Article

Comparative Cultivation and Biochemical Analysis of Iceberg Lettuce Grown in Sand Soil and Hydroponics With or Without Microbubbles and Macrobubbles

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Abstract

Freshwater resources comprise only 2.5–2.75% of all water on the Earth, 1.75–2% from them are frozen. We urgently desperately need to conserve water and find an effective alternative agriculture system. Other techniques-agricultural practices and food sources must be used to avoid disasters. We aimed to compare two farming systems (hydroponic with microbubbles or macrobubbles and sand soil) and to find the best system with the lowest cost and high production of low-water plants. We used three hydroponic system: (i) without the application of bubbles (T1), (ii) with the application of microbubbles (T2), (iii) macrobubbles (T3), and the conventional cultivation-based soil (T4). The results show significant differences in the morphological and biochemical parameters of lettuce plants grown in the hydroponic system and conventional cultivation-based soil. The morphological characteristic, chlorophyll, phenol, flavonoid content, enzymatic and non-enzymatic antioxidants, mineral content, and dissolved oxygen were significantly greater in plants grown in the microbubble hydroponic system. In addition, total soluble sugars, proline, and MDA content were significantly greater in plants grown in sand soil (T4) as compared to the plants grown in different hydroponic systems (T1, T2, T3). The results show that the water consumed in the hydroponic system is lower than used in sandy soil. Our findings suggest that the hydroponic system can increase income and reduce the amount of water consumed; therefore, plants grown in hydroponic systems with microbubbles have achieved the best plant growth, secondary metabolites, and antioxidants compared to plants grown in other systems.

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... Plant growth regulators play a key role in different physiological processes during the growth and developmental stages of plants [8][9][10][11][12][13]. Different types of cytokinin including kinetin are known to be more efficient in the proliferation of shoots such as 6-benzylaminopurine "BAP". ...
... The DPPH assay reflects the capability to scavenge free radicals, which incorporates hydrogen radicals from potential antioxidants [10]. Melatonin has been reported to enhanced phytochemical constituents and improved bio-reductive capacity [17]. ...
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Tissue culture technique is one of the best methods to reproduce salvia plant Therefore, the aim of this research was to enhance the in-vitro callus proliferation and production of secondary metabolites of S. moorcroftiana using different combinations of auxin, cytokinin and melatonin. Initially, callus induction was optimized using indole acetic acid (IAA), 2, 4-dichlorophenoxy acetic acid (2,4-D), and naphthalene acetic acid (NAA) applied at different concentrations in combination with 1 mg L-1 of 6-benzylaminopurine (BAP). The results indicates that earliest days to callus induction (14.67 days) was occurred in the media fortified with 2, 4-D+BAP (2.0+1.0 mgL-1). Whereas the highest callus initiation (100%) was induced on MS medium incorporated with 2,4-D+BAP (1+1mgL-1). Furthermore, maximum fresh weight was obtained when 2,4- D + BAP at the rate of (1+ 1mg L-1) was incorporated and dry weight was attained when 2,4- D + BAP at the rate of (2+1 mg L-1) was added to MS media. The maximum fresh and dry weight was obtained when melatonin at rate of 1.5 mg L-1 was supplemented with MS media including 2,4-D + BAP (1+1mg L-1), moreover the maximum DPPH scavenging activity, total phenolic and flavonoid content was noted when supplemented with melatonin at rate of 1.5 mg L-1. In conclusion, among various concentrations of plant growth regulators, 2,4- D + BAP at the rate of (1+ 1mg L-1) along with 1.5 g L-1 melatonin was the best for callus growth and production of secondary metabolites of S. moorcroftiana.
... Moreover, leaf length, leaf width, number of leaves, and leaf area of lettuce increased in the plant applying DO 8.6 mg·L -1 using microbubbles compared to the control plot (DO 6.15 mg·L -1 ) (Abu-Shahba et al., 2021). Vitamin C and water-soluble sugar content were highest in the 15 mg·L -1 treatment plot (Zhou et al., 2019). ...
... Moreover, for lettuce, leaf length, leaf width, number of leaves, and leaf area increased with statistical significance (p ≤ .05) when applying microbubble water with DO concentration of 8.6 mg·L -1 compared to the control plot (DO 6.15 mg·L -1 )(Abu-Shahba et al., 2021). On the other hand, leaf length and leaf width of watercress did not show a significant difference between the control plot and the treatment plot applying microbubbles(Bok et al., 2019).Ahmed et al. (2018) reported ...
Article
Background and objective: The nanobubbles remain stable in water, and it increased dissolved oxygen (DO) in the water that promotes the seed germination and the plant growth. We evaluated the seed germination and growth of sprouts (radish, wheat, and barley) and leafy vegetables (red mustard and pak choi) when irrigated with various DO of nanobubble water (NB).Methods: The oxygen NB was generated by surface friction and treated in 4 levels: NB 0% (control, DO 9.21 mg·L-1), NB 20% (DO 15.40 mg·L-1), NB 33% (DO 20.93 mg·L-1), and NB 100% (DO 39.29 mg·L-1).Results: The root length of radish and wheat increased more in NB 33% than the control plot. The fresh weight increased in NB 33% compared to the control plot in radish and wheat, and both fresh and dry weight increased more in NB 20%, NB 33%, and NB 100% than the control plot of barley. The leaf length and width of red mustard decreased more in NB 33% and NB 100% than the control plot and NB 20%, which indicated the leaf compactness. The fresh and dry weight of shoot and root increased more in NB 100% than the control plot in red mustard. In pak choi, the shoot fresh weight increased more in NB 100% than the control plot. In leafy vegetables, the germination rate of red mustard in NB 100% was higher than the control plot, however, it was not significantly different between oxygen NB plots in sprout vegetables.Conclusion: The results showed that the root growth and biomass increased after applying NB 33% in sprout vegetables. The leaf growth properties as the number of leaves and leaf size were not significantly different or decreased in NB treatments compared to control plots, but NB 100% (DO 39.29 mg·L-1) effectively increased the root growth and plant biomass in leafy vegetables.
... In the low soil fertility problem, there is a global climate change issue (Lehmann and Joseph 2015;Mohamed et al. 2016;Sofy et al. 2020a, b). Climate change has been expected to seriously affect the arid and semi-arid areas, where crop yields will decrease significantly (Mohamed et al. 2018a;Abu-Shahba et al. 2020). The improvement of soil fertility for crops over the years has restricted itself to mineral fertilizer usage, which, if unregulated, will decrease soil organic matter, acidification of soil, and physical soil harm. ...
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... Organic compost also plays an effective role in the management of nematodes. The addition of organic compounds to soil has been shown to be beneficial for soil fertility, plant growth, and disease management [20,21]. Different organic matters are used as organic compost, like animal waste, organic fertilizer, litterfall, and organic amendments that have shown nematotoxic properties against nematodes [20]. ...
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Meloidogyne incognita is a plant pathogen causing root-knot disease and loss of crop yield. The present study aimed to use Trichoderma harzianum as a biocontrol agent against plant-parasitic nematodes and used press mud, which is a solid waste by-product of sugarcane, as a biocontrol agent and biofertilizer. Therefore, the combined application of T. harzianum and press mud may enhance nematode control and plant growth. Elemental analysis of press mud using scanning electron microscopy (SEM) integrated with an Energy Dispersive X-ray (EDX) analyzer revealed the presence of different elements such as C, O, Mg, Si, P, K, Ca, Cu and Zn. In addition, a greenhouse study was conducted to investigate the combined effects of press mud and T. harzianum on M. incognita reproduction and growth and the biochemical features of Psoralea corylifolia. The results showed that plant length, dry biomass, leaf area, the number of seeds per plant, chlorophyll a, chl b, carotenoid content, nitrate reductase, carbonic anhydrase, and nitrogen content were significantly increased (P ≤ 0.05) in the T2 plants (plants were treated with 100 g of press mud + 50 mL T. harzianum before one week of M. incognita inoculation), over inoculated plants (IC). Antioxidant enzyme activity of ascorbate peroxidase (APX), catalase (CAT), perox-idase (POD), and superoxide dismutase (SOD) in the foliage of P. corylifolia was significantly increased when plants were treated with press mud + T. harzianum. A significant reduction in the number of egg masses, nematode population, and root-knot index (RKI) was found in plants with T2 plants. These results suggest that the combined application of T. harzianum and press mud has the potential to control the M. incognita infection and can be used as an environmentally safe alternative to chemical nematicides and also help in the removal of sugarcane waste that causes environmental pollution.
... Citric acid acts as a chelating agent and acidulant, which functionally inhibits poly phenol oxidase (PPO) activity [40]. Sulphate, which acts as a PPO inhibitor, reacts with intermediates to prevent pigmentation [41][42]. Similar results were observed by Hanif et al. [31] who reported that drying time increased by increasing the temperature and rate of mass flow. ...
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Open sun drying of horticultural produce results in contamination due to microbial and fungal attacks and could also be damaged by insects, pests, and rodents. Solar drying through solar collectors is, therefore, an important technique used for the preservation of foods and to extend the shelf life of produce, thereby reducing microbial attack and contamination. Therefore, an experiment was carried out to study the response of the drying kinetics of solar-dried tomatoes to the thin layer of preservatives on the drying and quality attributes. The tomato fruits were treated with natural preservatives (honey and aloe vera) and chemical preservatives (citric acid, sodium benzoate, and potassium meta-bisulfate). The tomato fruits were then kept at three (40, 45, and 50ºC) different temperatures using a parabolic trough solar air heater for drying purposes. Both the drying temperature and preservative levels significantly (P< 0.001) affected the drying and quality traits of tomato slices. At a temperature of 50 ºC and with citric acid as a preservative, the tomato attained the best average results for moisture lost hr-1, drying time, drying rate, total soluble solids (TSS) °Brix, fruit juice pH, titratable acidity (%) and vitamin C. Based on the average maximum results, 50°C temperature and citric acid as a coating material could be considered for attaining better quality attributes of dried tomatoes. A two-term exponential model on the moisture ratio of tomatoes was found to fit for correlation and regression.
... Plant nutrients are readily available in hydroponics systems through nutrient solution for easy plant uptake. As a result, lettuce and spinach biomass production was significantly influenced by hydroponic cultivation over conventionally grown system (Abu et al., 2021). ...
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The present study evaluated the growth response, yield and nutritional quality of lettuce and spinach grown in different hydroponic systems viz. circulated nutrient film technique (NFT) system and non-circulated system and compares them with conventional open field condition. Lettuce and spinach both exhibited significant improvement in leaf area, fresh weight and yield in NFT system of hydroponics compared to open field condition. However, plant height, root length and number of leaves per plant did not differ significantly among the treatments. There was 169 and 107% higher lettuce yield in NFT and non-circulating system, respectively, whereas the corresponding increase in spinach was 190 and 124%. Significantly higher content of nitrate, phosphorus and sulphur was observed in hydroponically grown lettuce and spinach, especially in NFT system. Higher soluble sugar content in hydroponic spinach as well as in lettuce indicated better quality produce in hydroponic system which affects the sweetness and crispness of leafy vegetables. Overall, from the study it can be said that NFT system of hydroponics is performing better than other growing systems for rapid harvesting, higher productivity and quality produce of leafy vegetables. Since NFT system requires small space, this system may be promoted in urban areas of India as an alternative to conventional farming.
... Chemical compounds that have unique physiological effects on human health remain in the plant's storage organs. Alkaloids, flavonoids, and phenolic compounds are the most common bioactive ingredients (Abu-Shahba et al. 2021;El-Beltagi et al. 2018;Saraf 2010;Sofy et al. 2021a). The antimicrobial properties of these various extracts are important. ...
