Thiourea improves yield and quality traits of Brassica napus L. by upregulating the antioxidant defense system under high temperature stress.

High temperature stress influences plant growth, seed yield, and fatty acid contents by causing oxidative damage. This study investigated the potential of thiourea (TU) to mitigate oxidative stress and restoring seed oil content and quality in canola. The study thoroughly examined three main factors: (i) growth conditions-control and high temperature stress (35 °C); (ii) TU supplementation (1000 mg/L)-including variations like having no TU, water application at the seedling stage, TU application at seedling stage (BBCH Scale-39), water spray at anthesis stage, and TU application at anthesis stage (BBCH Scale-60); (iii) and two canola genotypes, 45S42 and Hiola-401, were studied separately. High temperature stress reduced growth and tissue water content, as plant height and relative water contents were decreased by 26 and 36% in 45S42 and 27 and 42% Hiola-401, respectively, resulting in a substantial decrease in seed yield per plant by 36 and 38% in 45S42 and Hiola-401. Seed oil content and quality parameters were also negatively affected by high temperature stress as seed oil content was reduced by 32 and 35% in 45S42 and Hiola-401. High-temperature stress increased the plant stress indicators like malondialdehyde, H2O2 content, and electrolyte leakage; these indicators were increased in both canola genotypes as compared to control. Interestingly, TU supplementation restored plant performance, enhancing height, relative water content, foliar chlorophyll (SPAD value), and seed yield per plant by 21, 15, 30, and 28% in 45S42; 19, 13, 26, and 21% in Hiola-401, respectively, under high temperature stress as compared to control. In addition, seed quality, seed oil content, linoleic acid, and linolenic acid were improved by 16, 14, and 22% in 45S42, and 16, 11, and 23% in Hiola-401, as compared to control. The most significant improvements in canola seed yield per plant were observed when TU was applied at the anthesis stage. Additionally, the research highlighted that canola genotype 45S42 responded better to TU applications and exhibited greater resilience against high temperature stress compared to genotype Hiola-401. This interesting study revealed that TU supplementation, particularly at the anthesis stage, improved high temperature stress tolerance, seed oil content, and fatty acid profile in two canola genotypes.

Sodium nitroprusside modulates oxidative and nitrosative processes in Lycopersicum esculentum L. under drought stress.

KEY MESSAGE: Sodium nitroprusside mediates drought stress responses in tomatoes by modulating nitrosative and oxidative pathways, highlighting the interplay between nitric oxide, hydrogen sulfide, and antioxidant systems for enhanced drought tolerance. While nitric oxide (NO), a signalling molecule, enhances plant tolerance to abiotic stresses, its precise contribution to improving tomato tolerance to drought stress (DS) through modulating oxide-nitrosative processes is not yet fully understood. We aimed to examine the interaction of NO and nitrosative signaling, revealing how sodium nitroprusside (SNP) could mitigate the effects of DS on tomatoes. DS-seedlings endured 12% polyethylene glycol (PEG) in a 10% nutrient solution (NS) for 2 days, then transitioned to half-strength NS for 10 days alongside control plants. DS reduced total plant dry weight, chlorophyll a and b, Fv/Fm, leaf water potential (ΨI), and relative water content, but improved hydrogen peroxide (H2O2), proline, and NO content. The SNP reduced the DS-induced H2O2 generation by reducing thiol (-SH) and the carbonyl (-CO) groups. SNP increased not only NO but also the activity of L-cysteine desulfhydrase (L-DES), leading to the generation of H2S. Decreases in S-nitrosoglutathione reductase (GSNOR) and NADPH oxidase (NOX) suggest a potential regulatory mechanism in which S-nitrosylation [formation of S-nitrosothiol (SNO)] may influence protein function and signaling pathways during DS. Moreover, SNP improved ascorbate (AsA) and glutathione (GSH) and reduced oxidized glutathione (GSSG) levels in tomato plants under drought. Furthermore, the interaction of NO and H2S, mediated by L-DES activity, may serve as a vital cross-talk mechanism impacting plant responses to DS. Understanding these signaling interactions is crucial for developing innovative drought-tolerance strategies in crops.

Application of chitosan nanopriming on plant growth and secondary metabolites of Pancratium maritimum L.

