These strategies include altering root development direction, shortening the life cycle, accelerating dormancy, closing stomata to reduce transpiration and decreasing biomass. Apart from being a prime energy source, light is an environmental signal, which profoundly influences plant growth and development and also participates in plants’ response to salt stress. This review summarizes the regulatory network of salt tolerance by light signals in plants, which is vital to further understanding plants’ adaptation to high salinity. In addition, the review highlights potential future uses of genetic engineering and light supplement technology by light-emitting diode (LED) to improve crop growth in saline-alkali environments in order to make full use of the vast saline land.

Effects of biochar on growth and yield of Wheat (Triticum aestivum L.) under salt stress

Globally from abiotic stresses, salt stress is the major stress that limits crop production. One of them is wheat that has been utilized by more than 1/3 of the world population as staple food due to its nutritive value. Biochar is an activated carbon that can ameliorate the negative impacts on plants under saline conditions. The present study was conducted to examine the ameliorative impact of “Biochar application” to Triticum aestivum L. plant grown under salinity stress and evaluated on the basis of various growth, yield, physiological, biochemical attributes. Preliminary experiment was done to select the Triticum aestivum L. varieties with 90% germination rate for further experiment. The selected varieties, FSD08 and PUNJAB-11 of wheat were treated with two levels of sodium chloride (0 mM and 120 mM). Two varieties of wheat included FSD08 and PUNJAB-11 were treated with two levels of sodium chloride (0 mM and 120 mM). To address the impact of salt stress two levels of biochar 0% and 5% was used as exogenous application. A three way completely randomized experimentation was done in 24 pots of two wheat varieties with three replicates. The results demonstrated that salt stress affected growth, physiological attributes, yield and inorganic mineral ions (Ca2+ and K+) in roots and shoots parameters of wheat negatively while biochar overall improved the performance of plant. SOD, CAT, APX and POD activities enhanced during salt stress as the plant self-defense mechanism against salinity to minimize the damaging effect. Salt stress also significantly increased the membrane permeability, and levels of H2O2, MDA, Cl and Na ions. Biochar treatment nullified negative impacts of NaCl and improved the plant growth and yield significantly. Hence, biochar amendment can be suggested as suitable supplement for sustainable crop production under salinization.

Impact of NaCl stress on phytoconstituents and bioactivity of Matricaria chamomilla: a multi-analytical approach

Matricaria chamomilla (Asteraceae), commonly known as chamomile can tolerate freezing temperatures and grows in many soil types. This plant is found on all continents and has significant medicinal value. There are more than 120 chemicals detected in chamomile flowers, with the majority found in the essential oil. In this study, M. chamomilla was given the NaCl stress of 0 mM, 1 mM, 100 mM, and 150 mM concentrations This study was the first to assess the efficacy of German chamomile upon exposure to salt stress hence plant particles that had been dried and powdered were analyzed using, phytochemical tests, Fourier Transform Infrared and UV–Vis spectroscopy, thin layer chromatography, fluorescence recovery after photobleaching assay, antibacterial and antioxidant activity. The characterization and results of these activities show amazing results which enhance their antibacterial property with an increased zone of inhibition when the samples of salt stress of the above-given concentrations were compared to the control samples. More graph analysis indicates an effective impact of salt stress on the phytoconstituents of M. chamomilla. Other than that, there was a clear flower induction upon salt stress, as a variety of compounds are regarded as essential to the biological functions of chamomile flowers according to the phytoconstituent screening which can be further used in the cosmetic industry, pharmaceutical industry, and all other fields as well for various application as a nano-drug or bio-drug. Due to this, this plant became essential for plant biotechnology research.

Plant-associated halotolerant bacteria improving growth of Vicia faba L. Mariout-2 under salinity conditions