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In the current study, the polyurethane acrylate (PUA) polymer was synthesized by the addition reaction between an isophorone diisocyanate (IPDI) and 2-hydroxyethyl acrylate and cured by polyol. Different properties of the synthesized PUA were determined through diverse analysis methods. The polyurethane acrylate (PUA)/natural filler-based composite (rhizome water extract of Costus speciosus) was prepared as an antifouling agent. The results revealed that the lowest weight loss percentages were detected at 2 wt% PUA/natural filler composite loadings with Escherichia coli (ATCC 23,282) and Pseudomonas aeruginosa (ATCC 10,145). The decreased weight loss percentage may be attributed to the well dispersed natural composite resulting in a slippery surface that can prevent fouling adhesion. It was concluded that the PUA/natural filler composite might be considered an eco-friendly and economical solution to the biofouling problem. Key points • A novel strategy for anti-biofouling. • A new composite reduced Gram-negative bacteria.
... Hydrogen peroxide is one of the most effective, toxic, devastating ROS and more stable than the others (Quan et al. 2008;Abu-Shahba et al. 2021). Free radicals and cellular damage broke the balance between ROS formation and accumulation (Aly et al. 2013). ...
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Acid rain is one of the major environmental problems that causes plant morphological and physiological disorders. But there are few studies about the impact of acid rain on vegetable crops. This work aimed to study the various effects of simulated acid rain (SAR) at different levels of pH (5.0, 4.5, 4.0, 3.5 or 3.0) on growth, yield, pigment content, protein, carbohydrate, water content in leaves, minerals (NPK), oxidative damage and the activity of various antioxidants in pumpkin. The results show that the plant growth, yield, chlorophyll, carotenoids, protein, carbohydrates, leaf water content, NPK in the leaves of the pumpkin crop decreased significantly with increasing levels of acidity of SAR as compared to the untreated set. H2O2 and MDA are increased by SAR treatment which depends on the level of pH value of SAR. The highest value of hydrogen peroxide and malondialdehyde was recorded at pH 3.0 and lower at pH 5.0 of SAR treatment on the pumpkin crop. In contrast, superoxide dismutase, catalase, nitrate reductase and proline contents were accumulated at pH 3.0 and degraded at pH 5.0 of SAR treatment on pumpkin as compared to control. In conclusion, our findings suggest that pumpkin produces more reactive oxygen species (ROS) scavenging SAR stress through the production of enzyme and non-enzyme antioxidant compounds at 3.0 pH. Meanwhile, growth inhibition as well as the photosynthesis of pumpkin and the magnitude of oxidative damage increased as acidity increased (pH 3.0 of SAR).
... An increase in proline content was recorded in response to Cd toxicity in plants (Dinakar et al. 2008). Proline can minimize the dangerous effects of ROS by acting as a lipid peroxidizing inhibitor, a radical hydroxyl scavenger, and a singlet oxygen scavenger (Mohanty and Matysik 2001;Abu-Shahba et al. 2021). The increase in the potassium in faba bean plants irrigated with Cd and Pb and inoculated with endophytic fungi might play a positive role in plant cell metabolism and be a key part of oxidative stress reactions by helping to synthesize glutathione (GSH) related to stress tolerance (Khan and Lee 2013). ...
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Phytoremediation is an important solution to soil pollution management. The goal of this study is to determine the biosorption ability of the two selected fungi (Aspergillus niger and Penicillium chrysosporium) under heavy metal stress on faba bean plants. The fungal strains produced phytohormones, siderophore, ACC deaminase, and secondary metabolites. The biosorption capacity of A. niger and P. chrysosporium was 0.09 and 0.06 mg g−1 and 0.5 and 0.4 mg g−1 in media containing Cd and Pb, respectively. Fourier transform infrared spectroscopy of the fungal cell wall show primary functional groups like hydroxyl, amide, carboxyl, phosphoryl, sulfhydryl, and nitro. Therefore, A. niger and P. chrysosporium were inoculated to soils, and then the faba bean seeds were sown. After 21 days of sowing, the plants were irrigated with water to severe as control, with 100 mg L−1 of Cd and 200 mg L−1 of Pb. The results show that Cd and Pb caused a significant reduction in morphological characteristics, auxin, gibberellins, photosynthetic pigments, minerals content, and antioxidant enzymes as compared to control plants but caused a substantial boost in abscisic acid, ethylene, electrolyte leakage, lipid peroxidation, glutathione, proline, superoxide dismutase, secondary metabolites, and antioxidant capacity. In inoculated plants, metal-induced oxidative stress was modulated by inhibiting the transport of metal and decreased electrolyte leakage and lipid peroxidation. Finally, the inoculation of endophytic fungi contributed actively to the absorption of heavy metals and decreased their content in soil and plants. This could be utilized as an excellent technique in the fields of heavy metal–contaminated sustainable agriculture.
... Fertilizer usage has skyrocketed in recent years throughout the globe, creating severe environmental issues [14]. In addition, increased fertilizer usage in soil and plant systems may lead to the accumulation of heavy metals in the food supply chain [15]. ...
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Herein, a novel chitosan/silver/Mn0.5Mg0.5Fe2O4 (Cs/Ag/MnMgFe2O4) nanocomposite was synthesized with gamma irradiation assistant. The prepared Cs/Ag/MnMgFe2O4 nanocomposite was characterized via EDX, XRD, SEM, UV–vis spectroscopy. To evaluate the effects of soak low and high-dose nanocomposite on physiological parameters, photosynthetic pigments, antioxidant and non-antioxidant enzymes of cabbage under Cd stress, a factorial experiment was conducted based on CRD with five replications. The Cd stress decreased the morphological characteristics and photosynthetic pigments while increasing cabbage's antioxidant and non-antioxidant enzymes. The application of low and high-dose of nanocomposite decreased Cd content in leaves by about 42.86%, 60.48%, and the root by approximately 18.72%, 28.72%, respectively, and translocation factors and tolerance index, H2O2, O2, and malondialdehyde. In contrast, the application of high of the nanocomposite increased the values of SPAD chlorophyll about 27.50%, stomatal conductance about 87.18%, net photosynthetic rate about 44.90%, intercellular CO2 concentration about 32.00%, and transpiration rate about 85.20%, as compared to Cd stress. Furthermore, the application of low and high-dose Cs/Ag/MnMgFe2O4 nanocomposite enhances the antioxidant and non-antioxidant enzymes of the cabbage plant compared to Cd stress. Generally, it was conducted that Cs/Ag/MnMgFe2O4 nanocomposite can be used as a proper tool for increasing cabbage plants under Cd stress.
... Similar results were recorded in Batavia-type lettuce plants, where proline content was lower under full irrigation condition for almost all the tested biostimulants (except for Si and VP treatments where proline content increased compared with rain-fed conditions but decreased over the deficit irrigation regime; Table 6). Considering that free proline content is associated with the non-enzymatic antioxidant defense system of plants, our findings indicate that specific biostimulants may alleviate water-stress effects by inducing the accumulation of proline which acts as an osmoprotectant under stress conditions, modulates the activities of antioxidant enzymes and the subcellular functions, or acts as a cleansing molecule of reactive oxygen species [34,77]. Moreover, according to Malejane et al. [53] and Adhikari et al. [54], a variable response to water stress should be expected between different lettuce genotypes, which is in agreement with our results since the tested genotypes showed a variable content of free proline concerning the irrigation regime and biostimulant application. ...
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Τhe aim of this study, was to examine the potential of using biostimulant for the amelioration of deficit irrigation effects on field grown lettuce plants growth parameters (cv. Doris (Romaine type) and cv. Manchester (Batavia type)). Therefore, five biostimulatory products which differed in their composition were evaluated, including seaweed extracts, amino acids, humic and fulvic acids, macronutrients, Si and vegetable proteins, while a control treatment with no biostimu-lants were applied on plants was also considered. Plants were subjected to three irrigation re-gimes e.g. rain-fed plants (RF), deficit irrigation (I1; 50% of field capacity) and normal irrigation (I2; 100 of field capacity). The results indicate that the application of seaweed extracts, macronu-trients and amino acids (SW treatment) alleviated the negative effects of deficit irrigation on plant growth and chlorophyll content of Romaine type plants. On the other hand, Batavia type plants were more susceptible to water stress, since the highest crop yield plant was observed under the full irrigation treatment and the application of vegetal proteins and amino acids (VP treatment). In general, the application of biostimulants on the Romaine type improved plant growth under water shortage conditions compared to fully irrigated plants in almost all meas-urements, whereas the Batavia type plants appeared to be more sensitive to deficit irrigation. Therefore, the ecofriendly practices of deficit irrigation and biostimulant application could be useful in leafy vegetable production on a genotype depended manner
... Citric acid acts as a chelating agent and acidulant, which functionally inhibits poly phenol oxidase (PPO) activity [40]. Sulphate, which acts as a PPO inhibitor, reacts with intermediates to prevent pigmentation [41][42]. Similar results were observed by Hanif et al. [31] who reported that drying time increased by increasing the temperature and rate of mass flow. ...
Article
Full-text available
Open sun drying of horticultural produce results in contamination due to microbial and fungal attacks and could also be damaged by insects, pests, and rodents. Solar drying through solar collectors is, therefore, an important technique used for the preservation of foods and to extend the shelf life of produce, thereby reducing microbial attack and contamination. Therefore, an experiment was carried out to study the response of the drying kinetics of solar-dried tomatoes to the thin layer of preservatives on the drying and quality attributes. The tomato fruits were treated with natural preservatives (honey and aloe vera) and chemical preservatives (citric acid, sodium benzoate, and potassium meta-bisulfate). The tomato fruits were then kept at three (40, 45, and 50ºC) different temperatures using a parabolic trough solar air heater for drying purposes. Both the drying temperature and preservative levels significantly (P< 0.001) affected the drying and quality traits of tomato slices. At a temperature of 50 ºC and with citric acid as a preservative, the tomato attained the best average results for moisture lost hr-1, drying time, drying rate, total soluble solids (TSS) °Brix, fruit juice pH, titratable acidity (%) and vitamin C. Based on the average maximum results, 50°C temperature and citric acid as a coating material could be considered for attaining better quality attributes of dried tomatoes. A two-term exponential model on the moisture ratio of tomatoes was found to fit for correlation and regression.
... Plants exposed to biotic or abiotic stress experience deregulation or interruption of electrical transport chain, resulting in the overproduction of highly oxidized ROS and cell damage [69,70]. Plants are naturally resistant to stress because they produce and store antioxidants such as vitamin C, phenolic acids, glutathione, carotenoids, and flavonoids [8,9,71]. Ascorbic acid is a metabolite of significant relevance since it functions in the antioxidant plant protection mechanism, and is a primary substrate for detoxification and stable maintenance in chloroplasts, peroxisome, mitochondria and cell cytosol of reactive oxygen species [3]. ...
Article
Botrytis cinerea is considered one of the most important diseases, causing significant loss of strawberry fruits both before and after harvest. The current study sought to assess the green biosynthesis of calcium and iron nanoparticles from thyme plants as an alternative method to controlling strawberry preharvest diseases. Different concentrations of green synthesized calcium and iron nanoparticles (100 and 200 ppm) were foliar sprayed individually or in combination against B. cinerea. The treatments decreased the growth of B. cinerea. When compared to infected plants, treatment with 200 ppm calcium and iron individually or in combination resulted in a significant reduction in the disease incidence of gray mold. Furthermore, treatment with 200 ppm calcium and iron resulted in significant increases in vitamin content (E, C, A), peroxidase, β-1, 3-glucanase, phenylalanine ammonia lyase cell wall fractions (lignin, cellulose, pectin, hemicellulose), mineral content (Ca²⁺, Fe, N, P, K⁺, Mg²⁺ and Zn²⁺), phenolics, and flavonoids when compared to infected plants. As a result, high concentrations of calcium and iron nanoparticles, individually or in combination, may achieve an acceptable level of disease control while also inducing plant resistance against pathogens.