BACKGROUND: Nanotechnology has demonstrated its vital significance in all aspects of daily life. Our research was conducted to estimate the potential of primed seed with chitosan nanoparticles in seed growth and yield by inducing plant secondary metabolism of Pancratium maritimum L. one of the important medicinal plants. Petri dish and pot experiments were carried out. Seeds of Pancratium maritimum L. were soaked in Nano solution (0.1, 0.5, 1 mg/ ml) for 4, 8, 12 h. Germination parameters (germination percentage, germination velocity, speed of germination, germination energy, germination index, mean germination time, seedling shoot and root length, shoot root ratio, seedling vigor index, plant biomass and water content), alkaloids and antioxidant activity of Pancratium maritimum L. were recorded and compared between coated and uncoated seeds. RESULTS: Our results exhibited that chitosan nanopriming had a positive effect on some growth parameters, while it fluctuated on others. However, the data showed that most germination parameters were significantly affected in coated seeds compared to uncoated seeds. GC-MS analysis of Pancratium maritimum L. with different nanopriming treatments showed that the quantity of alkaloids decreased, but the amount of pancratistatin, lycorine and antioxidant content increased compared with the control. CONCLUSIONS: Applying chitosan nanoparticles in priming seeds might be a simple and effective way to improve the quantity of secondary metabolites of Pancratium maritimum L. valuable medicinal plant.

Titanium dioxide nanoparticles alleviates polystyrene nanoplastics induced growth inhibition by modulating carbon and nitrogen metabolism via melatonin signaling in maize.

BACKGROUND: Nanoplastics, are emerging pollutants, present a potential hazard to food security and human health. Titanium dioxide nanoparticles (Nano-TiO2), serving as nano-fertilizer in agriculture, may be important in alleviating polystyrene nanoplastics (PSNPs) toxicity. RESULTS: Here, we performed transcriptomic, metabolomic and physiological analyzes to identify the role of Nano-TiO2 in regulating the metabolic processes in PSNPs-stressed maize seedlings (Zea mays L.). The growth inhibition by PSNPs stress was partially relieved by Nano-TiO2. Furthermore, when considering the outcomes obtained from RNA-seq, enzyme activity, and metabolite content analyses, it becomes evident that Nano-TiO2 significantly enhance carbon and nitrogen metabolism levels in plants. In comparison to plants that were not subjected to Nano-TiO2, plants exposed to Nano-TiO2 exhibited enhanced capabilities in maintaining higher rates of photosynthesis, sucrose synthesis, nitrogen assimilation, and protein synthesis under stressful conditions. Meanwhile, Nano-TiO2 alleviated the oxidative damage by modulating the antioxidant systems. Interestingly, we also found that Nano-TiO2 significantly enhanced the endogenous melatonin levels in maize seedlings. P-chlorophenylalanine (p-CPA, a melatonin synthesis inhibitor) declined Nano-TiO2-induced PSNPs tolerance. CONCLUSIONS: Taken together, our data show that melatonin is involved in Nano-TiO2-induced growth promotion in maize through the regulation of carbon and nitrogen metabolism.

Analytical methods for stable isotope labeling to elucidate rapid auxin kinetics in Arabidopsis thaliana.

The phytohormone auxin plays a critical role in plant growth and development. Despite significant progress in elucidating metabolic pathways of the primary bioactive auxin, indole-3-acetic acid (IAA), over the past few decades, key components such as intermediates and enzymes have not been fully characterized, and the dynamic regulation of IAA metabolism in response to environmental signals has not been completely revealed. In this study, we established a protocol employing a highly sensitive liquid chromatography-mass spectrometry (LC-MS) instrumentation and a rapid stable isotope labeling approach. We treated Arabidopsis seedlings with two stable isotope labeled precursors ([13C6]anthranilate and [13C8, 15N1]indole) and monitored the label incorporation into proposed indolic compounds involved in IAA biosynthetic pathways. This Stable Isotope Labeled Kinetics (SILK) method allowed us to trace the turnover rates of IAA pathway precursors and product concurrently with a time scale of seconds to minutes. By measuring the entire pathways over time and using different isotopic tracer techniques, we demonstrated that these methods offer more detailed information about this complex interacting network of IAA biosynthesis, and should prove to be useful for studying auxin metabolic network in vivo in a variety of plant tissues and under different environmental conditions.

Deciphering the mechanistic role of Bacillus paramycoides (PM51) and Bacillus tequilensis (PM52) in bio-sorption and phyto-assimilation of Cadmium via Linum usitatissimum L. Seedlings.

