Decreased Electrolyte Leakage Research Articles

Alteration in certain growth, biochemical, and anatomical indices of grapevine (Vitis vinifera) in response to the foliar application of auxin under water deficit.

Drought-induced stress represents one of the most economically detrimental natural phenomena impacting grapevine (Vitis vinifera ) development, yield, and fruit characteristics. Also, auxin is one of the most important plant growth regulators that can reduce damage caused by stress in plants. In this study, the impact of exogenously sprayed auxin (0, 50, and 200mgL-1 ) on growth, biochemical, and anatomical parameters was investigated in two grapevine varieties (cvs. 'Rashe' and 'Fakhri') under water deficit. According to our findings, water deficit led to a notable decrease in growth, protein content, and anatomical parameters; but significantly enhanced electrolyte leakage. Grapevines exposed to water deficit exhibited substantial increases in total phenolic compounds and antioxidant activity. Applying 50mgL-1 napthalene acetic acid (NAA) reduced the effects of water deficit in both grapevine cultivars by decreasing electrolyte leakage (15% in 'Rashe' and 20% in 'Fakhri'), and accumulating protein content (22% 'Rashe' and 32% 'Fakhri'), total phenolic compounds (33%'Rashe' and 40% 'Fakhri'), and antioxidant capacity (11% 'Rashe' and 39% 'Fakhri'); anantomical parameters were also improved. However, application of 200mgL-1 NAA had adverse effects on growth and biochemical traits of grapevines, with a more pronounced impact on root growth and anatomical parameters compared to other NAA concentrations. In conclusion, the application of 50mgL-1 NAA enhanced grapevine growth, enabling them to better thrive under water deficit.

PGPR consortia enhance growth and yield in barley cultivars subjected to severe drought stress and subsequent recovery

With the continuous increase of land areas affected by drought due to climate change, barley, a cereal globally consumed by the human population, faces significant challenges from drought stress. The current study aims to showcase the effectiveness of two consortia based on Plant Growth-Promoting Rhizobacteria (PGPR) strains in promoting plant growth and recovery in post-drought conditions of drought-sensitive and tolerant barley cultivars. Inoculations with Consortium 1 and 2 enhance barley plant tolerance to drought stress by impacting relative water content, SPAD index, and Fv/Fm while decreasing electrolyte leakage. Similarly, in biochemical traits, both consortia influence proline, total soluble sugars, H2O2, and MDA contents, as well as catalase and ascorbate peroxidase activities. Regarding agro-morphological traits, the consortia contribute to increased root and vegetative shoot dry weights, along with a positive effect on grain yield and thousand-grain weight, achieving values equivalent to unstressed plants. The highest important effect in recovered plants was recorded in the case of the tolerant cultivar inoculated with Consortium 1, in most of the traits studied, there was no significant difference recorded between unstressed and recovered barley plants. Consortium 1 and Consortium 2 improve the tolerance of both sensitive and tolerant barley cultivars against drought, aiding recovered plants in regaining physiological status equivalent to unstressed ones.

Health Benefits of High Voltage Electrostatic Field Processing of Fruits and Vegetables.

High voltage electrostatic field processing (HVEF) is a food preservation procedure frequently used to produce healthy minimally processed fruits and vegetables (F&V) as it reduces the growth of microorganisms and activates or inhibits various enzymes, thus retarding their natural ripening while preserving and even enhancing native nutritional quality and sensory characteristics. HVEF is one of the various nonthermal processing technology (NTPT) regarded as abiotic stress that can activate the antioxidant system of F&V and can also inhibith spoilage enzymes as, polyphenol oxidase (PPO), lipoxygenase (LOX), pectin methylesterase (PME), polygalacturonase (PG), cellulase (Cel), β-xylosidase, xyloglucan and endotransglycosylase/hydrolase, bringing positive effect on hardness, firmness, colour attributes, electric conductivity, antioxidant compounds, microstructure and decreasing electrolyte leakage (EL), malondialdehyde (MDA) contents and browning degree. This technique can also increase the contents of fructose, glucose, and sucrose and decrease the production of CO2 and H2O2. Additionally, it has been reported that HVEF could be used with other treatments, such as modified atmosphere packaging (MAP) and acidic electrolyzed water (AEW) treatment, to enhance its effects. Future works should deepen on elucidating the activation of the antioxidant systems by applying HVEF of critical enzymes related to the synthesis pathways of phenolic compounds (PC) and carotenoids (Car). Holistic approaches to the effects of HVEF on metabolism based on systems biology also need to be studied by considering the overall biochemical, physical, and process engineering related aspects of this technique.

