Antioxidant Capacity Of Plants Research Articles

Non-enzymatic antioxidant capacity of Carex acuta L. (Cyperaceae)

Carex acuta leaves were sampled on the edge of the glacial lake Gornje bare (National Park “Sutjeska”, Zelengora mountain, Bosnia and Herzegovina). Two types of samples were taken: plants that grew on moist soil at the time of sampling, designated as CAm, and plants that grew partially submerged at the time of sampling were designated as CAs. Our work aimed to compare the content of photosynthetic pigments, concentration of total phenolic compounds and flavonoids as well as antioxidant capacity between two CAm and CAs samples. Our results showed that the concentration of total chlorophyll and carotenoids were higher in the CAm sample. Higher concentrations of phenolic compounds (28.987± 0.502 mg/g DW) and flavonoids (22.079 ± 1.471 mg/g DW) were measured in CAs samples. The antioxidant capacity measured by the ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) method and phosphomolybdenum method were higher in CAm extract. The abilities to reduce Fe3+ ions and to chelate Fe were higher for CAs samples. Obtained results indicate that the content of phenolic compounds and the antioxidant capacity of plants are significantly influenced by environmental conditions even for the same species. The present study provides the first insight into the antioxidant characteristics of C. acuta from the western Balkans.

Endophytic Beauveria bassiana Induces Oxidative Stress and Enhances the Growth of Fusarium oxysporum-Infected Tomato Plants.

Studying the mechanisms through which endophytic fungi confer protection to host plants against parasites will contribute toward elucidating the endophytic fungi-plant-pathogen relationship. In this study, we evaluated the effects of endophytic Beauveria bassiana on the antioxidant activity, oxidative stress, and growth of tomatoes infected with the fusarium wilt pathogen, Fusarium oxysporum f. sp. lycopersici (FOL). Tomato seedlings were inoculated with B. bassiana conidia and then contaminated with FOL experimentally. Four treatments (Control [T1], FOL only [T2], B. bassiana only [T3], and B. bassiana and FOL [T4]) were assessed. The plants from the B. bassiana and FOL treatment (T4) were significantly taller (DF = 3, 56; p < 0.001) and produced more leaves and aerial part biomass than those treated with only FOL (T2). Remarkably, plants in the two treatments with FOL (T2 and T4) had the lowest antioxidant activities; meanwhile, plants from the FOL treatment (T2) had the lowest ROS (superoxide and hydroxyl radicals) contents. Broadly, strong positive correlations between ROS and all the plant growth parameters were recorded in this study. While the current results revealed that the endophytic entomopathogen B. bassiana enhanced antioxidant capacity in plants, it did not improve the antioxidant capacity of F. oxysporum-infected plants. It is possible that the pathogenic FOL employed a hiding strategy to evade the host immune response and the antagonistic actions of endophytic B. bassiana. In conclusion, B. bassiana inoculum enhanced the growth of tomatoes infected with FOL, induced higher oxidative stress in both F. oxysporum-infected and -uninfected tomatoes, and improved antioxidant activities in plants inoculated with B. bassiana only.

Identification of the Major Effector StSROs in Potato: A Potential StWRKY-SRO6 Regulatory Pathway Enhances Plant Tolerance to Cadmium Stress.

SIMILAR TO RCD-ONE (SRO) family members and transcription factors (TFs) often improve plant antioxidant capacity through interaction and co-regulation and participate in plant resistance to drought and high-salt stress. However, whether SROs are involved in the response to heavy metal stress, especially SRO genes with a specific response and tolerance characteristics to cadmium (Cd) stress, remains unclear. We first identified six SRO genes in the potato genome by PARP and RST domains. Special and conserved StSROs were found, and the spatio temporal tissue-specific expression patterns and co-expression network diagrams of StSROs under the stress of 5 heavy metals were constructed. Second, we identified StSRO6 as a major effector gene (StSRO6-MEG) and StSRO5 as a secondary effector gene (StSRO5-SEG) through a comprehensive analysis. Interestingly, they may hold true for various physiological or stress responses in plants. In addition, using systematic genomics and comparative omics techniques, the key gene StSRO6 that affects the difference in Cd accumulation was discovered, cloned in the low-Cd accumulation "Yunshu 505", and transformed into the yeast mutant ycf1 for overexpression. The results proved that StSRO6 could confer Cd tolerance. Finally, through transient expression and in vitro culture tests, we hypothesized that StSROs 5/6 are regulated by the transcription factor StWRKY6 and mediates the reactive oxygen species (ROS) system to confer Cd tolerance. These findings offer a new perspective for understanding the mechanisms underlying Cd tolerance in plants, and simultaneously provide clues for the development of biological agents for preventing and controlling Cd migration and transformation.

