Enhanced Antioxidant Enzyme Activities Research Articles

Bacillus cereus enhances salt tolerance of cucumber seedlings by improving antioxidant metabolism and decreasing the ion toxicity

Salt stress poses a significant challenge to plants, exerting a detrimental impact on crop growth and yield. This study investigated the effects of the strain Bacillus cereus on plant growth, ion contents and antioxidant metabolism of cucumber seedlings under salt stress (150 mM NaCl). The results showed that B. cereus could colonize the roots system of cucumber, with peak colonization occurring on the 3rd day. Inoculation with B. cereus effectively alleviated the growth inhibition of cucumber seedlings induced by salt stress, resulting in improvements in plant height, stem diameter, fresh and dry weight. Furthermore, the Na+ content in cucumber seedlings subjected to salt stress was significantly reduced by 38.35 % in leaves and 38.19 % in roots upon B. cereus inoculation, while K+ content increased by 9.88 % and 168.34 % in leaves and roots, respectively. Additionally, B. cereus significantly enhanced antioxidant enzyme activity and antioxidant content, while reduced the levels of H2O2, MDA, and O2−. in cucumber seedlings under salt stress conditions. B. cereus-treated seedlings exhibited an increase in soluble sugar content by 35.27 % and 93.21 % in leaves, and 59.36 % and 128.78 % in roots, respectively. Moreover, B. cereus treatment significantly up-regulated the expression of salt tolerant gene in both cucumber leaves and roots. These results showed that B. cereus enhanced salt tolerance in cucumber seedlings by modulating the antioxidant defense system, maintaining ion homeostasis, and promoting the expression of stress-related genes, ultimately improving the growth of cucumber seedlings.

Genome-wide identification of DREB1 transcription factors in perennial ryegrass and functional profiling of LpDREB1H2 in response to cold stress.

Perennial ryegrass (Lolium perenne L.) is an outstanding turfgrass and forage cultivated in temperate regions worldwide. However, poor tolerance to extreme cold, heat, or drought limits wide extension and cultivation. DEHYDRATION-RESPONSIVE ELEMENT BINDING FACTOR1s (DREB1s) play a vital role in enhancing plant tolerance to abiotic stress, specifically for low-temperature stress. In this study, a total of 24 LpDREB1 family members were identified from the released genome of perennial ryegrass. Phylogenetic analysis showed that the LpDREB1 genes are divided into 7 groups that have close relationships with rice homologues. Conserved motif analysis revealed that members within the same group have similar conserved motif compositions. All LpDREB1s lack introns, and the promoter sequences of LpDREB1 genes contain multiple cis-acting elements associated with stress response, phytohormone signal transduction and plant growth and development. The majority of LpDREB1 genes were upregulated by drought, submergence, heat and cold stress treatments, including LpDREB1H2. Further investigation showed that LpDREB1H2 is localized in the nucleus. Overexpression of LpDREB1H2 in Arabidopsis induced the expression of cold-responsive (COR) genes, increased the levels of osmotic adjusting substances, and enhanced antioxidant enzyme activities, thus improving the cold tolerance of Arabidopsis. This study lays a foundation for further understanding the function of LpDREB1 genes in perennial ryegrass and provides insights for plant stress tolerance breeding.

Evaluation of Hepatoprotective Potential and oxidative stress of Allium ascalonicum L. methanol leaf extract on liver of Albino rats

