Changes In Peroxidase Activity Research Articles

Shelf-life enhancement and microbial load reduction of fresh-cut apple using ascorbic acid and carboxymethyl cellulose coating combined with ultrasound treatment.

The shelf-life of fresh-cut apples is limited because of their high water loss, deterioration rate, and surface browning. In this research, the effects of ultrasonic, ultrasonic + carboxymethyl cellulose (CMC) 1% coatings, ultrasonic + ascorbic acid (AA) 2%, and combination of ultrasonic + AA 2% and CMC 1% on fresh-cut apples were studied. Physicochemical, antioxidant properties, and microbial stability of ready to eat treated fresh-cut apple was investigated during storage at 4 °C for 12 days. Results showed that the treated fresh-cut had less changes of L*, flesh firmness, soluble solid content, and titratable acidity than that of untreated. Vitamin C, total phenol, total flavonoid, antioxidant capacity, and superoxide dismutase activity were greater in treated fresh-cut apple than that of untreated ones. Ultrasonic application mostly declined polyphenol oxidase and peroxidase activity changes. The combined treatment of ultrasonic + AA 2% + CMC 1% had the greatest impact on reducing microbial load among the treatments. These results revealed that the simultaneous application of ultrasonic and AA followed by CMC coating might have the potential to be used in minimally processed industry.

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.

Evaluating the physiological and biochemical responses of different mangrove species to upwelling

Mangroves are unique forest communities with an abundance of species, high productivity and high ecological, social and economic value. Evaluation of the stress resistance of mangrove plants has mainly focused on the effects of high salinity, heavy metals and flooding, with fewer studies evaluating resistance to upwelling stress. Mangrove species of Avicennia marina, Aegiceras corniculatum and Kandelia obovata were submitted to three temperature upwelling (5, 10 and 15°C) and several physiological and biochemical parameters were measured at six time points (0, 6, 12, 24, 72 and 168 h). The data demonstrated: a certain amount of damage occurred to mangrove plants in the face of prolonged upwelling; different mangrove plants have different response strategies to upwelling; mangrove plants are not sensitive to different upwelling temperatures; the resistance of mangrove plants to upwelling stress was in the following order: A. marina< K. obovata< A. corniculatum. Markers of damage such as relative electrical conductivity (REC), malondialdehyde (MDA) and reactive oxygen species (ROS) among all mangrove species were significantly higher with prolonged upwelling stress. The contents of photosynthetic pigments in all three mangrove species also increased. Superoxide dismutase activity (SOD) was maintained at a high level in both control and treatment groupss. By contrary, the change of peroxidase activity (POD) of A. marina and K. obovata was larger than that of A. corniculatum. Catalase activity (CAT) in A. marina and K. obovata significantly increased under upwelling at both 5 and 10°C while there was no obvious variation of CAT in A. corniculatum. Soluble protein and Soluble sugar contents showed no clear variation but stayed at fairly high levels. However, proline content in A. corniculatum significantly increased under long-term upwelling stress while this was not the case in the other two species. High correlation could be observed between A. marina and MDA, O2- and POD in PCA while A. corniculatum showed association with proline and soluble sugar. In conclusion, the ability of A. corniculatum to tolerate upwelling stress might be due mainly to increases in the activities of SOD and the inducing of proline biosynthesis, while, A marina and K. obovata tolerated upwelling stress by adjusting activity levels of SOD, POD and CAT. Segregation in both principal component analysis (PCA) and hierarchical cluster analysis (HCA) further indicated different tolerances and resistances to upwelling between the three species. Our study provides new insights into the stress response of mangroves to upwelling.

Expression Regulation Mechanisms of Sea Urchin (Strongylocentrotus intermedius) Under the High Temperature: New Evidence for the miRNA-mRNA Interaction Involvement.