Effects of semi-decomposed weeds as substrate on plant growth, antioxidant capacity, and leaf nutrition of plum trees

Sustainable practices are inevitable requirements for modern agriculture. Incorporating weed waste into an organic substrate is one of such sustainable agricultural practice. We aimed to investigate whether semi-decomposed, aboveground weed biomass can be used as a substrate for plums. “Qingcui” plums were planted in boxes with semi-composted weeds, and garden soil without composted weeds was used as a control. Plant branch characteristics, leaf antioxidant capacity, leaf nutrition, and numbers of opening flowers and bearing fruits were analyzed. The results showed that treatment with semi-composted weed treatment significantly increased the stem diameter, effective branch number, and effective branch angle. The contents of the reduced glutathione, oxidized glutathione, and the levels of total antioxidant capacity and catalase were significantly higher in semi-composted weeds than in the control group. The macroelement content in the semi-composted weed group was higher than that of the control group, but the microelement contents did not show any significant differences. However, the trace elements and heavy metals showed heterogeneous changes. The Σ DOP of macroelements, microelements, and trace elements in the weed-compost treatment were larger than that in the control. The chlorophyll content in the weed-compost group was significantly higher than that in the control during the leaf abscission period. The leaf weight per area was significantly higher than that of the control, but the growth time was longer. The numbers of total opening flowers and fruit were higher in the semi-composted weed group than in the control group. We demonstrated that semi-composted weeds as substrates have beneficial effects on plum branch characteristics, leaf antioxidant capacity, and generative growth. However, it increases the degree of nutritional imbalance and extends growth time.

Effects of LED Light Spectra on the Development, Phytochemical Profile, and Antioxidant Activity of Curcuma longa from Easter Island.

Curcuma longa (C. longa), an herbaceous plant used for medicinal purposes by the indigenous people of Easter Island, has been overexploited in its natural habitat, leading to its conservation status being designated as a vulnerable species. We have recently reported on the use of light-emitting diodes (LEDs) to improve the productivity of C. longa in vitro cultures under a temporary immersion system (TIS), but the effects of light quality on plant growth, phytochemical composition, and antioxidant capacity remained unexplored. Here, we set out to study these three aspects as observed at the end of TIS culture (day 0) and after 30 days of greenhouse acclimation (day 30). Thus, we evaluated plant morphological characteristics, phytochemical profile (polyphenols, tannins, flavonoids, reducing sugars, and curcumin), and radical scavenging activity by DPPH, ORAC, and FRAP assays. The results showed that, during in vitro cultivation under TIS, the red:blue (RB) LED light spectrum promoted C. longa shoot proliferation, with the resulting seedlings exhibiting greater fresh weight and no signs of etiolation. In the acclimation phase, the RB spectrum increased phytochemicals, such as polyphenols, flavonoids, and reducing sugars, and boosted curcumin synthesis. Nevertheless, the antioxidant activity of the plants under the RB light spectrum did not intensify. We surmise that this may be due to the premature intraplant allocation of metabolites to alternative pathways (e.g., curcumin synthesis) under RB light.

Salt Stress Induces Changes in Physiological Characteristics, Bioactive Constituents, and Antioxidants in Kenaf (Hibiscus cannabinus L.).