... This finding is supported by the increased leaf area of both cultivars when treated with PHs. Second, the very different growing systems also have an impact on this parameter: a consensus can be found in the available literature of leafy vegetables and in lettuce in particular grown in hydroponics having-other than the already mentioned advantages-higher leaf numbers compared to traditional soil and substrate-based systems [39][40][41], which is due to a variety of factors that are inherent to soil cultivation, such as suboptimal oxygen and moisture contents, competition from soil organisms and biotic and/or abiotic stresses [42][43][44][45] that are the prime culprits of yield losses. ...
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Lettuce (Lactuca sativa L.) is a leafy vegetable cultivated widely for its fast and year-round production and its beneficial phytochemical content, which may be boosted further by plant biostimulants that are considered eco-sustainable means for enhancing horticultural crop production. A greenhouse experiment was carried out to evaluate the yield and qualitative parameters of two differently pigmented lettuce cultivars grown in a floating raft system either untreated or treated (leaf, root or leaf/root application) with vegetal protein hydrolysates (PHs). For foliar application (F), lettuce plants were sprayed at a dose of 3 mL L−1, whereas for root application, 0.15 (T1) or 0.3 (T2) mL L−1 was applied to the nutrient solution alone or in combination with foliar spray (T1 + F and T2 + F) with the same foliar concentration. Bio-morphometric and production data were collected after harvest. Physiological and plant nutrition assays included leaf gas exchange, leaf fluorescence, SPAD index, mineral content, carotenoids, total phenols, total ascorbic acid content and antioxidant activities. Cultivar-specific reactions to biostimulant application were noted: whilst the green pigmented cultivar thrived under nutrient solution applications and recorded higher yield by 82.7% (T1) or (T1 + F) and 71.7% (T2), the red cultivar thrived under combined treatments, yielding 55.4% (T2 + F) higher than control and providing the most concentrated phytochemical content. These latter treatments also engendered the highest SPAD index, Fv/Fm ratio, CO2 assimilation, stomatal conductance and transpiration. In addition, the T2 + F treatment boosted ‘Canasta’ hydrophilic antioxidant activity (21.9%) and total ascorbic acid (5.6-fold). Nutrient solution treatments alone proved advantageous when compared to foliar treatments, while mixed treatments proved genotype- specific. New research on genotype specificity of biostimulant effects is warranted for future use, in order to rationalize biostimulant application modes and dosages.
... Similarly, the micronutrients and heavy metal contents in seed samples were measured after acid digestion as described by Abu-Shahba et al. [22]. A dry seed sample (0.5 g) was taken into a 50 ml Pyrex flask and 10 ml of nitric acid was added to it and the sample was kept overnight. ...
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Background Knowledge of the genetic diversity and population structure of germplasm collections is an important foundation for crop improvement. Rice production across a broad range of rice-growing environments results in a diverse array of local rice varieties. Many rice varieties have been lost as a result of biodiversity loss and are now grown in Pakistan.Methods and resultsTo protect the biodiversity of rice varieties, an experiment was carried out to check the genetic and morphological variations between 8 exotic and 7 local rice genotypes, using 5 different SSR markers, i.e., RM3, RM259, RM341, RM520, and RM11943. The analysis of morphological and quality traits of rice observed significant variation across genotypes. The results revealed that genotype Irri-Pak attained the highest plant height and primary branch plant-1, while genotype Mushkan produced a higher number of productive tillers and obtained a higher fertility factor (%). Similarly, the highest value for panicle length was observed for genotype Faker-e-Malakand, 1000-grains weight in genotype Calmochi, and maximum days to maturity was noticed in genotype Swati-2014. Moreover, the genotype Brio attained the highest value of stem diameter, while maximum seed length was noted in the genotype Sug Dasi. The highest number of primary branches plant−1 in genotype Ibge-I and secondary branches plant−1 in genotype Calmochi were noticed. A higher concentration of sodium and potassium was observed for the genotype Marte, while the genotype Muskan attained the maximum content of copper. Moreover, the highest concentration of iron in genotype Originario, zinc in genotype JP-5, and cadmium content were noticed in genotype Ibge. Similarly, the dendrogram analysis for quantitative parameters showed three clusters at 74.13% similarities. Whereas all the genotypes of European origin formed a separate cluster. A set of 5 simple sequence repeat primers, covering four chromosomes, amplified a total of 14 alleles and showed 100% polymorphism with an average PIC value ranging from 0.39 to 0.91. The UPGMA cluster analysis separated the 15 rice genotypes into 3 main groups based on 32.5% similarities and the highest genetic distance (45.1%) was observed between two genotypes (Fakher-e-malakand and Musa), having different geographical origins. There was no genetic distance between the genotypes Marte and Brio, irrespective of having the same origin.Conclusions The maximum genetic distances were noted for genotype, Fakhre-e-Malakand and Musa having a different origin, while the minimum genetic distance was shown by genotypes, Marte and Onice, from the same origin.
... Because of their hydrogen-donor capabilities, phenolic compounds with a redox character are thought to operate as free radical scavengers (Ahmed et al. 2015;Abu-Shahba et al. 2021). Diabetes, neuronal degeneration, cancer, as well as autoimmune diseases, cardiovascular, and pulmonary, can be well-treated (Uttara et al. 2009). ...
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Plants that produce bioactive chemicals provide a viable in vitro method for producing key nutraceutical substances, especially in the presence of appropriate elicitors. The goal of this study is to use elicitors in Hassawi rice cell suspension culture to enhance production of phenolic compounds. Salicylic acid (SA), yeast extract (YE), and pectin were utilized at 50, 100, and 200 mg L −1. Impacts of elicitors on cell culture were measured in terms of biomass packed cell volume (PCV), dry and fresh weight, total phenolic, total flavonoid, anthocyanin, tannins content, antioxidant activity, and phenolic compounds using ultra performance liquid chromatography mass spectrometry (UPLC-mass spec). Except for high doses of pectin (200 mg L −1), the 50, 100, and 200 mg L −1 SA-, YE-, and pectin-treated cell culture produced increased PCV, dry (DW), and fresh weight (FW), and all of the aforementioned contents. The cell suspension supplied with 50 mg L −1 SA demonstrated greatest increases in PCV, FW, DW, all total secondary metabolites, and antioxidant activities as compared to other treatments. The highest concentrations of epigallocatechin and chlorogenic acid were found in cell cultures supplied with 100 mg L −1 SA and 50 mg L −1 pectin. Rutin and quercetin-3-O-α-L-rhamnopyranosyl (1-2)-β-D-glucopyranoside-7-O-α-L-rhamnopyranoside were detected at highest concentrations in cultures supplied with 50, 100 mg L −1 YE and 200 mg L −1 SA, respectively. These findings would facilitate in vitro mass production of nutraceuticals using rice cell cultures to assist commercial agronomic sectors.
... Potassium phosphites activation of the phenylpropanoid pathway was linked to decrease internal stem necrosis and mango wilt, as described according to Araujo et al. (2015). Mn is also a cofactor of peroxidases, which is involved in the synthesis of lignin (Abu-Shahba et al., 2021), as well as an essential component of the enzyme superoxide dismutase (SOD), which protects tissues from oxidative stress caused by pathogen and pests infection (Mohamed and Abd-El Hameed, 2014). After inoculation with C. fimbriata, Araujo et al. (2015) found that mango plants had increased enzyme activity and concentrations of metabolites associated with oxidative stress responses. ...
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Broad bean mottle virus (BBMV) infects a wide range of hosts, resulting in significant production reductions. The lack of adequate and effective control methods involves implementing novel BBMV control strategies. Herein, we demonstrate the effect of different potassium concentrations (20, 40, and 60 mM) against BBMV in broad bean plants. Potassium could control BBMV infection in broad bean by inhibiting the virus. In addition, infection with BBMV caused a significant decrease in morphological criteria, SPDA, photosynthetic characteristics, phytohormones, and mineral content in broad bean leaves compared to control plants. The levels of reactive oxygen species (ROS) (hydrogen peroxide, hydroxyl radical, and oxygen anion) and ROS scavenging enzymes (catalase, superoxide dismutase, peroxidase, phenylaniline ammonia-lyase, chitinase, and 1,3-glucanase) increased significantly in plants inoculated with BBMV alone or in the presence of K +. In addition, proline and phenolic compounds increased significantly after being infected with BBMV. In conclusion, treatment with a high potassium concentration (60 mM) alleviates the adverse effect of BBMV on broad bean plants by boosting secondary metabolites, phytohormones, and enzymatic antioxidants.
... Five major types of factors are well known in this regard. These factors are effector proteins, cell wall degrading enzymes, exopolysaccharides, phytohormones, and toxins (Abu-Shahba et al., 2021;Gagne-Bourgue et al., 2013). Deleterious rhizobacteria (DRB) are rhizosphere bacteria that affect plants by their metabolites without parasitizing plant tissue. ...
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Pathogenicity of eight Bacillus strains to seedlings of four cotton cultivars was evaluated under greenhouse conditions. Each of the tested cultivars was individually treated with powdered inoculum of each bacterial strain. Untreated seeds were planted as control treatments in autoclaved soil. Effects of the tested strains on levels and activities of some biochemical components of the infected seedlings were also assayed. The biochemical components included total soluble sugars, total soluble proteins, total free amino acids, peroxidase, polyphenol oxidase, phenols, and lipid peroxidation. ANOVA showed that Bacillus strain (B) was a very highly significant source of variation in damping-off and dry weight. Cotton cultivar (V) was a nonsignifi-cant source of variation in damping-off while it was a significant source of variation in dry weight. B × V interaction was a significant source of variation in damping off and a nonsignificant source of variation in dry weight. Bacillus strain was the most important source of variation as it accounted for 59.36 and 64.99% of the explained (model) variation in damping-off and dry weight, respectively. The lack of significant correlation between levels and activities of the assayed biochemical components and incidence of damping-off clearly demonstrated that these biochemical components were not involved in the pathogenicity of the tested strains. Therefore, it was hypothesized that the pathogenicity of the tested strains could be due to the effect of cell wall degrading enzymes of pathogenic toxins. Based on the results of the present study, Bacillus strains should be considered in studying the etiology of cotton seedling damping-off.
... In another study, microbubbles were employed to foster the growth of iceberg lettuce in hydroponic systems. The results indicate that the application of microbubbles in the hydroponic system can significantly enhance plant growth and increase secondary metabolite and antioxidant levels (Abu-Shahba et al., 2021). ...
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Microbubbles are emerging as versatile tools in numerous scientific and engineering disciplines. However, the applications of microbubbles in agricultural fields require a simple and cost-effective device that can be used to generate microbubbles. In this study, a new approach to producing microbubbles was developed using perforated plates incorporated with glass columns. Two different plates with various numbers of holes were fabricated. Characterization of the microbubbles showed that the diameter of the microbubbles produced was in the range of 10.4 to 21.1 µm. The gas-liquid ratio tended to increase by around 30-40%, with increasing oxygen gas flow rate and gas-jetting time. The enhanced oxygen gas flow rate and gas-jetting time also prolonged the residence time of the microbubbles. In general, this technique is promising that can be implemented in agricultural sectors, especially in hydroponic systems.
... Bacteria can boost N2 fixation, which is regulated by the nif gene and other fundamental genes; they can also boost plant growth, yield, and sustain nitrogen content in the soil, as well as enhance soil characteristics (Damam et al. 2016). Phosphate is a structural and signaling chemical that is necessary for photosynthesis, energy conservation, and carbon metabolism (Abu-Shahba et al. 2021). Potassium controls cell expansion, plasma membrane potential and transport, pH value, and many other catalytic processes as the cell's primary osmoticum (Jha 2017a). ...