In the context of global warming and continuous high temperatures in the northern part of China during summer, the mortality rate of our main breeding species, Strongylocentrotus intermedius, reached 80% in 2020. How sea urchins respond to high temperatures is of great concern to academia and industry. In this study, we examined the antioxidant enzyme activities of different color tube-footed sea urchins under heat stress and compared their transcriptome and microRNA (miRNA) profiles using RNA-Seq. The results showed that the antioxidant enzyme activities of sea urchins were altered by thermal stress, and the changes in peroxidase activities of red tube-footed sea urchins were particularly significant. Investigations revealed that 1,079 differentially expressed genes (DEGs), 11 DE miRNAs, and 104 “DE miRNA-DEG” pairs in total were detected in sea urchins under high temperature stress. Several mRNA and miRNAs were significantly changed (e.g. HSP70, DnaJ11, HYAL, CALR, miR-184-p5, miR-92a, miR-92c, and miR-124-p5), suggesting these genes and miRNAs exerted important functions in response to high temperature. At the transcriptional level, red tube-footed sea urchins were found to be more sensitive to high temperature and could respond to high temperature rapidly. DE miRNA-mRNA network showed that miR-92b-3p and PC-5p-7420 were the most corresponding miRNAs. Five mRNAs (DnaJ11, SAR1B, CALR, HYOU1, TUBA) may be potential markers of sea urchin response to high temperature. Possible interaction between miRNA-mRNA could be linked to protein folding in the endoplasmic reticulum, Phagosomes, and calcium transport. This study provides a theoretical basis for the molecular mechanism of sea urchin heat tolerance and information that will aid in the selection and breeding of sea urchins with high temperature tolerance.

The Nitrate Transporter MtNPF6.8 Is a Master Sensor of Nitrate Signal in the Primary Root Tip of Medicago truncatula.

Nitrate is not only an essential nutrient for plants, but also a signal involved in plant development. We have previously shown in the model legume Medicago truncatula, that the nitrate signal, which restricts primary root growth, is mediated by MtNPF6.8, a nitrate transporter. Nitrate signal also induces changes in reactive oxygen species accumulation in the root tip due to changes in cell wall peroxidase (PODs) activity. Thus, it was interesting to determine the importance of the role of MtNPF6.8 in the regulation of the root growth by nitrate and identify the POD isoforms responsible for the changes in POD activity. For this purpose, we compared in M. truncatula a npf6.8 mutant and nitrate insensitive line deficient in MtNPF6.8 and the corresponding wild and sensitive genotype for their transcriptomic and proteomic responses to nitrate. Interestingly, only 13 transcripts and no protein were differently accumulated in the primary root tip of the npf6.8-3 mutant line in response to nitrate. The sensitivity of the primary root tip to nitrate appeared therefore to be strongly linked to the integrity of MtNPF6.8 which acts as a master mediator of the nitrate signal involved in the control of the root system architecture. In parallel, 7,259 and 493 genes responded, respectively, at the level of transcripts or proteins in the wild type, 196 genes being identified by both their transcript and protein. By focusing on these 196 genes, a concordance of expression was observed for most of them with 143 genes being up-regulated and 51 being down-regulated at the two gene expression levels. Their ontology analysis uncovered a high enrichment in POD genes, allowing the identification of POD candidates involved in the changes in POD activity previously observed in response to nitrate.

CHARACTERISTICS OF THE REDOX STATE OF THE LIGNIN-CARBOHYDRATE WOOD MATRIX AT THE INITIAL STAGES OF DEVELOPMENT ON THE EXAMPLE OF SCOTS PINE

The studies of wood formation at the initial stages allowed confirming the determining role of the redox transformations of monolignols in the lignification of plant matrix. The change in the composition of the phenolic fraction (conjugated and non-conjugated phenolic structures) of the phenol-quinone redox system of the cell wall was studied using the derivative and differential UV spectroscopy. It was shown that the accumulation of low-molecular phenolic compounds in the initial period of ontogenesis occurs mainly in the "needles" of plants. It was confirmed that the seedlings being removed to the hardening site adapt to the existing temperature regime. It is characterized by lower content of low-molecular phenolic compounds preventing the development of oxidative processes. The plant is exposed to oxidative stress at low temperatures, when the enzymatic (peroxidase activity) system of plant protection is activated. The change in the coniferyl alcohol content as a marker of the lignification is shown. The correlation of changes in peroxidase activity with the total content of phenolic compounds and coniferyl alcohol was shown. The IR spectroscopy method showed a change in the ratio of carbohydrate and lignin components at the initial stages of the development of seedlings of scots pine.

