ABSTRACT
Early season carrot (Daucus carota) production is being practiced in Punjab, Pakistan to meet the market demand but high temperature hampers the seed germination and seedling establishment which cause marked yield reduction. Seed priming with potassium nitrate breaks the seed dormancy and improves the seed germination and seedling growth potential but effects vary among the species and ecological conditions. The mechanism of KNO3 priming in high temperature stress tolerance is poorly understood yet. Thus, present study aimed to evaluate high temperature stress tolerance potential of carrot seeds primed with potassium nitrate and impacts on growth, physiological, and antioxidant defense systems. Carrot seeds of a local cultivar (T-29) were primed with various concentration of KNO3 (T0: unprimed (negative control), T1: hydroprimed (positive control), T2: 50 mM, T3:100mM, T4: 150 mM, T5: 200 mM, T6: 250 mM and T7: 300 mM) for 12 h each in darkness at 20 ± 2â. Seed priming with 50 mM of KNO3 significantly enhanced the seed germination (36%), seedling growth (28%) with maximum seedling vigor (55%) and also exhibited 16.75% more carrot root biomass under high temperature stress as compared to respective control. Moreover, enzymatic activities including peroxidase, catalase, superoxidase dismutase, total phenolic contents, total antioxidants contents and physiological responses of plants were also improved in response to seed priming under high temperature stress. By increasing the level of KNO3, seed germination, growth and root biomass were reduced. These findings suggest that seed priming with 50 mM of KNO3 can be an effective strategy to improve germination, growth and yield of carrot cultivar (T-29) under high temperature stress in early cropping. This study also proposes that KNO3 may induces the stress memory by heritable modulations in chromosomal structure and methylation and acetylation of histones that may upregulate the hormonal and antioxidant activities to enhance the stress tolerance in plants.
Subject(s)
Antioxidants , Daucus carota , Germination , Nitrates , Potassium Compounds , Seedlings , Seeds , Antioxidants/metabolism , Seedlings/growth & development , Seedlings/drug effects , Seedlings/physiology , Nitrates/metabolism , Nitrates/pharmacology , Seeds/drug effects , Seeds/growth & development , Seeds/physiology , Daucus carota/growth & development , Daucus carota/drug effects , Daucus carota/physiology , Potassium Compounds/pharmacology , Germination/drug effects , Hot TemperatureABSTRACT
Cherry is a fleshy drupe, and it is grown in temperate regions of the world. It is perishable, and several biotic and abiotic factors affect its yield. During April-May 2021, a severe fruit rot of cherry was observed in Swat and adjacent areas. Diseased fruit samples were collected, and the disease-causing pathogen was isolated on PDA. Subsequent morphological, microscopic, and molecular analyses identified the isolated pathogen as Aspergillus flavus. For the control of the fruit rot disease of cherry, iron oxide nanoparticles (Fe2O3 NPs) were synthesized in the leaf extract of Calotropis procera and characterized. Fourier transform infrared (FTIR) spectroscopy of synthesized Fe2O3 NPs showed the presence of capping and stabilizing agents such as alcohols, aldehydes, and halo compounds. X-ray diffraction (XRD) analysis verified the form and size (32 nm) of Fe2O3 NPs. Scanning electron microscopy (SEM) revealed the spinal-shaped morphology of synthesized Fe2O3 NPs while X-ray diffraction (EDX) analysis displayed the occurrence of main elements in the samples. After successful preparation and characterization of NPs, their antifungal activity against A. flavus was determined by poison technique. Based on in vitro and in vivo antifungal activity analyses, it was observed that 1.0 mg/mL concentration of Fe2O3 can effectively inhibit the growth of fungal mycelia and decrease the incidence of fruit rot of cherry. The results confirmed ecofriendly fungicidal role of Fe2O3 and suggested that their large-scale application in the field to replace toxic chemical fungicides.
