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1.
Soil contamination with toxic heavy metals [such as cadmium (Cd)] is becoming a serious global problem due
to rapid development of social economy. Iron (Fe), being an important element, has been found effective in enhancing
plant tolerance against biotic and abiotic stresses. The present study investigated the extent to which different levels of
Ferrous sulphate (FeSO 4) modulated the Cd tolerance of rice ( Oryza sativa L.), when maintained in artificially Cd
spiked regimes. A pot experiment was conducted under controlled conditions for 146 days, by using natural soil,
mixed with different levels of CdCl 2 [0 (no Cd), 0.5 and 1 mg/kg] together with the exogenous application of FeSO 4
at [0 (no Fe), 1.5 and 3 mg/kg] levels to monitor different growth, gaseous exchange characteristics, oxidative stress,
antioxidative responses, minerals accumulation, organic acid exudation patterns of O. sativa. Our results depicted that
addition of Cd to the soil significantly (P < 0.05) decreased plant growth and biomass, gaseous exchange parameters,
mineral uptake by the plants, sugars (soluble, reducing, and non-reducing sugar) and altered the ultrastructure of
chloroplasts, plastoglobuli, mitochondria, and many other cellular organelles in Cd-stressed O. sativa compared to
those plants which were grown without the addition of Cd in the soil. However, Cd toxicity boosted the production of
reactive oxygen species (ROS) by increasing the contents of malondialdehyde (MDA), which is the indication of
oxidative stress in O. sativa and was also manifested by hydrogen peroxide (H 2O 2) contents and electrolyte leakage to
the membrane bounded organelles. Although, activities of various antioxidative enzymes like superoxidase dismutase
(SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants like
phenolics, flavonoid, ascorbic acid, anthocyanin and proline contents increased up to a Cd level of 0.5 mg/kg in the
soil but were significantly diminished at the highest Cd level of 1 mg/kg in the soil compared to those plants which
were grown without the addition of Cd in the soil. The negative impacts of Cd injury were reduced by the application
of FeSO 4 which increased plant growth and biomass, improved photosynthetic apparatus, antioxidant enzymes, minerals uptake together with diminished exudation of organic acids as well as oxidative stress indicators in roots and
shoots of O. sativa by decreasing Cd retention in different plant parts. These results shed light on the effectiveness of
FeSO 4 in improving the growth and upregulation of antioxidant enzyme activities of O. sativa in response to Cd
stress. However, further studies at field levels are required to explore the mechanisms of FeSO 4-mediated reduction of
the toxicity of not only Cd, but possibly also other heavy metals in plants. 相似文献
2.
Waterlogging is an illustrious abiotic stress and the constrictions it enforces on plant roots have negative effects
on growth and development. This study was undertaken to investigate waterlogging stress tolerant potential in chilli
( Capsicum annum L.) genotypes through evaluating morphological, physiological, biochemical and anatomical
parameters. Thirty-five days old seedlings of 10 chilli genotypes were exposed to waterlogging stress maintaining
water height 3–5 cm over the soil surface artificially for three days. This duration (36–38 DAE) was termed as
waterlogging period, and subsequent withdrawal of waterlogging condition (39–45 DAE) was regarded as a recovery
phase. Based on their survival performance, two tolerant genotypes viz., SRC-517 and BARI morich-2 and two
susceptible genotypes viz., AHM-206 and RI-1(6) were selected for studying stress tolerance mechanism. Under
waterlogging, however, both genotypes (tolerant and susceptible) exhibited reduced root shoot length, dry weight
ratio, petiole weight and leaf area, and noticeable reduction regarding these parameters was observed in susceptible
genotypes. Moreover, tolerant genotypes displayed a higher recovery than susceptible genotypes after removal of
waterlogging stress. Lower reduction of leaf area and photosynthetic pigments as well as higher reduction of relative
water content (RWC) were noticed in susceptible genotypes. Higher accumulation of proline and total antioxidant
capacity (TAC) during waterlogging condition in tolerant genotypes suggested lower oxidative damage. Although both
genotypes lost total soluble sugar (TSS) relative to control at waterlogging stress, better performance was recorded in
tolerant genotypes. During the period after the removal of extra water, a similar genotypic response in terms of TSS
gain was seen. Undoubtedly, under flooding conditions, the development of aerenchyma cells in tolerant genotypes is
a means of tolerance mechanism for long-term survival. Thus, the morpho-physiological and biochemical changes
help to understand the tolerance mechanism in chilli under waterlogging stress. 相似文献
3.