Biochemical and hormonal changes associated with root growth restriction under cadmium stress during maize (Zea mays L.) pre-emergence

Cadmium (Cd) pollution of agricultural soils is a growing global concern. Plant growth restriction is the main visible symptom of Cd toxicity, and this metal may be particularly harmful to the preformed, seminal root during the pre-emergence stage. In the present study, we focused on Cd phytotoxicity in seminal root growth, nutrient composition, redox status, and hormone homeostasis during the pre-emergence stage of maize (Zea mays L) plants, distinguishing between the root apex and the remaining root tissue. After 72 h of metal exposure (50 and 100 µM CdCl2), root length and biomass, as well as Ca, Fe, Mg, and Mn contents, were diminished. A redox imbalance was evidenced by changes in peroxidase activities and the ascorbate–dehydroascorbate ratio decreased in both root parts. There were fewer carbonylated proteins in both root fractions after exposure to 50 µM Cd, compared to 100 µM Cd, which was related to increased 20S proteasome activities. Cd incremented ABA, IAA, and SA contents, but drastically reduced the biologically active gibberellin GA4 and the conjugate jasmonoyl-isoleucine (JA-Ile). We demonstrated that the whole root tissue is involved in the maize response to Cd stress, which entails redox and hormonal rearrangements, probably directed to widen the plant defense lines at the expense of root growth.

Влияние пирогенного воздействия на биологическую активность чернозема обыкновенного в модельных экспериментах

The influence of the pyrogenic effect on the biological properties of Haplic chernozem was investigated. For this, a series of model experiments was set up to simulate fires of various duration and intensity. A significant change in the biological properties of soils was found, as well as differences in the reactions of biological indicators to the pyrogenic effect. In different experiments, a different nature of changes in the reaction of the soil environment and the content of organic carbon, an increase in the content of readily soluble salts, was established. In all experiments, inhibition of catalase activity was noted, changes in peroxidase activity were more contradictory. In one of the experiments, stimulation of peroxidase activity was found. In order to study the methods of restoring the biological activity of post-pyrogenic soils, a model experiment was carried out using potassium humate, complex mineral fertilizer and phytoremediation. At the same time, no unambiguous results were obtained that would make it possible to recommend methods for the accelerated recovery of post-pyrogenic soils. Keywords: BIODIAGNOSTICS, FIRES, POSTPYROGENIC SOILS, ENZYME ACTIVITY, SOIL RESTORATION

Dynamic nutrient removal potential of a novel submerged macrophyte Rotala rotundifolia, and its growth and physiological response to reduced light available

Rotala rotundifolia is a novel submerged macrophyte able to survive across the winter under temperature as low as 4 °C. Dynamic nutrient removal potential of R. rotundifolia was estimated using the Eco-tank system simulating natural eutrophic waters. The growth and physiological response of R. rotundifolia by cutting and division propagation to light (100%, 60%, and 20% natural light) were investigated. The results showed that R. rotundifolia was superior in removing N and P from eutrophic waters. As influent concentrations of NH4+-N and total phosphorus (TP) were 4.81–5.87 and 0.61–0.78 mg L−1, effluent concentrations of NH4+-N, total nitrogen (TN), and TP were separately 0.06–1.10, 0.40–1.59, and 0.05–0.17 mg L−1, with removal efficiencies of 93.6%, 84.6%, and 82.5% at a flow rate of 200 L d−1. The growth and morphology of the plant under two propagation patterns were influenced by light and the responses were quite different. The biomass of the plant by cutting was higher at low light conditions, and the plant allocated more biomass on above ground. However, there was no significant difference in the height. By division, the plant preferred to high light. The biomass and height were significantly higher at 100% natural light. The peroxidase (POD), superoxide dismutase (SOD) and root activities of plant by cutting showed a trend of decrease and followed by an increase with light reduction, while by division, they increased with reduced light available. Variations of chlorophyll and soluble protein of the plant by cutting and division were contrary to the changes of POD activity. These results suggest that R. rotundifolia can be used to effectively remove nitrogen and phosphorus in eutrophic waters, and high light promotes the growth of the plant by division, while suitable shade is needed for the plant by cutting.