Salinity stress is a major environmental threat in agricultural systems. Kenaf is a promising crop for the future for cultivation in salinity-affected soils because of its high phytoremediation potential. The current study aimed to investigate the effects of salt stress using six different sodium chloride (NaCl) concentrations (0, 50, 100, 150, 200, and 250 mM) on the plant growth, physiological characteristics, bioactive constituents, and antioxidant capacity of H. cannabinus. The results indicated that the NaCl stress induced significant reductions in plant height and in the dry and fresh weights of the leaf tissue. In addition, the K, Ca, Mg, and P concentrations in this tissue also decreased under NaCl stress treatment conditions. In contrast, the NaCl stress led to the accumulation of hydrogen peroxide (H2O2), superoxide anion (O2•−), malondialdehyde (MDA), proline, total soluble sugar, and total soluble protein. Under NaCl stress, the levels of antioxidants, including phenolics and flavonoids, also increased. The gas chromatography–mass spectrometry (GC-MS) results showed that the volatile compounds, including heptacosane, 1-octadecanesulphonyl chloride, and tetratetracontane, were induced under the NaCl stress treatment. Furthermore, the salt stress significantly improved the antioxidant capacity of the leaf extracts. These findings may provide insight into how H. cannabinus plants respond to salt stress and may help improve its medicinal value under salt stress.

Screening of antioxidant capacity of Nepali medicinal plants with a novel singlet oxygen scavenging assay.

The online version contains supplementary material available at 10.1007/s10068-022-01175-z.

Overexpression of CsGSH2 Alleviates Propamocarb Residues and Phytotoxicity in Cucumber by Enhancing Antioxidant and Glutathione Detoxification Properties

Propamocarb is a pesticide widely used to control cucumber downy mildew. The overuse of propamocarb has resulted in residues and phytotoxicity. However, the detoxification and metabolic process of propamocarb have not been documented well. Our previous work showed differences in the propamocarb residues among the different genotypes of cucumber and their regulation by multiple genes. Based on the already reported data on gene expression profiles under propamocarb treatment, we identified the glutathione pathway, including six different genes (Csa4M303130, Csa3M133380, Csa5M409710, Csa7M395820, Csa3M597320, and Csa1M571280), involved in propamocarb detoxification. The qPCR analysis showed that Csa1M571280 (CsGSH2) was most significantly and differentially expressed at 48 h after propamocarb spray in the cucumber varieties Y3F604 (low propamocarb residues) and M729 (high propamocarb residues). In Y3F604, CsGSH2 expression increased from 6 to 48 h after spraying propamocarb, and the expression was positively correlated with propamocarb residues, whereas M729 showed no significant difference in CsGSH2 expression. Therefore, we presumed CsGSH2 as a key gene in managing propamocarb residues. Gene functional analysis showed that propamocarb residues decreased in CsGSH2-overexpressing plants and increased in CsGSH2-antisense plants. Overexpression of CsGSH2 enhanced glutathione (GSH) accumulation and glutathione S-transferase (GST), glutathione reductase (GR), and glutathione peroxidase (GPX) activities, probably for propamocarb detoxification. The activity of antioxidant enzymes (SOD, POD, CAT, and APX) increased to maintain a high antioxidant capacity in CsGSH2-overexpressing plants. The superoxide (O2−), hydrogen peroxide (H2O2), and malondialdehyde (MDA) levels decreased in CsGSH2-overexpressing plants, promoting the antioxidant system composed of ascorbic acid and glutathione (AsA-GSH). Thus, we conclude that CsGSH2 alleviates propamocarb residues and phytotoxicity by enhancing cucumber’s antioxidant and glutathione detoxification potential.

Interactions between hydrogen sulphide and rhizobia modulate the physiological and metabolism process during water deficiency-induced oxidative defense in soybean.