In this comprehensive investigation, we successfully isolated and characterized 40 distinct plant-associated halotolerant bacteria strains obtained from three halophytic plant species: Tamarix nilotica, Suaeda pruinosa, and Arthrocnemum macrostachyum. From this diverse pool of isolates, we meticulously selected five exceptional plant-associated halotolerant bacteria strains through a judiciously designed seed biopriming experiment and then identified molecularly. Bacillus amyloliquefaciens DW6 was isolated from A. macrostachyum. Three bacteria (Providencia rettgeri DW3, Bacillus licheniformis DW4, and Salinicoccus sesuvii DW5) were isolated for the first time from T. nilotica, S. pruinosa and S. pruinosa, respectively. Paenalcaligenes suwonensis DW7 was isolated for the first time from A. macrostachyum. These plant-associated halotolerant bacteria exhibited growth-promoting activities, including phosphate solubilization, nitrogen fixation, and production of bioactive compounds, i.e., ammonia, phytohormones, hydrogen cyanide, siderophores, and exopolysaccharides. A controlled laboratory experiment was conducted to reduce the detrimental impact of soil salinity. Vicia faba seedlings were inoculated individually or in mixtures by the five most effective plant-associated halotolerant bacteria to reduce the impact of salt stress and improve growth parameters. The growth parameters were significantly reduced due to the salinity stress in the control samples, compared to the experimental ones. The unprecedented novelty of our findings is underscored by the demonstrable efficacy of co-inoculation with these five distinct bacterial types as a pioneering bio-approach for countering the deleterious effects of soil salinity on plant growth. This study thus presents a remarkable contribution to the field of plant science and offers a promising avenue for sustainable agriculture in saline environments.

Physiological, genetical changes and cdc2 gene expression for osmotic stressed Vicia faba reveal the alleviation effect of gamma radiation and putrescine

Climate change caused increasing in soil salinity worldwide. Therefore, it is critical to enhance the capability of plant to tolerate salinity stress. For this goal, putrescine and irradiation by gamma radiation were used to improve the salt tolerance of Vicia faba (the most important human crop). The results indicated depression in mitotic division and all growth parameters associated with the induction of micronucleus (MN) when salinity increased to 100mM, while there was increase in mitotic aberrations. NaCl decreased total soluble sugar, while total N%, total free amino acid, proline and protein contents showed slight increase with increasing salinity stress. Putrescine and gamma radiation mitigated the effect of salinity on cell division and growth parameters. Salt stress decreased the expression of gene encoding cyclin-dependent kinase 2 (cdc2). Both putrescine and gamma radiation increased cdc2 expression. The genetic diversity has been detected among control and treated V. faba using ISSR and SCoT markers. Ten primers had successfully generated 129 reproducible polymorphic amplicons that were suitable for studying the genetic diversity between studied genotypes. ISSR markers provided more discriminating data and were more informative than SCoT markers. Besides, cluster analysis using UPGMA and PAC successfully explained the genetic diversity within studied genotypes. These findings emphasize the efficiency of putrescine and gamma radiation for alleviating the negative impact of salt stress. Moreover, prove the importance of assessing mitotic activity, chromosomes behavior, physiological parameters, the expression level of cdc2 and molecular diversity in V. faba under stress to improve the salt tolerance of it.

Effect of plant growth-promoting rhizobacteria (PGPR) on growth and yield of shallots on saline soils

Soil salinity is a limiting factor in agricultural productivity. One of the biological approaches to mitigate the impact of salt stress on plants is inoculating plant growth-promoting rhizobacteria (PGPR) to the plant roots. This study aimed to investigate the eff of PGPR dosage on the growth and yield of shallots at various salinity levels. This study was carried out in the experimental field of Poncokusumo, Malang. The treatments tested consisted of two factors. The first factor was soil salinity level, consisting of four levels: no salinity, NaCl 50 mM, NaCl 100 mM, and NaCl 150 mM. The second factor was PGPR concentration, consisting of four levels: no PGPR, PGPR 10 mL/L, PGPR 20 mL/L, and PGPR 30 mL/L. The sixteen treatment combinations were arranged in a randomized block design with three replications. The data obtained were subjected to the analysis of variance (ANOVA) at a significance level limit of 5%, followed by the Honestly Significant Difference (HSD) test at a 5% significance level for any significant differences. The results showed that the application of 30 mL/L of PGPR reduced EC of the soil and improved plant height, plant dry weight, leaf area, bulb diameter, bulb weight, and the number of bulbs per plant by 33%, 47.3%, 81%, 13%, 34.2%, 98.5%, and 31%, respectively, compared to the treatment without PGPR application under NaCl 150 mM salinity. The application of PGPR at 20 and 30 mL/L dosages significantly increased chlorophyll, flavonoid, and proline indices at NaCl at 100 mM and 150 mM salinity levels compared to the treatment without PGPR.

Impact of salt stress on the α-tocopherol, carotenoid derivatives and flocculation efficiency of Euglena sp., Indonesian Strain

Impact of salt stress on the α-tocopherol, carotenoid derivatives and flocculation efficiency of Euglena sp., Indonesian Strain

BR regulates wheat root salt tolerance by maintaining ROS homeostasis.