Objective: The aim of this study is to detect in vitro the synergetic activity of colistin in combination with
imipenem, amikacin or ciprofloxacin, at sub-inhibitory concentrations, against carbapenems-resistant (CR) Acinetobacter
baumannii and Pseudomonas aeruginosa strains isolated from various wards in Annaba teaching hospital in eastern Algeria.
Materials and Methods: The minimal inhibitory concentrations (MIC) were determined by broth macrodilution (BMD).
Carbapenemase encoding genes were screened using polymerase chain reaction (PCR). The activity of colistin in
combination with second antibiotic was evaluated by the Checkerboard Technique.
Results: 39 CR P. aeruginosa and 21 CR A. baumanni strains where collected. The MIC values ranging from (0.25 to
4 µg/ml) to colistin, ≥16 µg/ml for imipenem, ≥4 µg/ml to amikacin and ≥8 µg/ml ciprofloxacin. The PCR reveals the
presence of the genes bla OXA23 (n = 12), bla OXA24 (n = 6), bla NDM1 (n = 3) in A. baumannii and bla VIM2 (n = 12) in P.
aeruginosa. The combination of colistin with imipenem showed synergistic effect on 57.14% and 46.15% of A.
baumannii and P. aeruginosa isolates, respectively. For colistin and amikacin, the synergistic effect is detected in 28.6%
of A. baumannii and 30.8% of P. aeruginosa. While colistin and ciprofloxacin showed synergy on 14.29% and 15.38% of
A. baumannii and P. aeruginosa isolates, respectively.
Conclusion: CR A. baumannii and P. aeruginosa remain the most prevalent infection agents in patients from high-risk
wards at Annaba Hospital. Colistin associated with imipenem or with amikacin at sub-inhibitory concentrations gives
very encouraging results allowing better management of infections caused by this type of bacteria. 相似文献
5.
The studied hypothesis is that the herbicide glyphosate (GLY) can affect the oxidative balance in the hydrophobic intracellular medium in non-target Chlorella vulgaris cells. Analytical GLY and RoundUp (RUP) supplementation, affected the growth profile. A significant 42% decrease in the cellular biomass in stationary (St) phase was observed in cultures supplemented with either 5 µM of GLY or RUP, as compared to control cultures. The treatment with 0.3 µM of GLY generated non-significant effects on the oxidation rate of 2’, 7’ dichlorofluorescein diacetate (DCFH-DA), neither in exponential (Exp) nor in St phase of development, as compared to control cultures. However, the treatment with either 5 µM GLY or 0.3 and 5 µM RUP lead to a significant decrease in the DCFH-DA oxidation rate, as compared to control cultures. The lipid radical (LR●) generation rate, detected by Paramagnetic Resonance Spectroscopy (EPR), was significantly increased in the presence of RUP, in Lag and Exp phase of growth. The non-enzymatic antioxidants, α-Tocopherol (α-T) and β-Carotene (β-C), are aimed to protect membranes against the damage produced by the radical reactions. The content of β-C was not significantly affected, as compared to control cultures, by any of the treatments, in both growth phases of cellular development. The content of α-T was significantly decreased by the supplementation with either 0.3 or 5 µM of RUP or 5 µM GLY. The LR●/α-T ratio, used as indicator of the oxidative balance in the hydrophobic cellular media, was significantly different between samples obtained from control and RUP-exposed microalgae in both, Exp and St phase of development, with either 0.3 or 5 μM RUP. The data presented here showed evidence that suggested that oxidative balance in the hydrophobic environment was affected by either GLY or RUP. 相似文献
6.