Hydrogen sulphide (H2 S), a new gas signal molecule, participates in the regulation of various abiotic stresses in plants. However, how the tandem working of H2 S and rhizobia affects the adaptation of soybean to water deficiency is still unclear. In this study, we investigated the adaptation mechanism of H2 S and rhizobia in soybean to water deficiency. Our results revealed that H2 S and rhizobia jointly enhanced the leaf chlorophyll content and relative water content in plants, and caused an increase in the biomass of soybean seedlings under water deficiency. Besides, in the absence of water, H2 S enhanced the biomass by affecting the number of nodules and nitrogenase activity during vegetative growth. The expression of nodulation marker genes including early nodulin 40 (GmENOD40), ERF required for nodulation (GmERN) and nodulation inception genes (GmNIN1a, GmNIN2aand GmNIN2b) were upregulated by H2 S and rhizobia in the nodules. Moreover, the combined effect of H2 S and rhizobia was proved to affect the enzyme activities and gene expression level of antioxidants, as well as osmotic protective substance content and related gene expression levels under water deficiency in soybean seedlings. In addition, the metabolomic results suggested that the combined effect of H2 S and rhizobia remarkably promoted the contents of lipids and lipid-like molecules. Our results indicated that H2 S and rhizobia synergistically reduced the oxidative damage caused by water deficiency through increasing the accumulation of metabolites and strengthening the plant antioxidant capacity.

Peroxidase Activity in Tomato Leaf Cells under Salt Stress Based on Micro-Hyperspectral Imaging Technique

Salt stress has become a major problem in the tomato planting process, of which peroxidase (POD) activity is an important parameter reflecting the antioxidant capacity of plants. In order to explore the dynamic changes of catalase in leaves under different concentrations of NaCl stress, it is necessary to establish a rapid detection technology for changes of POD activity in micro-areas of leaves. In this study, a total of 139 microscopic images were obtained under different concentrations of salt stress (0 g/L, 1 g/L, 2 g/L, 3 g/L) in the spectral range of 400–1000 nm. Regions of interest were extracted according to the reflectance of the samples, and the model was established by combining POD activity. Various spectral pre-treatment combined with partial least-squares regression models was compared to original spectrum combined with partial least-squares regression model. The characteristic wavelength was extracted by four methods, and partial least-squares regression (PLSR) and principal component regression (PCR) were established according to the characteristic wavelength. The results show that multiple scattering correction (MSC) is optimized as the pre-treatment method. The partial least-squares regression model based on the interval variable iterative space contraction method is the best, and the coefficient of determination and root mean square error of prediction set (RMSEP) are 0.66 and 18.94 U/g·min, respectively. The results show that it is feasible to detect the peroxidase activity in tomato leaves by micro-hyperspectral imaging combined with stoichiometry.

Exogenous brassinolide improves the antioxidant capacity of Pinellia ternata by enhancing the enzymatic and nonenzymatic defense systems under non-stress conditions.

Brassinolide (BR) improves the antioxidant capacity of plants under various abiotic stresses. However, it is not clear about the effect of BR on the antioxidant capacity in plants under non-stress conditions. In the present study, the antioxidant defense response of Pinellia ternata was to be assessed by applying BR and propiconazole (Pcz) under non-stress conditions. BR treatment enhanced the flavonoid content, peroxidase, and ascorbate peroxidase (APX) activity by 12.31, 30.62, and 25.08% and led to an increase in 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity by 4.31% and a decrease in malondialdehyde content by 1.04%. Exogenous application of BR improved the expression levels of PAL, CHS, CHI, and DFR genes by 3. 18-, 3. 39-, 2. 21-, and 0.87-fold in flavonoid biosynthesis, PGI, PMI, and GME genes by 6. 60-, 1437. 79-, and 3.11-fold in ascorbic acid (ASA), biosynthesis, and γECs and GSHS genes by 6.08- and 2.61-fold in glutathione (GSH) biosynthesis pathway, and the expression of these genes were inhibited by Pcz treatment. In addition, BR treatment promoted the ASA–GSH cycle by enhancing the expression of APX, DHAR, and MDHAR genes, which were enhanced by 3. 33-, 157. 85-, and 154.91-fold, respectively. These results provided novel insights into the effect of BR on the antioxidant capacity in bulbil of P. ternata under non-stress conditions and useful knowledge of applying BR to enhance the antioxidant capacity of plants.