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Low temperature is an important abiotic variable that inhibits plant growth and yield by restricting plant distribution on land. Cold-tolerant plant growth-promoting rhizobacteria (PGPR) improve nutrient absorption and availability in plants through biochemical and physiological mechanisms. Furthermore, they increase the tolerance of plants to cold stress. Different strains of bacteria were isolated from the roots of Suaeda nudiflora. These isolates were identified using 16SrDNA as Lysinibacillus fusiformis strain YJ4 and Lysinibacillus sphaericus strain YJ5 and were used to study their role in alleviating the harmful effect of cold stress. The two bacterial strains have the ability to solubilize phosphorus and to produce gluconic acid, phytohormones, catechol and hydroxymate siderophores. The present study aimed to study the effect of inoculating maize seeds with PGPR and its use to alleviate the adverse effects of cold stress. The results showed that cold stress (4 °C) reduces germination, growth criteria, photosynthetic pigments (i.e., chl a, chl b, and carotenoids), photosynthetic rate, membrane stability index, phytohormones (auxin and gibberellin), and mineral contents (N, P, K, and Ca) while increasing conductivity, malondialdehyde (MDA), lignin, cell viability, osmolytes (proline, glycine betaine, and soluble sugars), phenolic content, abscisic acid, 1-aminocyclopropane-1-carboxylic acid (ACC) content and the antioxidant defense system in maize plants. Besides, the lignification, osmolytes, phenolic content, phytohormones, the enzymatic antioxidant defenses (i.e., superoxide dismutase, catalase, and phenylalanine ammonia-lyase), and mineral contents of maize plants increased after inoculation with L. fusiformis and L. sphaericus alone or in combination as compared to normal and cold stress conditions. In conclusion, the inoculation with L. fusiformis and L. sphaericus in maize plants induced resistance of osmotic and oxidative stress caused due to exposure to cold stress by upregulation of osmolytes, phenolics, phytohormones, and antioxidant enzymes. Also, L. sphaericus strains is more effective in tolerance to cold stress than L. fusiformis.
... This improvement is achieved by stimulating various physiological processes involved in plant growth and development, as well as improving final product quality ( Figure 10). The use of traditional chemical fertilizers has expanded dramatically as result of world's fast-growing population or ever-increasing food demand [307]. The usage of these chemical fertilizers, as well as their impacts, notably on environment, has become major source of worry [308]. ...
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Since ancient times, seaweeds have been employed as source of highly bioactive secondary metabolites that could act as key medicinal components. Furthermore, research into the biological activity of certain seaweed compounds has progressed significantly, with an emphasis on their composition and application for human and animal nutrition. Seaweeds have many uses: they are consumed as fodder, and have been used in medicines, cosmetics, energy, fertilizers, and industrial agar and alginate biosynthesis. The beneficial effects of seaweed are mostly due to the presence of minerals, vitamins, phenols, polysaccharides, and sterols, as well as several other bioactive compounds. These compounds seem to have antioxidant, anti-inflammatory, anti-cancer, antimicrobial, and anti-diabetic activities. Recent advances and limitations for seaweed bioactive as a nutraceutical in terms of bioavailability are explored in order to better comprehend their therapeutic development. To further understand the mechanism of action of seaweed chemicals, more research is needed as is an investigation into their potential usage in pharmaceutical companies and other applications , with the ultimate objective of developing sustainable and healthier products. The objective of this review is to collect information about the role of seaweeds on nutritional, pharmacological , industrial, and biochemical applications, as well as their impact on human health.
... More broadly, TMV and Tomato mosaic virus (ToMV) inoculated Nicotiana glutinosa seedlings demonstrated improved POD and CAT activity compared with uninfected seedlings [73]. Because SOD is an effective O 2scavenger, it is the plant's first defense against ROS [74,75], demonstrating the SOD's defensive role in biological systems. Moreover, POX and CAT may be considered radical scavengers and catalyzed H 2 O 2 producing H 2 O and O 2 [76,77]. ...
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During the spring of 2019, distinct virus-like symptoms were observed in the Kafr El-Sheikh Governorate in Egypt in naturally infected eggplants. Leaves of affected plants showed interveinal leaf chlorosis, net yellow, chlorotic sectors, mottling, blisters, vein enation, necrotic intervention, and narrowing symptoms. The Alfalfa mosaic virus (AMV) was suspected of to be involved in this disease. Forty plant samples from symptomatic eggplants and 10 leaf samples with no symptoms were collected. The samples were tested by double antibody sandwich ELISA (DAS-ELISA) using AMV-IgG. Six of the 40 symptomatic leaf samples tested positive for AMV, while, DAS-ELISA found no AMV in the 10 leaf samples without symptoms. The AMV Egyptian isolate (AMV-Eggplant-EG) was biologically isolated from the six positive samples tested by DAS-ELISA and from the similar local lesions induced on Chenopodium amaranticolor and then re-inoculated in healthy Solanum melongena as a source of AMV-Eggplant-EG and confirmed by DAS-ELISA. Reverse transcription polymerase chain reaction (RT-PCR) assay with a pair of primers specific for coat protein (CP) encoding RNA 3 of AMV yielded an amplicon of 666 bp from infected plants of Solanum melongena with AMV-Eggplant-EG. The amplified PCR product was cloned and sequenced. Analysis of the AMV-Eggplant-EG sequence revealed 666 nucleotides (nt) of the complete CP gene (translating 221 amino acid (aa) residues). Analysis of phylogeny for nt and deduced aa sequences of the CP gene using the maximum parsimony method clustered AMV-Eggplant-EG in the lineage of Egyptian isolates (shark-EG, mans-EG, CP2-EG, and FRE-EG) with a high bootstrap value of 88% and 92%, respectively. In addition to molecular studies, melatonin (MTL) and salicylic acid (SA) (100 μM) were used to increase the resistance of eggplant to AMV- infection. Foliar spray with MLT and SA caused a significant increase in the morphological criteria (shoot, root length, number of leaves, leaf area, and leaf biomass), chlorophyll and carotenoid content, antioxidant enzymes, and gene expression of some enzymes compared to the infected plants. On the other hand, treatment with MLT and SA reduced the oxidative damage caused by AMV through the reduction of hydrogen peroxide, superoxide anions, hydroxyl radicals, and malondialdehyde. In conclusion, MLT and SA are eco-friendly compounds and can be used as antiviral compounds.
... Salinity significantly alters its biochemical and physiological effects, leading to a dramatic reduction in the water absorption plant roots due to osmotic stress and ion toxicity (Alsaeedi et al. 2019) and the accelerated generation ROS (Abu-Shahba et al. 2021). Disorder in both of these biochemical processes and properties in plants grown under salt stress and photosynthesis mechanism and its efficacy inevitably leads to impairment and damage. ...
... The greater ROS levels trigger oxidative damage, containing lipid, pigment destruction, proline, phenol, ASA, and GSH, and ROS impairs enzyme activities [43]. So that organelles have developed antioxidant defence systems to protect plant cells from oxidative damage by scavenging ROS [44][45][46][47]. Proline is a non-enzymatic antioxidant capable of stabilizing subcellular materials such as cell membranes, proteins, buffering redox potential, and scavenging free radicals under stress conditions. ...
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Tomato mosaic virus (ToMV) is one of the economically damageable Tobamovirus infecting the tomato in Egypt that has caused significant losses. It is therefore of great interest to trigger systemic resistance to ToMV. In this endeavor, we aimed to explore the capacity of ZnO-NPs (zinc oxide nanoparticles) to trigger tomato plant resistance against ToMV. Effects of ZnO-NPs on tomato (Solanum lycopersicum L.) growth indices and antioxidant defense system activity under ToMV stress were investigated. Noticeably that treatment with ZnO-NPs showed remarkably increased growth indices, photosynthetic attributes, and enzymatic and non-enzymatic antioxidants compared to the challenge control. Interestingly, oxidative damage caused by ToMV was reduced by reducing malondialdehyde, H2O2, and O2 levels. Overall, ZnO-NPs offer a safe and economic antiviral agent against ToMV.
... As a result, the use of biofertilizers is an environmentally friendly way to reduce the use of synthetic fertilizers and can enhance crop production (Sofy et al. 2020a(Sofy et al. , b, 2021a. Hence, the role of microbes in promoting the growth of plants as biofertilizers regulates many processes like availability of nutrients, especially Mg, N, Fe, K, P. Organic material decomposition to improve crop growth is well understood (Lalitha 2017;Aly et al. 2012Aly et al. , 2013Aly et al. , 2017Abu-Shahba et al. 2021). Biofertilizer, known as a component of specific microbial cells, stimulates the growth of plants while increasing the rate of nutrients through the phosphorous cycle, and nitrogen fixation (Mohamed and Gomaa 2012) (Fig. 1). ...
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The perception of phytoremediation is efficiently utilized as an eco-friendly practice of green plants combating and cleaning up the stressed environment without harming it. The industrial revolution was followed by the green revolution which fulfilled the food demands of the growing population caused an increase in yield per unit area in crop production, but it also increased the use of synthetic fertilizers in agriculture. Globally, the intensive use of inorganic fertilizers in agriculture has led to serious health problems and irreversible environmental damage. Biofertilizers improve the growth of the plant and can be applied as an alternative to chemical/synthetic fertilizers. Cyanobacteria, bacteria, and fungi are known as some of the principal microbe groups used to produce biofertilizers that form symbiotic associations with plants. Microorganisms perform a key role in phosphate solubilization and mobilization, nitrogen fixation, nutrient management, biotic elicitors and probiotics, and pollution management (biodegradation agents), specifically bacteria which also help in atmospheric nitrogen fixation and are thus available for the growth of the plant. Management or biodegradation of hazardous chemical residues and heavy metals produced by a huge number of large-scale industries should be given primary importance to be transformed by various bacterial strains, fungi, algae. Currently, modern omics technologies such as metagenomic, transcriptomic, and proteomic are being used to develop strategies for studying the ecology of microorganisms, as well as their use in environmental monitoring and bioremediation. This review briefly discusses some of the major groups of microorganisms that can perform different functions responsible for plant health, crop production, phytoremediation and also focus on the omics techniques reportedly used in environmental monitoring to tackle the pollution load.
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Salinity is among the most significant threats hindering global food security. The impact of Trichoderma, biochar, and combination on Spinach plants under salt stress conditions was investigated. Our results confirmed that salt stress (75, 150 mM) negatively affected morphological and physiological parameters of Spinach plants such as shoot (26.4%, 45.9%), and root length (16.1%, 51.2%), fresh and dry weights of root and shoot, membrane stability index (9.8%, 18.5%), relative water content(4.5%, 16.8%), chlorophyll content, mineral contents, endogenous phytohormones (auxin, gibberellins, abscisic acid, jasmonic acid, and salicylic acid) and total soluble protein content. However, electrolyte leakage, lipid peroxidation, reactive oxygen species production (such as hydrogen peroxide and hydroxyl radical), sodium, soluble sugars, proline contents, and antioxidant enzymes activities (peroxidase, catalase, and superoxide dismutase) significantly increased as a response to salt stress. The use of Trichoderma, biochar, and combination led to significant increases in all the above parameters; nevertheless, these treatments led to significant decreases in EL%, MDA, ROS, and sodium content in the stressed plants. The results proved the combination of Trichoderma and biochar is the most effective in alleviating the damaging impacts of salt on Spinach plants by increasing the up-regulation of antioxidants and decreasing membrane leakage and ROS.