Climate change induces biotic and abiotic stress conditions, which badly affect the yield of crops with leading to the biochemical and physiological damages to plants. Biochar and plant growth promoting rhizobacteria (PGPR) alleviate the effect of drought condition therefore a field study was conducted to examine the single and combine application of drought tolerant Pseudomonas sp. and Staphylococcus sp. with biochar of Morus alba L. wood to mitigate the adverse effects of drought stress in two genotypes of Brassica napus L. including Punjab sarson and westar. Physioco-chemical analysis of biochar showed 5.4 cmol/kg cation exchange capacity, 6.9 ds/m electrical conductivity, pH of 9.6, 0.50 g/cm 3 bulk density, and organic carbon 3.64%. Synergistic application of PGPR and biochar developed the plant antioxidant enzyme including catalase (CAT) and ascorbate peroxidase (APX) and also enhanced the content of photosynthetic pigments like chlorophyll pigments, carotenoids content, and anthocyanin content. Scanning electron microscope (SEM) study revealed that biochar and PGPR improved epidermal vigor and stomatal physiology. Malondialdehyde (MDA), hydrogen peroxide (H 2O 2), APX, and osmolyte content including proline increased in drought stress, which were then decreased by these growth promoters. These results are very important as they illustrate the potential of PGPR and biochar to alleviate the adverse consequences of drought stress and offer a way of increasing the tolerance of B. napus L. plant grown under induced drought stress. 相似文献
8.
Micropropagation of Ilex dumosa var. dumosa R. (“yerba señorita”) from nodal segments containing one axillary bud was investigated. Shoot regeneration from explants of six-year-old plants was readily achieved in 1/ 4 strength Murashige and Skoog medium ( 1/ 4 MS) plus 30 gr·L -1 sucrose and supplemented with 4.4 µM BA. Further multiplication and elongation of the regenerated shoots were obtained by subculture in a fresh medium of similar composition with 1.5 gr·L -1 sucrose. Rooting induction from shoots were achieved in two steps: 1) 7 days in 1/ 4 MS (30 gr·L -1 sucrose, 0.25 % Phytagel ®) with 7.3 µM IBA and 2) 21 days in the same medium without IBA and 20 µM of cadaverine added. Regenerated plants were successfully transferred to soil. This micropropagation schedule can be implemented in breeding programs of Ilex dumosa. 相似文献
9.
Philodryas olfersii is found in South America, from Amazonas to Patagonia. It is important to characterize the venom of P. olfersii, who inhabits the North-East region of Argentina, since snake venoms are known to exhibit considerable variability in composition and biological activities. In this work, mice weighing 18-20 g ( n = 4 for each experimental group) were used. For the edematogenic activity mice were injected s.c. in the right foot pad with 50 µl of solutions containing different amounts of venom, whereas the left foot pad was injected with 50 µl of PBS. Two hours after injection mice were killed by cervical dislocation and both feet were cut off and weighed individually. For the myotoxic activity mice were injected i.m. with 100 µl of solutions containing 40 µg of venom. Blood samples were extracted after 1, 3, 6, 8, 10, 12, 14, 16 and 24 h of venom injection to determinate serum CPK activity and mice were sacrificed at the same time intervals to obtain the inoculated gastrocnemius muscle. They were fixed with Bouin solution and stained with Hematoxylin-Eosin. Results showed that P. olfersii venom exhibits a high edematogenic activity (MED = 0.31 µg) and a moderate myotoxic activity. Myonecrosis reached its highest level after 12 h of venom injection as shown by plasmatic CPK levels (5,401 ± 330 IU/l) and microscopic assay. It demonstrates the potential toxicity of the venom of P. olfersii, who inhabits the North-East region of Argentina. It also reinforces the original warning concerning the potential danger of bites by colubrids. 相似文献
10.
