Different Concentrations Of Salicylic Acid Research Articles

Physico-Chemical Responses of Alstroemeria spp. cv. Rebecca to the presence of Salicylic Acid and Sucrose in vase solution during postharvest life.

The primary challenge in the cut flower industry, specifically in the postharvest phase, is the short vase life of flowers. This issue, along with early leaf yellowing and perianth abscission, significantly diminishes the economic value of flowers due to their accelerated senescence. To tackle this, we conducted a factorial experiment on Alstroemeria cv. Rebecca, utilizing a completely randomized design with three replications. In this experiment the effects of varying concentrations of Salicylic acid (SA) (0, 1.5, and 3mM) and sucrose (SU) (0% and 3%) were investigated on the postharvest quality of leaves and florets, with systematic evaluations every three days throughout their vase life. This experiment revealed that the specific treatment combination of 1.5mM SA + 3% SU (T5) markedly improved various parameters, such as vase life, total chlorophyll content, membrane stability index, relative fresh weight, and water uptake of cut flowers. In our analysis, we observed that this preservative solution not only extended the vase life and enhanced water uptake but also effectively preserved total chlorophyll, mitigated the loss of fresh weight, and reduced membrane deterioration in petals. Additionally, our results showed an increase in the activities of catalase (CAT) and peroxidase (POD) enzymes, as well as total protein content, alongside a decrease in malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels. Moreover, this study noted a decrease in microbial populations in solutions containing different concentrations of salicylic acid. Our research demonstrated that alstroemeria flowers maintained in a solution with 1.5mM SA + 3% SU exhibited a significantly prolonged vase life of up to 21days, in contrast to the 15days observed in control flowers kept in water. These results are highly beneficial for manufacturers in the cut flower industry, as they provide a viable method to substantially extend the vase life of cut flowers. Such an enhancement in flower longevity can lead to increased market value and customer satisfaction. Furthermore, the reduction in flower senescence and decay rates can contribute to decreased waste and greater efficiency in cut flower distribution and sales, offering a substantial advantage to manufacturers in this competitive market. The extended vase life and reduced senescence observed in alstroemeria flowers treated with 1.5mM SA and 3% SU are attributed to SA's role in enhancing endogenous defense responses and sucrose's function as an energy source, collectively improving water uptake, and delaying the natural decay process.

Utilizing Plant-Derived Salicylic Acid to Inhibit Leafminer Moth (Noorda blitealis Walker) Infestation on Moringa Oleifera

The experimental trial was conducted at Sakab Farm Limited Satame, Makoda Local Government. Kano State (12°18’20’’N, 8°36’30’’E / 12°16’0’’N, 8°27’50’’E), from October, 2021 to November, 2022. The experiments were established in various field cages in a split plot design with various levels of Salicylic acid (SA) treatments representing the main plots and the spray regimes: 1 weeks after spray (1-WAS), 2 weeks after spray (2-WAS) and 3 weeks after spray (3-WAS), as subplots. Different Concentrations of SA (5mg/l, 10mg/l and 20mg/l) were extracted from plant sources and formed by serial dilution. Ten freshly emerged larvae of Noorda blitealis collected from infested fields were introduced into each of the treatment group containing the treated stands of drumstick. The set up was undisturbed but observed at regular intervals. The results shows that, mean percentage leaves damage varied significantly (P<0.001) among different concentrations of SA and the spray regimes. Larval development time was significantly (P<0.05) prolonged in the higher concentration (20mg/l. SA) and median spray regime (2-WAS). The mean percentage leaves damage and progeny emergence of the moths were considerably low at the same treatment combinations. Moringa plants treated with higher concentrations of SA were also less infested and apparently more tolerant than the other treatments owing to their lower index of susceptibilities. This facility should be incorporated into the integrated control for effective management of Insect pest.

