Microplastics (MPs) have become a global environmental issue, however, the threats of metal-associated MPs to soil ecosystems and their involved processes have not been fully disclosed. In this ...study, a microcosm experiment with co-exposure of polyethylene and cadmium was conducted to determine their joint effects on the earthworm Eisenia fetida and to explore their relationship with the soil Cd availability that affected by MPs. The results showed that 28-day co-exposure of MPs and Cd significantly induced higher avoidance responses, weight loss and reduced reproduction of earthworms with the increasing content of pollutants. MPs and Cd jointly inhibited the superoxide enzyme (SOD) and peroxidase (POD) activities while increasing the glutathione (GSH) and malondialdehyde (MDA) activities in E. fetida. Histopathological changes and DNA damage to earthworm sperm also occurred in an MPs-dose-dependent manner. In addition, the presence of MPs significantly increased the soil diethylenetriaminepentaacetic acid (DTPA)-Cd concentrations by 1.20-fold and 1.43-fold while increasing the Cd bioaccumulation in E. fetida by 2.65-fold and 1.42-fold in low- and high-Cd-contaminated soil, respectively, which potentially contributed to the aggravation of the joint toxicity to E. fetida. In conclusion, this study demonstrated that microplastics could enhance the cadmium availability in the co-exposure soil which resulted in the joint toxicity of metal-associated MPs to soil organisms.
MPs increased soil Cd availability and potentially aggravated the joint toxicity with Cd to Eisenia fetida.
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•Co-exposure to microplastics and cadmium inhibited earthworm growth and reproduction.•Co-exposure to microplastics and cadmium induced the oxidative stress of Eisenia fetida.•Combined exposure induced the histopathological and sperm DNA damages of Eisenia fetida.•Microplastics increased the cadmium bioaccumulation in Eisenia fetida.•Microplastics could enhance the cadmium availability in the co-exposure soil.
: Antioxidant enzymes form the first line of defense against free radicals in organisms. Their regulation depends mainly on the oxidant status of the cell, given that oxidants are their principal ...modulators. However, other factors have been reported to increase antioxidant enzyme activity and/or gene expression. During the last decade, the antioxidant melatonin has been shown to possess genomic actions, regulating the expression of several genes. Melatonin also influences both antioxidant enzyme activity and cellular mRNA levels for these enzymes. In the present report, we review the studies which document the influence of melatonin on the activity and expression of the antioxidative enzymes glutathione peroxidase, superoxide dismutases and catalase both under physiological and under conditions of elevated oxidative stress. We also analyze the possible mechanisms by which melatonin regulates these enzymes.
•Under normal conditions, Streptomyces strains increased tomato yield by 35 %.•Under drought stress, decreased in fruit weight (by 60 %) was significantly ameliorated by Streptomyces ...treatments.•Streptomyces strains suppress stress signals, at biochemical and molecular levels.
Application of PGPRs that are tolerant to abiotic stresses is a promising approach to reduce the negative effects of drought stress and increase crop production. This study was designed to select and evaluate stress-tolerance PGP Streptomyces strains based on in vitro and in vivo experiments. Our results showed that only a small percentage (14 %) of 107 Streptomyces can produce ACCD. The effect of two selected isolates, IT25 an ACCD producing and C-2012 which did not have this ability but was able to tolerate NaCl 13 %, was evaluated on the growth and yield of tomato plants under normal and drought stress conditions. Under normal conditions, strain IT25 and C-2012 increased tomato yield 35 and 32 % respectively. Besides, decreased in fruit weight (by 60 %) under drought stress was significantly ameliorated in plants treated with Streptomyces strains. Both isolates, increased leaf RWC, proline, MDA, H2O2 and total sugar content and APX activity and decreased CAT and GPX activity under stress conditions. Plants exposed to drought stress exhibited a highly increased expression of ERF1 and WRKY70 in the roots. Both isolates inhibited expression of the genes under stress conditions. Streptomyces strains suppress stress signals, at biochemical and molecular levels to halt the plant's understanding of stress whereas, through increasing leaf RWC, compensated for the decrease in the yield. In conclusion, ACCD producing and salt tolerant Streptomyces both have the potential to prevent yield losses in tomato fruits under drought stress. However, the precise mechanism of their impact on the plant still needs to be addressed in future researches.