Evaluation of UV-B lighting design for phenolic production in kale plants using optical simulation with three-dimensional plant models in plant factories

Although ultraviolet-B (UV-B, 280–315 nm) radiation has been known as an effective elicitor for improving bioactive compound contents in plants, its practical application to plant factories is still in its infancy. This study aimed to develop an evaluation method for optimising the lighting design of UV-B radiation in plant factories. To this end, a prediction model of phenolic content was adapted for kale ( Brassica oleracea L. var. acephala) plants grown in a plant factory using an optical simulation in a three-dimensional plant model. The prediction model was calibrated using experimental data with different 310 nm UV-B light-emitting diode (LED) arrangements. UV-B radiation significantly enhanced the total phenolic content, total flavonoid content, UV-B absorbing pigment content, and antioxidant capacity in kale plants. In scenario analysis with variables of lighting system, such as vertical or horizontal lighting distance and lighting angle of UV-B LED, the spatial distribution of phenolic accumulation was estimated using the calibrated model and simulated UV-B radiation interception. Although the uniformity and efficiency were opposite in most scenarios, both values for phenolic production increased with changes in horizontal position. The annual yields per electrical energy consumed for producing total phenolics and flavonoids were expected to improve by 14.2 and 34.0%, respectively, assuming the addition of UV-B LED as the optimal lighting design among the scenarios. These evaluation and optimisation methods using model-based simulations will help to design custom UV-B lighting systems for the production of bioactive compounds in commercial plant factories. • UV-B radiation for phenolic production in plant factories should be optimised. • Prediction model of phenolic content in 3D plant structure was adapted. • UV-B lighting systems was evaluated with estimated radiation use efficiency. • Yield per electrical energy consumed could be improved by 14.2–34.0%. • Novel evaluation and optimisation methods of UV-B lighting systems were suggested.

Effects of exogenous melatonin on antioxidant capacity and nutrient uptake of Lolium perenne and Medicago sativa under drought stress

To explore the effects of exogenous melatonin on antioxidant capacity and nutrient uptake of plants under drought stress, we used Lolium perenne and Medicago sativa potted seedlings for foliar spraying and root application of 100 μmol·L-1 melatonin, respectively. We measured the biomass, malondialdehyde (MDA) content, relative conductivity, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities, as well as nutrient contents (organic carbon, total nitrogen, total phosphorus) under drought stress. The results showed that the biomass of L. perenne and M. sativa decreased significantly under drought stress, and that external melatonin application could effectively alleviate the inhibitory effect of drought stress on L. perenne and M. sativa. Foliar spray and root application of melatonin under drought stress enhanced L. perenne biomass by 14.5% and 29.6%, and that of M. sativa by 36.6% and 49.1%, respectively. The SOD and POD activities in L. perenne and SOD activity in M. sativa significantly decreased under drought stress, and exogenous melatonin significantly increased SOD, POD and CAT activities in L. perenne and M. sativa, reduced the accumulation of MDA in leaves, caused a significant decrease in the relative conductivity of leaves, and significantly increased antioxidant capacity. Drought stress and exogenous melatonin did not affect organic carbon content of L. perenne and M. sativa. Under drought stress, the contents of N and P in L. perenne leaves and roots and the content of N in M. sativa roots decreased, while the application of melatonin increased the contents of N and P in roots and leaves of L. perenne and M. sativa, indicating that melatonin could regulate the nutrient absorption of L. perenne and M. sativa under drought stress. In conclusion, the melatonin application not only improved the antioxidant capacity of plants, but also regulated nutrient uptake to enhance plant resilience to drought stress. Foliar spraying of melatonin was more effective than root application.

Effect of Exogenous Melatonin Application on the Grain Yield and Antioxidant Capacity in Aromatic Rice under Combined Lead-Cadmium Stress.