Salicylic acid and putrescine treatments reduce yellowing, decay and retain postharvest quality of bitter gourd (Momordica charantia L.) during cold storage

Bitter gourd is a valuable cucurbitaceous vegetable rich in various beneficial phytochemicals such phenols, antioxidants, saponins, charantin etc. In spite of high medicinal value bitter gourd faces significant postharvest losses due to factors such as mass reduction, tissue softening, yellowing, and fungal contamination, especially when stored under ambient conditions. To combat these issues, immature green bitter gourd fruits (16 DAP) were subjected to different concentrations of salicylic acid (SA) at 5, 7.5, and 10 mM) and putrescine (PUT) at 1, 2, and 3 mM, through a 15-minute dipping process. In contrast, untreated fruits were dipped in distilled water and served as the control group. These treated and control fruits were subsequently stored at 10 ºC with a relative humidity range of 85–95 % for 20 days. Results showed that among all treatments, bitter gourd fruits treated with 10 mM SA exhibited the most noteworthy outcomes. They retained higher levels of total phenols (26.28 μg GAE 100 g-1), radical scavenging activity (27.95 %), ascorbic acid content (50.0 mg 100 g-1 FW), and total chlorophyll (0.32 mg g-1 FW) on the 20th day of storage. Additionally, the 10 mM SA treatment demonstrated the highest inhibition of α-amylase and α-glucosidase activity, as well as the lowest decay percentage when compared to the control. On the other hand, 3 mM PUT treatment resulted in greater fruit firmness (27.45 N), lower per cent postharvest loss weight (6.60 %), and reduced pectin methyl esterase (PME) activity (0.0075 µmol min-1 g-1 FW). These findings were further validated through principal component analysis (PCA), which highlighted that bitter gourd fruits could be effectively stored for up to 20 days at 10 ºC with pre-storage treatment involving 10.0 mM SA and 3.0 mM PUT. Overall higher quality and shelf-life of bitter gourd were obtained in bitter gourd treated with 10.0 mM SA. Consequently, it is recommended that the application of SA and PUT represents an environmentally friendly approach to preserve the quality of bitter gourd during storage, benefiting both retailers and consumers alike.

Antimicrobial effects of Arctium lappa against infectious bacteria: Experimental in vitro analysis

Arctium lappa (A. lappa) is one of the most significant edible medicinal plants with high antibacterial effects, in which it could be supposed to grow with more beneficial effects under administration by salicylic acid and chitosan based biofertilizers. Accordingly, the effects of salicylic acid, chitosan, and 50% moisture discharge were investigated in this work to see the antimicrobial treatments of some foodborne pathogens effects by A. lappa. To this aim, plants were cultivated based on different concentrations of salicylic acid and chitosan with/without drought stress, in which their extracted essential oils were examined for showing the antimicrobial effect against different bacterial agents. The results indicated that the salicylic acid and chitosan administrated A. lappa could work with improved inhibitory functions. Comparing with referenced antibiotics showed even higher antimicrobial effects of A. lappa against the targeted bacterial agents, in which the species with 14 mmol of salicylic acid and 2 g/l of chitosan was a distinguished one for approaching the purpose. Consequently, the achievements of this work could be further investigated for producing novel antibiotic drug agents.

Response Growth and Yield of Three Broad Bean Cultivars (Vicia faba L.) to Spraying with Different Concentrations of Salicylic Acid Under Saline Soil Conditions

South of Babylon province, at 32 degrees 40 minutes north latitude and 44 degrees 39 minutes east longitude, was the site of a field experiment run by the College of Agriculture at Al-Qasim Green University during the winter of 2022-2023. Three broad bean varieties were tested for their reactions to salicylic acid sprays of varying doses in saline soil. The experiment was conducted with a split plot arrangement according to The Randomized Complete Block Design (RCBD) with three replicates. The experiment included two factors: The first important factor was the cultivation of three cultivars of broad beans (Turkish, Spanish, and Dutch) which were placed in the main plot. As for, the sub-plot was included three concentrations of salicylic acid: control treatment, the spraying treatment with 100 mg L-1, and the spraying treatment with 200 mg L-1. The results showed that the Turkish cultivar was significantly excelled in the studied trait of plant height (118.46 cm), the number of branches (branch-1), and the biological yield (4.81 tons. ha-1), while the Spanish cultivar was excelled in leaf area (2505.8 cm2) and the number of pods (21.74 pods. plant -1), seed yield (2.49 ton. ha-1), and harvest index (56.15%). Where spraying with salicylic acid was significantly excelled on 200 mg L-1 in the studied traits for plant height (97.08 cm), the number of branches (10.87 branch.plant-1), the leaf area (2363.7 cm2), the number of pods (23.01 pods plant-1), seed yield (2.40 ton.ha-1), and the harvest index (49.23%).