Subject(s)
Calotropis , Metal Nanoparticles , Nanoparticles , Anti-Bacterial Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Fruit , Metal Nanoparticles/chemistry , Nanoparticles/chemistry , Plant Extracts/chemistry , Plant Extracts/pharmacology , Spectroscopy, Fourier Transform Infrared , X-Ray DiffractionABSTRACT
This study aimed to rigorously investigate and integrate the underlying hypothesis that an enhancing effect of gibberellic acid (GA3, 3 µM) with increased growth actually leads to a modification of the physiological role of polyamines during salinity stress (NaCl, 100 mM) in fennel. These analyses concern both reserve tissues (cotyledons) and embryonic axes in growth. Physiological results indicate a restriction of germination, growth, mineral nutrition and damages to membranes of salt-treated seedlings. This was partially attenuated in seedlings treated with an interaction effect of GA3 and NaCl. Peroxidase and catalase activities showed a reduction or an augmentation according to the treatments and organs. The three main polyamines (PA): putrescine, spermidine and spermine were elevated in the salt-treated seedlings. Meanwhile, GA3 seed priming was extremely efficient in reducing PA levels in salt-stressed seedlings compared to the control. Response of PA genes to salinity was variable. Up-regulation was noted for SPMS1, ODC1, and ADC1 in hypocotyls and cotyledons (H + C) and down-regulation for SAMDC1 in the radicle. Interaction of salt/GA3 treatment showed different responses, only ODC1 in (H + C) and ADC1 in both radicle and (H + C) were overexpressed. Concerning other genes, no change in mRNA abundance was observed in both organs compared to the salt-treated seedlings. From these results, it could be inferred that the fennel seedlings were NaCl sensitive. This sensitivity was mitigated when GA3 applied for seed priming and applied in combination with NaCl, which resulted in a reduction of the PA content. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01140-4.
ABSTRACT
[This corrects the article DOI: 10.1007/s12298-022-01140-4.].
ABSTRACT
This study explored treatment with Taif rosewater (RW) to protect against lead acetate-(PbAc) induced male testicular impairment. Male Wistar rats were divided into four groups and provided drinking water containing 4% Taif RW, PbAc, 4% Taif RW followed by PbAc or normal water (controls). Serum for hormonal assays and testicular tissue for histopathological and immunohistochemical examinations and molecular study were obtained. Epididymal spermatozoa were collected for analysis. PbAc significantly reduced serum levels of follicle-stimulating hormone (FSH), luteinising hormone (LH) and testosterone, as well as sperm count and motility percentage. It also caused a significant reduction in SOD and catalase activities, testicular CYTP450SCC , CYP17α, StAR mRNA expressions and the percentage of Bcl-2 immunoreactivity. The percentage of caspase-3 and NF-ĸB immunoreactivities, as well as sperm abnormalities, was increased, as did the testicular degeneration associated with vacuolation and necrosis of spermatogenic cells. Pretreatment with Taif RW significantly reduced the negative effects of PbAc as shown by the increases in serum gonadotropins level, SOD and catalase activities, and percentage of Bcl-2 immunoreactivity, decreases in the percentage of caspase-3 and NF-ĸB immunoreactivities, and improved testicular histology and sperm parameters. These data provide evidence that Taif RW protects against testicular toxicity caused by PbAc.
Subject(s)
Lead Poisoning/physiopathology , Plant Extracts/pharmacology , Spermatozoa , Testis/physiopathology , Animals , Follicle Stimulating Hormone/metabolism , Luteinizing Hormone/metabolism , Male , Oxidative Stress , Rats , Rats, Wistar , Sperm Count , Sperm Motility , Testosterone/metabolismABSTRACT
Seeds of snail medic (Medicago scutellata L.) were assessed for their response to salt at the germination and seedling stages. NaCl at concentrations 86 and 170 mM decreased the final germination percentage. Embryonic axis length, water content and dry weight of embryonic axis and cotyledons were also reduced by salt treatment. Furthermore, 28-d-old plants were grown hydroponically with different NaCl concentrations (0, 86 and 170 mM). After 7 days of treatment, growth, water content and development of the different organs of M. scutellata plant were affected especially at the highest NaCl concentration (170 mM). However, NaCl did not affect root length and the number of stem shoots but reduced stem length and total leaf area. Salt treatment increased markedly the concentration of Na+ in leaf and root tissues while reduced that of K+ only in root and stem tissues. Lipid peroxidation revealed the damage of the membranes of roots and leaves. Moreover, showed a more intense suberization and lignification at the cambial zone of roots of M. scutellata, were observed under the effect of NaCl.