Three Cd2+ resistant bacterium's minimal inhibition concentrations were assessed and their percentages of Cd2+ accumulation were determined by measurements using an atomic absorption spectrophotometer (AAS). The results revealed that two isolates Bacillus paramycoides (PM51) and Bacillus tequilensis (PM52), identified by 16S rDNA gene sequencing, showed a higher percentage of Cd2+ accumulation i.e., 83.78% and 81.79%, respectively. Moreover, both novel strains can tolerate Cd2+ levels up to 2000 mg/L isolated from district Chakwal. Amplification of the czcD, nifH, and acdS genes was also performed. Batch bio-sorption studies revealed that at pH 7.0, 1 g/L of biomass, and an initial 150 mg/L Cd2+ concentration were the ideal bio-sorption conditions for Bacillus paramycoides (PM51) and Bacillus tequilensis (PM52). The experimental data were fit to Langmuir isotherm measurements and Freundlich isotherm model R2 values of 0.999 for each of these strains. Bio sorption processes showed pseudo-second-order kinetics. The intra-diffusion model showed Xi values for Bacillus paramycoides (PM51) and Bacillus tequilensis (PM52) of 2.26 and 2.23, respectively. Different surface ligands, was investigated through Fourier-transformation infrared spectroscopy (FTIR). The scanning electron microscope SEM images revealed that after Cd2+ adsorption, the cells of both strains became thick, adherent, and deformed. Additionally, both enhanced Linum usitatissimum plant seed germination under varied concentrations of Cd2+ (0 mg/L, 250 mg/L,350 mg/L, and 500 mg/L). Current findings suggest that the selected strains can be used as a sustainable part of bioremediation techniques.

The freeze-thaw cycle exacerbates the ecotoxicity of polystyrene nanoplastics to Secale cereale L. seedlings.

In the context of global climate change, recurrent freeze-thaw cycles (FTC) and concurrent exposure to polystyrene nanoplastics (PSNPs) directly impact crop growth and indirectly affect resilience to abiotic stress. In January 2023, experiments at the Environmental Biology Laboratory, Jilin University, Changchun, China, exposed rye seedlings to 100 nm PSNPs at concentrations of 0, 10, 50, and 100 mg/L for seven days, followed by three FTC. Scanning electron microscopy (SEM) demonstrated that PSNPs migrated from the roots to the leaves, with FTC significantly exacerbating their accumulation within plant tissues. Transmission electron microscopy (TEM) observations showed that FTC disrupted normal cell division, and combined stress from NPs damaged plant organs, particularly chloroplasts, thereby substantially inhibiting photosynthesis. FTC delayed plant phenological stages. Under combined stress, malondialdehyde (MDA) accumulation in plant tissues increased by 15.6%, while hydrogen peroxide (H2O2) content decreased. Simultaneously, the activities of peroxidase (POD) and catalase (CAT) increased by 34.2% and 38.6%, respectively. Molecular docking unveiled that PSNPs could bind to the active center of POD/CAT through hydrogen bonding or hydrophobic interactions. The Integrated Biomarker Response (IBR) index highlighted FTC as a crucial determinant for pronounced effects. Moreover, an apparent dose-dependent effect was observed, with antioxidant enzyme activities in rye seedlings induced by low pollutant concentrations and inhibited by high concentrations. These results indicate that FTC and PSNPs can disrupt plant membrane systems and cause severe oxidative damage. Overall, this study provides compelling scientific evidence of the risks associated with NPs exposure in plants subjected to abiotic stress.

Azolla filiculoides extract improved salt tolerance in wheat (Triticum aestivum L.) is associated with prompting osmostasis, antioxidant potential and stress-interrelated genes.

The growth and productivity of crop plants are negatively affected by salinity-induced ionic and oxidative stresses. This study aimed to provide insight into the interaction of NaCl-induced salinity with Azolla aqueous extract (AAE) regarding growth, antioxidant balance, and stress-responsive genes expression in wheat seedlings. In a pot experiment, wheat kernels were primed for 21 h with either deionized water or 0.1% AAE. Water-primed seedlings received either tap water, 250 mM NaCl, AAE spray, or AAE spray + NaCl. The AAE-primed seedlings received either tap water or 250 mM NaCl. Salinity lowered growth rate, chlorophyll level, and protein and amino acids pool. However, carotenoids, stress indicators (EL, MDA, and H2O2), osmomodulators (sugars, and proline), antioxidant enzymes (CAT, POD, APX, and PPO), and the expression of some stress-responsive genes (POD, PPO and PAL, PCS, and TLP) were significantly increased. However, administering AAE contributed to increased growth, balanced leaf pigments and assimilation efficacy, diminished stress indicators, rebalanced osmomodulators and antioxidant enzymes, and down-regulation of stress-induced genes in NaCl-stressed plants, with priming surpassing spray in most cases. In conclusion, AAE can be used as a green approach for sustaining regular growth and metabolism and remodelling the physio-chemical status of wheat seedlings thriving in salt-affected soils.