Melatonin induced reversibility of vanadium toxicity in muskmelon by regulating antioxidant defense and glyoxalase systems

Agricultural lands with vanadium (V), pose a significant and widespread threat to crop production worldwide. The study was designed to explore the melatonin (ME) treatment in reducing the V-induced phytotoxicity in muskmelon. The muskmelon seedlings were grown hydroponically and subjected to V (40 mg L−1) stress and exogenously treated with ME (100 μmol L−1) to mitigate the V-induced toxicity. The results showed that V toxicity displayed a remarkably adverse effect on seedling growth and biomass, primarily by impeding root development, the photosynthesis system and the activities of antioxidants. Contrarily, the application of ME mitigated the V-induced growth damage and significantly improved root attributes, photosynthetic efficiency, leaf gas exchange parameters and mineral homeostasis by reducing V accumulation in leaves and roots. Additionally, a significant reduction in the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA) along with a decrease in electrolyte leakage was observed in muskmelon seedlings treated with ME under V-stress. This reduction was attributed to the enhancement in the activities of antioxidants in leaves/roots such as ascorbate (AsA), superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione peroxidase (GPX), glutathione S-transferase (GST) as compared to the V stressed plants. Moreover, ME also upregulated the chlorophyll biosynthesis and antioxidants genes expression in muskmelon. Given these findings, ME treatment exhibited a significant improvement in growth attributes, photosynthesis efficiency and the activities of antioxidants (enzymatic and non-enzymatic) by regulating their expression of genes against V-stress with considerable reduction in oxidative damage.

APPLICATION OF USING SLAUGHTERHOUSE WASTE FOR BOOSTING THE GROWTH OF SPINACH

Slaughterhouse waste is capable of causing serious bacterial, viral and pathogenic diseases both in humans and animals. Slaughterhouse wastewater contains fat, proteins, suspended solids and diluted blood. Due to this, organic as well as nutrient profusion in wastewater is very high. These partially solubilized residues pose a real threat to human health if left out in riverbeds and other water bodies untreated. Processing of blood requires a high capital investment on heavy instruments for slaughtering and collection of blood. The hazard could be minimized by environmentally friendly and cost-effective disposal methods. This waste could be used for land application via composting, as it is a rich source of primary plant nutrients i.e. N, P and K as well as growth promoting microbes and organic substances. Keeping in view the above-mentioned facts, a pot trial was conducted in the wire house of the Institute of Soil and Environmental Sciences. We mixed the soil with slaughterhouse waste before sowing. Three seedlings of spinach were maintained after germination. Water was applied as needed by the plants. Recommended doses of N, P, and K fertilizers were applied. Data regarding physiological parameters, growth and yield was collected and analyzed at appropriate growth stages. After harvesting, plant tissues (root and leave) and soil samples was subjected to analysis for plant nutrients provision. Analysis of data was done following standard statistical procedure. Slaughterhouse waste improves the plant growth. Results showed that blood, intestine and dry matter significantly affect the plant growth parameter of spinach in natural soil. Plant height was increased up to 92 %, root length 194 %, shoot dry weight 60 % and root dry weight 169 % with blood at (120 ml), intestine (100 g) and dry matter (20 g) as compared to control. All the treatments significantly improved these parameters but blood, intestine and dry matter increased chlorophyll contents 84%, relative water contents 21 %, photosynthetic rate 91%, transpiration rate 95%, and stomatal conductance 58 %, and decreased electrolyte leakage up to 54% in spinach.