Exogenous Salicylic Acid Alleviates NO2 Damage by Maintaining Cell Stability and Physiological Metabolism in Bougainvillea × buttiana 'Miss Manila' Seedlings.

Exogenous substances can alleviate plant damage under adverse conditions. In order to explore whether different concentrations of salicylic acid (SA) can play a role in the resistance of Bougainvillea × buttiana 'Miss Manila' to nitrogen dioxide (NO2) stress and the relevant mechanisms of their effects, different concentrations of SA were applied locally under the control experiment condition of 4.0 μL·L-1 NO2, and the role of SA in alleviating injury was studied. The findings noted a significant increase in metabolic adaptations and antioxidant enzyme activities following 0.25-0.75 mM SA application (p < 0.05), except 1 mM. Superoxide dismutase (SOD) and catalase (CAT) in particular increased by 21.88% and 59.71%, respectively. Such an increase led to effective control of the reduction in photosynthetic pigments and the photosynthetic rate and protection of the structural stability of chloroplasts and other organelles. In addition, the activity of nitrate reductase (NR) increased by 83.85%, and the content of nitrate nitrogen (NO3--N) decreased by 29.23% in nitrogen metabolism. Concurrently, a principal component analysis (PCA) and a membership function analysis further indicated that 0.75 mM SA provided the most notable improvement in NO2 resistance among the different gradients. These findings suggest that 0.25-0.75 mM SA can relieve the stress at 4 μL·L-1 NO2 injury by effectively improving the antioxidant enzyme activity and nitrogen metabolizing enzyme activity, protecting the photosynthetic system and cell structure, but 1 mM SA had the opposite effect. In the future, the specific reasons for inhibition of SA at high concentrations and the comprehensive effects of the application of other exogenous compounds should be further studied.

The Effects of Foliar Salicylic Acid and Zinc Treatments on Proline, Carotenoid, and Chlorophyll Content and Anti-Oxidant Enzyme Activity in Galanthus elwesii Hook

Galanthus elwesii Hook. is an important plant species of the Amaryllidaceae family and is used for the medicinal purposes of its valuable bioactive compounds. The present study was conducted to investigate the effects of foliar salicylic acid (SA) and zinc (Zn) treatments on the proline, carotenoid, and chlorophyll content and the anti-oxidant enzyme activity in G. elwesii. The ascorbate peroxidase (APX) enzyme activity, catalase (CAT) enzyme activity, and protein contents were determined with ascorbate oxidation, hydrogen peroxide (H2O2), and Bradford experiments, respectively. The plants were treated with three different concentrations of SA (0.5, 1, and 2 mM) and Zn (40, 80, and 120 mM) and were compared with the control. Fresh leaves were harvested in the study. APX (3.99 ± 0.58 EU/mg protein) and CAT (154.64 ± 4.10 EU/mg protein) were obtained from Zn 80 and 120 mM treatments at the highest level, respectively. The proline, chlorophyll b, and carotenoid content increased 12.4, 1.54, and 3.95-fold, respectively, in 0.5 mM SA treatments, when matched with the control group. It was found that increasing doses of SA and Zn increased the content of malondialdehyde (MDA), but this was not at a significant level. The total chlorophyll content increased 2.27-fold in Zn 120 mM + SA 2 mM treatment and the chlorophyll content increased 2.41-fold in Zn 40 mM + SA 1 mM treatment.