Temperature-Caused Changes in Raman Pattern and Protein Profiles of Winter Triticale (x Triticosecale, Wittm.) Field-Grown Seedlings.

Climate change, which causes periods with relatively high temperatures in winter in Poland, can lead to a shortening or interruption of the cold hardening of crops. Previous research indicates that cold acclimation is of key importance in the process of acquiring cereal tolerance to stress factors. The objective of this work was to verify the hypothesis that both natural temperature fluctuations and the plant genotype influence the content of metabolites as well as proteins, including antioxidant enzymes and photosystem proteins. The research material involved four winter triticale genotypes, differing in their tolerance to stress under controlled conditions. The values of chlorophyll a fluorescence parameters and antioxidant activity were measured in their seedlings. Subsequently, the contribution of selected proteins was verified using specific antibodies. In parallel, the profiling of the contents of chlorophylls, carotenoids, phenolic compounds, and proteins was carried out by Raman spectroscopy. The obtained results indicate that a better PSII performance along with a higher photosystem II proteins content and thioredoxin reductase abundance were accompanied by a higher antioxidant activity in the field-grown triticale seedlings. The Raman studies showed that the cold hardening led to a variation in photosynthetic dyes and an increase in the phenolic to carotenoids ratio in all DH lines.

Seeds Priming with Melatonin Improves Root Hydraulic Conductivity of Wheat Varieties under Drought, Salinity, and Combined Stress.

Drought and salinity stress reduce root hydraulic conductivity of plant seedlings, and melatonin application positively mitigates stress-induced damage. However, the underlying effect of melatonin priming on root hydraulic conductivity of seedlings under drought-salinity combined remains greatly unclear. In the current report, we investigated the influence of seeds of three wheat lines' 12 h priming with 100 µM of melatonin on root hydraulic conductivity (Lpr) and relevant physiological indicators of seedlings under PEG, NaCl, and PEG + NaCl combined stress. A previous study found that the combined PEG and NaCl stress remarkably reduced the Lpr of three wheat varieties, and its value could not be detected. Melatonin priming mitigated the adverse effects of combined PEG + NaCl stress on Lpr of H4399, Y1212, and X19 to 0.0071 mL·h-1·MPa-1, 0.2477 mL·h-1·MPa-1, and 0.4444 mL·h-1·MPa-1, respectively, by modulating translation levels of aquaporin genes and contributed root elongation and seedlings growth. The root length of H4399, Y1212, and X19 was increased by 129.07%, 141.64%, and 497.58%, respectively, after seeds pre-treatment with melatonin under PEG + NaCl combined stress. Melatonin -priming appreciably regulated antioxidant enzyme activities, reduced accumulation of osmotic regulators, decreased levels of malondialdehyde (MDA), and increased K+ content in stems and root of H4399, Y1212, and X19 under PEG + NaCl stress. The path investigation displayed that seeds primed with melatonin altered the modification of the path relationship between Lpr and leaf area under stress. The present study suggested that melatonin priming was a strategy as regards the enhancement of root hydraulic conductivity under PEG, NaCl, and PEG + NaCl stress, which efficiently enhanced wheat resistant to drought-salinity stress.

Silicon regulates phosphate deficiency through involvement of auxin and nitric oxide in barley roots.