Background: For decades, the leaves of Allium ascalonicum (commonly known as Alubosa elewe) from the Liliaceae family have been widely used in Nigeria for managing disorders. Despite its extensive use in traditional medicine, there is no scientific validation to support this traditional use. Aim: This study aimed to evaluate the hepatoprotective effect of Allium ascalonicum methanol extract (A. AMLE) in albino rats with acetaminophen-induced liver injury. Methods: Standard procedures were employed to conduct a phytochemical screening of A. AMLE. The hepatoprotective effect of A. AMLE was assessed using biomarkers of hepatocellular indices, oxidative stress, and lipid peroxidation. Albino rats were administered distilled water or A. AMLE at doses of 100, 200, or 400 mg/kg body weight, respectively, for seven days. The treatment groups were challenged with 300 mg/kg body weight of acetaminophen on the sixth day. Results: The phytochemical screening revealed the presence of flavonoids, saponins, anthraquinones, alkaloids, and tannins in A. AMLE. Oral administration of A. AMLE significantly (p < 0.05) attenuated acetaminophen-induced alterations in serum alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin, and total bilirubin levels. Additionally, the acetaminophen-mediated decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were significantly ameliorated in the liver of albino rats. Elevated levels of malondialdehyde, conjugated dienes, lipid hydroperoxides, tumor necrosis factor-α, and interleukins-6 and -8 were significantly reduced by A. AMLE. Conclusion: This study scientifically validates the traditional use of Allium ascalonicum leaves for liver disorder management by demonstrating that its methanol extract mitigates acetaminophen-induced hepatotoxicity through enhanced antioxidant enzyme activity, highlighting its potential as a natural hepatoprotective agent and paving the way for further research and clinical application.

Response of tomatoes to inactivated endophyte LSE01 under combined stress of high-temperature and drought

Endophytes can assist crops in adapting to high temperatures and drought conditions, thereby reducing agricultural losses. However, the mechanism through which endophytes regulate crop resistance to high temperatures and drought stress remains unclear, and concerns regarding safety and stability exist with active endophytes. Thus, heat-treated endophytic bacteria LSE01 (HTB) were employed as a novel microbial fertilizer to investigate their effects on plant adaptation to high temperatures and drought conditions. The results indicated that the diameter and weight of tomatoes treated with HTB under stress conditions increased by 23.04% and 71.15%, respectively, compared to the control. Tomato yield did not significantly decrease compared to non-stress conditions. Additionally, the contents of vitamin C, soluble sugars, and proteins treated with HTB increased by 18.81%, 11.54%, and 99.75%, respectively. Mechanistic research revealed that HTB treatment enhances tomato's stress resistance by elevating photosynthetic pigment and proline contents, enhancing antioxidant enzyme activities, and reducing the accumulation of MDA. Molecular biology research demonstrates that HTB treatment upregulates the expression of drought-resistant genes (GA2ox7, USP1, SlNAC3, SlNAC4), leading to modifications in stomatal conductance, plant morphology, photosynthetic intensity, and antioxidant enzyme synthesis to facilitate adaptation to dry conditions. Furthermore, the upregulation of the heat-resistant gene (SlCathB2-2) can increases the thickness of tomato cell walls, rendering them less vulnerable to heat stress. In summary, HTB endows tomatoes with the ability to adapt to high temperatures and drought conditions, providing new opportunities for sustainable agriculture.

Cardioprotective effects of Ganoderma atrum polysaccharide in a type 2 diabetes mellitus involvement with gut-derived metabolites and NLRP3 inflammasome

The study aimed to explore the effects of Ganoderma atrum polysaccharide (PSG) on diabetic cardiomyopathy in type 2 diabetic rats. Results suggested that PSG significantly attenuated diabetic cardiomyopathy, as evidenced by alleviating heart histopathological changes and LDH release, mitigating weight loss, and improving fasting blood glucose and serum insulin levels. PSG could also reduce ROS generation and malondialdehyde contents, while significantly enhancing antioxidant enzyme activities and Nrf2 expression. Furthermore, PSG reduced inflammation by suppressing NLRP3 inflammasome, caspase-1, TLR4, NF-κB p65 expression, IL-1β and IL-6 secretion. Moreover, PSG treatment significantly manipulated intestinal microbiota metabolites, including short-chain fatty acids, plasma lipopolysaccharide, and trimethylamine N-oxide. These metabolites might mediate gut-heart communication through interaction with NLRP3 inflammasome. Collectively, PSG attenuated diabetic cardiomyopathy by activating the Nrf2 antioxidant pathway, controlling inflammation via NLRP3/Caspase-1/IL-1β signaling, and using gut microbial metabolites as alternative biomarkers for predicting the mechanisms of diabetic cardiomyopathy and assessing PSG interventions.