Subject(s)
Medicago/drug effects , Medicago/physiology , Salinity , Sodium Chloride/toxicity , Cell Membrane/drug effects , Permeability/drug effectsABSTRACT
We aimed to examine the response of three tomato introgression lines (IL925.3, IL925.5 and IL925.6) to NaCl stress. These lines originated from a cross between M82 (Solanum lycopersicum) and the wild salttolerant tomato Solanum pennellii, each line containing a different fragment of the S.pennellii genome. Salt-sensitive phenotypes related to plant growth and physiology, and the response of antioxidants, pigments and antioxidant enzymes were measured. In general, salt stress decreased the fresh weight of leaves, leaf area and leaf number and an increase of Na+ accumulation in aerial parts was observed, which caused a reduction in the absorption of K+ and Ca2+. Salt stress also induced a decrease in chlorophyll, carotenoids and lipid peroxidation (MDA) and an increase in anthocyanins and reduced ascorbate, although some differences were seen between the lines, for example for carotenoid levels. Guaiacol peroxidase, catalase and glutathione reductase activity enhanced in aerial parts of the lines, but again some differences were seen between the three lines. It is concluded that IL925.5 might be the most sensitive line to salt stress as its dry weight loss was the greatest in response to salt and this line showed the highest Na+ ion accumulation in leaves.
Subject(s)
Plants, Genetically Modified/drug effects , Salt Tolerance , Sodium Chloride/pharmacology , Solanum lycopersicum/drug effects , Anthocyanins/metabolism , Ascorbic Acid/metabolism , Carotenoids/metabolism , Chlorophyll/metabolism , Crosses, Genetic , Enzymes/metabolism , Genotype , Lipid Peroxidation/drug effects , Solanum lycopersicum/genetics , Solanum lycopersicum/growth & development , Solanum lycopersicum/metabolism , Oxidative Stress/drug effects , Phenotype , Plants, Genetically Modified/genetics , Plants, Genetically Modified/growth & development , Plants, Genetically Modified/metabolism , Salt Tolerance/genetics , Sodium Chloride/metabolismABSTRACT
Experiments were conducted to evaluate the role of exogenously applied jasmonic acid (JA; 0.1 and 0.5 µM) in alleviating the toxic effects of arsenic (As; 5 and 10 µM) stress in rice. Plants treated with As showed considerable decline in growth attributes like height, fresh and dry weight of plant. Arsenic stress reduced the content of δ-amino livulenic acid (δ-ALA), glutamate 1-semialdehyde (GSA), total chlorophylls and carotenoids, with more reduction evident at higher (10 µM) As concentrations, however exogenously supplied JA alleviated the decline to considerable extent. Arsenic stress mediated decline in photosynthetic gas exchange parameters, Fv/Fm (PSII activity) and Rubisco activity was alleviated by the exogenous treatment of JA. Arsenic stress caused oxidative damage which was evident as increased lipid peroxidation, lipoxygenase activity and hydrogen peroxide concentrations however, JA treatment declined these parameters. Treatment of JA improved the activity of nitrate reductase and glutamate synthase under unstressed conditions and also alleviated the decline triggered by As stress. Activity of antioxidant enzymes assayed increased due to As stress, and the supplementation of JA caused further increase in their activities. Moreover, the content of proline, free amino acids and total phenols increased significantly due to JA application under stressed and unstressed conditions. Treatment of JA increased the content of nitrogen and potassium while as reduced As accumulation significantly.