MAIN CONCLUSION: Silicon application mitigates phosphate deficiency in barley through an interplay with auxin and nitric oxide, enhancing growth, photosynthesis, and redox balance, highlighting the potential of silicon as a fertilizer for overcoming nutritional stresses. Silicon (Si) is reported to attenuate nutritional stresses in plants, but studies on the effect of Si application to plants grown under phosphate (Pi) deficiency are still very scarce, especially in barley. Therefore, the present work was undertaken to investigate the potential role of Si in mitigating the adverse impacts of Pi deficiency in barley Hordeum vulgare L. (var. BH902). Further, the involvement of two key regulatory signaling molecules--auxin and nitric oxide (NO)--in Si-induced tolerance against Pi deficiency in barley was tested. Morphological attributes, photosynthetic parameters, oxidative stress markers (O2·-, H2O2, and MDA), antioxidant system (enzymatic--APX, CAT, SOD, GR, DHAR, MDHAR as well as non-enzymatic--AsA and GSH), NO content, and proline metabolism were the key traits that were assessed under different treatments. The P deficiency distinctly declined growth of barley seedlings, which was due to enhancement in oxidative stress leading to inhibition of photosynthesis. These results were also in parallel with an enhancement in antioxidant activity, particularly SOD and CAT, and endogenous proline level and its biosynthetic enzyme (P5CS). The addition of Si exhibited beneficial effects on barley plants grown in Pi-deficient medium as reflected in increased growth, photosynthetic activity, and redox balance through the regulation of antioxidant machinery particularly ascorbate-glutathione cycle. We noticed that auxin and NO were also found to be independently participating in Si-mediated improvement of growth and other parameters in barley roots under Pi deficiency. Data of gene expression analysis for PHOSPHATE TRANSPORTER1 (HvPHT1) indicate that Si helps in increasing Pi uptake as per the need of Pi-deficient barley seedlings, and also auxin and NO both appear to help Si in accomplishing this task probably by inducing lateral root formation. These results are suggestive of possible application of Si as a fertilizer to correct the negative effects of nutritional stresses in plants. Further research at genetic level to understand Si-induced mechanisms for mitigating Pi deficiency can be helpful in the development of new varieties with improved tolerance against Pi deficiency, especially for cultivation in areas with Pi-deficient soils.

The tetraploid wheat (Triticum dicoccum (Schrank) Schuebl.) improves nitrogen uptake and assimilation adaptation to nitrogen-deficit stress.

MAIN CONCLUSION: The genetic diversity in tetraploid wheat provides a genetic pool for improving wheat productivity and environmental resilience. The tetraploid wheat had strong N uptake, translocation, and assimilation capacity under N deficit stress, thus alleviating growth inhibition and plant N loss to maintain healthy development and adapt to environments with low N inputs. Tetraploid wheat with a rich genetic variability provides an indispensable genetic pool for improving wheat yield. Mining the physiological mechanisms of tetraploid wheat in response to nitrogen (N) deficit stress is important for low-N-tolerant wheat breeding. In this study, we selected emmer wheat (Kronos, tetraploid), Yangmai 25 (YM25, hexaploid), and Chinese spring (CS, hexaploid) as materials. We investigated the differences in the response of root morphology, leaf and root N accumulation, N uptake, translocation, and assimilation-related enzymes and gene expression in wheat seedlings of different ploidy under N deficit stress through hydroponic experiments. The tetraploid wheat (Kronos) had stronger adaptability to N deficit stress than the hexaploid wheats (YM25, CS). Kronos had better root growth under low N stress, expanding the N uptake area and enhancing N uptake to maintain higher NO3- and soluble protein contents. Kronos exhibited high TaNRT1.1, TaNRT2.1, and TaNRT2.2 expression in roots, which promoted NO3- uptake, and high TaNRT1.5 and TaNRT1.8 expression in roots and leaves enhanced NO3- translocation to the aboveground. NR and GS activity in roots and leaves of Kronos was higher by increasing the expression of TANIA2, TAGS1, and TAGS2, which enhanced the reduction and assimilation of NO3- as well as the re-assimilation of photorespiratory-released NH4+. Overall, Kronos had strong N uptake, translocation, and assimilation capacity under N deficit stress, alleviating growth inhibition and plant N loss and thus maintaining a healthy development. This study reveals the physiological mechanisms of tetraploid wheat that improve nitrogen uptake and assimilation adaptation under low N stress, which will provide indispensable germplasm resources for elite low-N-tolerant wheat improvement and breeding.

Enhancing iron content and growth of cucumber seedlings with MgFe-LDHs under low-temperature stress.