Assessment of chemical compositions and antibacterial activity of the essential oil of Mentha piperita in response to salicylic acid

Mentha piperita, as a species of the mint family, is used in various medical, cosmetic, industrial and culinary products. The effect of different concentrations of salicylic acid (SA) (0. 0.5, 1 mM) on phytochemical activity and antimicrobial potential of Mentha piperita essential oil against six human pathogenic bacteria (Streptococcus agalactiae, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Listeria monocytogenes) were investigated. According to the results to prevent the growth of L. monocytogenes and S. agalactiae, Gram-positive bacteria, peppermint, essential oil treatment with 1 mM salicylic acid is suggested. But to prevent the growth of Gram-negative bacteria P. aeruginosa and E. coli, peppermint essential oil of control plants is proposed. These results showed that salicylic acid elicitor changed the type and amount of peppermint essential oil compounds. Probably, salicylic acid elicitor improved antimicrobial properties of peppermint essential oil with a change in essential oil components. The inhibitory activity of essential oil depends on the type of microorganism, the concentration of essential oil and the concentration and time of salicylic acid treatment.

Foliar application of salicylic acid inhibits the cadmium uptake and accumulation in lettuce (Lactuca sativa L.).

Salicylic acid (SA) is a multi-functional endogenous phytohormone implicated in the growth, development, and metabolism of many plant species. This study evaluated the effects of different concentrations of SA (0, 25, 100, 200, and 500 mg/L) on the growth and cadmium (Cd) content of lettuce (Lactuca sativa L.) under Cd stress. The different concentrations of SA treatments were administered through foliar application. Our results showed that 100-200 mg/L SA significantly increased the plant height and biomass of lettuce under Cd stress. When SA concentration was 200 mg/L, the plant height and root length of lettuce increased by 19.42% and 22.77%, respectively, compared with Cd treatment alone. Moreover, 200 mg/L and 500mg/L SA concentrations could reduce peroxidase (POD) and superoxide dismutase (SOD) activities caused by Cd stress. When the concentration of exogenous SA was 500 mg/L, the POD and SOD activities of lettuce leaves decreased by 15.51% and 19.91%, respectively, compared with Cd treatment. A certain concentration of SA reduced the uptake of Cd by the lettuce root system and the transport of Cd from the lettuce root system to shoots by down-regulating the expression of Nramp5, HMA4, and SAMT, thus reducing the Cd content of lettuce shoots. When the concentration of SA was 100 mg/L, 200 mg/L, and 500 mg/L, the Cd contents of lettuce shoots were 11.28%, 22.70%, and 18.16%, respectively, lower than that of Cd treatment alone. Furthermore, principal component and correlation analyses showed that the Cd content of lettuce shoots was correlated with plant height, root length, biomass, antioxidant enzymes, and the expression level of genes related to Cd uptake. In general, these results provide a reference for the mechanism by which SA reduces the Cd accumulation in vegetables and a theoretical basis for developing heavy metal blockers with SA components.

Effect of foliar application of different concentrations of salicylic acid on Washington navel orange trees under water stress

BackgroundA field experiment was performed from 2021 to 2022 on 10-year-old Washington navel orange trees (Citrus sinensis) budded on sour orange rootstock (Citrus aurantium) under sandy loam soil conditions in the region of Belbeis—El Sharkia Governorate, Egypt. This study was carried out to increase water use efficiency, maximize water utilization and determine the most effective treatment of Washington navel orange trees by using different concentrations of salicylic acid (control, 250, 500, and 750 ppm) under some levels of water stress (100, 75 and 50% of estimated crop water requirement).ResultsIn this scenario, the water use efficiency increased with 750 ppm of salicylic acid under 75% of the estimated crop water requirement, which produced 2.27 and 3.09 kg of fruit for each cubic meter of irrigation water in the first and second seasons, respectively. In addition, using salicylic acid treatment with 750 ppm under 75% of the estimated crop water requirement had a high economic return through increasing water unit return, while using less water irrigation amount by 25% at the same time, which reached 9.06 and 12.38 EGP per every cubic meter of irrigation water in the first and the second seasons, respectively.ConclusionIn summary, the data cleared that the irrigation water quantity could reduce by 25% while maintaining the production and the possibility of increasing it by using salicylic acid with the highest concentration. Thus, we recommend applying the treatment of the estimated crop water requirement with 75% combined with salicylic acid 750 ppm to Washington navel orange trees budded on sour orange rootstock to gain a high economic return.