This study aimed to determine the mechanism of exogenous melatonin application in alleviating the combined Pb and Cd (Pb-Cd) toxicity on aromatic rice (Oryza sativa L.). In this study, a pot experiment was conducted; two aromatic rice varieties, Yuxiangyouzhan and Xiangyaxiangzhan, were selected, and sprays using 50, 100, 200, and 400 μmol L−1 melatonin (denoted as S50, S100, S200, and S400) and irrigation using 100, 300, and 500 μmol L−1 melatonin (denoted as R100, R300, and R500) were also selected. The results showed that, under the S50, S100, and S200 treatments, the Pb content of aromatic rice grain decreased, and the grain yield increased significantly. Moreover, the application of exogenous melatonin significantly reduced the accumulation of H2O2 in rice leaves at maturity under Cd–Pb stress and reduced the MDA content in Xiangyaxiangzhan leaves. In addition, the microbial community structure changed significantly under S50 and R300 treatments. Some pathways, such as the synthesis of various amino acids and alanine, aspartate, and glutamate metabolism, were regulated by S50 treatment. Overall, melatonin application improved aromatic rice grain yield while reducing heavy metal accumulation by regulating the antioxidant capacity and metabolites in aromatic rice plants and altering the physicochemical properties and microbial community structures of the soil.

The Nutritional and Functional Aspects of White Vegetables

Vegetables have an imperative role in human nutrition and make up a significant portion of daily diet. Vegetables are grouped into many categories such as green, red, yellow, white etc. White vegetables are higjh in carbohydrates, proteins, minerals, vitamins, dietary fibres, and other bioactive compounds. They are nutritionally equivalent to any other coloured veggies. The bright or rainbow-colored foods have traditionally enticed and motivated humans when choosing meals, particularly vegetables. Though colour is thought a good indicator of a plant's antioxidant capacity, that doesn't mean that white vegetables aren't rich in antioxidants. Due to the presence of glucosinolates, cauliflower and turnip have long been known to have anti-carcinogenic properties. Similarly, white onion and garlic have beneficial properties and aid in disease prevention. It is believed that mushrooms can reduce the risk of developing health conditions such as Alzheimer’s disease, heart ailment, cancer, and diabetes. Potatoes contribute important nutrients including potassium, vitamin C, and dietary fiber to the human diet and have been a mainstay of human diets for centuries. Potato also contains a number of bioactive components that extend disease prevention capacity. A variety of nutritional and functional benefits can be associated with white vegetables and should be incorporated into diet.

Identification and Characterization of Two Bibenzyl Glycosyltransferases from the Liverwort Marchantia polymorpha.

Liverworts are rich in bibenzyls and related O-glycosides, which show antioxidant activity. However, glycosyltransferases that catalyze the glycosylation of bibenzyls have not yet been characterized. Here, we identified two bibenzyl UDP-glucosyltransferases named MpUGT737B1 and MpUGT741A1 from the model liverwort Marchantia polymorpha. The in vitro enzymatic assay revealed that MpUGT741A1 specifically accepted the bibenzyl lunularin as substrate. MpUGT737B1 could accept bibenzyls, dihydrochalcone and phenylpropanoids as substrates, and could convert phloretin to phloretin-4-O-glucoside and phloridzin, which showed inhibitory activity against tyrosinase and antioxidant activity. The results of sugar donor selectivity showed that MpUGT737B1 and MpUGT741A1 could only accept UDP-glucose as a substrate. The expression levels of these MpUGTs were considerably increased after UV irradiation, which generally caused oxidative damage. This result indicates that MpUGT737B1 and MpUGT741A1 may play a role in plant stress adaption. Subcellular localization indicates that MpUGT737B1 and MpUGT741A1 were expressed in the cytoplasm and nucleus. These enzymes should provide candidate genes for the synthesis of bioactive bibenzyl O-glucosides and the improvement of plant antioxidant capacity.

Influence of radio-grain priming on growth, antioxidant capacity, and yield of barley plants

The study aimed to examine the influence of different doses (0, 5, 10, and 20 Gray) of gamma radiation on growth, yield traits, and biochemical constituents of barley plants. The low doses (5 and 10 Gy) significantly improved the growth and yield of barley crop. Surprisingly, a higher dose (20 Gy) increased shoot growth and tillers number. Photosynthetic pigments were increased markedly at low doses (5 Gy) whereas decreased at high one. Gamma radiation enhanced total phenols, total flavonoids, total amino acids, antioxidant enzymes and H2O2. In addition, the protein profile showed varies in response depending on the applied dose. Conversely, gamma rays resulted in lower total sugars and proline than the corresponding control values. Ultimately, the modified antioxidant potential, protein pattern, and metabolic changes of barley exhibited the effectiveness of low doses of gamma irradiation in improving growth, and yield of barley plants.