THE ACID-BASE PROCESSES' CHANGES IN THE BODY OF WHITE RATS UNDER THE INFLUENCE OF NITROGEN-CONTAINING SURFACE-ACTIVE MATERIAL

Relevance. Everyday contact of the population with surfactants (SAS) in drinking water poses the problem of timely and prompt substantiation of pre-nosological highly sensitive indicators of early manifestations of biological activity of detergents and operational control over the health of the population and the environment. But today the mechanisms of biotransformation, toxicodynamics, toxicokinetics, and metabolic processes that underlie the formation of structural and metabolic disorders when exposed to a surfactant, taking into account possible long-term effects, have not yet been fully elucidated.
 Objective: to investigate the effect of nitrogen-containing surfactants on redox processes in the body of experimental animals.
 Materials and methods. The experiments were carried out on 620, and acute experiments on 128 white rats (weight 180-220 g). We used four ionic nitrogen-containing surfactants with specified technical and physicochemical characteristics: FOM 9, FOM 9-4, FOM 9-12, and FOM 9-20. Doses were chosen so as to determine the lethal effect in the lethal dose (LD) range from 0 to 100. The LD50 was calculated. The substances were introduced into the stomach in pure form using a metal probe. The animals were observed for up to 15 days. The time of death of the animals and the total amount of the introduced substance was recorded. The animals were subjected to postmortem examination. Redox processes were qualitatively assessed by the activity of enzymes: cholinesterase, cerulose plasmin, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, peroxidase, catalase, cytochrome oxidase, by the content of SH-groups in the blood, by the concentration of biogenic monoamines.
 Results. Nitrogen-containing surfactants caused a change in peroxidase activity both upwards and downwards. In all cases, 1/1000 LD50 was inactive. On the 15th day of the experiment, neonol FOM 9-12 reduced the activity of the enzyme, and other substances did not affect it. By the end of the subacute experiment, neonol FOM 9-4 and neonol FOM 9-12 were reduced, and neonol FOM 9-20 increased peroxidase activity. A similar effect was on the activity of catalase: in all groups, except 1/1000 LD50, on day 30 there was a decrease in its activity. Cholinesterase activity increased. For the content of SH-groups in the blood on the 15th day, there was a tendency to decrease, which turned into significant differences on the 30th day in 1/10 LD50. The effect of 1/100 and 1/1000 LD50 did not violate the content of SH-blood groups. A similar effect was on the content of glutathione in the blood. In a subacute experiment, in groups, 1/10 and 1/100 LD50, the content of norepinephrine, tryptophan, serotonin in the liver increased and DOPA and dopamine decreased. The dynamics of adrenaline did not change. The content of dopamine and norepinephrine increased to a lesser extent in the brain; DOPA and adrenaline did not differ from the control; tryptophan increased only under the influence of FOM-9. 1/1000 LD50 did not affect the dynamics of the content of biogenic monoamines. The tested drugs have a similar effect on the body.
 Conclusions. A more toxic substance in a subacute experiment is FOM-9. The severity of violations in the dynamics of monitoring the activity of enzymes has a close dose-dependence. The effective dose is set at 1/10, the threshold – 1/100, and the inactive – 1/1000 LD50. Common features of the biological action of nitrogen-containing surfactants are the violation of redox processes, bioenergy, oxidative phosphorylation, which under appropriate conditions lead to the pathology of vital organs, functions, and systems of the body.

Effect of Antioxidants on Heavy Metals Induced Conformational Alteration of Cytochrome C and Myoglobin.

The exposure to heavy metals due to unrestrained industrialization, pollution and non-degradability imposes a significant risk to human health. Proteins are prime targets of heavy metal stress, however, the underlying mechanisms and its impact on heme proteins is still not entirely clear. To analyze the deleterious effect of heavy metals such as cadmium, chromium and mercury on conformation of two proteins namely, cytochrome c and myoglobin. The protective effect of glycine and ascorbic acid (animal origin), gallic acid and sesamol (plant origin) on heavy metal exposure was studied. Far- and near-UV Circular Dichroism (CD) measurements monitored the changes in secondary and tertiary structure. Absorption Soret spectroscopy study revealed changes in heme-protein interaction. Peroxidase activity has been assayed to measure the absorption of tetraguaiacol. The interaction of heme proteins with different heavy metals was done using docking study. Far- and near-UV CD measurements reveal that heavy metals disrupt the secondary and tertiary structure of heme proteins. Antioxidants counteract the deleterious effect of heavy metals. Absorption spectroscopy revealed changes in the Soret region of these heme proteins. Changes in peroxidase activity was observed on addition of heavy metals and antioxidants. Molecular docking validated interaction of the heavy metals with proteins with a significant binding affinity (-2.3 kcal/- mol). Heavy metals interfered and disrupted both the heme proteins and mercury showed the maximum deleterious effect, further, chromium showed detrimental effect at very small concentration. The antioxidants from animal origin exhibited better protective response than those from plant source.