Antioxidant Defense System and Physiological Insights to Drought Stress in Urtica dioica L.

Urtica dioicais an endemic perennial plant of rocky habitat of Western Black Sea region of Turkey. To understand drought responses and tolerance mechanism of Seseli resinosum Freyn & Sint., relative water content (RWC), chlorophyll fluorescence, proline accumulation, lipid peroxidation (TBARS), hydrogen peroxide (H2O2) content and changes in antioxidant enzymes were assayed in polyethylene glycol (PEG) 6000 (5, 10 and 15%) induced drought stress in the present study. Leaf RWC maintained unchanged, while chlorophyll fluorescence reduced with high level of PEG (15%). Additionally, H2O2 and proline accumulation were determined with the increase of PEG application, but no increase in the amount of TBARS was determined. Moreover, the increment in H2O2 content under drought was accompanied by increased in glutathione reductase, catalase and superoxide dismutase activities. On the other hand, PEG-induced drought stress caused a reduction in peroxidase and ascorbate peroxidase activities. These results suggest that endemic Urtica dioica plant have an efficient drought tolerance, as displayed by enhanced antioxidant enzyme activities with maintaining water status under drought conditions. In this study, important information about physiological and antioxidative responses of endemic Urtica dioica was revealed for the first time.

Endophytic fungi are able to induce tolerance to salt stress in date palm seedlings (Phoenix dactylifera L.).

Date palm, typically considered a salinity-resistant plant, grows in arid and semi-arid regions worldwide, and experiences decreased growth and yields under salt stress. This study investigates the efficacy of endophytic fungi (EF) in enhancing the salinity tolerance of date palm seedlings. In this experiment, EF were isolated from date tree roots and identified morphologically. Following molecular identification, superior strains were selected to inoculate date palm seedlings (Phoenix dactylifera L., cv. Mazafati). The seedlings were subjected to varying levels of salinity stress for 4months, utilizing a completely randomized factorial design with two factors: fungal strain type (six levels) and salinity stress (0, 100, 200, and 300mM sodium chloride). The diversity analysis of endophytic fungi in date palm trees revealed that the majority of isolates belonged to the Ascomycota family, with Fusarium and Alternaria being the most frequently isolated genera. In this research, the application of fungal endophytes resulted in increased dry weight of roots, shoots, root length, plant height, and leaf number. Additionally, EF symbiosis with date palm seedling roots led to a reduction in sodium concentration and an increase in potassium and phosphorus concentrations in aerial parts under salt-stress conditions. While salinity elevated lipid peroxidation, consequently increasing malondialdehyde (MDA) levels, EF mitigated damage from reactive oxygen species (ROS) by enhancing antioxidant enzyme activity, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), while promoting proline and total soluble sugar (TSS) accumulation. The colonization percentage generally increased with salinity stress intensity in most strains. According to the results, the application of EF can alleviate the adverse effects of salinity stress and enhance the growth of date palm seedlings under saline conditions.

Selenomethionine alleviates decabromodiphenyl ether-induced oxidative stress and ferroptosis via the NRF2/GPX4 pathway in the chicken brain