Despite the great potential of photosynthetic microbes in the production of renewable fuels, value-adding
chemicals, and water treatment, etc., commercial utilization of them is significantly hindered by the lack of techniques
to accurately monitor the thermodynamic and kinetic characteristics of the In-situ growth of microbes under
controlled light illumination for optimal cultivation. Herein, we demonstrated that a newly developed highly sensitive
photo-microcalorimetric system successfully captured the impacts of the light wavelength and strength on the
thermodynamic and kinetic parameters of the In-situ growth of Rhodopseudomonas palustris, a representative
photosynthetic microorganism. To our best knowledge, this is the first time that highly precise microcalorimetry is
employed to monitor exam the in-situ growth of photosynthetic microorganisms under controllable photo
illumination. We envision this technique can help for the optimization of the growth conditions of photosynthetic
microorganisms for scale-up applications. 相似文献
12.
Chloris gayana Kunth is a grass species valuable as forage which was introduced into Argentina to be used as pasture in saline soils of subtropical and warm-temperate zones, given its good adaptability
to drought, salinity and mild freezing. However, its tolerance varies according to the cultivar. In tetraploid
cultivars, important reductions in yield have been observed. Here, a study of the variations produced on the
root and stem system by salinity at different NaCl concentrations (0, 150 y 250 mM) was performed in the
Boma cultivar, with the aim of determining the anatomical and morphological alterations produced by the
salt excess. Plants cultivated with the highest level of salinity showed, in the whole, significant differences in
the measured variables.
A diminution in absolute values of the variables and a major reduction in vascular tissue dimensions were
observed, which suggests that the lack of tolerance to salt stress could be related to a deficient adaptation to
absorb and transport water and nutrients from the roots. 相似文献
13.
HMA2 (heavy metal ATPase 2) plays a crucial role in extracellular and intracellular Zn 2+ transport across biomembranes, maintaining ion homeostasis, and playing an important role in the normal physiological metabolism, growth, and development of plants. In our study, a novel HMA2 gene, named MaHMA2, was isolated and cloned from white mulberry ( Morus alba L.). The gene sequence obtained was 1,342 bp long, with an open reading frame of 1,194 bp, encoding a protein of 397 amino acids, with a predicted molecular mass of 42.852 kD and an isoelectric point of 7.53. This protein belonged to the PIB-type ATPase transport protein family. We analyzed the expression of the MaHMA2 gene by quantitative real-time PCR. The results showed that the level of MaHMA2 gene expression decreased to a Zn concentration of 800 mg/kg. Malondialdehyde and proline levels increased and responded to increasing Zn when the MaHMA2 gene was silenced, whereas the activities of peroxidase and superoxide dismutase tended to increase in response to increasing Zn 2+ ion stress concentrations but were lower in the gene-silenced plants. These findings suggested that the MaHMA2 gene played an active role in the tolerance response of mulberry to Zn stress. 相似文献
14.
To investigate the effects of arbuscular mycorrhizal (AM) fungi on the growth and saline–alkaline tolerance of
Potentilla anserina L., the seedlings were inoculated with Claroideoglomus etunicatum (W.N. Becker & Gerd.) C. Walker &
A. Schüßler in pot cultivation. After 90 days of culture, saline–alkaline stress was induced with NaCl and NaHCO 3
solution according to the main salt components in saline–alkaline soils. Based on the physiological response of P. anserina
to the stress in the preliminary experiment, the solution concentrations of 0 mmol/L, 75 mmol/L, 150 mmol/L, 225 mmol/L
and 300 mmol/L were treated with stress for 10 days, respectively. The mycorrhizal colonization rate, mycorrhizal
dependence, chlorophyll content, malondialdehyde content, antioxidant enzyme activities, osmoregulation substances
content and water status were measured. The results showed that with the increase of NaCl and NaHCO 3 stress
concentration, mycorrhizal colonization rate, colonization intensity, arbuscular abundance and vesicle abundance
decreased, and reached the lowest value at 300 mmol/L. Strong mycorrhizal dependence was observed after the symbiosis
with AM fungus, and the dependence was higher under NaHCO 3 treatment. Under NaCl and NaHCO 3 stress, inoculation
with AM fungus could increase chlorophyll content, decrease malondialdehyde content, increase activities of superoxide
dismutase, peroxidase and catalase, increase contents of proline, soluble sugar and soluble protein, increase tissue relative
water content and decrease water saturation deficit. It was concluded that salt–alkali stress inhibited the colonization of
AM fungus, but the mycorrhiza still played a positive role in maintaining the normal growth of plants under salt–alkali stress. 相似文献
15.