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Approximately 6% of the world’s total land area and 20% of the irrigated land are affected by salt stress. Egypt is one such country affected by salt-stress problems. This paper focuses on the role of isolated bacteria, such as Bacillus subtilis and Pseudomonas fluorescens, in alleviating the harmful effects of salt stress. The results show that the irrigation of plants with different concentrations of saline water (0, 75, and 150 mM NaCl) leads to significantly decreased growth criteria, photosynthetic pigments (i.e., chl a, chl b, and carotenoids), and membrane stability index (MSI) values. Moreover, malondialdehyde (MDA), glutathione content, endogenous proline, the antioxidant defense system, 1-aminocyclopropane-1-carboxylic acid (ACC) content, ACC synthase (ACS), ACC oxidase (ACO), and Na+ content were significantly increased under NaCl-stress exposure. On the contrary, treatment with endophytic bacteria significantly increased the resistance of pea plants to salt stress by increasing the enzymatic antioxidant defenses (i.e., superoxide dismutase, catalase, peroxidase, and glutathione reductase), non-enzymatic antioxidant defenses (i.e., glutathione), osmolyte substances such as proline, and antioxidant enzyme gene expression. As a result, endophytic bacteria’s use was significantly higher compared to control values for indole-3-acetic acid (IAA), gibberellic acid GA3, MSI, and photosynthetic pigments. The use of endophytic bacteria significantly decreased Na+ accumulation while, at the same time, promoting K+ uptake. In conclusion, the induction of endophytic bacterium-induced salt tolerance in pea plants depends primarily on the effect of endophytic bacteria on osmoregulation, the antioxidant capacity, and ion uptake adjustment by limiting the uptake of Na+ and, alternatively, increasing the accumulation of K+ in plant tissue.
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Cadmium (Cd) contamination can pose a severe threat to food production and human health. The accumulation of Cd in rice will decrease rice biomass, photosynthetic activity, and antioxidant capacity, affecting crop yield. The effects of different nanobubbles on the growth and Cd accumulation of rice seedlings under hydroponic conditions were investigated in this study. The results showed that the biomass, photosynthetic pigment content, and antioxidant enzyme activity of rice seedlings decreased when treated with Cd alone and that Cd induced lipid peroxidation in rice seedlings. However, when different types of nanobubbles were introduced into the nutrient solution, the bioavailability of Cd in the solution was reduced. As a result, the Cd content in rice was significantly decreased compared to treatment with Cd alone. Nanobubbles increased the biomass of rice, enhanced photosynthesis, and improved the antioxidant capacity of rice by increasing antioxidant enzyme activities to alleviate Cd-induced oxidative stress. At the same time, nanobubbles increased the Fe content in rice, which decreased the Cd content, as Cd is antagonistic to Fe. In conclusion, these results suggested that nanobubbles are a potential method of mitigating Cd stress that may help to improve rice yield and could be further explored in production.
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The aid of beneficial microbes, which is a well-accepted strategy, may improve plant salt tolerance. However, the mechanisms that underpin it are unclear. In this study, seedling experiments were carried out to assess the effect of Bradyrhizobium and Enterobacter on the germination, growth, nonenzymatic and enzymatic content in soybean (Glycine max L.) under salt stress. Water was sprayed on the seeds as a control, and with 75 mM, 150 mM NaCl as salt stress. The findings demonstrate that salt stress (75, 150 mM) caused a significant decrease in germination, morphological criteria, and membrane stability index (MSI) when compared to control seeds but increased lipid peroxidation (MDA), electrolyte leakage (EL), osmotic pressure, proline, citric acid, sugar content, antioxidant enzymes. Furthermore, endophytic Bradyrhizobium and Enterobacter inoculation resulted in a significant rise in all of the above metrics.; however, these treatments resulted in significant reductions in ROS, EL, and MDA in stressed plants. Finally, the findings showed that combining Bradyrhizobium and Enterobacter was the most efficient in reducing the harmful effects of salt on soybean plants by boosting antioxidant up-regulation and lowering membrane leakage and ROS.
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Root-knot nematodes are believed to be amongst the biological constraints causing severe damage and a great reduction in the productivity of okra. The purpose of this study was to apply organic matter and non-symbiotic nitrogen-fixing bacteria to minimize the addition of chemical fertilizers that constantly pollute the environment. Experimental studies were conducted in the field for two summers to determine the effect of inoculations of non-symbiotic nitrogen-fixing bacteria, such as Azotobacter chroococcum and Azospirillum brasilense singly and in combinations, with different recommended doses of inorganic nitrogen as well as organic matter such as neem seed cake on the growth, yield, and organic parameters of the okra crop towards the management of plant-parasitic nematodes. The results show a significant reduction in nematode multiplication through soil application of nitrogen-fixing bacteria and neem seed cake along with different recommended doses of nitrogen inoculated plants. Azotobacter was found to be less effective than Azospirillum in agronomic parameters and nematode control. The most pronounced increases were observed in the yield and growth parameters such as plant height, fresh as well as dry weights, fruit weights/plant, number of total fruits/plant and primary branches, chlorophyll content, and ascorbic acid content when A. chroococcum and A. brasilense were added concomitantly in various combinations. Agronomic parameters such as NPK content in the plant as well as in residual soil increased considerably in almost all the combinations irrespective of these biofertilizers and neem seed cake. In conclusion, the combined application of a 100% recommended dose of nitrogen fertilizer along with Azospirillum and neem seed cake is recommended for better growth and yield of okra with better control of nematodal population
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The potential of nanotechnology for the development of sustainable agriculture has been promising. The initiatives to meet the rising food needs of the rapidly growing world population are mainly powered by sustainable agriculture. Nanoparticles are used in agriculture due to their distinct physicochemical characteristics. The interaction of nanomaterials with soil components is strongly determined in terms of soil quality and plant growth. Numerous research has been carried out to investigate how nanoparticles affect the growth and development of plants. Nanotechnology has been applied to improve the quality and reduce post-harvest loss of agricultural products by extending their shelf life, particularly for fruits and vegetables. This review assesses the latest literature on nanotechnology, which is used as a nano-biofertilizer as seen in the agricultural field for high productivity and better growth of plants, an important source of balanced nutrition for the crop, seed germination, and quality enrichment. Additionally, post-harvest food processing and packaging can benefit greatly from the use of nanotechnology to cut down on food waste and contamination. It also critically discusses the mechanisms involved in nanoparticle absorption and translocation within the plants and the synthesis of green nanoparticles.
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Soil salinity is the main obstacle to worldwide sustainable productivity and food security. Zinc sulfate (Zn) and paclobutrazol (PBZ) as a cost-effective agent, has multiple biochemical functions in plant productivity. Meanwhile, their synergistic effects on inducing salt tolerance are indecisive and not often reported. A pot experiment was done for evaluating the defensive function of Zn (100 mg/L) or PBZ (200 mg/L) on salt (0, 50, 100 mM NaCl) affected pea plant growth, photosynthetic pigment, ions, antioxidant capacity, and yield. Salinity stress significantly reduces all growth and yield attributes of pea plants relative to nonsalinized treatment. This reduction was accompanied by a decline in chlorophyll, nitrogen, phosphorus, and potassium (K+), the ratio between K+ and sodium (Na+), as well as reduced glutathione (GSH) and glutathione reductase (GR). Alternatively, salinity increased Na+, carotenoid (CAR), proline (PRO), ascorbic acid (AsA), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) over nonsalinized treatment. Foliar spraying with Zn and PBZ under normal condition increased plant growth, nitrogen, phosphorus, potassium, K+/Na+ ratio, CAR, PRO, AsA, GSH, APX, GR, and yield and its quality, meanwhile decreased Na+ over nonsprayed plants. Application of Zn and PBZ counteracted the harmful effects of salinity on pea plants, by upregulating the antioxidant system, ion homeostasis, and improving chlorophyll biosynthesis that induced plant growth and yield components. In conclusion, Zn plus PBZ application at 30 and 45 days from sowing offset the injuries of salinity on pea plant growth and yield by upregulating the antioxidant capacity and increasing photosynthetic pigments.
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In recent years, nutrient management has gained much attention as a way to mitigate heavy metal stress. Silicon (Si) promotes plant defense responses against toxic metal stresses. In this study, we evaluated the effects of silicon (Si) on copper (Cu) toxicity in two flax genotypes (Sakha 1 and Sakha 2) as it relates to plant growth, yield attributes, total chlorophyll, nucleic acid content, enzymatic and non-enzymatic antioxidants, oxidative damage, lipid peroxidation, copper and silicon content, and fatty acid composition. The results showed that Cu (100 and 200 µM) inhibited plant growth and increased Cu accumulation in soil, roots, and shoots. Cu significantly decreased the yield attributes, total chlorophyll by 9.5% and 22% in Sakha 1 and by 22.5% and 29% in Sakha 2, and enhanced the accumulation of non-enzymatic (tocopherol), enzymatic antioxidants such as superoxide dismnutase, peroxidase, ascorbate peroxidase and catalase) and secondary metabolites (phenol and flavonoids). The DNA content significantly decreased in stressed plants with 100 and 200 µM Cu about 22% and 44%, respectively, in Sakha 1 and about 21.6% and 34.7% in Sakha 2, and RNA content also decreased by about 20% and 29%, respectively, in Sakha 1 and by about 2% and 13% in Sakha 2 compared to the control plant. Furthermore, Cu stress accelerated the generation of reactive oxygen species (ROS), such as hydrogen peroxide (H 2 O 2) and induced cellular oxidative injury caused by lipid peroxidation. In parallel, Cu induced a change in the composition of fatty acids, resulting in lower unsaturated fatty acid levels and increased saturated fatty acids (increased saturation/unsaturation ratio for both genotypes). Treating the flax plants with irrigation three times with Si protected the plants from Cu toxicity. Si treatment decreased the uptake and the transport of Cu to the shoots and harvested seeds and promoted plant growth, yield attributes, and antioxidant defense systems by reducing Cu accumulation, lipid peroxidation, and the generation of H 2 O 2. In addition, the alleviation of Cu toxicity correlated with increased Si accumulation in the roots and shoots. In conclusion, Si can be used to improve the resistance of flax plants to Cu toxicity by up-regulating the antioxidant defense system such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX) and catalase (CAT) and decreasing the oxidative damage caused by reactive oxygen species (ROS).
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Cucumber mosaic cucumovirus (CMV) is a deadly plant virus that results in crop-yield losses with serious economic consequences. In recent years, environmentally friendly components have been developed to manage crop diseases as alternatives to chemical pesticides, including the use of natural compounds such as glycine betaine (GB) and chitosan (CHT), either alone or in combination. In the present study, the leaves of the cucumber plants were foliar-sprayed with GB and CHT—either alone or in combination—to evaluate their ability to induce resistance against CMV. The results showed a significant reduction in disease severity and CMV accumulation in plants treated with GB and CHT, either alone or in combination, compared to untreated plants (challenge control). In every treatment, growth indices, leaf chlorophylls content, phytohormones (i.e., indole acetic acid, gibberellic acid, salicylic acid and jasmonic acid), endogenous osmoprotectants (i.e., proline, soluble sugars and glycine betaine), non-enzymatic antioxidants (i.e., ascorbic acid, glutathione and phenols) and enzymatic antioxidants (i.e., superoxide dismutase, peroxidase, polyphenol oxidase, catalase, lipoxygenase, ascorbate peroxidase, glutathione reductase, chitinase and β-1,3 glucanase) of virus-infected plants were significantly increased. On the other hand, malondialdehyde and abscisic acid contents have been significantly reduced. Based on a gene expression study, all treated plants exhibited increased expression levels of some regulatory defense genes such as PR1 and PAL1. In conclusion, the combination of GB and CHT is the most effective treatment in alleviated virus infection. To our knowledge, this is the first report to demonstrate the induction of systemic resistance against CMV by using GB.
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Lead (Pb) is a toxic heavy metal (HM) that harms plant growth and productivity. Phytohormones, such as jasmonic acid (JA) and salicylic acid (SA), and osmoprotectants, such as proline (Pro), play an important role in the physiological and biochemical processes of plants. We investigated the effect of exogenous applications of JA, SA, Pro, and their combination on Pb-stress tolerance in maize as well as their effect on physiological, biochemical, and yield traits. Pb exposure severely affected maize plants, reducing growth, yield, photosynthetic pigments, and mineral (nitrogen, phosphorus, and potassium) nutrients, as well as enhancing electrolyte leakage (EL), malondialdehyde (MDA) accumulation, osmolytes, and non-enzymatic and enzymatic antioxidants. The application of JA, SA, Pro, and their combination enhanced plant growth and induced pigment biosynthesis, and decreased EL, MDA accumulation, and Pb concentration. All treatments enhanced Pro and total soluble sugar production, glutathione activity, ascorbic acid, phenol, superoxide dismutase, catalase, peroxidase, and mineral nutrients. JA, SA, and Pro application improved physiological processes directly or indirectly, thereby enhancing the ability of maize plants to overcome oxidative damage caused by Pb toxicity. The combination of JA, SA, and Pro was the most efficient treatment for maize plant growth and development, eliminating the negative consequences of Pb stress.
