How Do Plants Respond to Combined Drought and Salinity Stress?-A Systematic Review

Enhancement in Tomato Yield and Quality Using Biochar Amendments in Greenhouse under Salinity and Drought Stress

Enhancing saline water productivity in arid regions is essential for sustainable agriculture. Adding biochar can improve the quantity and quality of tomato yield under higher levels of salinity and lower levels of irrigation. The experiment aimed to evaluate the effects of biochar on enhancing tomato fruit quality and yield under salinity and drought stress. The experiment combines two treatments for irrigation water quality (0.9 and 2.3 dS m-1), four irrigation levels (40, 60, 80, and 100%) of crop evapotranspiration (ETc), and the addition of 5% of biochar to treated soil (BC5%) and untreated soil (BC0%). The results showed that the decrease in the water quality and irrigation levels negatively impacted the yield and properties of tomato fruit, while 5% of biochar application positively improved the yield. Adding biochar decreased the tomato yield by 29.33% and 42.51% under lower-saline-irrigation water than the control, negatively affecting the fruit's physical parameters and mineral content. In contrast, adding biochar and irrigating with saline water at 60% of ETc improved the firmness and quality characteristics of the fruit by 56.60%, 67.19, 99.75, and 73.57% for vitamin C (VC), total titratable acidity (TA), total soluble solids (TSS), and total sugars (TS), respectively, compared to the control, and also reduced the sodium content of the fruits under all irrigation levels compared to untreated plants by biochar. Generally, biochar with saline water under deficit irrigation with 80 and 60% of ETc could be an excellent strategy to enhance the qualitative characteristics of tomato fruits and save approximately 20-40% of the applied water.

Endophyte-mediated enhancement of salt resistance in Arachis hypogaea L. by regulation of osmotic stress and plant defense-related genes

Introduction

Soil salinization poses a significant environmental challenge affecting plant growth and agricultural sustainability. This study explores the potential of salt-tolerant endophytes to mitigate the adverse effects of soil salinization, emphasizing their impact on the development and resistance of Arachis hypogaea L. (peanuts).

Methods

The diversity of culturable plant endophytic bacteria associated with Miscanthus lutarioriparius was investigated. The study focused on the effects of Bacillus tequilensis, Staphylococcus epidermidis, and Bacillus siamensis on the development and germination of A. hypogaea seeds in pots subjected to high NaCl concentrations (200 mM L-1).

Results

Under elevated NaCl concentrations, the inoculation of endophytes significantly (p < 0.05) enhanced seedling germination and increased the activities of enzymes such as Superoxide dismutase, catalase, and polyphenol oxidase, while reducing malondialdehyde and peroxidase levels. Additionally, endophyte inoculation resulted in increased root surface area, plant height, biomass contents, and leaf surface area of peanuts under NaCl stress. Transcriptome data revealed an augmented defense and resistance response induced by the applied endophyte (B. tequilensis, S. epidermidis, and B. siamensis) strain, including upregulation of abiotic stress related mechanisms such as fat metabolism, hormones, and glycosyl inositol phosphorylceramide (Na+ receptor). Na+ receptor under salt stress gate Ca2+ influx channels in plants. Notably, the synthesis of secondary metabolites, especially genes related to terpene and phenylpropanoid pathways, was highly regulated.

Conclusion

The inoculated endophytes played a possible role in enhancing salt tolerance in peanuts. Future investigations should explore protein-protein interactions between plants and endophytes to unravel the mechanisms underlying endophyte-mediated salt resistance in plants.