Improvement of Phytopharmaceutical and Alkaloid Production in Periwinkle Plants by Endophyte and Abiotic Elicitors

Periwinkle plant represents a major source of immensely vital terpenoid indole alkaloids and natural antioxidants which are widely used in cancer chemotherapy. A pot experiment was done to evaluate the role of two periwinkle endophytes (Streptomyces sp. and Bacillus sp.) with or without abiotic elicitors (aluminum chloride, tryptophan, and chitosan) on plant biomass, physio-biochemical attributes, phytopharmaceutical constituents, and alkaloid production. Inoculation with endophyte microbes significantly increased plant growth, nitrogen, phosphorus, potassium, carotenoids, ascorbic acid, and alkaloid yield. It also decreased oxidative biomarkers (hydrogen peroxide and malondialdehyde) and had no significant effects on flavonoids and anthocyanin. In this regard, Streptomyces sp. was more effective than Bacillus sp. Foliar spraying with chitosan significantly increased plant growth, chlorophyll, ions, antioxidant capacity, phytopharmaceutical constituents (total soluble phenols, flavonoids, and anthocyanin), and alkaloid yield, associated with a decline in oxidative biomarkers. Conversely, aluminum chloride application generally increased oxidative biomarkers, which was associated with a decreasing effect on plant growth, chlorophyll, and ions. Application of either tryptophan or chitosan with endophyte microbes increased plant growth, chlorophyll, ions, antioxidants, and alkaloid; meanwhile, it decreased oxidative biomarkers. On the contrary, aluminum chloride with endophytes evoked oxidative damage that was associated with a reduction in plant growth, chlorophyll, ions, and phytopharmaceutical constituents. The current study provides a proof-of-concept of the use of the endophyte Streptomyces sp. with chitosan for enhancing periwinkle plant biomass, phytopharmaceuticals accumulation, and alkaloid production.

Research Progress in the Effects of Steam Explosion on Plant Polyphenols and Antioxidant Capacity

Research Progress in the Effects of Steam Explosion on Plant Polyphenols and Antioxidant Capacity

Zincum Metallicum, a homeopathic drug, alleviates Zn-induced toxic effects and promotes plant growth and antioxidant capacity in Lepidium sativum L.

In this study, we investigated the effect of the homeopathic drug Zincum Metallicum (ZM) on zinc (Zn) toxicity in the plant species Lepidium sativum L. We focused on growth parameters, Zn uptake and numerous biochemical parameters. Seedlings were hydroponically subjected during 7days to 0.05, 500, 1000, 1500 and 2000µM Zn2+, in the absence or presence of 15ch or 9ch ZM. In the absence of ZM, Zn induced negative effect on growth especially at the dose of 2mM. Zn induced also chlorosis, reduced total chlorophyll and/or carotenoid content and increased the level of malondialdehyde (MDA). Under Zn toxicity (500, 1000 and 1500µM), the superoxide dismutase (SOD), catalase (CAT), gaiacol peroxidase (GPX) and glutathione reductase (GR) activities were increased or not significantly affected, while at 2000µM Zn affected the activity of these enzymes. At the highest Zn level (2mM), proline and total polyphenol and flavonoid contents were markedly increased in leaves and roots of L. sativum. Additionally, ZM supply considerably ameliorated the plant growth, photosynthetic pigment contents and increased non-enzymatic antioxidant molecules and enzymatic activities against Zn-induced oxidative stress. Our data suggest that homeopathic properties of ZM may be efficiently involved in the restriction of Zn-induced oxidative damages, by lowering Zn accumulation and translocation in the leaves and roots of Lepidium sativum L.