Differential response of biochar in mitigating salinity stress in periwinkle (Catharanthus roseus L.) as an ornamental-medicinal plant species

To investigate the effect of various levels of salinity and biochar on the growth and biochemical traits of Catharanthus roseus L., a medicinal plant, a factorial experiment with three levels of biochar (0, 2, and 4%) and four levels of salinity (0, 1,000, 2,000, and 3,000 mg/kg soil) was conducted in pots under greenhouse conditions, in three replications, 36 pots, and 6 plants/plot. Salinity reduced the vegetative and reproductive growth and Ca and K uptake, and chlorophyll content of the plants, and increased the Na+, Cl−, electrolyte leakage, and antioxidant enzyme (SOD, CAT, GPX) activities. Biochar improved all the vegetative and reproductive growth and biochemical traits of Catharanthus roseus L. and enhanced soil fertility. The application of biochar at the rate of 2% at all four levels of NaCl reduced the activity of antioxidants and decreased electrolyte leakage, reflecting the alleviation of salinity effects and the retention of cell health for survival. The application of biochar 2% was more effective than biochar 4% in alleviating salinity stress. Therefore, by using 2% biochar, it is possible to improve saline soils (soils containing 1,000 or 2,000 mg/kg NaCl) and grow periwinkle ornamental-medicinal plant in it. The plants showed acceptable performance at salinity levels of 1,000 or 2,000 mg/kg with biochar 2%.

Enhancing maize growth through the synergistic impact of potassium enrich biochar and spermidine

Maize cultivated for dry grain covers approximately 197 million hectares globally, securing its position as the second most widely grown crop worldwide after wheat. Although spermidine and biochar individually showed positive impacts on maize production in existing literature, their combined effects on maize growth, physiology, nutrient uptake remain unclear and require further in-depth investigation. That’s why a pot experiment was conducted on maize with spermidine and potassium enriched biochar (KBC) as treatments in Multan, Pakistan, during the year 2022. Four levels of spermidine (0, 0.15, 0.30, and 0.45mM) and two levels of potassium KBC (0 and 0.50%) were applied in completely randomized design (CRD). Results showed that 0.45 mM spermidine under 0.50% KBC caused significant enhancement in maize shoot length (11.30%), shoot fresh weight (25.78%), shoot dry weight (17.45%), root length (27.95%), root fresh weight (26.80%), and root dry weight (20.86%) over control. A significant increase in maize chlorophyll a (50.00%), chlorophyll b (40.40%), total chlorophyll (47.00%), photosynthetic rate (34.91%), transpiration rate (6.51%), and stomatal conductance (15.99%) compared to control under 0.50%KBC validate the potential of 0.45 mM spermidine. An increase in N, P, and K concentration in the root and shoot while decrease in electrolyte leakage and antioxidants also confirmed that the 0.45 mM spermidine performed more effectively with 0.50%KBC. In conclusion, 0.45 mM spermidine with 0.50%KBC is recommended for enhancing maize growth.

Exogenous silicon induces aluminum tolerance in white clover (Trifolium repens) by reducing aluminum uptake and enhancing organic acid secretion.

Excessive aluminum (Al) in acidic soils is a primary factor that hinders plant growth. The objective of the present study was to investigate the effect and physiological mechanism of exogenous silicon (Si) in alleviating aluminum toxicity. Under hydroponic conditions, 4 mM Al significantly impeded the growth of white clover; however, pretreatments with 1 mM Si mitigated this inhibition, as evidenced by notable changes in growth indicators and physiological parameters. Exogenous silicon notably increased both shoot and root length of white clover and significantly decreased electrolyte leakage (EL) and malondialdehyde (MDA) content compared to aluminum treatments. This positive effect was particularly evident in the roots. Further analysis involving hematoxylin staining, scanning electron microscopy (SEM), and examination of organic acids (OAs) demonstrated that silicon relieved the accumulation of bioactive aluminum and ameliorated damage to root tissues in aluminum-stressed plants. Additionally, energy-dispersive X-ray (EDX) analysis revealed that additional silicon was primarily distributed in the root epidermal and cortical layers, effectively reducing the transport of aluminum and maintaining the balance of exchangeable cations absorption. These findings suggest that gradual silicon deposition in root tissues effectively prevents the absorption of biologically active aluminum, thereby reducing the risk of mineral nutrient deficiencies induced by aluminum stress, promoting organic acids exudation, and compartmentalizing aluminum in the outer layer of root tissues. This mechanism helps white clover alleviate the damage caused by aluminum toxicity.