Decabromodiphenyl ether (BDE209) is a toxic environmental pollutant that can cause neurotoxicity, behavioral abnormalities, and cognitive impairment in animals. However, the specific mechanisms of BDE209-induced neurological injury and effective preventative and therapeutic interventions are lacking. Even though selenomethionine (Se-Met) has a significant detoxification effect and protects the nervous system, it remains unclear whether Se-Met can counteract the toxic effects of BDE209. For the in vivo test, we randomly divided 60 1-week-old hy-line white variety chicks into the Con, BDE209, Se-Met, and BDE209 +Se-Met groups. In vitro experiments were performed, exposing chick embryo brain neurons to BDE209, Se-Met, N-Acetylcysteine (NAC, a ROS inhibitor), and RSL3 (a GPX4 inhibitor). We demonstrated that BDE209 induced oxidative stress and ferroptosis in the chicken brain, which mainly manifested as mitochondrial atrophy, cristae breakage, increased Fe2+ and MDA content, decreased antioxidant enzyme activity, and the inhibition of the NRF2/GPX4 signaling pathway in the brain neurons. However, Se-Met supplementation reversed these changes by activating the NRF2/GPX4 pathway, reducing mitochondrial damage, enhancing antioxidant enzyme activity, and alleviating ferroptosis. This study provides insight into the mechanism of BDE209-related neurotoxicity and suggests Se-Met as an effective preventative and control measure against BDE209 poisoning.

Effects of Plant Regulators on the Seed Germination and Antioxidant Enzyme Activity of Cotton under Compound Salt Stress.

Salinity stress significantly hampers cotton seed germination and seedling growth. Employing plant growth regulators stands out as an effective strategy to mitigate salt stress. In this study, we assessed the impact of varying concentrations of natural composite salt conditions (0%, 0.6%, and 1.2%) on cotton seed germination, seedling growth, and physiology. Additionally, we explored the effects of compound sodium nitrophenolate (CSN: 2 mg·L-1 and 10 mg·L-1), 24-epibrassinolide (EBR: 0.02 mg·L-1 and 0.1 mg·L-1), and gibberellic acid (GA: 60 mg·L-1 and 300 mg·L-1), against a control (CK: distilled water) group. The results indicate that with an increase in the composite salt concentration, the germination potential (GP) and germination rate (GR) of cotton seeds gradually decrease. Simultaneously, the fresh weight and root vitality of seedlings also correspondingly decrease, while the degree of membrane lipid peroxidation increases. Under high-salt (1.2%) conditions, soaking treatments with CSN and EBR significantly enhance both GP (45-59% and 55-64%) and GR (30-33% and 39-36%) compared to the CK. However, the GA treatment does not increase the GP and GR of cotton. Moreover, under high-salt (1.2%) conditions, CSN and EBR treatments result in the increased activities of superoxide dismutase (56-66% and 71-80%), peroxidase (20-24% and 37-51%), and catalase (26-32% and 35-46%). Consequently, cotton exhibits a relatively good tolerance to natural composite salts. Soaking treatments with CSN and EBR effectively improve cotton germination by enhancing antioxidant enzyme activities, thereby strengthening cotton's tolerance to salt stress. These findings offer new insights for enhancing the salt tolerance of cotton.

Sodium nitroprusside (SNP) treatment increases the postharvest resistance of apple fruit to Alternaria alternata by enhancing antioxidant enzyme activity

Black spot disease, caused by the fungal pathogen Alternaria alternata, commonly infects apple (Malus domestica) during postharvest storage and transportation, diminishing fruit quality, contaminating the fruit with toxins, and causing significant economic losses. Here, we investigated the effect of 0.1 mmol L−1 sodium nitroprusside (SNP), a nitric oxide donor, on lesion diameter, fruit quality, and reactive oxygen species (ROS) metabolism in A. alternata-inoculated apples. SNP not only effectively decreased lesion diameter but also maintained fruit quality and cell membrane integrity. Additionally, SNP enhanced antioxidant enzyme activity and genes encoding of peroxidase (POD), glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), and decreased hydrogen peroxide (H2O2) and superoxide anion (O2•−) production, malondialdehyde (MDA) concentration, and membrane permeability. Collectively, these results demonstrate that SNP inhibits ROS accumulation and increases antioxidant enzyme activity, and that the mechanism of SNP-induced resistance is related to the regulation of ROS metabolism.

Coronatine-Induced Maize Defense against Gibberella Stalk Rot by Activating Antioxidants and Phytohormone Signaling.