Trace amounts of epibrassinolide (EpiBL) could partially rescue wheat root length inhibition in salt-stressed situation by scavenging ROS, and ectopic expression of TaDWF4 or TaBAK1 enhances root salt tolerance in Arabidopsis by balancing ROS level. Salt stress often leads to ion toxicity and oxidative stress, causing cell structure damage and root development inhibition in plants. While prior research indicated the involvement of exogenous brassinosteroid (BR) in plant responses to salt stress, the precise cytological role and the function of BR in wheat root development under salt stress remain elusive. Our study demonstrates that 100mM NaCl solution inhibits wheat root development, but 5nM EpiBL partially rescues root length inhibition by decreasing H2O2 content, oxygen free radical (OFR) content, along with increasing the peroxidase (POD) and catalase (CAT) activities in salt-stressed roots. The qRT-PCR experiment also shows that expression of the ROS-scavenging genes (GPX2 and CAT2) increased in roots after applying BR, especially during salt stress situation. Transcriptional analysis reveals decreased expression of BR synthesis and root meristem development genes under salt stress in wheat roots. Differential expression gene (DEG) enrichment analysis highlights the significant impact of salt stress on various biological processes, particularly "hydrogen peroxide catabolic process" and "response to oxidative stress". Additionally, the BR biosynthesis pathway is enriched under salt stress conditions. Therefore, we investigated the involvement of wheat BR synthesis gene TaDWF4 and BR signaling gene TaBAK1 in salt stress responses in roots. Our results demonstrate that ectopic expression of TaDWF4 or TaBAK1 enhances salt tolerance in Arabidopsis by balancing ROS (Reactive oxygen species) levels in roots.

The Coupling Effects of PGPR Inoculation and Foliar Spraying of Strigolactone in Mitigating the Negative Effect of Salt Stress in Wheat Plants: Insights from Phytochemical, Growth, and Yield Attributes

Salt stress has detrimental effects on wheat plants at several physiological, biochemical, and molecular levels. This stress leads to suppressed growth, reduced grain yield, and poor quality of harvested grains. However, two approaches have shown promise for improving wheat salt tolerance: using a synthetic strigolactone analog called GR24 and applying plant growth-promoting rhizobacteria (PGPR). GR24 plays a vital role in regulating plant growth and development and in defense against various stresses. Conversely, PGPR are beneficial bacteria that colonize the rhizosphere of plants and promote their growth through multiple mechanisms. In our study, we investigated the effects of salinity on the growth and yield traits of two different wheat cultivars and explored the combined role of PGPR and GR24 in mitigating the impact of salt stress. We created three different salinity levels using NaCl in pots (original, 5 dS m−1, and 10 dS m−1) and inoculated wheat seeds with a salt-tolerant Bacillus velezensis UTB96 strain. In addition, we applied 10 μM GR24 via foliar application during the pollination stage. Our observations showed that salt stress negatively affected wheat’s growth, yield, and phytochemical properties compared to the control. However, both single and combined applications of PGPR and GR24 mitigated the adverse effects of salinity. The combined treatment had a more substantial impact than either alone in inducing and improving biochemical and ionic characteristics. These included decreasing Na+ content in both leaves and roots, and EL, H2O2, and MDA content in leaves while increasing K+ content in both leaves and roots, growth and yield-related traits, RWC, chlorophyll pigments, total protein, soluble sugar, starch, proline, GB, and antioxidant enzyme activity (APX, POX, and CAT) of leaves. In conclusion, integrating PGPR and GR24 can efficiently induce salt tolerance and improve plant growth under stressed conditions. This combined approach has the potential for broad applicability in supporting plant growth in the presence of salt stress.

Potential of melatonin and Trichoderma harzianum inoculation in ameliorating salt toxicity in watermelon: Insights into antioxidant system, leaf ultrastructure, and gene regulation