Dehydrins (DHNs), as members of the late embryogenesis abundant protein family, play critical roles in the protection of seeds from dehydration and plant adaptation to multiple abiotic stresses. Vitrification is a basic method in plant cryopreservation and is characterized by forming a glassy state to prevent lethal ice crystals produced during cryogenic storage. In this study, ApSK3 type DHN was genetically transformed into embryogenic calluses (EC) of Agapanthus praecox by overexpression (OE) and RNA interference (RNAi) techniques to evaluate the in vivo protective effect of DHNs during cryopreservation. The cell viability showed a completely opposite trend in OE and RNAi cell lines, the cell relative death ratio was decreased by 20.0% in ApSK3-OE EC and significantly increased by 66.15% in ApSK3-RNAi cells after cryopreservation. Overexpression of ApSK3 increased the content of non-enzymatic antioxidants (AsA and GSH) and up-regulated the expression of CAT, SOD, POD, and GPX genes, while ApSK3-RNAi cells decreased antioxidant enzyme activities and FeSOD, POD, and APX genes expression during cryopreservation. These findings suggest that ApSK 3 affects ROS metabolism through chelating metal ions (Cu 2+ and Fe 3+), alleviates H 2O 2 and OH· excessive generation, activates the antioxidant system, and improves cellular REDOX balance and membrane lipid peroxidation damage of plant cells during cryopreservation. DHNs can effectively improve cell stress tolerance and have great potential for in vivo or in vitro applications in plant cryopreservation. 相似文献
16.
Somatic embryogenesis is an asexual reproduction process that occurs in many plant species, including rice.
This process contains several totipotency markers such as Somatic Embryogenesis Receptor-like Kinase (SERK), Leafy
Cotyledon1 (LEC1) and WUSCHEL-Related Homeobox4 (WOX4) and also a helpful model for embryo development
and clones and transformations. Here, we report the gene expression during somatic embryo development correlates
with regeneration frequency in 14 Javanica rice (pigmented and non-pigmented) using modifified N6 media
supplemented with Kinetin (2.0 mg/L) and NAA (1.0 mg/L). Although there have been advances in understanding
the genetic basis of somatic embryogenesis in other varieties, rice is still unexplored, especially during somatic embryo
development. Moreover, for the formation of callus induction from immature embryos, 2,4-D (2.0 mg/L, 3.0 mg/L)
was used. This study analysed the gene expression of OsSERK, OsWOX4 and OsLEC1 genes through RT-PCR analysis.
Higher expression of the OsLEC1 gene indicates that their function may correlate in the in vitro with the high
response of rice after transfer to regeneration media. This study found that rice varieties of pigmented rice (MS
Pendek and Gogoniti II) and non-pigmented rice (Pandan Ungu) showed high regeneration frequency, showing
higher OsLEC1 expression than other varieties because OsLEC1 promotes the maturation of somatic embryos in plant
regeneration on day 14. However, the contrast with Genjah nganjuk may be effective because of other regulatory
genes. RT-PCR analysis showed OsSERK had less expression level than OsLEC1 and OsWOX4 in the varieties, which
correlate with the percentage of plant regeneration, but not for Gogoniti II. In conclusion, the higher percentage of
plant regeneration correlates with the higher expression level of OsLEC1 at day 14 of media regeneration of rice. 相似文献
17.