Heat stress leads to an array of physiological, biochemical, and molecular changes in plants affecting its growth and development. An experiment was conducted to find out the effect of short-term ...heat stress on osmo-protectant and antioxidants in 37 genotypes (32 mutants and five varieties) of moth bean (Vigna aconitifolia). Seeds were grown in plastic pots containing sterilized vermiculite. Heat stress conditions were created by exposing seven days old seedlings at 42°C for one hour in hot air oven. Analysis of various parameters was carried out at three days after heat stress. A significant over-accumulation of total sugar and proline along with an increased activity of CAT, GPOX and SOD was observed in most of the genotypes under heat stress. However, correlation analysis among heat stress induced biochemical parameters suggests that none of these traits were associated with the level of thermo-tolerance except GPOX activity. Among 37 genotypes, on the basis of number of fresh plants with least wilting symptoms, six were categorized as tolerant, 13 as moderately tolerant and 18 as susceptible accession. Eventually, it is evident that thermo tolerance and biochemical parameters can be efficiently altered and improved through mutagenesis, though this altered tolerance level could not be associated with the parameters studied in the present investigation.
To compare gill hypoxia adaptation mechanisms, the hypoxia-related physiological indices were measured in F3 self-crossing population of blunt snout bream (Megalobrama amblycephala)♀ × topmouth ...culter (Culter alburnus)♂ hybrids. The critical oxygen pressure (Pcrit) of F3 population was 28.33 ± 1.58 Torr, which is higher than topmouth culter (21.69 ± 0.85 Torr) and lower than blunt snout bream (33.00 ± 0.97 Torr). Moreover, the lower oxygen tension threshold for loss of equilibrium (LOEcrit) of F3 hybrids was 1.09 mg·L−1 higher than topmouth culter (0.91 mg·L−1) and lower than blunt snout bream (1.30 mg·L−1). These results indicated that the hypoxia tolerance of F3 hybrid fish was significantly higher than that of blunt snout bream. In the hypoxic environment, gill remodeling reactions increased the mass-specific lamellar area. In this study, gill remodeling was observed in blunt snout bream, topmouth culter and F3 hybrids. However, a particularly intriguing finding was that the gill recovery ability of F3 population was better than that of blunt snout bream after reoxygenation treatment. This might be related to the capability of physiological and biochemical regulation and lactic acid excretion of F3 hybrids. Together, these results showed that the F3 population inherited the gill remodeling mechanism of their parents, which had better hypoxia tolerance than blunt snout bream, and they could change the morphology and physiological and biochemical levels of gill tissue to cope with hypoxia.
•F3 population inherited gill remodeling mechanism of blunt snout bream × topmouth culter.•The hypoxia tolerance of F3 population is significantly higher than that of blunt snout bream.•Different hypoxia tolerance in F3 fish is related to differences in the adaptability of gills to hypoxia.
•UV-C applied to grapevine cuttings for the first time induces abiotic stress, causing physiological and biochemical changes and affecting the growth of the cuttings.•The marked increase of ...trans-resveratrol and antioxidant activity in leaves highlights the potential of UV-C and increases the efficiency of plant defense mechanisms.•UV-C application increases photosynthetic processes through an increase in photosynthetic pigments, promoting plant metabolism and enhancing development.
In this study, UV-C was applied to the cuttings of Cabernet Sauvignon and Cabernet Franc cv.’s at three different durations to simulate abiotic stress, with subsequent monitoring of resultant changes upon the formation of at least six leaves. In both grape varieties, total phenolic compounds and antioxidant capacity in leaves reached the highest levels after 60 min of UV-C treatment. Trans-resveratrol content reached its highest level with an increase of 157 %. The activity of superoxide dismutase enzyme reached its highest level with an increase of 630 %, especially in Cabernet Franc. Total chlorophyll, chlorophyll a, chlorophyll b contents reached their highest levels after 60 min of UV-C treatment. UV-C treatments did not affect shoot number. However, parameters such as fresh and dry shoot weight, shoot length, fresh and dry root weight reached their highest levels after 45 min of UV-C stress. In correlation analysis, the highest correlation was found between trans-resveratrol and chlorophyll b. In principal component analysis, 6 min of UV-C stress had the highest loading on component 1 and 45 min of UV-C stress had the highest loading on component 2. These results suggest that UV-C treatment may be a potential method to improve grape quality and plant health by inducing important physiological responses in grapevines. This is the first study to investigate the effects of UV-C treatment on grapevine cuttings.