The development of cost-effective and eco-friendly fertilizers is crucial for enhancing iron (Fe) uptake in crops and can help alleviate dietary Fe deficiencies, especially in populations with limited access to meat. This study focused on the application of MgFe-layered double hydroxide nanoparticles (MgFe-LDHs) as a potential solution. We successfully synthesized and characterized MgFe-LDHs and observed that 1-10 mg/L MgFe-LDHs improved cucumber seed germination and water uptake. Notably, the application of 10 mg/L MgFe-LDHs to roots significantly increased the seedling emergence rate and growth under low-temperature stress. The application of 10 mg/L MgFe-LDHs during sowing increased the root length, lateral root number, root fresh weight, aboveground fresh weight, and hypocotyl length under low-temperature stress. A comprehensive analysis integrating plant physiology, nutrition, and transcriptomics suggested that MgFe-LDHs improve cold tolerance by upregulating SA to stimulate CsFAD3 expression, elevating GA3 levels for enhanced nitrogen metabolism and protein synthesis, and reducing levels of ABA and JA to support seedling emergence rate and growth, along with increasing the expression and activity of peroxidase genes. SEM and FTIR further confirmed the adsorption of MgFe-LDHs onto the root hairs in the mature zone of the root apex. Remarkably, MgFe-LDHs application led to a 46% increase (p < 0.05) in the Fe content within cucumber seedlings, a phenomenon not observed with comparable iron salt solutions, suggesting that the nanocrystalline nature of MgFe-LDHs enhances their absorption efficiency in plants. Additionally, MgFe-LDHs significantly increased the nitrogen (N) content of the seedlings by 12% (p < 0.05), promoting nitrogen fixation in the cucumber seedlings. These results pave the way for the development and use of LDH-based Fe fertilizers.

Nitric oxide alleviates programmed cell death induced by cadmium in Solanum lycopersicum seedlings through protein S-nitrosylation.

Cadmium (Cd), as a non-essential and toxic heavy metal in plants, has deleterious effects on plant physiological and biochemical processes. Nitric oxide (NO) is one of the most important signaling molecules for plants to response diverse stresses. Here, we found that Cd-induced programmed cell death (PCD) was accompanied by NO bursts, which exacerbated cell death when NO was removed and vice versa. Proteomic analysis of S-nitrosylated proteins showed that the differential proteins in Cd-induced PCD and in NO-alleviated PCD mainly exist together in carbohydrate metabolism and amino acid metabolism, while some of the differential proteins exist alone in metabolism of cofactors and vitamins and lipid metabolism. Meanwhile, S-nitrosylation of proteins in porphyrin and chlorophyll metabolism and starch and sucrose metabolism could explain the leaf chlorosis induced by PCD. Moreover, protein transport protein SEC23, ubiquitinyl hydrolase 1 and pathogenesis-related protein 1 were identified to be S-nitrosylated in vivo, and their expressions were increased in Cd-induced PCD while decreased in NO treatment. Similar results were obtained in tomato seedlings with higher S-nitrosylation. Taken together, our results indicate that NO might be involved in the regulation of Cd-induced PCD through protein S-nitrosylation, especially proteins involved in PCD response.

Cold atmospheric plasma enhances morphological and biochemical attributes of tomato seedlings.

Cold atmospheric plasma (CAP) is a physical technology with notable effects on living organisms. In the present study, tomato seeds (Solanum lycopersicum var. Bassimo Mill.) were exposed to CAP for various time intervals, ranging from 1 to 5 min, in both continuous and intermittent periods, and were compared with a control group that received no CAP treatment. Seedlings grown from treated seeds exhibited improvements in levels of growth traits, photosynthetic pigments, and metabolite contents when compared to the control group. Seedlings from seeds treated with S04 displayed significant increases in shoot and root lengths, by 32.45% and 20.60% respectively, compared to the control group. Moreover, seedlings from seeds treated with S01 showed a 101.90% increase in total protein, whereas those treated with S02 experienced a 119.52% increase in carbohydrate content. These findings highlight the substantial improvements in growth characteristics, photosynthetic pigments, and metabolite levels in seedlings from treated seeds relative to controls. Total antioxidant capacity was boosted by CAP exposure. The activities of enzymes including superoxide dismutase, catalase, and peroxidases were stimulated by S02 and exceeded control treatment by (177.48%, 137.41%, and 103.32%), respectively. Additionally, exposure to S04 increased the levels of non-enzymatic antioxidants like flavonoids, phenolics, saponins, and tannins over the control group (38.08%, 30.10%, 117.19%, and 94.44%), respectively. Our results indicate that CAP-seed priming is an innovative and cost-effective approach to enhance the growth, bioactive components, and yield of tomato seedlings.

Utilizing transcriptomics and proteomics to unravel key genes and proteins of Oryza sativa seedlings mediated by selenium in response to cadmium stress.