Co-application of biochar and plant growth regulators improves maize growth and decreases Cd accumulation in cadmium-contaminated soil

To ensure the sustainable cultivation of agronomic crops in agricultural soils polluted with cadmium (Cd), the integrated application of Cd-remediation strategies at edaphic and foliar levels has been examined. However, the integrated application of biochar (BC) and plant growth regulators (PGRs) for mitigating Cd stress, especially in maize, remains unexplored. Additionally, the expression patterns of PGRs and heavy metal transporters during Cd stress are unknown. To address these gaps, a pot experiment (having four replications) was performed to explore the potential effects of the integrated application of BC (B0 = no BC added; B1 = low BC at 2.5% w/w; and B2 = high BC at 5% w/w) and PGRs (H0 = control; WS = water spray; GA = gibberellin, and IAA = auxin) on maize growth, Cd remediation, and productivity. The study was conducted following a factorial completely randomized design. The pots were artificially spiked with Cd (30 ppm) by using Cd(NO3)2 as a source. The synergistic application of IAA/GA and BC, improved the morphological characteristics, photosynthetic activity, stomatal conductance, and catalase activity of maize under Cd stress while simultaneously decreasing electrolyte leakage and oxidant activity. The leaf area, shoot fresh biomass (SFB), and root fresh biomass (RFB), were increased by (13.4, 11.7%), (52.8, 39.3%), and (89.2, 74.3%) in the synergistic application of PGRs (i.e., IAA and GA) + BC (5% w/w) treatments, respectively, than control. Furthermore, a drastic reduction in Cd uptake was observed in maize leaves by (201.53, 179.24%) under the dual application of PGRs + BC (5% w/w) treatments, compared to control, which altered Cd bioconcentration in plant parts and modified Cd species in the soil. Decreased expression of heavy metal transporter PMPCB gene and YCF1 indicated reduced Cd uptake in 5% w/w BC based on RT-PCR quantification. The synergistic application of BC with PGRs can serve as an environmentally friendly remediation to mitigate the hazardous effects of Cd stress on cultivated maize. This was achieved by reducing the bio-concentration and metal transport coefficients of Cd in plants through BC's absorption properties. Overall, applying BC and foliar application of PGRs could be suggested as a sustainable approach for cultivating crops on Cd-contaminated soils while ensuring safety.

Role of gum Arabic combined with cinnamic acid coating on quality and cell wall degradation enzymes of mango fruits at low temperature

Mango exhibits a short shelf life when kept under ambient conditions. Therefore, this study was carried out to assess the synergistic effect of gum Arabic (GA) and cinnamic acid (CA) coatings on mango fruits stored for 28 days at 12 ± 1 °C. The treatments included GA 10 and 20 % sole and its formulation with CA 0.2 % while the uncoated fruits were used as control. The results revealed that GA + CA coatings exhibited reduced weight loss, flesh firmness, delayed respiratory peak, retained soluble solids content (SSC), titratable acidity (TA) and skin colour, retarded spoilage, and decreased electrolyte leakage of fruit as compared to uncoated fruit during storage. Among all, the coating GA 20 % + CA 0.2 % maintained higher firmness (16.6 N), SSC (20.1 %), TA (0.71 %), total flavonoid content (152 mg/kg) and total carotenoids content (45.1 mg/kg) and retained the higher sensory quality of mango fruit at the end of storage. Additionally, the GA 20 % + CA 0.2 % coating suppressed activities of polygalacturonase (PG), cellulase (CL) and pectin methyl esterase (PME) in stored mango fruits.