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In recent years, the harmful effects of drought stress have been be mitigated by using bioactive compounds such as antioxidants and osmolytes. In this research, pot experiments were carried out to investigate the effects of ascorbic acid, glutathione and proline on alleviating the harmful effect of drought stress in chickpea plants during season 2017. Chickpea plant seeds were soaked in ascorbic acid (0.75 mM), glutathione (0.75 mM), proline (0.75 mM) singly and/or in sequence combinations for 4 h and then planted in pots. The pots were irrigated with water after seven days (to serve as control), after 14 days (moderate drought stress) and after 28 days (severe drought stress). The sequence combination of antioxidants and proline under drought stress has not been studied yet. The results showed significantly decreased in plant growth, yielding characteristics, photosynthetic pigments and soluble protein content in response to moderate and severe drought stress. Moreover, treatment with antioxidants caused increment the antioxidant enzyme activity, non-enzymatic antioxidant (ascorbic acid and glutathione) contents and endogenous proline in stressed and unstressed plants. In conclusion, The sequence combination of antioxidants and proline caused improvement in plant growth under drought stress by up-regulating the antioxidant defense system and osmolyte synthesis.
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Background: In response to various environmental stresses, many plant species synthesize L-proline in the cytosol and accumulates in the chloroplasts. L-Proline accumulation in plants is a well-recognized physiological reaction to osmotic stress prompted by salinity, drought and other abiotic stresses. L-Proline plays several protective functions such as osmoprotectant, stabilizing cellular structures, enzymes, and scavenging reactive oxygen species (ROS), and keeps up redox balance in adverse situations. In addition, ample-studied osmoprotective capacity, L-proline has been also ensnared in the regulation of plant improvement, including flowering, pollen, embryo, and leaf enlargement. Scope and conclusions: Albeit, ample is now well-known about L-proline metabolism, but certain characteristics of its biological roles are still indistinct. In the present review, we discuss the L-proline accumulation, metabolism, signaling, transport and regulation in the plants. We also discuss the effects of exogenous L-proline during different environmental conditions. L-Proline biosynthesis and catabolism are controlled by several cellular mechanisms, of which we identify only very fewer mechanisms. So, in the future, there is a requirement to identify such types of cellular mechanisms.
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Rapid industrialization and urbanization have contributed to eutrophication of urban landscape waters in China. As an important part of aquatic ecosystem, macrophytes have many advantages in controlling eutrophication and blooming....
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Background Clostridium acetobutylicum is a model fermentative anaerobe for consolidated bioprocessing of lignocellulose hydrolysates into acetone–butanol–ethanol (ABE). However, the main inhibitors (acids, furans and phenols) ubiquitous in lignocellulose hydrolysates strictly limit the conversion efficiency. Thus, it is essential to understand the underlying mechanisms of lignocellulose hydrolysate inhibitors to identify key industrial bottlenecks that undermine efficient biofuel production. The recently developed omics strategy for intracellular metabolites and protein quantification now allow for the in-depth mapping of strain metabolism and thereby enable the resolution of the underlying mechanisms. Results The toxicity of the main inhibitors in lignocellulose hydrolysates against C. acetobutylicum and ABE production was systematically investigated, and the changes in intracellular metabolism were analyzed by metabolomics and proteomics. The toxicity of the main lignocellulose hydrolysate inhibitors at the same dose was ranked as follows: formic acid > phenol > furfural. Metabolomic analysis based on weighted gene coexpression network analysis (WGCNA) revealed that the three inhibitors triggered the stringent response of C. acetobutylicum. Proteomic analysis based on peptide mass spectrometry (MS) supported the above results and provided more comprehensive conclusions. Under the stress of three inhibitors, the metabolites and key enzymes/proteins involved in glycolysis, reductive tricarboxylic acid (TCA) cycle, acetone–butanol synthesis and redox metabolism were lower than those in the control group. Moreover, proteins involved in gluconeogenesis, the oxidative TCA cycle, thiol peroxidase (TPX) for oxidative stress were significantly upregulated, indicating that inhibitor stress induced the stress response and metabolic regulation. In addition, the three inhibitors also showed stress specificity related to fatty acid synthesis, ATP synthesis, nucleic acid metabolism, nicotinic acid metabolism, cell wall synthesis, spore synthesis and flagellum synthesis and so on. Conclusions Integrated omics platforms provide insight into the cellular responses of C. acetobutylicum to cytotoxic inhibitors released during the deconstruction of lignocellulose. This insight allows us to fully improve the strain to adapt to a challenging culture environment, which will prove critical to the industrial efficacy of C. acetobutylicum. Electronic supplementary material The online version of this article (10.1186/s13068-019-1440-9) contains supplementary material, which is available to authorized users.
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Conventional soil and hydroponic growing systems have inherent differences in water and nutritional availability. These differences may affect plant physiological development and biochemistry. The objective of this study was to evaluate lettuce (Lactica sativa) cv. ‘Crocantela’development in either a hydroponic system or in soil through analyses of vegetative growth; chlorophyll abundance; and sugar and starch content. We evaluated the dry mass (DM), fresh mass (FM), number of leaves (LN), stomatal density and contents of chlorophyll, carotenoids, sugars and starch. Due to the improved nutritional conditions, especially in relation to macronutrients, plants grown in hydroponic system presented significant differences in chlorophyll a (0.4481 mg/g), b (0.1233 mg/g) and total chlorophyll content (0.5714 mg/g), as well as greater biomass when compared to plants cultivated in pots (FM: 342.69 g; DM: 21.13 g; NL: 17.75 g). The lower water availability for plants cultivated in pots influenced the increase in carbohydrate concentration and stomatal density in leaves (adaxial: 45.83 stomates/mm2; abaxial: 64.75 stomates/mm2) of lettuce plants.
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A study was conducted with green and red-leaf lettuce cultivars grown in a deep-water culture production system. Plants were seeded in rockwool and germinated under greenhouse conditions at 25/20 °C (day/night) for 21 days before transplanting. The experimental design was a randomized complete block with a 2 × 3 factorial arrangement of cultivar and nutrient treatments that consisted of six replications. Treatments consisted of two lettuce genotypes, (1) green (Winter Density) and (2) red (Rhazes), and three nutrient treatments containing electroconductivity (EC) levels of (1) 1.0; (2) 2.0; and (3) 4.0 mS·cm−1. After 50 days, plants were harvested, processed, and analyzed to determine marketable yield, biomass, plant height, stem diameter, phenolics, and elemental nutrient concentrations. An interaction between growing season and lettuce cultivar was the predominant factor influencing yield, biomass, and quality. Nutrient solution EC treatment significantly affected biomass and water content. EC treatments significantly impacted concentrations of 3-O-glucoside and uptake of phosphorous, potassium, iron, boron, zinc, and molybdenum. Effects of growing season and cultivar on leafy lettuce yield and quality were more pronounced than the effect of nutrient solution EC treatment. Thus, greenhouse production of green and red-leaf lettuce cultivars in the south-eastern United States should be conducted in the spring and fall growing seasons with elevated nutrient solution EC of ≈4.0 mS·cm−1 to maximize yield and quality.
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Fungicides using for an effective control of plant diseases have become crucial in the last decades in the agricultural system. The efficiency of seed dressing fungicides in controlling damping off caused by Rhizoctonia solani under greenhouse conditions and its effect on plant growth and metabolism of cotton plant seeds was studied by treatment with systemic and contact fungicides. The results showed that Monceren showed the highest efficiency (72%) while each of Montoro and Sumi-8 showed the lowest efficiency (48% and 36 % respectively) in controlling damping off. Significant decrease in plant height, dry weight of plant, phytohormones, photo-synthetic pigments, soluble sugars, soluble proteins, total free amino acids, polyphenol oxidase caused by Bastin fungicide, but caused significant increases in total phenols, flavonoids, antioxidant enzymes, reduced glutathione, lipid peroxidation and hydrogen peroxide as compared with untreated plants. On the other hand, Topsim and Monceren fungicides increased all the above recorded parameters except phenols, MDA and H2O2 as compared with untreated plants. Our results indicated that Topsim Monceren and Premis fungicides can be used as growth regulators and decreased plant diseases.
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Hydroponics is a technology that can contribute to fulfilling demand for vegetables year-round even where normal agricultural practices cannot be undertaken. However, it is still in its nascent stage and crop production techniques for lettuce (Lactuca sativa L.) have not been standardized. Moreover, effect of organic concoction in conjunction with nutrient solution on qualitative and quantitative parameters of plant needs to be established. An experiment was carried out to examine the effect of Hoagland Nutrient Solution (HNS) and jeevamrut (made from 10 kg cow dung plus 10 L cow urine added to 100 L of water plus 2 kg jaggery, prepared filtered, boiled, sugarcane juice which is concentrated and cooled to produce jaggery blocks plus 2 kg of flour and a small amount of soil fermented for 7 days) on growth, yield and quality of lettuce using Nutrient Film Technique compared to grow bags. Treatment with Hoagland Nutrient Solution+5% application of jeevamrut in Nutrient Film Technique increased numbers of leaves, root length, leaf area and yield by 40, 34, 24 and 24%, respectively, over the control (fertigation with Hoagland Nutrient Solution in grow bags). The water used for hydroponics was 22 times less compared to grow bags. Growing lettuce in hydroponics fertilized with Hoagland Nutrient Solution+5% application of jeevamrut using the Nutrient Film Technique produced good quality lettuce with higher yields.
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The present study was undertaken to examine the possible roles of sodium nitroprusside in protection against oxidative damage due to zinc toxicity in sunflower plants. Physiochemical parameters in sunflower plants exposed to Zn2+ (100, 200 and 300 mg/kg soil) alone or combined with SNP were measured. The results showed that excess of Zn decreased plant growth, seed yield components and photosynthetic pigments content. On the other hand, Zn stress increased the level of non-enzymatic antioxidants (ascorbic acid and reduced glutathione) and enzymatic antioxidants (superoxide dismutase, ascrobate peroxidase and glutathione reductase), coupled with the appearance of novel protein bands. Furthermore, Zn stress increased Zn content in roots and shoots. The amounts of Zn in roots were higher than shoots. A marked increase in total saturated fatty acids accompanied by a decrease in total unsaturated fatty acids was observed. Exogenously application of SNP (20 μM) increased growth parameters, photosynthetic pigmen...
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Iron (Fe) and zinc (Zn) are essential nutrients for plant growth and development. Therefore, a pot experiment was conducted to examine the role of Zn and Fe on vegetative growth, photosynthetic pigments, soluble sugars, soluble protein, nitrate reductase (NR), ascorbate peroxidase (APX), catalase (CAT), minerals content, amino acid composition fraction, isozymes, and protein electrophoresis in faba bean plants foliar sprayed with FeSO4 and ZnSO4. The results revealed that foliar spray with 1 or 3 g/L of FeSO4 and ZnSO4 significantly increased all the abovementioned parameters compared to control plants. The activity of esterase increased with increasing concentration of Fe and Zn as compared to control plants. The most pronounced increase was found in plants treated with 3 g/L ZnSO4. Three bands of peroxidase isozyme were exhibited with different densities and intensities in all treatments. Three types of modification were observed in the protein patterns of faba bean leaves. Some protein bands disappeared, while other increased and synthesis of a new set of proteins was induced. It could be concluded that foliar spray with the two concentrations (1 or 3 g/L) of ZnSO4 and FeSO4 helped faba bean plants to overcome the deficiency in these minerals by producing antioxidant enzymes. Improved faba bean growth through adequate Fe and Zn foliar spray is likely a promising strategy to improve Vicia faba plants.