One of the most destructive diseases, Gibberella stalk rot (GSR), caused by Fusarium graminearum, reduces maize yields significantly. An induced resistance response is a potent and cost-effective plant defense against pathogen attack. The functional counterpart of JAs, coronatine (COR), has attracted a lot of interest recently due to its ability to control plant growth and stimulate secondary metabolism. Although several studies have focused on COR as a plant immune elicitor to improve plant resistance to pathogens, the effectiveness and underlying mechanisms of the suppressive ability against COR to F. graminearum in maize have been limited. We investigated the potential physiological and molecular mechanisms of COR in modulating maize resistance to F. graminearum. COR treatment strongly enhanced disease resistance and promoted stomatal closure with H2O2 accumulation, and 10 μg/mL was confirmed as the best concentration. COR treatment increased defense-related enzyme activity and decreased the malondialdehyde content with enhanced antioxidant enzyme activity. To identify candidate resistance genes and gain insight into the molecular mechanism of GSR resistance associated with COR, we integrated transcriptomic and metabolomic data to systemically explore the defense mechanisms of COR, and multiple hub genes were pinpointed using weighted gene correlation network analysis (WGCNA). We discovered 6 significant modules containing 10 candidate genes: WRKY transcription factor (LOC100279570), calcium-binding protein (LOC100382070), NBR1-like protein (LOC100275089), amino acid permease (LOC100382244), glutathione S-transferase (LOC541830), HXXXD-type acyl-transferase (LOC100191608), prolin-rich extensin-like receptor protein kinase (LOC100501564), AP2-like ethylene-responsive transcription factor (LOC100384380), basic leucine zipper (LOC100275351), and glycosyltransferase (LOC606486), which are highly correlated with the jasmonic acid-ethylene signaling pathway and antioxidants. In addition, a core set of metabolites, including alpha-linolenic acid metabolism and flavonoids biosynthesis linked to the hub genes, were identified. Taken together, our research revealed differentially expressed key genes and metabolites, as well as co-expression networks, associated with COR treatment of maize stems after F. graminearum infection. In addition, COR-treated maize had higher JA (JA-Ile and Me-JA) levels. We postulated that COR plays a positive role in maize resistance to F. graminearum by regulating antioxidant levels and the JA signaling pathway, and the flavonoid biosynthesis pathway is also involved in the resistance response against GSR.

Enhancing cold and drought tolerance in cotton: a protective role of SikCOR413PM1

The present study explored the potential role of cold-regulated plasma membrane protein COR413PM1 isolated from Saussurea involucrata (Matsum. & Koidz)(SikCOR413PM1), in enhancing cotton (Gossypium hirsutum) tolerance to cold and drought stresses through transgenic methods. Under cold and drought stresses, the survival rate and the fresh and dry weights of the SikCOR413PM1-overexpressing lines were higher than those of the wild-type plants, and the degree of leaf withering was much lower. Besides, overexpressing SikCOR413PM1 overexpression increased the relative water content, reduced malondialdehyde content and relative conductivity, and elevated proline and soluble sugar levels in cotton seedlings. These findings suggest that SikCOR413PM1 minimizes cell membrane damage and boosts plant stability under challenging conditions. Additionally, overexpression of this gene upregulated antioxidant enzyme-related genes in cotton seedlings, resulting in enhanced antioxidant enzyme activity, lowered peroxide content, and reduced oxidative stress. SikCOR413PM1 overexpression also modulated the expression of stress-related genes (GhDREB1A, GhDREB1B, GhDREB1C, GhERF2, GhNAC3, and GhRD22). In field trials, the transgenic cotton plants overexpressing SikCOR413PM1 displayed high yields and increased environmental tolerance. Our study thus demonstrates the role of SikCOR413PM1 in regulating stress-related genes, osmotic adjustment factors, and peroxide content while preserving cell membrane stability and improving cold and drought tolerance in cotton.