Seed priming attenuates the impact of salt stress and enhances lettuce yields

Salt stress is a major factor that contributes to reduced lettuce productivity. Seed priming has emerged as a promising technique to improve crop stress tolerance. In this study, Romaine lettuce seeds were primed with calcium chloride (CaCl2), distilled water (hydro), and potassium nitrate (KNO3) to test their effectiveness in improving salt stress tolerance. Lettuce seeds treated with hydro, 50 mM CaCl2, and 0.5% KNO3 were exposed to 0 or 100 mM sodium chloride (NaCl). Priming treatments significantly increased lettuce's fresh mass by 22%–61% under salt stress. Hydro-primed lettuce showed the most significant increase in root mass (109%), a 38% higher root length, a 35% increase in surface area, and a 25%–40% increase in volume, tips, forks, and crossings of roots. The hydro-primed lettuce had higher gas exchange rates than the non-primed control, followed by the KNO3- and the CaCl2-primed lettuce. Furthermore, hydro-primed seedlings exhibited the highest proline accumulation (105%) under salt stress. The accumulation of sugars (up to 50%) in hydro- and CaCl2-primed lettuce led to a 56% decrease in electrolyte leakage and membrane damage. The correlation network analysis of the traits revealed that hydro-primed seedlings exhibited a higher + ve/-ve edge ratio, which indicates their greater resilience to salt stress than other priming techniques. Priming of seeds before planting offers the potential for improving resilience to stress.

Regulatory effects of Hemin on prevention and rescue of salt stress in rapeseed (Brassica napus L.) seedlings

BackgroundSalt stress severely restricts rapeseed growth and productivity. Hemin can effectively alleviate salt stress in plants. However, the regulatory effect of Hemin on rapeseed in salt stress is unclear. Here, we analyzed the response and remediation mechanism of Hemin application to rapeseed before and after 0.6% (m salt: m soil) NaCl stress. Experiment using two Brassica napus (AACC, 2n = 38) rapeseed varieties Huayouza 158R (moderately salt-tolerant) and Huayouza 62 (strongly salt-tolerant). To explore the best optional ways to improve salt stress resistance in rapeseed.ResultsOur findings revealed that exogenous application of Hemin enhanced morph-physiological traits of rapeseed and significantly attenuate the inhibition of NaCl stress. Compared to Hemin (SH) treatment, Hemin (HS) significantly improved seedlings root length, seedlings height, stem diameter and accumulated more dry matter biomass under NaCl stress. Moreover, Hemin (HS) significantly improved photosynthetic efficiency, activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and decreased electrolyte leakage (EL) and malondialdehyde (MDA) content, thus resulting in the alleviation of oxidative membrane damage. Hemin (HS) showed better performance than Hemin (SH) under NaCl stress.ConclusionHemin could effectively mitigate the adverse impacts of salt stress by regulating the morph-physiological, photosynthetic and antioxidants traits of rapeseed. This study may provide a basis for Hemin to regulate cultivated rapeseed salt tolerance and explore a better way to alleviate salt stress.

Remediation potential of biochar and selenium for mitigating chromium-induced stress in spinach to minimize human health risk

The contamination of agricultural soils with metals and metalloids significantly affects crop productivity. The objective of the present study was to investigate how the combined application of biochar and selenium (Se) could mitigate the adverse effects of chromium (Cr) stress on spinach. The effects of selenium (Na2SeO4) (1 mg L − 1) and biochar (5 %, w/w) application both individually and in combination were evaluated on the basis of growth, physio-biochemical and antioxidant potential of spinach grown under Cr stress (100 µM [29.40 mg] using K2Cr2O7 of soil) and without Cr stress as control (0 µM). The results indicated that Cr stress decreased the root length (34.62 %), shoot length (35.32 %), number of leaves (23.18 %), root dry weight (12.00 %), and leaf dry weight (24.36 %) under Cr stress by lowering relative water content (RWC) and chlorophyll concentrations due to increased electrolyte leakage (64.03 %) and the Cr accumulation in leaves. However, the combined application of biochar and Se significantly enhanced the fresh and dry biomass under Cr stress and control conditions. The synergistic effect of Se and biochar partly alleviates the effects of Cr stress in spinach by up-regulating the antioxidant system, reducing lipid peroxidation (60.00 %), increasing leaf soluble sugars (25.22 %), and simultaneously decreasing electrolyte leakage. The combined effect of Se and biochar proved better results as compared to the sole application in minimizing Cr uptake in leaves (52.08 %) and limiting the health risk assessment values. Overall, this study highlights that the combined application of biochar and Se is an innovative and eco-friendly approach to improving the physio-biochemical defense responses against Cr stress in spinach plants.