Effects of Humanlike Mutations on Yeast Iso-1-Cytochrome C

Apoptosis is a key process in various human diseases. It is initiated in the mitochondria, where changes in the local environment cause cytochrome c (cytc) to become competent for peroxidase activity. Human cytc has 20- to 30-fold lower peroxidase activity than yeast cytc, which we hypothesize allows for tighter control of apoptosis in higher eukaryotes. Many residues that have evolved between yeast and human are found in Ω-loops C and D, which are some of the most dynamic regions of cytc. The Ω-loops are thought to control the dynamics of opening the heme crevice, and thus peroxidase activity. Residues present in human are larger and more hydrophobic than in yeast cytochrome c, so mutations have been made in yeast to reflect that. By mutating residues S40, N63, V57, and A81I, which are larger and more hydrophobic in human cytc, both individually and pairwise in yeast iso-1-cytc, we expect to see corresponding changes in peroxidase activity with minimal changes in overall structure. Circular dichroism was used to monitor guanidine unfolding and assess changes in global stability between each of the variants. The alkaline transition was monitored to estimate the effect of these mutations on Ω-loop D stability. Peroxidase activity measurements were conducted using stopped-flow with guaiacol as a substrate. Our results indicate that single mutations usually have small effects, however in some instances double mutations have more pronounced effects than either single mutation alone. These results seem to indicate that the combined effects of these residues form a network that modulates the peroxidase activity in human cytochrome c, as opposed to one single residue being mainly responsible for these differences.

Nitrate inhibits primary root growth by reducing accumulation of reactive oxygen species in the root tip in Medicago truncatula

In Medicago truncatula, nitrate, acting as a signal perceived by NITRATE TRANSPORTER1/PEPTIDE TRANSPORTER FAMILY 6.8 (MtNPF6.8), inhibits primary root growth through a reduction of root cell elongation. Since reactive oxygen species (ROS) produced and converted in root tip (O2•− → H2O2 → •OH) have been reported to control cell elongation, the impact of nitrate on the distribution of these ROS in the primary root of M. truncatula was analyzed. We found that nitrate reduced the content of O2•−, H2O2 and •OH in the root tip of three wild type genotypes sensitive to nitrate (R108, DZA, A17), inhibition of root growth and O2•− accumulation being highly correlated. Nitrate also modified the capacity of R108 root tip to produce or remove ROS. The ROS content decrease observed in R108 in response to nitrate is linked to changes in peroxidase activity (EC1.11.1.7) with an increase in peroxidative activity that scavenge H2O2 and a decrease in hydroxylic activity that converts H2O2 into •OH. These changes impair the accumulation of H2O2 and then the accumulation of •OH, the species responsible for cell wall loosening and cell elongation. Accordingly, nitrate inhibitory effect was abolished by externally added H2O2 or mimicked by KI, an H2O2 scavenger. In contrast, nitrate has no effect on ROS production or removal capacities in npf6.8-2, a knockdown line insensitive to nitrate, affected in the nitrate transporter MtNPF6.8 (in R108 background) by RNAi. Altogether, our data show that ROS are mediators acting downstream of MtNPF6.8 in the nitrate signaling pathway.