Surviving a Double-Edged Sword: Response of Horticultural Crops to Multiple Abiotic Stressors

Climate change-induced weather events, such as extreme temperatures, prolonged drought spells, or flooding, pose an enormous risk to crop productivity. Studies on the implications of multiple stresses may vary from those on a single stress. Usually, these stresses coincide, amplifying the extent of collateral damage and contributing to significant financial losses. The breadth of investigations focusing on the response of horticultural crops to a single abiotic stress is immense. However, the tolerance mechanisms of horticultural crops to multiple abiotic stresses remain poorly understood. In this review, we described the most prevalent types of abiotic stresses that occur simultaneously and discussed them in in-depth detail regarding the physiological and molecular responses of horticultural crops. In particular, we discussed the transcriptional, posttranscriptional, and metabolic responses of horticultural crops to multiple abiotic stresses. Strategies to breed multi-stress-resilient lines have been presented. Our manuscript presents an interesting amount of proposed knowledge that could be valuable in generating resilient genotypes for multiple stressors.

Delineating the role of host plants in regulating the water and salinity stress induced changes in sandalwood roots

The interaction of root hemi-parasite (sandalwood) with its hosts is crucial for establishing successful plantations under abiotic stresses. In the present study, we explored the best possible host for sandalwood along with its effect on sandalwood physiology in terms of water and nutrients. Interactive effects of host species (Alternanthera sp., Azadirachta indica, Dalbergia sissoo, Melia dubia, and Aquilaria malaccensis) with sandalwood were observed under eight treatments {100% best available water (BAW); 100% BAW + nutrient medium; 50% water deficit; 50% water deficit + nutrient medium; 100% saline water (ECiw 8ds/m); 100% saline water (ECiw 8ds/m) + nutrient medium; 50% water deficit + saline water (ECiw 8ds/m); and 50% water deficit + saline water (ECiw 8ds/m) + nutrient medium}. A significant change in morpho-physiological traits of sandalwood roots was observed under different stress conditions, which were slightly improved through external supply of nutrient medium. Dalbergia sissoo (Shisham) and Melia dubia (Dek) seemed to be the best host plants providing better environment for sandalwood growth and development, i.e., higher plant height (59.7 and 53.68 cm) and collar diameter (3.24 and 3.07 mm) under stresses by maintaining water and ionic balance. Root length is an important parameter that was reduced by 27.58%, 19.22%, and 36.3% under water deficit, salinity, and combined stress of water deficit and salinity. Sandalwood grown with D. sissoo and M. dubia maintained the lowest Ψw (- 1.38 MPa) and Ψs (- 1.47 and - 1.48 MPa), respectively. In addition, sandalwood cultivated with D. sissoo and A. indica had higher accumulation of soluble proteins (0.48 and 0.42 mg/g) and soluble sugars (98.56 and 91.04 mg/g) in their roots. Results also showed that sandalwood roots had higher K+/Na+ with compatible host, i.e., with A. indica (1.85) and D. sissoo (1.83) than other studied hosts. It was also observed that sandalwood plants could not grow and survive alone under stress conditions even with application of nutrient medium. Based on the morphological traits, it was observed that sandalwood grown with hosts, Dalbergia sissoo and Melia dubia, was able to tolerate stress conditions better than other studied hosts. We can further recommend growing sandalwood with D. sissoo and M. dubia as a viable option to endure adverse environmental conditions.

Exploring the potential of endophyte-plant interactions for improving crop sustainable yields in a changing climate

Climate change poses a major threat to global food security, significantly reducing crop yields as cause of abiotic stresses, and for boosting the spread of new and old pathogens and pests. Sustainable crop management as a route to mitigation poses the challenge of recruiting an array of solutions and tools for the new aims. Among these, the deployment of positive interactions between the micro-biotic components of agroecosystems and plants can play a highly significant role, as part of the agro-ecological revolution. Endophytic microorganisms have emerged as a promising solution to tackle this challenge. Among these, Arbuscular Mycorrhizal Fungi (AMF) and endophytic bacteria and fungi have demonstrated their potential to alleviate abiotic stresses such as drought and heat stress, as well as the impacts of biotic stresses. They can enhance crop yields in a sustainable way also by other mechanisms, such as improving the nutrient uptake, or by direct effects on plant physiology. In this review we summarize and update on the main types of endophytes, we highlight several studies that demonstrate their efficacy in improving sustainable yields and explore possible avenues for implementing crop-microbiota interactions. The mechanisms underlying these interactions are highly complex and require a comprehensive understanding. For this reason, omic technologies such as genomics, transcriptomics, proteomics, and metabolomics have been employed to unravel, by a higher level of information, the complex network of interactions between plants and microorganisms. Therefore, we also discuss the various omic approaches and techniques that have been used so far to study plant-endophyte interactions.