Alleviation of cadmium and drought stress in wheat by improving growth and chlorophyll contents amended with GA3 enriched deashed biochar

Drought and cadmium (Cd) stress are both major issues that significantly affect the growth and development of wheat plants. Both drought stress and Cd toxicity disrupt physiological processes i.e., nutrient uptake, cell expansion, and enzymatic reactions resulting in poor crop growth. To overcome these issues, the use of activated carbon and gibberellic acid (GA3) are considered valuable amendments. However, the current study aimed to add value using GA3-enriched biochar (GA3-BC). That’s why, a lab experiment was conducted on wheat to assess the effectiveness of GA3-BC against Cd and drought stress. For GA3 enrichment in biochar, 10 µg GA3/g biochar was mixed. There were 3 levels of GA3-BC i.e., 0, 0.6 (GA3-BC1), and 0.9% (GA3-BC). All levels were applied in 3 replicates under no stress (0Cd + no drought), drought stress (DS), and 6 mg Cd/ kg soil (6Cd). Results showed that GA3-BC2 caused a significant improvement in shoot length (44.99%), root length (99.73%), seedling length (60.13%) and shoot fresh weight (63.59%) over control at 6Cd + drought stress. A significant improvement in chlorophyll a, chlorophyll b, and total chlorophyll while a decrease in electrolyte leakage and regulation of antioxidants i.e., lipid peroxidation, SOD, CAT, APx, GR, GPx, GST, and DPHH also signified the effectiveness of GA3-BC2 compared to control at 6Cd + drought stress. In conclusion, GA3-BC2 is an efficacious amendment for simultaneously alleviating drought and Cd stress in wheat. More investigations are recommended at the field level on different cereal crops cultivated in different soil textures to declare GA3-BC2 as the best treatment for mitigation of drought stress and Cd toxicity.

Simultaneous Promotion of Salt Tolerance and Phenolic Acid Biosynthesis in Salvia miltiorrhiza via Overexpression of Arabidopsis MYB12.

Transcription factors play crucial roles in regulating plant abiotic stress responses and physiological metabolic processes, which can be used for plant molecular breeding. In this study, an R2R3-MYB transcription factor gene, AtMYB12, was isolated from Arabidopsis thaliana and introduced into Salvia miltiorrhiza under the regulation of the CaMV35S promoter. The ectopic expression of AtMYB12 resulted in improved salt tolerance in S. miltiorrhiza; transgenic plants showed a more resistant phenotype under high-salinity conditions. Physiological experiments showed that transgenic plants exhibited higher chlorophyll contents, and decreased electrolyte leakage and O2- and H2O2 accumulation when subjected to salt stress. Moreover, the activity of reactive oxygen species (ROS)-scavenging enzymes was enhanced in S. miltiorrhiza via the overexpression of AtMYB12, and transgenic plants showed higher superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities compared with those of the wild type (WT) under salt stress, coupled with lower malondialdehyde (MDA) levels. In addition, the amount of salvianolic acid B was significantly elevated in all AtMYB12 transgenic hair roots and transgenic plants, and qRT-PCR analysis revealed that most genes in the phenolic acid biosynthetic pathway were up-regulated. In conclusion, these results demonstrated that AtMYB12 can significantly improve the resistance of plants to salt stress and promote the biosynthesis of phenolic acids by regulating genes involved in the biosynthetic pathway.