Pre-storage calcium chloride and aloe vera gel coatings mitigate internal browning and senescence scald in ‘Conference’ pears

Physiological disorders pose significant challenges to the quality and shelf life of ‘conference’ pears. This study investigates the efficacy of calcium chloride (CaCl2) and aloe vera (AV) gel treatments in reducing internal browning and senescence scald in ‘Conference’ pears. Four groups were evaluated: a control, individual 2 % CaCl2, 15 % AV gel treatments, and a combined CaCl2 and AV gel treatment. Pears having following maturity indices (TSS 12 %, ho 90, and Firmness 67 N) were then stored at 2 ± 1 °C, 85±5 % RH for 180 d The fruits were removed from cold storage to room temperature and kept at 20±3 °C and 65±5 % RH followed by physicochemical and sensory analyses. The combined treatment proved most effective in preserving quality and reducing internal browning and senescence scald. Treated pears displayed reduced respiration rates, ethylene production, internal browning, senescence scald, and weight loss. Moreover, the combined treatment resulted in higher TA and lower TSS compared to the control after 180 d of storage. The reduction in internal browning and senescence scald can be attributed to enzyme activity modulation. The combined treatment increased catalase (CAT) and superoxide dismutase (SOD) activity, reducing oxidative stress. This, in turn, minimized oxidative reactions leading to internal browning. Furthermore, the treatment inhibited polyphenol oxidase (PPO) and peroxidase (POD) activity, enzymes responsible for browning reactions. Lower PPO and POD activity contributed to reduced internal browning and senescence scald. The combined actions of enhanced antioxidant enzymes and decreased browning-related enzymes synergistically reduced internal browning. In conclusion, the combined CaCl2 and AV gel treatment effectively mitigated internal browning and senescence scald in pears and also received the highest score in sensory analysis. Enhanced antioxidant enzyme activity (CAT and SOD) and reduced PPO and POD activity collectively contributed to this reduction. This eco-friendly approach presents a sustainable strategy for extending shelf life and enhancing pear quality, providing an alternative to traditional chemical interventions for managing physiological disorders.

Methyl jasmonate reduces cadmium toxicity by enhancing phenol and flavonoid metabolism and activating the antioxidant defense system in pigeon pea (Cajanus cajan)

Cadmium (Cd) is absorbed by plant roots from soil along with essential nutrients and affects plant growth and productivity. Methyl jasmonate (Me-JA) play important roles to mitigate Cd toxicity in plants. We have investigated the role of Me-JA to ameliorate Cd toxicity in Pigeon pea (Cajanus cajan). Plant root growth, biomass, cellular antioxidant defense system and expression of key regulatory genes in molecular and signaling process have been analyzed. Two Cajanus cajan varieties AL-882 and PAU-881 were grown at 25 °C, 16/8h light/dark conditions in three biological replicates at 5 mM Cd concentration, three concentration of Me-JA (0, 10 nM, 100 nM) and two concentrations in combination of Me-JA + Cd (10 nM Me-JA +5 mM Cd, 100 nM Me-JA +5 mM Cd). The seedlings were exposed to Cd stress consequently plants showed decrease in primary root growth (60.71%, in AL-882 and 8.33%, in PAU-881), shoot and root biomass and antioxidant enzymes activities. Me-JA treatment resulted in increased primary root growth (63.64%, in AL-882) and overall plant biomass. Oxidative stress generated due to Cd stress was counter balanced by Me-JA treatment. Me-JA reduced H2O2 free radicals formation and enhanced antioxidant enzyme activities and phenolic content in stressed seedlings. Me-JA treatment increased expression of CALM, IP3, CDPK2, MPKs (involved in calcium and kinase signaling pathways) and reduced expression of metal transporters (IRT1 and HMA3) genes. This reduction in metal transporters gene expression is a probable reason for low toxicity effect of Cd in root after Me-JA treatment which has potential implications in reducing the risk of Cd in the food chain.