Effects of Three Exogenous Substances on Heat Tolerance of Peony Seedlings

In this study, one-year-old seedlings of Paeonia ostii ‘Fengdan’ were used as materials. The method of spraying exogenous salicylic acid (SA), calcium chloride (CaCl2) and abscisic acid (ABA) was used. The effects of different concentrations of SA, CaCl2 and ABA on the heat tolerance of peony seedlings under high temperature stress were studied. The optimum concentration and mechanism of SA-, CaCl2- and ABA-induced heat tolerance of peony seedlings under high temperature stress were discussed. The results showed that 100 μmol/L SA, 40 mmol/L CaCl2 and 40 mg/L ABA had the best induction effect on the heat tolerance of peony. The effects of three exogenous substances on the heat resistance of peony seedlings were ranked as SA &gt; CaCl2 &gt; ABA. The three exogenous substances mainly alleviated high temperature damage by alleviating the degradation of chlorophyll (Chl), relative electrical conductivity (Rec) content, increasing superoxide dismutase (SOD) activity, soluble proteins (SPs), free proline (Pro) and soluble sugars (SSs) content, and reducing SSs content under high temperature stress. The five indices had the most significant effect on the three exogenous substances in improving the heat resistance of peony seedlings. These could be used as an index to identify the heat resistance.

Exogenous Salicylic Acid Induced Drought Stress Tolerance in Immature Tea (&lt;em&gt;Camellia sinensis&lt;/em&gt; L.) Plants

Salicylic acid (SA) has been known to induce drought tolerance in many plant species. In this study, we investigated the potential of exogenous application of SA to enhance drought tolerance in immature tea plants under glasshouse conditions at the Tea Research Institute in Talawakelle, Sri Lanka. One-year-old potted tea cultivars known for drought tolerance were used in the study. The plants were subjected to a drying cycle while being foliar sprayed with different concentrations of SA along with well-watered (WW), water-spray (WS) and no-spray (NS) treatments. Data were collected at 18 hours, 14 days after spraying (DAS), 21 DAS, and during the recovery after re-watering at 21 DAS. Based on the results obtained from the glasshouse study, the effective concentration of 150 mg L-1 SA was selected for further testing under field conditions in Talawakelle using three-year-old tea plants. The field experiment followed a randomized complete block design (RCBD) with three blocks. When the plants reached a moderate moisture stress level, they were foliar-sprayed with 150 mg L-1 SA, WS and NS treatments were included as controls. Data were collected at 7 DAS, 14 DAS, 21 DAS, and during the recovery phase after rain. The results showed that drought stress led to a decline in gas exchange parameters, relative water content, and an increase in the accumulation of osmolytes. However, the exogenous application of 150 mg L-1 SA significantly improved physiological processes such as gas exchange, osmolyte accumulation, and antioxidant activity, thus effectively enhancing drought tolerance in immature tea plants.

Bioactive metabolites from germinated Cajanus cajan (L.) Millsp. seeds after treating with different concentrations of salicylic acid

Salicylic acid (SA) is an effective elicitor for enhancing product formation in various agricultural practices. This study examined the diverse responses to physiological metabolites and the pathway modifications in broad-spectrum resistance-1 (BSR1) of Cajanus cajan after treatment with SA using a metabolomics technique. The significance of the SA function at the metabolite level was examined by treating C. cajan with various concentrations of SA and germinated by soaking in water for different time periods. The secondary metabolites were recovered and investigated by gas chromatography-mass spectrometry for all the periodic conditions. Chemometric analysis of the collected samples showed that the seeds responded to the SA treatment. Acetic acid increased in germinated seeds after the SA treatment. In addition, the up-regulated metabolite production was downregulated in the C. cajan seeds before germination. The levels of metabolites, including hyacinthin, furaneol, citramalic acid, palmitate, stearate, linoleate, tocopherol, glucobrassicin, syringol, and hydroxy acetophenone, were increased after the SA treatment compared to control. Hence, the SA-treated seedling is a potential bio-factory for nutraceutical products to provide significant health benefits to the human population.