Alleviation of cadmium toxicity and fortification of zinc in wheat cultivars cultivated in Cd contaminated soil

To address food production challenges and combat heavy metal toxicity, an economically viable and sustainable approach is essential. Cadmium (Cd) contamination poses risks to crops and human health. Leveraging the structural similarity between zinc (Zn) and cadmium, we explored foliar Zn spray's potential to alleviate Cd toxicity and enhance wheat yield. Our field study near Peshawar, Pakistan, during the 2021–2022 winter, employed a split-plot design to investigate Zn's impact on wheat biofortification. Across three wheat varieties (JANBAZ-10, Pirsabak (PS)-2013, PS-2015), four foliar Zn levels (0 %, 0.5 %, 1.0 %, 1.5 % solution) were tested at various growth stages. Pirsabak-2015 exhibited optimal results, with a 1 % foliar Zn treatment producing the highest grain yield (3409 kg ha−1), biological yield (9022 kg ha−1), grains per spike (56), and 1000-grain weight (40.6 g). Application of 1 % biochar also significantly increased grain yield. Zn concentration peaked in grains and leaves with 1.5 % Zn solution, followed by 1.0 % Zn in the PS-2015 cultivar. Moreover, 1 % Zn application enhanced photosynthetic parameters and significantly reduced cadmium concentrations in leaves and grains. Notably, 1.0 % Zn led to improved stress tolerance as indicated by decreased electrolyte leakage and increased superoxide dismutase and peroxidase activities. Applying 1.0 % Zn solution as a foliar spray during different growth stages demonstrates the potential to enhance wheat yield, increase grain Zn content, and mitigate Cd toxicity in Cd-contaminated soil. Further research across diverse cereal crops and climates will help establish 1.0 % Zn foliar spray as an effective Cd stress mitigation strategy.

CsABF3-activated CsSUT1 pathway is implicated in pre-harvest water deficit inducing sucrose accumulation in citrus fruit

Pre-harvest water deficit (PHWD) plays an important role in sugar accumulation of citrus fruit. However, the mechanism is not known well. Here, it was confirmed that PHWD promoted sucrose accumulation of citrus fruit, but had limited effect on fructose, glucose and total acid. A sucrose transporter, CsSUT1, which localizes to the plasma membrane, was demonstrated to function in sucrose transport induced by PHWD. Compared to wild-type, CsSUT1 overexpression in citrus calli stimulated sucrose, fructose and glucose accumulation, while its silencing in juice sacs reduced sucrose accumulation. Increased sugar accumulation in transgenic lines enhanced plant drought tolerance, and resulted in decreased electrolyte leakage, malondialdehyde and hydrogen peroxide contents, as well as increased superoxide dismutase activity and proline contents. An abscisic acid (ABA)-responsive transcription factor, CsABF3, was found with a same expression pattern with CsSUT1 under PHWD. Yeast one-hybrid, electrophoretic mobility shift assay and dual-luciferase assays all revealed that CsABF3 directly bound with the CsSUT1 promoter by ABA responsive elements. When CsABF3 was overexpressed in citrus calli, the sucrose, fructose and glucose concentration increased correspondingly. Further, transgenic studies demonstrated that CsABF3 could affect sucrose accumulation by regulating CsSUT1. Overall, this study revealed a regulation of CsABF3 promoting CsSUT1 expression and sucrose accumulation in response to PHWD. Our results provide a detail insight into the quality formation of citrus fruit.

Starch/carboxymethyl cellulose-based photodynamic packaging material delays the quality deterioration of snap beans via ROS metabolism regulation

Snap beans (Phaseolus vulgaris L.) are prone to rapid senescence and quality deterioration during postharvest storage. In this study, the effect of a novel carbon dot/g-C3N4-mediated starch/carboxymethyl cellulose-based photodynamic film (CCPF) on the postharvest quality deterioration and reactive oxygen species (ROS) metabolism of snap bean pods was investigated. CCPF packaging influenced gas composition regulation, ethylene degradation and microbial infection, which resulted in snap bean pods with lower respiratory metabolism and less quality loss. In addition, the snap bean pods in the CCPF group maintained the content of nonenzymatic antioxidants, low activities of pro-oxidative enzymes and high activities of antioxidant enzymes compared to other groups, thus decreasing electrolyte leakage, malondialdehyde accumulation, H2O2 accumulation and the O2·- generation rate. Overall, CCPF packaging effectively delayed postharvest senescence and extended the shelf life of snap beans by reducing respiration and regulating ROS metabolism. Pearson’s correlation analysis confirmed that postharvest senescence correlated with ROS metabolism in snap bean pods. This study offers theoretical evidence for a method to preserve snap bean pods and can be used as a valuable reference for the practical application of novel CCPF packaging.