Various antioxidant responses to hyperthermia in anatomically different species of the genus Rosa

The heat and drought resistance of plants depend on their anatomical and biochemical features. In the present study, the adaptive features of three species of wild rose (Rosaceae, Rosales) under the short-term impact of high-temperature stress have been characterized. Plants of the species Rosa donetzica Dubovik, R. reversa Waldst. et Kit. and R. spinosissima L. were exposed to a temperature of 40 degrees C for 3 hours, following which peroxidase and superoxide dismutase activity, photosynthetic pigments and flavonoids’ content, and lipid peroxide oxidation level in the leaf were determined. In our investigation, the anatomical structure of leaves and drought resistance of three species of Rosa were studied. Xeromorphic features are the most expressed for R. reversa and R. spinosissima and almost absent for R. donetzica. It has been established that R. spinosissima is photophilous whereas R. donetzica is shade-tolerant. The relatively lower development of epidermic tissue in R. donetzica could probably contribute to more active destruction of the pigment complex under high temperature stress. The obtained data about changes in activity of peroxidase, superoxide dismutase, content of photosynthetic pigments and flavonoids, and level of lipid peroxidation indicate the low heat resistance of R. donetzica in comparison with the other two species. R. reversa, R. spinosissima were more tolerant to short-term hyperthermia. They showed faster antioxidant response, mainly due to the induction of peroxidase activity under stress. The species with the most expressed xerophytic features of anatomical structures have rapid antioxidant response and are more resistant to short-term hyperthermia. The induction of some activity of antioxidant enzymes "in reserve" is a less effective form of adaptation in wild roses. Such activation of enzymes is observed in plants with a more mesophytic structure. Flavonoids and superoxide dismutase were thermolabile to short-term influence of high temperature; therefore they play an insignificant role as antioxidants in the protecton against oxidative stress caused by high temperature stress in wild roses.

Maize seedling performance as a potential index for drought tolerance

Twenty-six maize landraces were tested in order to evaluate maize seedling performance as an index for drought tolerance in adult plants. Samples were subjected to polyethylene glycol-induced osmotic stress at the early seedling stage. Grain yield was obtained in field experiments under well-watered (OC) and a combination of drought and high plant density (HD) conditions. Osmotic stress caused a reduction in seedling growth (length, fresh and dry weight), and increase in the shoot and in particular the root proline contents in the majority of landraces, and variations in root peroxidase (POD) activity. Genotypes displaying more pronounced root growth reduction and higher proline contents exhibited decreased POD activity under osmotic stress. Direct positive correlations between the proline content and growth inhibition, and between the proline and soluble protein content were established. Correlations between the changes in POD activity and growth parameters were significant and positive, and significant but negative with the changes in the proline content. In the field, water stress led to a reduction in grain yield in all of the tested landraces. Correlations between grain yield from both experimental sets (OC and HD) and osmotic-induced changes in seedling root growth were negative, which was opposite to the highly significant and positive correlations between the changes in the seedling root proline content and yield. Also, genotypes with the highest seedling root proline content increase under osmotic stress, exhibited the highest stress tolerance index (STI) based on grain yield achieved under both field conditions. Our results indicate that lower changes in POD activity and especially an increased proline content after exposure to osmotic stress during the early seedling stage could be considered as useful indices to facilitate selection efficiency for drought tolerance in adult plants.