BACKGROUND: Cadmium (Cd) pollution has declined crop yields and quality. Selenium (Se) is a beneficial mineral element that protects plants from oxidative damage, thereby improving crop tolerance to heavy metals. The molecular mechanism of Se-induced Cd tolerance in rice (Oryza sativa) is not yet understood. This study aimed to elucidate the beneficial mechanism of Se (1 mg/kg) in alleviating Cd toxicity in rice seedlings. RESULTS: Exogenous selenium addition significantly improved the toxic effect of cadmium stress on rice seedlings, increasing plant height and fresh weight by 20.53% and 34.48%, respectively, and increasing chlorophyll and carotenoid content by 16.68% and 15.26%, respectively. Moreover, the MDA, ·OH, and protein carbonyl levels induced by cadmium stress were reduced by 47.65%, 67.57%, and 56.43%, respectively. Cell wall metabolism, energy cycling, and enzymatic and non-enzymatic antioxidant systems in rice seedlings were significantly enhanced. Transcriptome analysis showed that the expressions of key functional genes psbQ, psbO, psaG, psaD, atpG, and PetH were significantly up-regulated under low-concentration Se treatment, which enhanced the energy metabolism process of photosystem I and photosystem II in rice seedlings. At the same time, the up-regulation of LHCA, LHCB family, and C4H1, PRX, and atp6 functional genes improved the ability of photon capture and heavy metal ion binding in plants. Combined with proteome analysis, the expression of functional proteins OsGSTF1, OsGSTU11, OsG6PDH4, OsDHAB1, CP29, and CabE was significantly up-regulated under Se, which enhanced photosynthesis and anti-oxidative stress mechanism in rice seedlings. At the same time, it regulates the plant hormone signal transduction pathway. It up-regulates the expression response process of IAA, ABA, and JAZ to activate the synergistic effect between each cell rapidly and jointly maintain the homeostasis balance. CONCLUSION: Our results revealed the regulation process of Se-mediated critical metabolic pathways, functional genes, and proteins in rice under cadmium stress. They provided insights into the expression rules and dynamic response process of the Se-mediated plant resistance mechanism. This study provided the theoretical basis and technical support for crop safety in cropland ecosystems and cadmium-contaminated areas.

The conversion of monolignans to sesquilignans and dilignans is closely correlated to the regulation of Arctium lappa seed germination.

MAIN CONCLUSION: The secondary metabolic conversion of monolignans to sesquilignans/dilignans was closely related to seed germination and seedling establishment in Arctium lappa. Arctium lappa plants are used as a kind of traditional Chinese medicines for nearly 1500 years, and so far, only a few studies have put focus on the key secondary metabolic changes during seed germination and seedling establishment. In the current study, a combined approach was used to investigate the correlation among secondary metabolites, plant hormone signaling, and transcriptional profiles at the early critical stages of A. lappa seed germination and seedling establishment. Of 50 metabolites in methonolic extracts of A. lappa samples, 35 metabolites were identified with LC-MS/MS and 15 metabolites were identified with GC-MS. Their qualitative properties were examined according to the predicted chemical structures. The quantitative analysis was performed for deciphering their metabolic profiles, discovering that the secondary metabolic conversion from monolignans to sesquilignans/dilignans was closely correlated to the initiation of A. lappa seed germination and seedling establishment. Furthermore, the critical transcriptional changes in primary metabolisms, translational regulation at different cellular compartments, and multiple plant hormone signaling pathways were revealed. In addition, the combined approach provides unprecedented insights into key regulatory mechanisms in both gene transcription and secondary metabolites besides many known primary metabolites during seed germination of an important traditional Chinese medicinal plant species. The results not only provide new insights to understand the regulation of key medicinal components of 'ARCTII FRUCTUS', arctiin and arctigenin at the stages of seed germination and seedling establishment, but also potentially spur the development of seed-based cultivation in A. lappa plants.

Amelioration of chromium toxicity in wheat plants through exogenous application of nano silicon.