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Cadmium (Cd) level is continuously increasing in agricultural soils mainly through anthropogenic activities. Cadmium is one of the most phytotoxic metals in soils. The present study investigates the ...possible role of exogenously applied glycinebetaine (GB) in alleviating Cd toxicity in cotton (Gossypium hirsutum L.) plants in a hydroponic system. Three concentrations of Cd (0, 1.0, and 5.0 μM) were tested with and without foliar application of GB (1.0 mM). Cadmium toxicity caused a significant decrease in plant height, root length, number of leaves per plant, fresh and dry weights of leaf, stem and root and intensively increased Cd concentration in different plant parts. Cadmium toxicity also decreased photosynthetic pigments and gas exchange characteristics in leaves. Superoxide dismutase (SOD), guaiacol peroxidase (POD), catalases (CAT) and ascorbate (APX) activities increased under lower Cd stress (1.0 μM) while decreased under higher Cd stress (5.0 μM). Cadmium toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA), hydgrogen peroxide (H2O2) and electrolyte leakage in both leaves and roots. Application of GB decreased Cd concentration in different plant parts, alleviated Cd-induced inhibition in plant growth and biomass and led to a significant increase in photosynthetic pigments, protein contents and antioxidant enzymes. Glycinebetaine application alleviated the oxidative damage as evidenced by the decreased production of electrolyte leakage, H2O2 and MDA contents. These results revealed that GB might alleviate Cd toxicity in cotton plants through lowering Cd concentrations and regulating Cd induced oxidative stress in different plant parts possibly by increasing the performance of the antioxidant enzymatic system.
•Cadmium stress reduced antioxidant enzyme activities in both leaves and roots.•Application of glycinebetaine alleviated Cd toxicity in cotton.•Glycinebetaine enhanced antioxidant enzyme activities, photosynthesis and plant growth.•Glycinebetaine might be useful candidate for reduction of Cd uptake in cotton seedlings.
Introduction Rose is one of the important cut flowers, which has different types. Extending the vase life of rose-cut flowers is very important in the floriculture industry. Every year, due to the ...lack of proper storage conditions after harvesting, the efficiency of rose production decreases. Therefore, always using materials that help increase the shelf life of cut flowers is valuable. Today, substances that improve the quality of cut flowers are very important. They include materials such as calcium and silver. Nanoparticles are materials with sizes smaller than 100 nanometers. On the other hand, the important role of calcium and silver in improving quality of the cut flowers is interesting for scientists. In this research, the effect of pre-harvest application of calcium nanoparticles along with the post-harvest application of silver nanoparticles on the morpho-physiological characteristics of rose cut flowers (CV: Classic Cezanne) was investigated. Material and Methods The current research was carried out during the year 2021 in a commercial rose production greenhouse in Nazarabad city. calcium nanoparticles with different concentrations (0, 5 and 10 mg.L-1) were sprayed on rose bushes every ten days (two months before harvest). After harvesting the flowers and transferring them to the laboratory, silver nanoparticles were added to the flower preservation solution at different concentrations (0, 5 and 10 mg.L-1). After harvesting, the traits (vase life, flower diameter, fresh weight, vase solution uptake, total protein, malondialdehyde and superoxide dismutase) were evaluated on the treated flowers (on days 0, 4, 8 and 12). Experiment was performed as factorial based on completely randomized design, included 9 treatments with 3 replications. Results and Discussion Based on the results of analysis of variance of treatment with calcium nanoparticles and silver nanoparticles for the quality of shelf life at the 1% level of Duncan's test, it showed a significant difference. Also, based on the results, the highest amount of vase life is related to the treatment of calcium nanoparticles with a concentration of 10 mg.L-1 with the silver nanoparticle treatment in the time after harvesting was at concentrations of 5 and 10 mg (11 days) and the lowest amount was related to the control treatment (7 days).Vase life increased under the effect of treatment with calcium nanoparticles and silver nanoparticles (10 mg.L-1) and caused an increase of 4 days compared to the control (0 mg.L-1) The treatments decreased the amount of malondialdehyde and also increased the relative amount of absorbed solution, total protein and superoxide dismutase enzyme. Based on the results of this study, calcium and silver nanoparticles improved qualitative traits. The simultaneous treatment of calcium and silver nanoparticles (concentration 10 mg.L-1) compared to the control (0 mg.L-1) caused an increase (14%) in flower diameter, fresh weight (12%), vase solution uptake (46%), superoxide dismutase (21%) and malondialdehyde reduction (37%). Two other important findings emerged from this work: (1) The nanoparticles used in this experiment caused the activation of the enzyme antioxidant system in the treatments (2) The simultaneous treatment of nanoparticles calcium before harvesting and silver nanoparticles treatment after harvesting by activating the antioxidant enzyme system and maintaining the ability to absorb the solution increased the vase life of rose cut flowers. In general, the treatment with calcium nanoparticles at a concentration of 10 mg. L-1 before harvesting and the treatment with silver nanoparticles at a concentration of 10 mg.L-1 after harvesting were the most effective treatments in most traits. Conclusion Calcium is one of the most effective factors in increasing the vase life of rose cut flowers. Treatments containing calcium increase absorption of vase solution uptake. The treatment of calcium nanoparticles increases the total protein and superoxide enzyme compared to the control, so that the simultaneous use of silver and calcium nanoparticles increases the vase life of rose-cut flowers compared to the control. Calcium probably activated a chain of reactions by activating the message transmission system and caused the expression of genes involved in the antioxidant system of the samples. silver nanoparticles by affecting the absorption of vase solution uptake and reducing the amount of malondialdehyde and increasing the total protein and superoxide dismutase enzyme compared to the control, increase the vase life of cut flowers. According to the results obtained from the present research, it can be concluded that use of calcium nanoparticles with silver nanoparticles had great effects on most of traits in compared to control treatment. The use of calcium nanoparticles with silver nanoparticles improves the vase life conditions by increasing water uptake and consequently increasing the relative fresh weight.