Melatonin (MT) is an extensively studied biomolecule with dual functions, serving as an antioxidant and a signaling molecule. Trichoderma Harzianum (TH) is widely recognized for its effectiveness as a biocontrol agent against many plant pathogens. However, the interplay between seed priming and MT (150 μm) in response to NaCl (100 mM) and its interaction with TH have rarely been investigated. This study aimed to evaluate the potential of MT and TH, alone and in combination, to mitigate salt stress (SS) in watermelon plants. The findings of this study revealed a significant decline in the morphological, physiological, and biochemical indices of watermelon seedlings exposed to SS. However, MT and TH treatments reduced the negative impact of salt stress. The combined application of MT and TH exerted a remarkable positive effect by increasing the growth, photosynthetic and gas exchange parameters, chlorophyll fluorescence indices, and ion balance (decreasing Na+ and enhancing K+). MT and TH effectively alleviated oxidative injury by inhibiting hydrogen peroxide formation in saline and non-saline environments, as established by reduced lipid peroxidation and electrolyte leakage. Moreover, oxidative injury induced by SS on the cells was significantly mitigated by regulation of the antioxidant system, AsA-GSH-related enzymes, the glyoxalase system, augmentation of osmolytes, and activation of several genes involved in the defense system. Additionally, the reduction in oxidative damage was examined by chloroplast integrity via transmission electron microscopy (TEM). Overall, the results of this study provide a promising contribution of MT and TH in safeguarding the watermelon crop from oxidative damage induced by salt stress.

Nutrient status and production of fodder beet irrigated with saline-sodic water in Mediterranean calcareous soils

ABSTRACT The impact of drip irrigation with saline-sodic water on the nutrient status and productivity of fodder beet (Beta vulgaris) was evaluated in rainy and dry Mediterranean cropping seasons. Two field experiments were conducted during two growing seasons (winter and summer) in calcareous soil (31% CaCO3) of Sais area, Northwestern Morocco. The rainfall was 337 mm for winter and 53 mm for summer. Four salinity levels of irrigation water (ECi) were investigated: control (1ds m−1), 4, 6, and 10 ds m−1. The ECi levels were prepared by adding sodium chloride (NaCl, laboratory grade, 99.5%) to water. The results showed that the soil salinity (ECs) was related to the growing season and the irrigation water salinity (ECi). The depressive effect of salinity on the whole plant dry biomass (−25% as average) was observed only in the summer crop cycle at different ECi ≥ 4 ds m−1 compared to control. The plant NaCl uptake for both seasons could be predicted by a linear model: Y (kg ha−1 of NaCl) = 36.3 ECi + 23.6 Q − 101.3 (adjusted R2 = 0.88) where Q = total dry biomass (t ha−1). Saline-sodic irrigation water reduced the contents of boron, calcium, and magnesium in the plants. The exchangeable sodium percentage (ESP) in the soil exceeded 41% at ECi ≥ 4 ds m−1 for both seasons. The study demonstrated that fodder beet escapes the negative impact of salt stress in the rainy season. However, the high ESP recorded at harvest did not reveal the efficacy of fodder beet in NaCl removal from the soil.

Salt stress and exclusion mechanism in woody plants

Many fruit tree species that are widely available in the world market continue to grow and bear fruit in the face of environmental stress. The negative impact of salt stress causes fruit trees to weaken and reduce their yield and quality. However, unlike annual plants, perennial fruit trees, which are exposed to many biotic and abiotic stresses under natural conditions, have developed many complex tolerance mechanisms to maintain their vital activities. Some fruit trees that can tolerate salt stress are able to exclude salt by maintaining their physiological and biochemical activities. In this review, we share the current knowledge on salt effects and tolerance in fruit trees and assess how salt is physiologically excluded from various parts of woody plants through the interaction of environmental factors.

S-ABA Enhances Rice Salt Tolerance by Regulating Na+/K+ Balance and Hormone Homeostasis.

In order to explore the regulating role and the physiological and biochemical mechanisms of trans-abscisic acid (hereinafter referred as S-ABA) in the process of rice growth and development under salt stress, we took Chaoyou 1000 and Yuxiangyouzhan as materials and set up three salt concentration treatments, CK0 (Control treatment), N1 (50 mmol L-1 NaCl), and N2 (100 mmol L-1 NaCl), in potted trials; we aimed to study the mechanism of rice's response to salt stress from the perspective of agricultural traits and physiological biochemicals and to improve rice's resistance to salt stress through exogenously applying the regulating technology of S-ABA. The following results were obtained: Under salt stress, the growth of rice was significantly suppressed compared to CK0, exhibiting notable increases in agricultural indicators, photosynthesis efficiency, and the NA+ content of leaves. However, we noted a significant decrease in the K+ content in the leaves, alongside a prominent increase in NA+/K+ and a big increase in MDA (malondialdehyde), H2O2 (hydrogen peroxide), and O2- (superoxide anion). This caused the cytomembrane permeability to deteriorate. By applying S-ABA under salt stress (in comparison with salt treatment), we promoted improvements in agronomic traits, enhanced photosynthesis, reduced the accumulation of NA+ in leaves, increased the K+ content and the activity of antioxidant enzymes, and reduced the active oxygen content, resulting in a sharp decrease in the impact of salt stress on rice's development. The application of S-ABA decreased the endogenous ABA (abscisic acid) content under salt stress treatment but increased the endogenous GA (gibberellin) and IAA (indole acetic acid) contents and maintained the hormonal homeostasis in rice plants. To summarize, salt stress causes damage to rice growth, and the exogenous application of S-ABA can activate the pouring system mechanism of rice, suppress the outbreak of active oxygen, and regulate NA+/K+ balance and hormone homeostasis in the blades, thus relieving the salt stress.