Melatonin seed priming improves growth and physio-biochemical aspects of Zinnia elegans under salt stress

Salt stress is a major abiotic aspect that inhibits plant development, growth, and productivity of ornamental plants. In recent years, there has been a lot of interest in seed priming and biological treatments for salt stress mitigation in plants. Melatonin (MLT) is a versatile signaling molecule detected in higher plants. Its function is involved in various signaling and physiological processes, particularly under severe environmental conditions. The aim of this study was to assess the performance of different levels of MLT (0, 1, 10, 20 μM) primed zinnia plants (Zinnia elegans cv. ‘Super Yoga’) under salt stress (100 mM NaCl). Salt stress exposure reduced growth and physiological variables and increased oxidative stress, recorded as a rise in stress markers. The results showed that seed priming with MLT improved morphological characteristics of zinnia, such as shoot and root length, shoot diameter, leaf length, root collar diameter, number of roots, root fresh, and dry weight. MLT based seed priming also increased photosynthesis pigments and reduced salt induced oxidative damage by enhancing the activity of antioxidant enzymes (i.e. superoxide dismutase-SOD, peroxidase-POD, and catalase-CAT). The reduction in oxidative stress was recorded as decrease in electrolyte leakage (EL), hydrogen peroxide (H2O2), and malondialdehyde (MDA). Primed plants also showed significant increase in the osmoprotectants proline and glycine betaine, as compared to the non-primed salt stress plants. Exposure of plants to salt stress lead to an increase in sodium (Na+) and potassium (K+) contents in plant tissues in the non-primed plants. However, priming with MLT reduced the uptake of Na+ and improved the uptake of K+ in the leaves of zinnia. Overall, these results provided evidence that MLT seed priming may ameliorate the ill effects of salt-induced oxidative stress in zinnia plants.

Cyclic guanosine monophosphate improves salt tolerance in Solanum lycopersicum

The cyclic nucleotide cyclic guanosine monophosphate (cGMP) is a powerful cell signaling molecule involved in biotic and abiotic stress perception and signal transduction. In the model plant Arabidopsis thaliana, salt and osmotic stress rapidly induce increase in cGMP which plays role by modulating the activity of monovalent cation transporters, possibly by direct binding to these proteins and by altering the expression of many abiotic stress responsive genes. In a recent study, a membrane permeable analogue of cGMP (8-bromo-cGMP) was found to have a promotive effect on soluble sugar, flavonoids and lignin content, and membrane integrity in Solanum lycopersicum seedlings under salt stress. However, it remains to be elucidated how salt stress affects the endogenous cGMP level in S. lycopersicum and if Br-cGMP-induced improvement in salt tolerance in S. lycopersicum involves altered cation fluxes. The current study was conducted to answer these questions. A rapid increase (within 30 s) in endogenous cGMP level was determined in S. lycopersicum roots after treatment with 100 mM NaCl. Addition of membrane permeable Br-cGMP in growth medium remarkably ameliorated the inhibitory effects of NaCl on seedlings’ growth parameters, chlorophyll content and net photosynthesis rate. In salt stressed plants, Br-cGMP significantly decreased Na+ content by reducing its influx and increasing efflux while it improved plants K+ content by reducing its efflux and enhancing influx. Furthermore, supplementation with Br-cGMP improved plant’s proline content and total antioxidant capacity, resulting in markedly decreased electrolyte leakage under salt stress. Br-cGMP increased the expression of Na+/H+ antiporter genes in roots and shoots of S. lycopersicum growing under salt stress, potentially enhancing plant’s ability to sequester Na+ into the vacuole. The findings of this study provide insights into the mechanism of cGMP-induced salt stress tolerance in S. lycopersicum.