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Mining of nutrients from soil is a major problem in developing countries causing soil degradation and threaten long-term food production. The present study attempts to apply NUTrient MONitoring (NUTMON) model for carrying out nutrient budgeting to assess the stocks and flows of nitrogen (N), phosphorus (P), and potassium (K) in defined geographical unit based on the inputs, viz., mineral fertilizers, manures, atmospheric deposition, and sedimentation, and outputs, viz., harvested crop produces, residues, leaching, denitrification, and erosion losses. The study area covers Coimbatore and Erode Districts, which are potential agricultural areas in western agro-ecological zone of Tamil Nadu, India. The calculated nutrient balances for both the districts at district scale, using NUTMON methodology, were negative for nitrogen (N −3.3 and −10.1 kg ha−1) and potassium (K −58.6 and −9.8 kg ha−1) and positive for phosphorus (P +14.5 and 20.5 kg ha−1). Soil nutrient pool has to adjust the negative balance of N and K; there will be an expected mining of nutrient from the soil reserve. A strategy was attempted for deriving the fertilizer recommendation using Decision Support System for Integrated Fertilizer Recommendation (DSSIFER) to offset the mining in selected farms. The results showed that when DSSIFER recommended fertilizers are applied to crops, the nutrient balance was positive. NUTMON-Toolbox with DSSIFER would serve the purpose on enhancing soil fertility, productivity, and sustainability. The management options to mitigate nutrient mining with an integrated system approach are also discussed.
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Lettuce (Lactuca sativa L.) is the most commonly consumed leaf vegetable in the Brazilian diet, and it is a good source of vitamins and minerals. It is widely grown in the conventional farming system. However, the hydroponic farming system has been gaining importance in the market, wining confidence from consumers, who are becoming increasingly more demanding on food quality. The objective of this study was to evaluate the performance of two lettuce cultivars on hydroponic and conventional farming systems for the production of fresh mass (FM) and dry mass (DM), photosynthesis, contents of chlorophyll and anthocyanin. The following two experiments were carried out: hydroponics farming (HF) and conventional farming (CF), performed in protect and unprotect environments, respectively, in Floriano´polis, SC. Mimosa Verde cultivar (MV) showed greater fresh mass than Mimosa Roxa (MR), in both farming systems and the two cultivars presented better performance in the hydroponic system (287.7 g MV and 139.1 g MR) than the conventional system (129.7 g MV and 111.8 g MR). Mimosa Verde cultivar presented lower average contents of total chlorophyll (7.7 mg g-1 FM) than Mimosa Roxa (11.8 mg g-1FM), and both cultivars displayed higher means for this variable in the hydroponic farming system. Mimosa Roxa presented higher contents of anthocyanin in the conventional system (88.24 mg g-1 FM) than the ones in the hydroponic system (36.89 mg g-1 FM). The best results for CO2 net assimilation rate regarded to photosyntheticaly active photon flux density were found in the hydroponic system, for both lettuce cultivars. Variation in the contents of chlorophyll were also found. Those variations were higher in the protected system than in the hydroponic system and contents of anthocyanin were higher in the conventional system.
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The nitrate reductase (NR) activity and chlorophyll content were determined in two lettuce cultivars grown in three crop systems: hydroponics (floating root system), organics and traditional. Data were analyzed through randomized complete block design with a factorial arrangement (system × cultivar). The NR activity was expressed as μM of NO2- formed (g fresh weight h-1). Greater NR activity was observed in the plants grown in the hydroponics (0.0234 μM NO2- g-1 fresh weight h-1) than in the organics and traditional systems (0.0149 and 0.0120 μM NO2- g-1 fresh weight h-1 respectively). Also the total chlorophyll content was greater in the lettuce plants grown hydroponically than in the plants grown traditionally and organically (0.00144, 0.00104 and 0.00072 mg g-1 fresh weight h-1, respectively). Yield was greater in the lettuces grown hydroponically (220.75 g plant-1) than organically (44.50 g plant-1) and traditionally grown (63.50 g plant-1). During the crop cycle (90 days), two harvests of lettuce were obtained in floating root system and only one harvest in the traditional and organics culture. The lettuce culture through hydroponics showed greater NR activity and chlorophyll content and for this reason it can be a good alternative to produce lettuce with low nitrate content.
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The land, water, and energy requirements of hydroponics were compared to those of conventional agriculture by example of lettuce production in Yuma, Arizona, USA. Data were obtained from crop budgets and governmental agricultural statistics, and contrasted with theoretical data for hydroponic lettuce production derived by using engineering equations populated with literature values. Yields of lettuce per greenhouse unit (815 m2) of 41 ± 6.1 kg/m2/y had water and energy demands of 20 ± 3.8 L/kg/y and 90,000 ± 11,000 kJ/kg/y (±standard deviation), respectively. In comparison, conventional production yielded 3.9 ± 0.21 kg/m2/y of produce, with water and energy demands of 250 ± 25 L/kg/y and 1100 ± 75 kJ/kg/y, respectively. Hydroponics offered 11 ± 1.7 times higher yields but required 82 ± 11 times more energy compared to conventionally produced lettuce. To the authors' knowledge, this is the first quantitative comparison of conventional and hydroponic produce production by example of lettuce grown in the southwestern United States. It identified energy availability as a major factor in assessing the sustainability of hydroponics, and it points to water-scarce settings offering an abundance of renewable energy (e.g., from solar, geothermal, or wind power) as particularly attractive regions for hydroponic agriculture.
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Crop water requirements of crops in agro-ecological units (AEUs) of Palakkad district of humid tropical Kerala computed with CROPWAT 8.0 using the meteorological parameters.The major cultivated crops are rice, coconut, banana, arecanut, vegetables, pulses, rubber, tea, coffee, cotton etc. The total water requirement for these crops in various agro-ecological zones has been computed. Using the evapotranspiration (ET0) and effective rainfall in each agro-ecological unit (AEU), a climatic water balance has been worked out. The net irrigation demand, the gross irrigation demand and irrigation interval for the various crops grown in different AEUs have been computed. The gross irrigation demand for the district is 1146 Mm3, in which 981 Mm3 is from surface water and 165 Mm3 from groundwater sources. Water balance analysis was done for the current scenario and future demand for agriculture, domestic and industrial demand. The projected future total water demands for irrigation, drinking and industrial purpose will be 3841 Mm3. However, the secondary data showed that utilizable water resources of Palakkad district is less and will create a deficit scenario. This deficit indicates that if the total area is brought under irrigation there will be deficit years and during such periods deficit irrigation or reduction in command area may have to be adopted. A wide spectrum of scenarios has been discussed in the paper along with the guidelines for future management of water resources.
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The driving force of future agricultural industry is to provide sufficient yield that satisfy the needs of consumers and meet their interests in terms of quality. Soilless cultivation is intensively used in protected agriculture to improve control over the growing environment and to avoid uncertainties in the water and nutrient status of the soil. Recently the type of soilless culture transformed from open to close-loop system. This system is known for better result in water use efficiency, while maintaining the quality of the yield. This study aims to describe the specific purpose of soilless culture specifically in close-loop system and how substrate nutrition produces the better quality of the yields.
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Spinach plants (Spinacia oleracea L. cv. Paruku) were grown in deep hydroponic culture while concentrations of oxygen dissolved in the culture medium were varied by either elevating the temperature of the medium or increasing the partial pressure of oxygen. An increase of the solution temperature caused a decrease of oxygen concentration in the medium solution, and reduced respiration rates in roots. Subsequently, photosynthesis was decreased, resulting in reduction of growth. Such growth inhibition was avoided by increasing oxygen concentration in the solution, using an oxygen enricher.
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The aim of this study was to investigate the effect of macro-anion (NO 3-, H2PO4-, and SO 42-) and macro-cation (K+, Ca2+ and Mg2+) proportions in the nutrient solution during two consecutive growing seasons (spring and summer) on yield and leaf quality (chlorophyll content, color parameters, carbohydrates and mineral composition) of Lactuca sativa L. var. acephala grown in a floating system. Marketable yield, shoot biomass and leaf area index were unaffected by nutrient solution composition. A high proportion of calcium in the nutrient solution increased the quality attributes in particular calcium, chlorophyll, glucose and fructose concentrations. Plants grown in the spring season exhibited a lower yield, growth (total dry biomass and leaf area index), leaf mineral content (N, K and Mg), total carotenoids and water use efficiency than those grown in the summer season but were influenced positively by some quality parameters (higher content of glucose and fructose and lower nitrate content). The results demonstrated, that the effect of growing season on leafy lettuce performance (yield and quality) was more pronounced than the effect of nutrient solution composition.
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A field trial was conducted in 2009/2010 and 2010/2011 growing seasons at Giza Agricultural Research Station to examine correlations between some biochemical componets and powdery mildews () resistance in flax cultivars. Nine flax cultivars could be divided into five distinct groups, i.e., highly susceptible (Cortland and C.I. 2008), moderately susceptible (Giza 7, and Marshall), moderately resistant (Cass), resistant (Koto, Dakota and Wilden), and highly resistant (Ottowa 770B). The cultivars showed considerable variation in PM severity ranged from 8.05 on Ottowa 770B to 97.02% on Cortland. Total soluble proteins, total phenols, antioxidant enzymes (peroxidase and polyphenoloxidase), ascorbic acid, tocopherol, and malondialdehyde (MDA), were determined in uninfected leaves of the tested cultivars. Pearson's correlation coefficient was calculated to measure the degree of association between PM severity and each component. All components showed significant (P < 0.05) or highly significant (P < 0.01) negative correlation with PM severity except MDA, which showed positive correlation (P < 0.01). Linear regression analysis was used to evaluate the causal relationship between the biochemical components (independent variables) and PM severity (dependent variable). Coefficient of determination () values of the generated models ranged from 48.76 to 77.15%. Tocopherol, MDA, and proteins were the most important contributors to the total variation in PM severity as the values of their models were 71.78, 75.28, and 77.15%, respectively. The results of the present study suggest that tocopherol, MDA, and proteins in uninfected leaves can be used as biochemical markers to predict PM resistance in flax.
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The study was conducted in greenhouse at horticulture department of the Instituto Federal do Espírito Santo, Campus Itapina, Colatina, northwestern Espírito Santo state, Brazil, with the objective of evaluating the effect of cooling and electrical conductivity of nutrient solution on growth and development of lettuce cv. Vitória de Santo Antão in hydroponics. The study was conducted in a completely randomized design with two factors (control of the maximum temperature of the nutrient solution: 26ºC and without control; and electrical conductivity, EC, of the solution: 1, 2 and 3 dS m-1) with three repetitions. The plants were harvested fifty-two days after sowing (DAS). We evaluated the dry and fresh mass of leaves, stems and roots, stem and root length, root volume and plant water content (%). The temperature of the nutrient solution influenced the behavior of lettuce influenced by the electrical conductivity, showing that the increase of the EC did not reduce the lettuce productivity when the maximum temperature of the nutrient solution is limited, which in this experiment was tested at 26ºC. The cooling of the nutrient solution provided greater accumulation of mass and a higher water percentage in plants, increasing the productivity of hydroponic lettuce in tropical climate.