Storage Stability Assessment of Indigenous Guava Fruits (Psidium guajava L.) cv. “Gola” in Response to γ-Irradiation

Postharvest losses in fruits and vegetables pose a key challenge to the global horticulture industry. Improved storage stability of horticultural commodities through irradiation is a technological intervention which has greater compliance over more than 60 foods and food products. The present study was intended to explore the effect of γ-irradiation doses on the postharvest quality of fresh guava fruits stored under ambient (temperature 20 ± 2 °C, RH 85%) conditions. Various storage specific quality attributes including physiological weight loss, respiration rate (CO2), ethylene estimation, ripening index, fruit firmness, ascorbic acid, nutraceutical potential, and enzyme kinetics were evaluated during postharvest storage at four days of interval. The results indicated that the fruits irradiated at doses (0.8 kGy and 1.0 kGy) exhibited significant reduction in physiological parameters in contrast with untreated fruit samples. Firmness, total phenolic compounds, flavonoids, and radical scavenging activity were successfully retained in irradiated fruit samples up to twenty days of storage. The respiration and ethylene production rates were suppressed in irradiated guava fruits compared to control. Moreover, it has also been discovered that the fruits exposed to 1.0 kGy had considerably decreased the polyphenol oxidase (PPO) activity compared to nonirradiated fruits, thus resulting in lowering the enzymatic browning. Aside from that, irradiation guava fruits had considerably enhanced antioxidant enzyme activity ( P ≤ 0.05 ) in terms of catalase, peroxidase, and superoxide dismutase. In conclusion, the study revealed that γ -rays irradiation doses up to 1.0 kGy might be considered effective to improve the postharvest storage of native guava fruits variety with intact nutritional attributes.

Seed treatment with ascorbic acid and proline improved salt tolerance in tomato (Solanum lycopersicum L. cv. Roma) by enhancing antioxidant enzyme activity

Seed treatment with ascorbic acid and proline improved salt tolerance in tomato (Solanum lycopersicum L. cv. Roma) by enhancing antioxidant enzyme activity

Browning inhibition in fresh-cut Chinese water chestnut under high pressure CO2 treatment: Regulation of reactive oxygen species and membrane lipid metabolism.

Fresh-cut Chinese water chestnut (CWC) was treated with high pressure CO2 (HPCD) to inhibit the browning reactions, and the underlying mechanism was investigated in this study. Results showed that HPCD at 2MPa pressure significantly inhibited lipoxygenase activity and enhanced superoxide dismutase activity, leading to decreased malondialdehyde and H2O2 contents in surface tissue. Moreover, HPCD could reduce total phenols/flavonoids content of surface tissue. Compare with control, homoeriodictyol, hesperetin, and isorhamnetin contents of 2MPa HPCD-treated samples on day 10 were reduced by 95.72%, 94.31%, and 94.02%, respectively. Furthermore, HPCD treatment enhanced antioxidant enzyme activities, and improved the O2- scavenging ability and reducing power of inner tissue. In conclusion, by regulating ROS and membrane lipid metabolism, HPCD treatment with appropriate pressure could retard the biosynthesis of flavonoids and enzymatic oxidation of phenolic compounds in surface tissue, and enhance antioxidant activity of inner tissue, thereby, delaying the quality deterioration of fresh-cut CWC.

Physiological factors contribute to increased competitiveness of grass relative to sedge, forb and legume species under different N application levels