A meta-analysis highlights the cross-resistance of plants to drought and salt stresses from physiological, biochemical, and growth levels

In nature, drought and salt stresses often occur simultaneously and affect plant growth at multiple levels. However, the mechanisms underlying plant responses to drought and salt stresses and their interactions are still not fully understood. We performed a meta-analysis to compare the effects of drought, salt, and combined stresses on plant physiological, biochemical, morphological and growth traits, analyze the different responses of C3 and C4 plants, as well as halophytes and non-halophytes, and identify the interactive effects on plants. There were numerous similarities in plant responses to drought, salt, and combined stresses. C4 plants had a more effective antioxidant defense system, and could better maintain above-ground growth. Halophytes could better maintain photosynthetic rate (Pn) and relative water content (RWC), and reduce growth as an adaptation strategy. The responses of most traits (Pn, RWC, chlorophyll content, soluble sugar content, H2O2 content, plant dry weight, etc.) to combined stress were less-than-additive, indicating cross-resistance rather than cross-sensitivity of plants to drought and salt stresses. These results are important to improve our understanding of drought and salt cross-resistance mechanisms and further induce resistance or screen-resistant varieties under stress combination.

Silicon nanoparticles improved the osmolyte production, antioxidant defense system, and phytohormone regulation in Elymus sibiricus (L.) under drought and salt stress

Drought and salt stress negatively influence the growth and development of various plant species. Thus, it is crucial to overcome these stresses for sustainable agricultural production and the global food chain. Therefore, the present study investigated the potential effects of exogenous silicon nanoparticles (SiNPs) on the physiological and biochemical parameters, and endogenous phytohormone contents of Elymus sibiricus under drought and salt stress. Drought stress was given as 45% water holding capacity, and salt stress was given as 120 mM NaCl. The seed priming was done with different SiNP concentrations: SiNP1 (50 mg L-1), SiNP2 (100 mg L-1), SiNP3 (150 mg L-1), SiNP4 (200 mg L-1), and SiNP5 (250 mg L-1). Both stresses imposed harmful impacts on the analyzed parameters of plants. However, SiNP5 increased the chlorophylls and osmolyte accumulation such as total proteins by 96% and 110% under drought and salt stress, respectively. The SiNP5 significantly decreased the oxidative damage and improved the activities of SOD, CAT, POD, and APX by 10%, 54%, 104%, and 211% under drought and 42%, 75%, 72%, and 215% under salt stress, respectively. The SiNPs at all concentrations considerably improved the level of different phytohormones to respond to drought and salt stress and increased the tolerance of Elymus plants. Moreover, SiNPs decreased the Na+ and increased K+ concentrations in Elymus suggesting the reduction in salt ion accumulation under salinity stress. Overall, exogenous application (seed priming/dipping) of SiNPs considerably enhanced the physio-biochemical and metabolic responses, resulting in an increased tolerance to drought and salt stresses. Therefore, this study could be used as a reference to further explore the impacts of SiNPs at molecular and genetic level to mitigate abiotic stresses in forages and related plant species.