The Investigation of the Effect of the Salicylic Acid on the Antioxidant Potential, Vitamin C Content and DNA Protection Activity of Wheatgrass (Triticum aestivum L.)

Wheatgrass is considered as a superfood because of its high antioxidant potential and beneficial ingredients. Especially in recent years, wheatgrass juice and its powder have been tested in vivo animal models and clinical studies against some diseases. Salicylic acid (SA) one of the important phytohormones controlling plant growth is used as an exogenous elicitor to increase plant bioactive compounds. The aim of this study was to investigate antioxidant potential, vitamin C content and DNA protection of wheatgrass grown from SA pre-treated seeds. For this purpose, total antioxidant statue, total oxidant statue, oxidative stress index and vitamin C level were determined. Additionally, pUC19 plasmid was incubated with Fenton’s solution to determine DNA protection activity of lyophilized wheatgrass extract. Bread wheat caryopses were imbibed in different concentrations of SA for 2 hours. Wheatgrass grown from seeds pre-treated with 10-8 M SA had significantly higher total antioxidant statue, vitamin C and soluble protein content than control. It was observed that wheatgrass extracts had a DNA protective role against hydroxyl radicals. It was concluded that SA pretreatment of seeds could be a good approach to increase their antioxidant potential, soluble protein content and vitamin C level of plants used as antioxidant sources by people.

Salicylic Acid Pre-Treatment Reduces the Physiological Damage Caused by the Herbicide Mesosulfuron-methyl + Iodosulfuron-methyl in Wheat (Triticum aestivum)

Chemical herbicides are the most common method of weed control in crops, but they can also negatively affect the host crops, such as wheat (Triticum aestivum L.). The damage caused to the crop plants is often temporary and minor, but sometimes, it can be more substantial, requiring remedial measures. Salicylic acid (SA) is a plant hormone widely used to promote plant growth and to mitigate oxidative stress through its exogenous application. We evaluated the role of exogenously applied SA (as a pre-treatment) in ameliorating the oxidative damage caused by the herbicide mesosulfuron-methyl + iodosulfuron-methyl in wheat plants. The herbicide disrupted the physiological function of plants by affecting several enzymatic antioxidants. The hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents increased at herbicide concentrations higher than 18 g ai ha−1 compared with the untreated control. However, the SA decreased the H2O2 and MDA contents compared with plants that were not treated with SA prior to the herbicide application. The activity of superoxide dismutase (SOD) and polyphenol oxidase (PPO) enzymes increased with increasing rates of the herbicide, as well as over time, regardless of the SA treatment. The activity of catalase (CAT) increased up to the herbicide rate of 18 g ai ha−1 and then decreased at the higher rates, while SA pre-treatment enhanced the CAT activity. The activities of ascorbate peroxidase, peroxidase, and glutathione-S-transferase enzymes generally increased in response to the herbicide application and SA pre-treatment, but fluctuated across different days of sampling following the herbicide application. Herbicide stress also induced high levels of proline production in wheat leaves as compared with the untreated control, while SA pre-treatment decreased the proline contents. Overall, the pre-treatment with different concentrations of SA mitigated the herbicide damage to the physiological functions by regulating the enzymatic antioxidants.

Effects of Salicylic Acid on Heavy Metal Resistance in Eukaryotic Algae and Its Mechanisms.