In alpine grasslands, increased N deposition is increasing the dominance of grasses relative to other functional types according to our previous study Shen et al. (2022). However, the mechanisms that drive this compositional change are not fully understood. We measured the effects of 4–6 years' N addition to simulate N deposition at rates of 0 (CK), 8 (N1), 24 (N2), 40 (N3), 56 (N4), and 72 (N5) kg N ha−1 year−1 on dominant representatives of four functional types, Leymus secalinus (grass), Carex capillifolia (sedge), Potentilla multifidi (non-leguminous forb), and Medicago ruthenica (legume), in the alpine grassland on the Qinghai-Tibetan Plateau (QTP). In-situ experiment showed that N addition increased aboveground biomass in L. secalinus but had negative or neutral effects on aboveground biomass in the other species. Consistent with this finding, N addition increased net photosynthesis, chlorophyll content, and rubisco activity in L. secalinus with less positive effects on the other species. Nitrogen addition increased leaf N content in L. secalinus and C. capillifolia and reduced leaf non-structural carbohydrate content in all four species. In L. secalinus, the highest N addition rate (N5) reduced MDA content, a marker of oxidative stress, by enhancing antioxidant enzyme activity. Overall, our findings suggested that physiological factors can contribute to increased competitiveness of grass relative to sedge, forb and legume species under high N application levels. The rapid growth of this grass species reduces resource availability to non-grass species, increasing its dominance in the alpine meadow.

Assessment of application of ZnO nanoparticles on physiological profile, root architecture and antioxidant potential of Solanum lycopersicum

Plant growth can be impacted by ZnO nanoparticles (ZnO-NPs), in addition to their effects on photosynthesis and seed germination. The degree to which nanoparticles (NPs) enhance or inhibit shoot and root growth can vary depending on the specific type of NPs and their concentrations. This research aimed to explore the effects of ZnO-NPs on tomato plants (Solanum lycopersicum L.). The study measured the growth of the plants, their photosynthetic abilities, chlorophyll, physiology responses, antioxidant activities in 24-day-old plants. The results indicated that ZnO-NPs applications improved germination percentage (30.7%), shoot length (47.6%) and root length (33.1%) of the tomato plants, particularly at 75 μg/mL, and enhanced chlorophyll content in a manner proportional to the concentration. Moreover, in current research, it has been found that ZnO-NPs applications improved antioxidant response, and production of antioxidant enzymes. ZnO-NPs also had a beneficial impact on various root parameters including number of root tips (29.6%), number of branching points (16.6%), average diameter (46.2%), branching frequency (26.6%), total root length (33.1%), network area (26.3%), surface area (24.0%), perimeter (22.0%) and root volume (25.2%). Above 75 μg/mL, a reduction in all of them have been noticed, which indicates that concentrations of ZNPs above 75 μg/mL are harmful to tomato plants. Moreover, ZNPs appear to stimulate the transcription of various genes which have antioxidant activities, implying that they may bolster the plant's defense mechanism by enhancing antioxidant enzyme activity. According to our best knowledge, this is a novel aspect to study of impact of ZnO-NPs on root architecture of Solanum lycopersicum L.

Melatonin interaction with abscisic acid in the regulation of abiotic stress in Solanaceae family plants.

Solanaceous vegetable crops are cultivated and consumed worldwide. However, they often confront diverse abiotic stresses that significantly impair their growth, yield, and overall quality. This review delves into melatonin and abscisic acid (ABA) biosynthesis and their roles in abiotic stress responses. It closely examines the intricate interplay between melatonin and ABA in managing stress within plants, revealing both collaborative and antagonistic effects and elucidating the underlying molecular mechanisms. Melatonin and ABA mutually influence each other's synthesis, metabolism and that of other plant hormones, a key focus of this study. The study highlights melatonin's role in aiding stress management through ABA-dependent pathways and key genes in the melatonin-ABA interaction. Specifically, melatonin downregulates ABA synthesis genes and upregulates catabolism genes, leading to reduced ABA levels. It also directly scavenges H2O2, enhancing antioxidant enzyme activities, thereby underscoring their collaborative role in mediating stress responses. Moreover, the interplay between melatonin and ABA plays an essential role in multiple physiological processes of plants, including stomatal behaviors, wax accumulation, delay leaf senescence, seed germination, and seedlings growth, among others. Recognizing these relationships in Solanaceae vegetable crops holds great importance for improving agricultural practices and crop quality. In summary, this review offers a comprehensive overview of recent studies on the melatoninand ABA interplay, serving as a valuable resource for researchers and breeders dedicated to fortifying crop resilience and productivity within challenging environments.