Transcriptome Profiling of a Soybean Mutant with Salt Tolerance Induced by Gamma-ray Irradiation

Salt stress is a significant abiotic stress that reduces crop yield and quality globally. In this study, we utilized RNA sequencing (RNA-Seq) to identify differentially expressed genes (DEGs) in response to salt stress induced by gamma-ray irradiation in a salt-tolerant soybean mutant. The total RNA library samples were obtained from the salt-sensitive soybean cultivar Kwangan and the salt-tolerant mutant KA-1285. Samples were taken at three time points (0, 24, and 72 h) from two tissues (leaves and roots) under 200 mM NaCl. A total of 967,719,358 clean reads were generated using the Illumina NovaSeq 6000 platform, and 94.48% of these reads were mapped to 56,044 gene models of the soybean reference genome (Glycine_max_Wm82.a2.v1). The DEGs with expression values were compared at each time point within each tissue between the two soybeans. As a result, 296 DEGs were identified in the leaves, while 170 DEGs were identified in the roots. In the case of the leaves, eight DEGs were related to the phenylpropanoid biosynthesis pathway; however, in the roots, Glyma.03G171700 within GmSalt3, a major QTL associated with salt tolerance in soybean plants, was differentially expressed. Overall, these differences may explain the mechanisms through which mutants exhibit enhanced tolerance to salt stress, and they may provide a basic understanding of salt tolerance in soybean plants.

Jasmonic acid improves barley photosynthetic efficiency through a possible regulatory module, MYC2-RcaA, under combined drought and salinity stress

The combined stress of drought and salinity is prevalent in various regions of the world, affects several physiological and biochemical processes in crops, and causes their yield to decrease. Photosynthesis is one of the main processes that are disturbed by combined stress. Therefore, improving the photosynthetic efficiency of crops is one of the most promising strategies to overcome environmental stresses, making studying the molecular basis of regulation of photosynthesis a necessity. In this study, we sought a potential mechanism that regulated a major component of the combined stress response in the important crop barley (Hordeum vulgare L.), namely the Rubisco activase A (RcaA) gene. Promoter analysis of the RcaA gene led to identifying Jasmonic acid (JA)-responsive elements with a high occurrence. Specifically, a Myelocytomatosis oncogenes 2 (MYC2) transcription factor binding site was highlighted as a plausible functional promoter motif. We conducted a controlled greenhouse experiment with an abiotic stress-susceptible barley genotype and evaluated expression profiling of the RcaA and MYC2 genes, photosynthetic parameters, plant water status, and cell membrane damages under JA, combined drought and salinity stress (CS) and JA + CS treatments. Our results showed that applying JA enhances barley's photosynthetic efficiency and water relations and considerably compensates for the adverse effects of combined stress. Significant association was observed among gene expression profiles and evaluated physiochemical characteristics. The results showed a plausible regulatory route through the JA-dependent MYC2-RcaA module involved in photosynthesis regulation and combined stress tolerance. These findings provide valuable knowledge for further functional studies of the regulation of photosynthesis under abiotic stresses toward the development of multiple-stress-tolerant crops.

Exogenous γ-aminobutyric acid improves the photosynthesis efficiency, soluble sugar contents, and mineral nutrients in pomegranate plants exposed to drought, salinity, and drought-salinity stresses

BACKGROUND

γ-aminobutyric acid (GABA), as a regulator of many aspects of plant growth, has a pivotal role in improving plant stress resistance. However, few studies have focused on the use of GABA in increasing plants' resistance to interactional stresses, such as drought-salinity. Therefore, the focus of this study was to examine the effect of foliar application of GABA (0, 10, 20, and 40 mM) on growth indices and physio-biochemical parameters in plants of two pomegranate cultivars, 'Rabab' and 'Atabaki' exposed to drought, salinity, and drought-salinity.