Assessment of photosynthetic capacity of two blackberry cultivars subjected to salt stress by the JIP fluorescence test

BACKGROUND: Salt stress has recently emerged as one of the most significant abiotic stresses with negative impact on crop production. Photosynthesis is a vital biochemical process in plants, very sensitive to environmental constraints, including salt stress. OBJECTIVE: The aim of this study was to evaluate the impact of salt stress on photosystem II in the leaves of blackberry cultivars (Rubus fructicosus L.). METHODS: Two blackberry cultivars (Thornfree and Boysen) were exposed to salt stress (20, 40, and 60 mM NaCl) for 28 days in in vitro culture. The photosynthetic activity was evaluated by probing chlorophyll a fluorescence (JIP test) and photosynthetic pigments. RESULTS: The maximum quantum yield of PSII (Fv/Fm), performance indexes (PIABS and PItotal), and photosynthetic driving force (DFABS) were greatly affected by salt stress in the leaves of Boysen cultivar. Lower photosynthetic efficiency was confirmed by the increased values of absorption flux per RC (ABS/RC), trapping flux per PSII RC (TR0/RC), dissipation flux per RC (DI0/RC), decreased values of chlorophyll and carotenoid contents, disruption in the interaction between the light-harvesting complex and the core proteins of PSII, as well as disruption of the oxygen-evolving complex. CONCLUSIONS: The provided informations suggest that the photosynthetic apparatus of Thornfree cultivar was found to be more tolerant to salt stress compared to Boysen.

Enhancing salt stress tolerance in kidney beans: The synergistic effects of biochar and salicylic acid in arid and semi-arid regions

Salt stress is one of the most damaging environmental stresses of recent times and poses a significant threat to food security. Here, we conducted an experimental study over two consecutive years (2022–2023) to evaluate the physiological and biochemical characteristics of kidney beans. The study used a randomized complete block design with 4 replications (n = 4). The experiment included three levels of salicylic acid (SA): SA0 (0 mM), SA0.5 (0.5 mM) and SA1 (1 mM). The study also used biochar in four levels, without biochar as the control treatment (B0), regular biochar (Rb) by 2.5 % per soil weight, modified biochar with phosphoric acid (PA) by 1.25 % per soil weight, and modified biochar with sulfuric acid (Sb) by 1.25 % per soil weight. Additionally, salt stress (SS) was induced using NaCl in three levels, SS0 (distilled water), SS4 (4 4 dS m−1), and SS8 (8 dS m−1). The results showed that salt stress, biochar, and salicylic acid significantly affected the measured parameters. Salt stress (SS4 and SS8) negatively affected the measured parameters compared to the control. However, the application of biochar and salicylic acid regulated the alleviation of the impact of salt stress. Under SS4, the application of Rb along with SA1 resulted in the highest value of proline content. The highest enzymatic activity of catalase was observed due to the use of PA in combination with SA0.5 under non-saline soil conditions. The use of PA under SS8 increased the hydrogen peroxide and caused the highest activity, while the lowest activity was obtained under non-saline soil conditions with the application of Sb. In the first year of the experiment, it was found that the use of SA1 without biochar under non-stress conditions resulted in the highest levels of malondialdehyde. Likewise, in the second year, the highest malondialdehyde activity was observed by applying Rb and SA1 under SS8. The research concludes that kidney bean plants are significantly impacted by salt stress, which affects their biochemical characteristics. Nonetheless, the combined application of biochar and salicylic acid showed promise in addressing these challenges. This approach could be particularly effective in managing salinity issues in arid and semi-arid regions, highlighting the potential of biochar and salicylic acid for improving plant resilience under such conditions.