Drought is a main abiotic stress that restricts plant growth and development. The increased global demand of anti-cancer alkaloids extracted from periwinkle (Catharanthus roseus) is mainly related to ...plant growth and development, which are severely affected by drought. Chitosan nanoparticles (CSNPs) have been used to boost plant growth and defense mechanism, however their impact to alleviate drought stress of C. roseus has not been investigated yet. In this study, control and stressed plants (100 and 50% of field capacity FC, respectively) were subjected to CSNPs application at 1%. Drought stress considerably reduced plant growth, relative water content (RWC), stomatal conductance and total chlorophyll; however, CSNPs mitigated these effects. They enhanced proline accumulation and the activity of catalase (CAT) and ascorbate peroxidase (APX) with possible mitigation of drought-induced oxidative stress. Therefore, they reduced H2O2 and malondialdehyde (MDA) accumulation, and eventually preserved membrane integrity. Drought stress increased alkaloid accumulation, and further increase was observed with the application of CSNPs. High alkaloid content was associated with induced gene expression of strictosidine synthase (STR), deacetylvindoline-4-O-acetyltransferase (DAT), peroxidase 1 (PRX1) and geissoschizine synthase (GS) up to 5.6 folds under drought stress, but more accumulation was noticed with the application of CSNPs. Overall, this study is the first on using CSNPs to mitigate drought stress of C. roseus by inducing the antioxidant potential and gene expression of alkaloid biosynthesis.
•Application of CSNPs enhanced the growth of water-stressed C. roseus.•Accumulation of MDA and H2O2 were lowered due to CSNPs treatment.•CSNPs induced the activities of CAT and APX enzymes under drought.•CSNPs afforded considerable protection against water-induced oxidative damage.•CSNPs increased alkaloid content and STR, DAT, PRX1 and GS genes expressions under drought.
Phthalates (phthalic acid esters) have been widely applied as plasticizers. They are ubiquitous contaminants in soils, thereby posing a threat to human health. In this study, ecotoxicological effects ...of three typical PAEs (dimethyl phthalate-DMP, di-n-octyl phthalate-DOP and butyl benzyl phthalate-BBP) were investigated. As a biological indicator, earthworms (Eisenia fetida) were exposed to phthalates at various doses (0, 0.1, 1, 10 and 50 mg/kg) for different times (7, 14, 21, and 28 d). We evaluated the effects of phthalates on reactive oxygen species (ROS) generation, antioxidant enzymes (superoxide dismutase-SOD, peroxidase-POD and catalase-CAT) activities, glutathione S-transferase enzyme (GST) activity, malondialdehyde (MDA) content and DNA damage. Results showed that ROS content increased with increasing phthalates, whereas ROS content generally increased and then decreased with exposure time. However, antioxidant enzymes activities in earthworms displayed different trends. The GST activity in high-dose treatment group was significantly activated. For DMP and DOP, lipid peroxidation mainly occurred between 14 and 28 d, while for BBP, it primarily existed after 7 d and then disappeared after 28 d. Besides, comet assay indicated that there was a dose-response relationship between the DNA damage and phthalate dose, following DMP > DOP > BBP. Given their toxicity, it is important to understand the mechanisms associated with their eco-toxicity and to reduce their adverse impacts on the environment.
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•Phthalates induced oxidative stress and DNA damage in earthworms.•Phthalates enhanced ROS generation and lipid peroxidation, and activated GST.•Different antioxidant enzymes responded differently to DMP, DOP and BBP.•Phthalate-generated DNA damage followed DMP > DOP > BBP.
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