RESULTS

Under stress conditions, the photosynthetic capacity of two pomegranate cultivars, including transpiration rate, net photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance of water vapour, and mesophyll conductance, was significantly reduced. This resulted in a decrease in root morphological traits such as fresh and dry weight, diameter, and volume, as well as the fresh and dry weight of the aerial part of the plants. However, the application of GABA reversed the negative effects caused by stress treatments on growth parameters and maintained the photosynthetic capacity. GABA application has induced the accumulation of compatible osmolytes, including total soluble carbohydrate, starch, glucose, fructose, and sucrose, in charge of providing energy for cellular defense response against abiotic stresses. Analysis of mineral nutrients has shown that GABA application increases the absorption of potassium, potassium/sodium, magnesium, phosphorus, manganese, zinc, and iron. As concentration increased up to 40 mM, GABA prevented the uptake of toxic ions, sodium and chloride.

CONCLUSIONS

These findings highlight the potential of GABA as a biostimulant strategy to enhance plant stress tolerance.

An overview of image-based phenotyping as an adaptive 4.0 technology for studying plant abiotic stress: A bibliometric and literature review

Improving the tolerance of crop species to abiotic stresses that limit plant growth and productivity is essential for mitigating the emerging problems of global warming. In this context, imaged data analysis represents an effective method in the 4.0 technology era, where this method has the non-destructive and recursive characterization of plant phenotypic traits as selection criteria. So, the plant breeders are helped in the development of adapted and climate-resilient crop varieties. Although image-based phenotyping has recently resulted in remarkable improvements for identifying the crop status under a range of growing conditions, the topic of its application for assessing the plant behavioral responses to abiotic stressors has not yet been extensively reviewed. For such a purpose, bibliometric analysis is an ideal analytical concept to analyze the evolution and interplay of image-based phenotyping to abiotic stresses by objectively reviewing the literature in light of existing database. Bibliometricy, a bibliometric analysis was applied using a systematic methodology which involved data mining, mining data improvement and analysis, and manuscript construction. The obtained results indicate that there are 554 documents related to image-based phenotyping to abiotic stress until 5 January 2023. All document showed the future development trends of image-based phenotyping will be mainly centered in the United States, European continent and China. The keywords analysis major focus to the application of 4.0 technology and machine learning in plant breeding, especially to create the tolerant variety under abiotic stresses. Drought and saline become an abiotic stress often using image-based phenotyping. Besides that, the rice, wheat and maize as the main commodities in this topic. In conclusion, the present work provides information on resolutive interactions in developing image-based phenotyping to abiotic stress, especially optimizing high-throughput sensors in image-based phenotyping for the future development.

Melatonin enhances salt tolerance in sorghum by modulating photosynthetic performance, osmoregulation, antioxidant defense, and ion homeostasis

Melatonin is a potent antioxidant that can prevent plant damage caused by adverse stresses. It remains unclear whether exogenous melatonin can mitigate the effects of salt stress on seed germination and seedling growth of sorghum (Sorghum bicolor (L.) Moench). The aim of this study was to decipher the protective mechanisms of exogenous melatonin (100 μmol/L) on sorghum seedlings under NaCl-induced salt stress (120 mmol/L). Plant morphological, photosynthetic, and physiological characteristics were analyzed at different timepoints after sowing. Results showed that salt stress inhibited seed germination, seedling growth, and plant biomass accumulation by reducing photosynthetic pigment contents, photosynthetic efficiency, root vigor, and mineral uptake. In contrast, seed priming with melatonin enhanced photosynthetic pigment biosynthesis, photosynthetic efficiency, root vigor, and K+ content under salt stress. Melatonin application additionally enhanced the activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase) and increased the levels of non-enzymatic antioxidants (reduced glutathione, ascorbic acid) in the leaves. These changes were accompanied by increase in the leaf contents of soluble sugars, soluble proteins, and proline, as well as decrease in hydrogen peroxide accumulation, malondialdehyde content, and electrolyte leakage. Our findings indicate that exogenous melatonin can alleviate salt stress-induced damage in sorghum seedlings through multifaceted mechanisms, such as improving photosynthetic performance and root vigor, facilitating ion homeostasis and osmoregulation, and promoting antioxidant defense and reactive oxygen species scavenging.