紫穗槐幼苗根系生理特性和解剖结构对PEG-6000模拟干旱的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 紫穗槐幼苗根系生理特性和解剖结构对PEG-6000模拟干旱的响应 DOI: 10.5846/stxb201610312216 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中央高校基本科研业务费专项（2572014CA27） Response of physiological characteristics and anatomical structure of roots in Amorpha fruticosa seedlings exposed to simulated drought with PEG-6000 Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用PEG-6000模拟干旱胁迫处理，测定了紫穗槐幼苗根系的可溶性糖、可溶性蛋白质、丙二醛、游离脯氨酸含量及SOD、POD酶活性变化以及解剖结构特征，旨在比较不同干旱程度对紫穗槐幼苗根系生理指标、内部解剖结构的影响，探索紫穗槐幼苗对水分胁迫的适应能力，揭示紫穗槐幼苗根系对土壤水分胁迫的响应和调控机制。结果表明：丙二醛含量变化显示当PEG-6000溶液浓度超过50g/L以后，紫穗槐幼苗根的膜系统开始受到损伤，并在PEG-6000溶液浓度达到250g/L受损程度显著增强，达到了对照的1.6倍，同时启动渗透调节作用（游离脯氨酸含量显著增加），达到了对照的3.8倍，在PEG-6000溶液浓度低于200g/L时，紫穗槐幼苗根系中至少没有启动以游离脯氨酸为主的渗透调节过程。可溶性糖和可溶性蛋白质含量及SOD、POD酶活性的变化印证了胞内发生的生理代谢变化，在PEG-6000溶液浓度为200g/L时，可溶性糖含量仅为0.121mg/g，达到最低点，随后上升，当PEG-6000溶液浓度进一步增加到250g/L时，紫穗槐幼苗根系中的可溶性糖含量则迅速回升到0.64mg/g，为对照组的63.37%。可溶性蛋白质含量在低浓度PEG-6000溶液（50g/L）处理下即有明显反应，下降到对照的61.5%，随后呈波动性变化。SOD和POD活性对PEG-6000模拟干旱胁迫的响应规律类似，均对PEG-6000模拟干旱胁迫处理迅速响应且活性增加。当PEG-6000溶液浓度达到50g/L至100g/L时，抗氧化酶的合成量最高，而后活性下降。60d的PEG-6000模拟干旱胁迫处理影响了紫穗槐幼苗根系的生长发育，随着PEG-6000溶液浓度增加，维管柱的直径变大，木质部厚度增大，导管直径变小、但导管密度增加，当PEG-6000溶液浓度达到250g/L时，导管密度比对照组增加了41.3%，木质部厚度比对照组增加了91.5%。以上结果表明，PEG-6000模拟干旱胁迫处理下，不同胁迫程度紫穗槐内部生理和根系解剖结构变化不同，通过改变自身生理代谢和根系内部解剖结构，以适应土壤水分胁迫的逆境条件，来满足自身生长和发育的需求平衡。 Abstract:In this study, we used the PEG-6000 to simulate drought stress, and determined the content of soluble sugars, soluble protein, MDA(Malondialdehyde), and free proline, and changes in enzyme activities of SOD(Superoxide dismutase) and POD(Peroxidase) in roots of Amorpha fruticosa seedlings and in their anatomical features. Our objectives were to examine the effects of different levels of drought on the physiological indices and internal anatomical structures of seedlings of Amorpha fruticosa. Furthermore, we explored the adaptability response and regulation mechanism to water stress of Amorpha fruticosa seedlings. The results indicated that MDA appeared when the concentration of PEG-6000 was more than 50g/L, and the membrane system of Amorpha fruticosa seedling roots began to suffer damage. When the PEG-6000 concentration reached 250g/L, the extent of damage was significantly enhanced, reaching 1.6 times that of the the control group, and at the beginning of osmotic adjustment (free proline content increased significantly), it reached 3.8 times that of the control group. When the concentration of PEG-6000 solution was less than 200g/L, the osmotic adjustment process was not initiated in the roots of Amorpha fruticosa seedlings with free proline. The physiological metabolism of the cell was verified through changes in soluble sugar and soluble proteincontent, and SOD and POD activity. When the concentration of PEG-6000 was 200g/L, the soluble sugar content was 0.121mg/g, reached its lowest point, and then increased. As the PEG-6000 solution concentration further increased to 250g/L, the soluble sugar content in the roots of Amorpha fruticosa seedlings rapidly increased to 0.64mg/g, which was 63.37% of that of the control group. Soluble protein content in the low concentration of PEG-6000 solution (50g/L) treatment decreased to 61.5% of that of the control group, followed by fluctuating changes. SOD and POD activities were similar to PEG-6000 simulated drought stress, and rapidly responded to PEG-6000 simulated drought stress treatment. Simultaneously, the enzyme activity of POD and SOD were increased. When the concentration of PEG-6000 was 50g/L to 100g/L, the synthesis of antioxidant enzyme was the highest, and then it decreased. SOD amplitude activity differed by more than six fold. Changes in POD activity were relatively small, and the difference in amplitude was less than a multiple of one. The 60-、day PEG-6000 solution simulating the drought stress affected the growth and development of the root system of the Amorpha fruticosa seedlings. With the increasing concentration of PEG-6000, the diameter of the vascular bundles increased. At the same time, the diameter of the catheter decreased, but its density increased. When the concentration of PEG-6000 reached 250g/L, the catheter density increased by 41.3% compared with that of the control group, and xylem thickness increased by 91.5% compared with that of the control group. The results showed that under different levels of drought stress treatments, the internal physiology and root anatomical structures of Amorpha fruticosa varied. The stress conditions of water and self-、growth and development balance needs were satisfied by altering their physiological metabolism and the internal anatomical structure of the roots. 参考文献 相似文献 引证文献