Heavy metal pollution and water eutrophication are still the main issues to be solved in the environmental field. To find a biological control method for Cd2+-contaminated water or combined eutrophication and Cd2+ pollution water, the effects of salicylic acid on heavy metal Cd2+ resistance in eukaryotic algae Scenedesmus obliquus and Chlorella pyrenoidosa and its mechanisms were studied. The results showed that the inhibition rates of 3.0 mg/L Cd2+ stress group at 96 h were 67.0% on S. obliquus and 61.4% on C. pyrenoidosa and their uptake of Cd2+ was 0.31 mg/g and 0.35 mg/g, respectively. When adding the different concentrations of salicylic acid while stressed by 3.0 mg/L Cd2+, the hormesis phenomenon of low dose stimulation and high dose inhibition could be seen, and the inhibition rates of 30 mg/L~90 mg/L salicylic acid addition groups were significantly lower than those of the Cd2+ stress group alone, which were statistically significant (p < 0.05) and the absorption of Cd2+ was dramatically improved. Except for the 120 mg/L salicylic acid addition group, the chlorophyll fluorescence parameters (Fv/Fm and YII), glutathione peroxidase (GSH-Px) and glutathione-S-transferase (GST) activities of all the other concentration groups were significantly higher than those of the Cd2+ stress group alone, p < 0.05.; the algal cell morphology in low concentration groups (30 mg/L and 60 mg/L) was also less damaged than those in the Cd2+ stress group alone. These indicate that the low concentrations of salicylic acid can counteract or protect the algal cells from Cd2+ attack, the mechanisms, on the one hand, might be related to the chelation of heavy metals by salicylic acid, resulting in the decrease of the toxicity of Cd2+; on the other hand, low concentrations of salicylic acid can stimulate the growth of these two algae, improve their photosynthetic efficiency and antioxidant capacity, as well as maintain the relative integrity of algal morphological structure.

Effects of Salicylic Acid Concentration and Post-Treatment Time on the Direct and Systemic Chemical Defense Responses in Maize (Zea mays L.) Following Exogenous Foliar Application.

Salicylic acid (SA) plays a critical role in allergic reactions of plants to pathogens and acquired systemic resistance. Thus far, although some research has been conducted on the direct effects of different concentrations of SA on the chemical defense response of treated plant parts (leaves) after at multiple post-treatments times, few research has reported on the systematic effects of non-treated parts (roots). Therefore, we examined direct and systemic effects of SA concentration and time following foliar application on chemical defense responses in maize variety 5422 with two fully expanded leaves. In the experiments, maize leaves were treated with different SA concentrations of 0.1, 0.5, 1.0, 2.5, 5.0 mM, and then, the presence of defense chemicals and enzymes in treated leaves and non-treated roots was measured at different time points of 3, 12, 24, 48, 72 h following SA foliar application. The results showed that direct and systemic effects of SA treatment to the leaf on chemical defense responses were related to SA concentration and time of measurement after spraying SA. In treated leaves, total phenolics content increased directly by 28.65% at the time point of 12 h following foliar application of 0.5 mM SA. DIMBOA (2,4-dihydroxy-7-methoxy-2H, 1, 4-benzoxazin-3 (4H)-one) content was directly enhanced by 80.56~551.05% after 3~72 h following 0.5~5.0 mM SA treatments. Polyphenol oxidase and superoxide dismutase activities were directly enhanced after 12~72 h following 0.5~5.0 mM SA treatments, whereas peroxidase and catalase activities were increased after 3~24 h following application of 1.0~5.0 mM SA. In non-treated roots, DIMBOA content and polyphenol oxidase activity were enhanced systematically after 3~48 h following 1.0~5.0 mM SA foliar treatments. Superoxide dismutase activities were enhanced after 3~24 h following 0.5~2.5 mM SA applications, but total phenolics content, peroxidase and catalase activity decreased in some particular concentrations or at the different times of measurement in the SA treatment. It can be concluded that SA foliar application at 1.0 and 2.5 mM produces strong chemical defense responses in maize, with the optimal induction time being 24 h following the foliar application.