Nutrient resorption responses of female and male Populus cathayana to drought and shade stress

Nutrient resorption can increase nutrient use and play important roles in terrestrial plant nutrient cycles. Although several studies have reported individual responses of plant nutrient resorption to drought or shade stress, the interaction of drought and shade remains unclear, especially for dioecious plants. This study explored whether nutrient resorption is correlated to growth characteristics (such as biomass and root/shoot ratio [R/S ratio]) and leaf economics (such as leaf thickness, leaf mass per area [LMA] and leaf vein density [LVD]) in female and male Populus cathayana across different conditions. We found that drought stress significantly increased nitrogen (N) resorption efficiency (NRE) in both sexes, but shade and interactive stress decreased NRE in P. cathayana females. Under drought stress, nutrient resorption was sexually dimorphic such that P. cathayana males have higher NRE than females. Furthermore, NRE and phosphorous (P) resorption efficiency (PRE) were positively related to R/S ratio, leaf thickness, LMA, and LVD in both sexes across different treatments. Our study is the first to present how nutrient resorption is related to biomass accumulation and allocation, and leaf economics, suggesting that nutrient uptake may be modulated by R/S ratio and leaf economics, which is important for understanding the conservation mechanism of plant nutrients.

Salt and drought stress-mitigating approaches in sugar beet (Beta vulgaris L.) to improve its performance and yield

MAIN CONCLUSION

Although sugar beet is a salt- and drought-tolerant crop, high salinity, and water deprivation significantly reduce its yield and growth. Several reports have demonstrated stress tolerance enhancement through stress-mitigating strategies including the exogenous application of osmolytes or metabolites, nanoparticles, seed treatments, breeding salt/drought-tolerant varieties. These approaches would assist in achieving sustainable yields despite global climatic changes. Sugar beet (Beta vulgaris L.) is an economically vital crop for ~ 30% of world sugar production. They also provide essential raw materials for bioethanol, animal fodder, pulp, pectin, and functional food-related industries. Due to fewer irrigation water requirements and shorter regeneration time than sugarcane, beet cultivation is spreading to subtropical climates from temperate climates. However, beet varieties from different geographical locations display different stress tolerance levels. Although sugar beet can endure moderate exposure to various abiotic stresses, including high salinity and drought, prolonged exposure to salt and drought stress causes a significant decrease in crop yield and production. Hence, plant biologists and agronomists have devised several strategies to mitigate the stress-induced damage to sugar beet cultivation. Recently, several studies substantiated that the exogenous application of osmolytes or metabolite substances can help plants overcome injuries induced by salt or drought stress. Furthermore, these compounds likely elicit different physio-biochemical impacts, including improving nutrient/ionic homeostasis, photosynthetic efficiency, strengthening defense response, and water status improvement under various abiotic stress conditions. In the current review, we compiled different stress-mitigating agricultural strategies, prospects, and future experiments that can secure sustainable yields for sugar beets despite high saline or drought conditions.

Molecular Mechanisms Determining the Role of Bacteria from the Genus Azospirillum in Plant Adaptation to Damaging Environmental Factors

Agricultural plants are continuously exposed to environmental stressors, which can lead to a significant reduction in yield and even the death of plants. One of the ways to mitigate stress impacts is the inoculation of plant growth-promoting rhizobacteria (PGPR), including bacteria from the genus Azospirillum, into the rhizosphere of plants. Different representatives of this genus have different sensitivities or resistances to osmotic stress, pesticides, heavy metals, hydrocarbons, and perchlorate and also have the ability to mitigate the consequences of such stresses for plants. Bacteria from the genus Azospirillum contribute to the bioremediation of polluted soils and induce systemic resistance and have a positive effect on plants under stress by synthesizing siderophores and polysaccharides and modulating the levels of phytohormones, osmolytes, and volatile organic compounds in plants, as well as altering the efficiency of photosynthesis and the antioxidant defense system. In this review, we focus on molecular genetic features that provide bacterial resistance to various stress factors as well as on Azospirillum-related pathways for increasing plant resistance to unfavorable anthropogenic and natural factors.