The effect of microelements on the activities of peroxidase and polyphenoloxidase in eggplant lieaves and fruit

The influence of microelements (B, Zn, Cu, Co, Mn) on the peroxidase and polyphenol oxidase activity in eggplant leaves and fruit was studied. Activity of the enzymes under the study varies in different phases of plant vegetation. It can be explained by the fact that eggplant bears the technically, physiologically mature and crude fruit as well as buds and blossoms together. In both the control and microelement group with the increase of the peroxidases activity the polyphenol oxidase activity decreases. Compared to the control group the polyphenol oxidase activity increased the most in the phase of vegetation of 4–5 leaves, after treatment with boron and then with cobalt. Boron and zinc have similar action on the enzyme activity. Under the action of boron the polyphenol oxidases activity especially increases in the phase of vegetation of 4–5 leaves and in the later phase decreases. The peroxidase activity changes accordingly. After pre-sowing treatment of eggplant seeds with zinc the peroxidase activity decreases in leaves (in their early phase of vegetable) and fruit. It reaches its maximum in leaves in the fruit bearing period. Under the influence of copper and cobalt the peroxidase activity in fruit increases. In leaves it increases in the late phase of vegetation. The Mn influence on the activity of polyphenol oxidase is less in the early phase of vegetation then in the late phase. In eggplants with the increase of polyphenol oxidase activity the peroxidase activity decreases

Growth inhibition and efficiency of the antioxidant system in spring barley and common radish grown on soil polluted ionic liquids with iodide anions

Ionic liquids (ILs) constitute a huge group of substances that are increasingly common in the commercial use. This situation may lead to the contamination of the soil environment which being the basic of plants vegetation. This paper presents the effect of four ILs with I- anion on the growth and development of spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. subvar. radicula Pers) and changes in metabolism of the plants. Seedlings of spring barley and common radish cultivated on soil with increasing ILs concentration exhibited typical phytotoxicity symptoms. A considerable reduction of shoot and root lengths, decrease of fresh weight (FW) and increase of dry weight (DW) occurred in both test plants. Ionic liquids concentration increase in soil was correlated with the decrease of concentrations of all photosynthetic pigments in the plants. The observed increase of malondialdehyde (MDA) concentration and changes in the H2O2 level indicated presence of oxidative stress in spring barley and common radish, which usually led to the increase of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity. The most reliable biomarker of oxidative stress was chlorophyll level and changes in POD activity.

Combined toxic effects and mechanisms of microsystin-LR and copper on Vallisneria Natans (Lour.) Hara seedlings

Microcystin-LR (MCLR) and copper are commonly found in eutrophic water bodies because of eutrophic run-offs, cyanobacterial blooms, and copper algicide applications. However, the ecotoxicological risk of their combination remains unknown. This study investigated the effect of MCLR, Cu, and their mixture on the growth and physiological responses of Vallisneria natans. Results showed that the combined toxicity of them was concentration dependent. Synergistic effects were elicited at low concentrations of MCLR and Cu exposure (≤0.25+0.64mg/L). Additive or antagonistic effects were induced at higher concentrations. Single and combined exposures could induce oxidative stress, such as increased superoxide anion radical levels. To cope with oxidative stress, V. natans could activate their antioxidant defense systems, such as enhanced superoxide dismutase production and changes in peroxidase activities. Exposure to combined MCLR and Cu (even only with 0.005+0.041mg/L) adversely affected their antioxidant defense systems. As a consequence, malondialdehyde levels significantly increased. The interaction of MCLR and Cu could also significantly increase the bioaccumulations of MCLR and Cu. This increase could be accounted for their synergistic toxic effects on V. natans. Our results suggested that the exacerbated ecological hazard of MCLR and Cu with environmental concentrations may harm aquatic ecosystems.

The features of stability processes of mono- and dicotyledonous plants under xenobiotic influence

Parameters of anatomical, morphological, physiological and biochemical levels of feather grass plants with chronic nuclear decay products effect and lettuce with long-term exposure to toxic cadmium ions have been studied. Similar changes in test plants anatomical structure, aimed to strengthening the mechanical elements and improving the barrier function were observed. Nonspecific adaptive changes in peroxidase activity by the action of radiation and cadmium influence was showed