Efficacy of fungicide alternatives against late wilt disease of maize and their influence on plant morphogenesis and yield characters

Summary Efficiency of various organic acids, organic salts, essential oils, algae (an extract of Chlorella vulgaris and a commercial product), and bioagents against Magnaporthiopsis maydis, causing maize late wilt disease, was evaluated in laboratory and field conditions. For the in vitro tests, isolated M. maydis field strains from Egypt were used. Additionally, in field experiments different application methods were tested for their efficacy throughout two successive growing seasons. Results showed maximum growth inhibition of M. maydis at different concentrations of salicylic acid, ascorbic acid, benzoic acid and humic acid as well as sodium benzoate, potassium sorbate, di-potassim phosphate and calcium choloride, in descending order. The essential oils of carnation, lemongrass and black seed followed a similar trend. The minimum pathogenic fungal growth was achieved when the pathogen was exposed to the antagonistic Trichoderma viride followed by Trichoderma harzianum, Bacillus subtilis and Pseudomonas fluorescens treatments. Under field conditions, the highest disease reduction was recorded after treatment with salicylic acid (all application methods), humic acid (all application methods), sodium benzoate (seed dressing), carnation oil (seed dressing or seed dressing +foliar spray) and the bioagents B. subtilis and P. fluorescens (soil drench). Overall, all treatments and all application methods led to significant lower disease incidence compared to the untreated control in both growing seasons. Additionally, all treatments achieved an enhancement of plant morpho-genesis and yield characters. The most effective combinations of compounds/bioagents and application methods can be considered for future use in IPM management of late wilt disease of maize.

The Effect of Combining Post-Harvest Calcium Nanoparticles with a Salicylic Acid Treatment on Cucumber Tissue Breakdown via Enzyme Activity during Shelf Life.

In the present study, an experiment was carried out on the postharvest of cucumber fruit during a 14-day shelf life. The aim was to assess the impact of calcium nanoparticles (CaNPs) blended with different concentrations of salicylic acid (SA) on the shelf life of cucumbers during the seasons of 2018 and 2019. The investigation further monitored the influences of CaNPs-SA on some physical properties of cucumber, including the percentage weight loss, color, and fruit firmness. In addition, chemical properties, such as total soluble solids (SSC%), total acidity (TA%), total soluble sugars, and chlorophyll pigmentation of the fruit skin, were assessed during a 14-day shelf lifeCell wall degradation enzymes (CWEAs) such as polygalacturonase (PG), cel-lulase (CEL), xylanase (XYL), and pectinase (PT) were also researched. In addition, the generation rates of H2O2 and O2•− were calculated, as well as the reduction of DPPH. The lipid peroxidation (malondialdehyde, MDA) and cell membrane permeability (IL%) of cell wall composites were also determined. CaNPs-SA at 2 mM suppressed CWEAs, preserved fruit quality, reduced weight loss throughout the shelf-life period, and reduced the percent leakage value. At this concentration, we also found the lowest levels of MDA and the highest levels of DPPH.

Salicylic Acid Treatment Reduces Lipid Peroxidation and Chlorophyll Degradation and Preserves Quality Attributes of Pointed Gourd Fruit

The marketability of pointed gourd fruit is drastically reduced after harvest due to moisture loss, chlorophyll degradation, yellowing of the skin, and shriveling. The present investigation studied the effect of exogenous salicylic acid (SA) treatment on senescence and fruit quality attributes of pointed gourd during storage under ambient conditions. Fruits were treated by immersing them in different concentrations of SA (1.0 mM, 2.0 mM, and 3.0 mM) and distilled water (control) for 5 minutes. The investigation showed beneficial effects of 3.0 mM SA treatment in lowering weight loss (16.8%), maintaining higher chlorophyll (32.8%) in the skin, and reducing lipid peroxidation (20.2%) compared to the control. SA (3.0 mM)-treated fruits retained 15.3% higher ascorbic acid and about 18% higher total phenol, flavonoids, and radical scavenging activity over pointed gourd fruits in the control group. However, significant difference in the total antioxidant capacity after 6 days of storage was not noted between SA-treated and control fruit. Thus, postharvest salicylic acid treatment can beneficially be used to extend marketability and delay quality deterioration of pointed gourd fruits stored under ambient conditions.