Application of Magnesium and Calcium Sulfate on Growth and Physiology of Forage Crops under Long-Term Salinity Stress

Soil salinity is major threat to crop growth and reducing cultivated land areas and salt-resistant crops have been required to sustain agriculture in salinized areas. This original research was performed to determine the effectiveness of MgSO₄ (MS) and CaSO₄ (CS) for each species and assess changes in the physiology and growth of fodder crops after short and long-term salt stress. Six treatments (CON (control); NaCl (NaCl 100 mM); 1 MS (1 mM MgSO₄ + 100 mM NaCl); 2 MS (2 mM MgSO₄ + 100 mM NaCl); 7.5 CS (7.5 mM CaSO₄ + 100 mM NaCl); and 10 CS (10 mM CaSO₄ + 100 mM NaCl)) were applied to Red clover (Trifolium pratense) and Tall fescue (Festuca arundinacea) under greenhouse conditions. Cultivars were evaluated based on their dry weights, physiological parameters, forage quality, and ion concentrations. The biomass of both species decreased significantly under NaCl treatments and increased under the MS and CS treatments compared to solely salinity treatments. Salinity caused a decrease in the photosynthetic rate, but compared to CON, the MS and CS treatments yielded superior results. Moreover, the Na⁺/K⁺ ratio increased as Na⁺ concentration increased but crop quality (CP, NDF, ADF) did not show significant differences under salinity. Overall, we concluded that these T. pratense and F. arundinacea species demonstrated various responses to salinity, MS, and CS by different physiological and morphological parameters and it turned out to be efficient under salinity stress.

Simultaneous Action of Silymarin and Dopamine Enhances Defense Mechanisms Related to Antioxidants, Polyamine Metabolic Enzymes, and Tolerance to Cadmium Stress in Phaseolus vulgaris

Silymarin (Sm) and dopamine (DA) act synergistically as potential antioxidants, mediating many physiological and biochemical processes. As a first report, we investigated the synergistic effect of Sm and DA in mitigating cadmium stress in Phaseolus vulgaris plants. Three experiments were conducted simultaneously using 40 cm diameter pots to elucidate how Sm and DA affect cadmium tolerance traits at morphological, physiological, and biochemical levels. Cadmium stress triggered a marked reduction in growth, productivity, and physio-biochemical characteristics of common bean plants compared to unstressed plants. Seed priming (SP) and foliar spraying (FS) with silymarin (Sm) or dopamine (DA) ((DA (SP) + Sm (FS) and Sm (SP) + DA (FS)) ameliorated the damaging effects of cadmium stress. Sm seed priming + DA foliar spraying (Sm (SP) + DA (FS)) was more efficient. The treated stressed common bean plants showed greater tolerance to cadmium stress by diminishing oxidative stress biomarkers (i.e., O₂^•-, H₂O₂, and MDA) levels through enhanced enzymatic (SOD, CAT, POD, APX) and non-enzymatic (ascorbic acid, glutathione, α-tocopherol, choline, phenolics, flavonoids) antioxidant activities and osmoprotectants (proline, glycine betaine, and soluble sugars) contents, as well as through improved photosynthetic efficiency (total chlorophyll and carotenoids contents, photochemical activity, and efficiencies of carboxylation (iCE) and PSII (Fv/Fm)), polyamines (Put, Spd, and Spm), and polyamine metabolic enzymes (ADC and ODC) accumulation. These findings signify that Sm and DA have remarkable anti-stress effects, which can help regulate plant self-defense systems, reflecting satisfactory plant growth and productivity. Thus, realizing the synergistic effect of Sm and DA in cadmium tolerance confers potential new capabilities for these compounds to function in sustainable agriculture.