Chromium (Cr) contamination in agricultural soils poses a risk to crop productivity and quality. Emerging nano-enabled strategies show great promise in remediating soils contaminated with heavy metals and enhancing crop production. The present study was aimed to investigate the efficacy of nano silicon (nSi) in promoting wheat growth and mitigating adverse effects of Cr-induced toxicity. Wheat seedlings exposed to Cr (K2Cr2O7) at a concentration of 100 mg kg-1 showed significant reductions in plant height (29.56%), fresh weight (35.60%), and dry weight (38.92%) along with enhanced Cr accumulation in roots and shoots as compared to the control plants. However, the application of nSi at a concentration of 150 mg kg-1 showcased substantial mitigation of Cr toxicity, leading to a decrease in Cr accumulation by 27.30% in roots and 35.46% in shoots of wheat seedlings. Moreover, nSi exhibited the capability to scavenge oxidative stressors, such as hydrogen peroxide (H2O2), and malondialdehyde (MDA) and electrolyte leakage, while significantly enhancing gas exchange parameters, total chlorophyll content, and antioxidant activities (enzymatic and nonenzymatic) in plants grown in Cr-contaminated soil. This study further found that the reduced Cr uptake by nSi application was due to downregulating the expression of HMs transporter genes (TaHMA2 and TaHMA3), alongwith upregulating the expression of antioxidant-responsive genes (TaSOD and TaSOD). The findings of this investigation highlight the remarkable potential of nSi in ameliorating Cr toxicity. This enhanced efficacy could be ascribed to the distinctive size and structure of nSi, which augment its ability to counteract Cr stress. Thus, the application of nSi could serve as a viable solution for production of crops in metal contaminated soils, offering an effective alternative to time-consuming and costly remediation techniques.

Toxicity and fate of cadmium in hydroponically cultivated lettuce (Lactuca sativa L.) influenced by microplastics.

Although more attention has been paid to microplastics (MPs) pollution in environment, research on the synthetic influence of microplastic and heavy metals remains limited. To help fill this information gap, we investigated the adsorption behavior of virgin polyvinyl chloride microplastics (PVCMPs) (≤450 µm white spherical powder) on cadmium (II). The effects on seed germination, seedling growth, photosynthetic system, oxidative stress indicators of lettuce, and changes in Cd bioavailability were evaluated under Cd2+ (25 µmol/L), PVCMPs (200 mg/L), and PVCMP-Cd combined (200 mg/L + 25 µmol/L) exposures in hydroponic system. The results demonstrated that the PVCMPs effectively adsorbed Cd ions, which validated by the pseudo-second-order kinetic and the Langmuir isotherm models, indicating the sorption of Cd2+ on the PVCMPs was primary chemisorption and approximates monomolecular layer sorption. Compared to MPs, Cd significantly inhibits plant seed germination and seedling growth and development. However, Surprising improvement in seed germination under PVCMPs-Cd exposure was observed. Moreover, Cd2+ and MPs alone or combined stress caused oxidative stress with reactive oxygen species (ROS) including H2O2, O2- and Malondialdehyde (MDA) accumulation in plants, and substantially damaged to photosynthesis. With the addition of PVCMPs, the content of Cd in the leaves significantly (P<0.01) decreased by 1.76-fold, and the translocation factor and Cd2+removal rate in the water substantially (P<0.01) decreased by 6.73-fold and 1.67-fold, respectively in contrast to Cd2+ stress alone. Therefore, it is concluded the PVCMP was capable of reducing Cd contents in leaves, alleviating Cd toxicity in lettuce. Notably, this study provides a scientific foundation and reference for comprehending the toxicological interactions between microplastics and heavy metals in the environment.

Effects of zeolite imidazole frameworks on rice seedlings (Oryza sativa L.): Phytotoxicity, transformation, and bioaccumulation.

Zeolite imidazole frameworks (ZIFs), a class of the metal organic framework, have been extensively studied in environmental applications. However, their environmental fate and potential ecological impact on plants remain unknown. Here, we investigated the phytotoxicity, transformation, and bioaccumulation processes of two typical ZIFs (ZIF-8 and ZIF-67) in rice (Oryza sativa L.) under hydroponic conditions. ZIF-8 and ZIF-67 in the concentration of 50 mg/L decreased root and shoot dry weight maximally by 55.2% and 27.5%, 53.5% and 37.5%, respectively. The scanning electron microscopy (SEM) imaging combined with X-ray diffraction (XRD) patterns revealed that ZIFs on the root surface gradually collapsed and transformed into nanosheets with increasing cultivation time. The fluorescein isothiocyanate (FITC) labeled ZIFs were applied to trace the uptake and translocation of ZIFs in rice. The results demonstrated that the transformed ZIFs were mainly distributed in the intercellular spaces of rice root, while they cannot be transported to culms and leaves. Even so, the Co and Zn contents of rice roots and shoots in the ZIFs treated groups were increased by 1145% and 1259%, 145% and 259%, respectively, compared with the control groups. These findings suggested that the phytotoxicity of ZIFs are primarily attributed to the transformed ZIFs and to a less extent, the metal ions and their ligands, and they were internalized by rice root and increased the Co and Zn contents of shoots. This study reported the transformation of ZIFs and their biological effectiveness in rice, highlighting the potential environmental hazards and risks of ZIFs to crop plants.