Article
Bean yellow mosaic virus (BYMV) is the main cause of the mosaic and malformation of many plants, worldwide. Thus, the triggering of plant systemic resistance against BYMV is of great interest. In this endeavor, we aimed to explore the capacity of new carboxymethyl chitosan-titania nanobiocomposites (NBCs, NBC1,2) to trigger faba bean plants resistance against BYMV. Effects of NBCs on faba bean (Vicia faba L.) disease severity (DS), growth parameters, and antioxidant defense system activity were investigated under BYMV stress. Noticeably that the DS in NBCs-treated faba bean was significantly reduced compared to untreated plants. Moreover, treatment with NBCs was remarkably increased growth indices, photosynthetic pigments, membrane stability index, and relative water content compared to challenge control. Additionally, enzymatic and non-enzymatic antioxidants and total soluble protein were significantly increased. Contrary, electrolyte leakage, hydrogen peroxide, and lipid peroxidation were reduced. Interestingly that NBC1 has higher efficacy than NBC2 in triggering plant immune-system against BYMV as indicated from DS percentage (DS = 10.66% and 19.33% in case of plants treated with NBC1 and NBC2, respectively). This could be attributed to the higher content of TNPs in NBC1 (21.58%) as compared to NBC2 (14.32%). Overall, NBCs offer safe and economic antiviral agents against BYMV.
Article
This paper reports the role of exogenous glycine betaine (25 and 50 mM GB at a rate of 50 mL per plant) in enhancing NaCl-stress tolerance in common bean (Phaseolus vulgaris L.). Irrigating plants by simulated saline water, containing 0, 50 and 100 mM sodium chloride (NaCl), significantly reduced the growth dynamics, photosynthetic pigments (i.e., Chl a, Chl b, and carotenoids), membrane stability index (MSI), relative water content (RWC), and pod yield. While, malondialdehyde (MDA), endogenous proline, and glutathione contents, electrolyte leakage (EL), antioxidant defense system, and Na + accumulation markedly increased upon exposure to NaCl-stress. However, the application of exogenous GB significantly improved salt tolerance of common bean as it increased the antioxidant defense including both enzymatic (i.e., peroxidase, superoxide dismutase, and catalase) and nonenzymatic (i.e., proline and glutathione) agents. Consequently, MSI, RWC, EL, and photosynthetic pigments have been improved recording significantly higher values than the control. Moreover, the pod yield increased by 29.8 and 59.4% when plants grown under 50 and 100 mM NaCl, respectively, were sprayed with 25 mM GB. Our results show that GB-induced slat tolerance in common bean plants mainly depends on the osmoregulation effect of GB and to a lesser extent on its antioxidant capacity. Foliar application of GB significantly reduced the accumulation of Na + and at the same time induced K + uptake maintaining a higher K + /Na + ratio. Despite some changes in the activities of antioxidant enzymes induced by the application of GB, no consistent contribution in the salt tolerance could be cited in this study. Therefore, we suggest that salt tolerance is largely unrelated to the antioxidant defense ability of GB in common bean. While the potential role of GB in ameliorating salt tolerance is mainly due to the adjustment of ions uptake through limiting Na + uptake and alternatively increasing K + accumulation in plant tissues.
Article
Lettuce (Lactuca sativa) is one of the most popular leafy vegetables in the world, characterized by a diverse composition of phytochemical compounds but at low levels. However, their content may be increased with abiotic stresses. Accordingly, phytochemical enhancement and related microbiological and organoleptic quality and peroxidase (POD) and polyphenol oxidase (PPO) activities of Butterhead lettuce elicited during preharvest with natural compounds (chitosan 10 g L⁻¹ and tea tree essential oil 2.7 mL L⁻¹) were studied. Quality indices were evaluated at harvest and during 21 days of refrigerated storage (0–2 °C). Treatments with chitosan and tea tree increased the total phenolic content of freshly lettuces by 30.5 and 21.1%, respectively, and the total flavonoids concentration by 43.3 and 36.4%, respectively, compared with control samples. The antioxidant capacity at harvest of the elicited plants, measured with DPPH and TEAC assays, was also higher. Notably, these improvements were maintained during refrigerated storage. Conversely, although a higher concentration of ascorbic acid was initially detected in treated plants with chitosan and tea tree, these differences were not observed at later storage times. No differences were detected in the organoleptic quality of elicited and control plants, meanwhile the microbiological quality and enzymatic activity were affected by the preharvest treatments. In particular, the application of chitosan exerted a fungistatic effect reducing yeast and molds population counts by 1.6 log throughout the storage, compared with control samples. Furthermore, chitosan also reduced the activities of PPO and POD, enzymes related with browning processes. Preharvest treatments with chitosan and tea tree enhanced the content of health-promoting phytochemicals in lettuce, without affecting its organoleptic quality. Moreover, chitosan treatment appears as a promising method to improve the safety and reduce the enzymatic activity of lettuce.
Article
Microbubbled air may be efficiently supplied to the culture solution since microbubbles are more efficiently dissolved in water than millibubbles. To establish an enhanced air supply method in the hydroponic culture of vegetables, microbubbles were applied using the deep flow technique to a hydroponic culture system of spinach. Spinach was cultivated in culture solution treated microbubbles for 21 days, then harvested and measured growth and concentrations of inorganic components and chlorophyll in the leaf blade. The results showed that microbubbles applied to the culture solution promoted the growth of spinach more than that by millibubbles. Using microbubbles, cultivars maintained a high concentration of dissolved oxygen at the middle growth stage, during which the dissolved oxygen concentration in the culture solution was reduced by the active root respiration. This result suggests that microbubbles are more effective than millibubbles in the hydroponic culture of vegetables.
Book
An understanding of the mineral nutrition of plants is of fundamental importance in both basic and applied plant sciences. The Second Edition of this book retains the aim of the first in presenting the principles of mineral nutrition in the light of current advances. This volume retains the structure of the first edition, being divided into two parts: Nutritional Physiology and Soil-Plant Relationships. In Part I, more emphasis has been placed on root-shoot interactions, stress physiology, water relations, and functions of micronutrients. In view of the worldwide increasing interest in plant-soil interactions, Part II has been considerably altered and extended, particularly on the effects of external and interal factors on root growth and chapter 15 on the root-soil interface. The second edition will be invaluable to both advanced students and researchers.
Article
The use of fungicides for an effective control of plant diseases has become crucial in the last decades in the agriculture system. Seeds of cotton plants were treated with systemic and contact fungicides to study the efficiency of seed dressing fungicides in controlling damping off caused by Rhizoctonia solani under greenhouse conditions and its effect on plant growth and metabolism. The results showed that Mon-cut showed the highest efficiency (67.99%) while each of Tondro and Hemixet showed the lowest efficiency (31.99%) in controlling damping off. Rhizolex T, Mon-cut and Tondro fungicides caused significant decrease in plant height, dry weight of plant, phytohormones, photosynthetic pigments, soluble sugars, soluble proteins, total free amino acids but caused significant increases in total phenols, flavonoids, antioxidant enzymes, ascorbic acid, reduced glutathione, MDA and hydrogen peroxide as compared with untreated plants. On the other hand, the other fungicides (Maxim, Hemixet and Flosan) increased all the above recorded parameters as compared with untreated plants. Our results indicated that the fungicides application could be a potential tool to increase plant growth, the antioxidative defense mechanisms and decreased infection with plant diseases.
Chapter
Lactuca sativa Linn. (or lettuce) is a well known plant worldwide due to its use in the preparation of salad, soup, and vegetable curries. This plant also has excellent medicinal properties. Lettuce is cultivated worldwide, and is one of the most consumed green leafy vegetables in the raw form for its taste and high nutritive value. It is regarded as an important source of phytonutrients. It is characterized by considerable morphological and genetic variations. This leaf vegetable was first cultivated by the Egyptians. Today, it is produced all over the world and is used in forensic medicine for many ailments including pain, stomach problems and inflammation, and urinary tract infections. Different studies provided the scientific evidence of its pharmacological potential including antimicrobial, antioxidant, neuroprotective, and hypnotic effects. The chemical composition of the plant revealed the presence of different classes of secondary metabolites, such as terpenoids, flavonoids, and phenols which should be responsible for its biological activities. The plant also contains essential elements, such as vitamins as well as minerals and organic substances.
Article
We developed a discharge plasma reactor under liquid fertilizer for inactivating bacteria in the recirculation system of hydroponics. The plasma reactor consisted of a wire electrode that was placed in an insulating circular cylinder and a grounded electrode on a cylinder outside. The reactor was sunk under liquid fertilizer when used. Atmospheric air was injected into the cylinder using a gas pump and released through arrayed tiny holes of the reactor. Repetitive nanosecond high-voltage pulses were applied to the wire electrode using a magnetic pulse compression pulsed-power generator. The performance of the developed reactor was evaluated using tomato (Solanum lycopersicum L., Rinka 409) seedlings in hydroponics. In this study, 15 L of liquid fertilizer was contaminated with Ralstonia solanacearum, a plant pathogenic bacterium, after 40 min of discharge plasma treatment. The discharge plasma treatment was then continued for 100 min. Results showed that the number of colony forming units (CFU) of R. solanacearum in the liquid fertilizer decreased from 10⁷ to 10² CFU/mL using the discharge plasma treatment. Seedlings with discharge plasma treatment were relatively healthy; in contrast, all seedlings in the positive control wilted and died from infection of R. solanacearum after 12 d. Disease severity was also suppressed after discharge plasma treatment.
Article
The development of controlled environment agriculture techniques such as hydroponics offers a viable alternative to obtain a high efficiency in water use and higher productivity in an environmentally sustainable way. A study was undertaken to assess the feasibility of growing Mentha spicata under hydroponic conditions and to compare its biochemical properties with that of soil-grown plants. The results confirmed that the productivity of M. spicata was higher in terms of crop biometric properties, yield and its influence on the biochemical properties. The per cent yield in M. spicata was 61% higher than the conventional soil farming. The antioxidant activity, enzyme activity and active compounds present in the plant extracts and presence of organic acids were higher in hydroponically grown plants when compared to the soil-grown plants. Similarly, the higher value of phenol and proline in soil-grown plants when compared to hydroponic plants indicated that the plants were subjected to some form of abiotic and biotic stress. Hence, it is suggested that the cultivation of these medicinal plants under hydroponic condition is a viable alternative in urban and peri-urban areas and avoids the problems that are characteristic in conventional cultivation of these plants.
Article
In recent years, there has been a growing trend towards cultivating leafy vegetables in hydroponic systems. Floating system is an alternative hydroponic system suitable for the production of baby vegetable products, ready-to eat salads and minimally processed leafy vegetables. However, the implementation of this system for the production of fully grown leafy vegetables is not sufficiently studied. The aim of the present study was to examine the potential of floating system as an alternative growing technique of lettuce and rocket plants, as well as the effect of nitrogen (N) application rate (three treatments 100, 150 and 200 mg L-1 of N) on plant physiology, quality and yield during three growing periods. The results showed that increasing the N application rate resulted in an increase of fresh weight of the aerial parts of both lettuce and rocket, while total yield ranged between 12.0 to 41.9 and 8.0 to 30.2 kg m-2 of fresh leaves, for lettuce and rocket, respectively. In addition, increasing the nitrogen rate resulted in higher number of leaves for lettuce and rocket, as well as in a significant increase in the rate of photosynthesis. A similar increase was observed in nitrate, K, Mg and Mn content in the leaves, without however exceeding the permissible limits for nitrates in any case. In conclusion, the use of floating raft technique for lettuce and rocket cultivation in order to produce not only seedlings production or baby products, but also fully grown plants of high quality is highly recommended.
Article
Aerobic organisms survive low oxygen (O2) through activation of diverse molecular, metabolic, and physiological responses. In most plants, root water permeability (in other words, hydraulic conductivity, Lpr) is downregulated under O2 deficiency. Here, we used a quantitative genetics approach in Arabidopsis to clone Hydraulic Conductivity of Root 1 (HCR1), a Raf-like MAPKKK that negatively controls Lpr. HCR1 accumulates and is functional under combined O2 limitation and potassium (K⁺) sufficiency. HCR1 regulates Lpr and hypoxia responsive genes, through the control of RAP2.12, a key transcriptional regulator of the core anaerobic response. A substantial variation of HCR1 in regulating Lpr is observed at the Arabidopsis species level. Thus, by combinatorially integrating two soil signals, K⁺ and O2 availability, HCR1 modulates the resilience of plants to multiple flooding scenarios.