Amphibians respond to microbial infection through cellular and humoral defense mechanisms such as antimicrobial protein secretion. Most humoral defense proteins are synthetized in the skin. In this study we isolated two β-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the skin of Bufo arenarum. These lectins have significant hemagglutination activity against trypsinized rabbit erythrocytes, which was inhibited by galactose-containing saccharides. They are water-soluble and independent of the presence of calcium. The antimicrobial analysis for each lectin was performed. At µmolar concentration lectins show strong bacteriostatic activity against Gram negative bacteria ( Escherichia coli K12 4100 and wild strains of Escherichia coli and Proteus morganii) and Gram positive bacteria ( Enterococcus faecalis). The antibacterial activity of these lectins may provide an effective defense against invading microbes in the amphibian Bufo arenarum. 相似文献
18.
Gibberellins (GAs) are an important hormone in regulating plant growth and development, and DELLA protein is an essential negative regulator of GA signal transduction. The aim of the study was to clone a GA-inhibiting protein DELLA from trifoliate orange ( Poncirus trifoliata L. Raf.) and to analyze the bioinformations and expression patterns of the protein gene in tissues and in response to drought stress. A DELLA protein was isolated from trifoliate orange and named as PtGai (Genebank number: MZ170959). The PtGai protein had 1731 bp open reading frames, along with 576 amino acid codes, and also grouped with sweet orange (XM_006430552.4). The PtGai protein sequence was 65% homology with the sequences of DELLA proteins in other plant families. PtGai protein existed in the nucleus based on the prediction of subcellular localization. PtGai protein could be expressed in roots, stems, and leaves, along with the highest expression in stems. PtGai was upregulated by drought stress in leaves and roots, along with the decrease of root total GA concentration and the inhibition of shoot and root biomass production. It indicated the characteristics of PtGai protein and the roles of PtGai in GA synthesis and plant growth. 相似文献
19.
Cadmium (Cd) causes oxidative stress, which leads to the oxidation of various biomolecules by the production of reactive oxygen species (ROS) to facilitate programmed cell death (PCD). The antioxidant defense system fails to detoxify ROS when it is produced in excess. Nitric oxide (NO), a gaseous free radical and a phytohormone, regulates various physiological processes of plants. Therefore, this work was undertaken to study the effects of the application of exogenous sodium nitroprusside (SNP, a NO donor) on growth parameters, oxidative stress, accumulation of secondary metabolites, and activities of antioxidant enzymes under Cd stress. Mild (50 µM) and severe (200 µM) Cd stress were applied to hydroponically grown pea (Pisum sativum L.) plants with or without 50 µM SNP. Severe Cd stress had a substantial impact on the plants. The effectiveness of NO in reducing Cd-induced negative effects on plant height, fresh weight, dry weight, protein content, nitrite content, nitrate reductase (NR) activity, catalase activity, and peroxidase activity were investigated. Seedling development, protein content, nitrite content, nitrate reductase (NR) activity, antioxidant defense systems disruption, overproduction of reactive oxygen species, and oxidative damage were observed. The antioxidant defense system (catalase and peroxidase activities) was activated by NO, which resulted in lower lipid peroxidation and lower hydrogen peroxide (H2O2) levels in Cd-exposed plants. SNP treatment boosted endogenous NO levels and NR activity in Cd-stressed plants while also enhanced proline levels to preserve osmotic equilibrium. The presence of total phenols and flavonoids increased after SNP treatment, indicating that SNP enhanced stress recovery and boosted plant development in Cd-stressed plants. 相似文献
20.
CG 10-248 (3,4-dihydro-2,2 dimethyl-9-chloro-2H-naphtho[1,2b]pyran-5,6-dione), a ß-lapachone analogue, modified the ultrastructure of rat liver mitochondria in vitro, in the absence of added oxidizable substrates. The condensed mitochondrial state was replaced by the orthodox or swollen state to a significant degree. The number of modified mitochondria depended on incubation time and quinone concentration, in the 25-100 µM range. Under the same experimental conditions, mitochondrial respiration was uncoupled as indicated by the increase in the rate of succinate oxidation by controlled mitochondria in metabolic state “4” (not in state “3”), and by the activation of latent F 0 F 1 -ATP synthase. Taking into account structural similarities, the results reported here may be valid for other o-naphthoquinones, such as ß-lapachone. 相似文献
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