ABSTRACT
Traditional medicinal plants play an important role in primary health care worldwide. The phytochemical screening and activities of Geranium pusillum were investigated in this research. The dried plant leaves were extracted with ethanol, n-hexane, chloroform, dichloromethane, methanol, acetone, and aqueous solvents. These extracts were qualitatively analyzed, GC-MS, antimicrobial activities by using the disc diffusion method, antioxidant activity was determined by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging, and cytotoxic activity was analyzed by the hemolytic activity of human red blood cells. The results showed phytochemicals such as flavonoids, terpenoids, steroids, phenols, saponins, tannins, and cardiac glycosides were detected in plant leaves. The ethanol extract at a concentration of 10 mg/mL showed a maximum inhibition zone 17.5 ± 0.09, 15.6 ± 0.11, 14.2 ± 0.17, 18.4 ± 0.11, 16.6 ± 0.15, 12.5 ± 0.13, 15.9 ± 0.10, and 13.1 ± 0.11 mm, and at 15 mg/mL showed 24.5 ± 0.09, 27.2 ± 0.12, 26.3 ± 0.17, 28.4 ± 0.10, 27.9 ± 0.16, 22.5 ± 0.13, 27.1 ± 0.10, and 24.1 ± 0.16 mm against Escherichia coli, Pasturella multocida (gram-negative), Staphylococcus aureus, Bacillus subtilus (gram-positive), Rhizopus solani, Aspergillus flavus, Aspergillus niger, and Alternaria alternate (fungal strain), respectively, and dichloromethane showed a minimum inhibition zone as compared to other extracts against bacterial as well as fungal strains. Chloroform extract had maximum antioxidant activity (45.00 ± 0.08%) and minimum in dichloromethane (12.20 ± 0.04%). Cytotoxic activity was found maximum in acetone extract (19.83 ± 0.07%) and minimum in ethanol extract (4.72 ± 0.04%). It is concluded that phytochemicals like phenols, flavonoids, and others may be responsible for these activities, which is why this plant is used for traditional medicine. RESEARCH HIGHLIGHTS: Geranium pusillum has therapeutic properties that exhibit various biological activities beneficial for human health. G. pusillum has significant inhibitory effects against bacterial and fungal strains. Chloroform solvent extract indicates potential free radical scavenging abilities. Acetone extract exhibits notable effects on human red blood cells and demonstrates significant cytotoxic activity.
Subject(s)
Anti-Bacterial Agents , Antioxidants , Geranium , Phytochemicals , Plant Extracts , Plant Leaves , Plant Leaves/chemistry , Antioxidants/pharmacology , Antioxidants/chemistry , Plant Extracts/pharmacology , Plant Extracts/chemistry , Phytochemicals/pharmacology , Phytochemicals/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Humans , Geranium/chemistry , Microbial Sensitivity Tests , Bacteria/drug effects , Hemolysis/drug effects , Erythrocytes/drug effects , Plants, Medicinal/chemistryABSTRACT
The aim of this study was to investigate the effect of a variable supply of potassium to culture medium on physiological and anatomical parameters (histological sections at the third internode) in basil, Ocimum basilicum. Thirty-four-day-old plants grown on basic nutrient medium were divided into four batches and grown on media with varying doses of potassium: 0.375 mM, 0.250 mM, 0.125 mM and 0 mM K+. After 64 days of culture, a final harvest was performed. The results showed that root and shoot growth in basil was decreased with decreased K+ concentration. This restriction was associated with a reduction in root elongation and leaf expansion, which was coupled with a decrease in chlorophyll and carotenoid contents. The estimation of electrolyte leakage reveals that this parameter was increased by potassium deficiency. With respect to total polyphenol and flavonoid contents, only the third leaf-stage extracts exhibited a decrease under low-K+ conditions. However, variability in response of phenolic compounds was recorded depending on the organ and the K+ concentration in the medium. Stem cross sections of potassium-deficient basil plants revealed a decrease in the diameter of these organs, which can be attributed to a restriction of the extent of different tissue territories (cortex and medulla), as well as by a reduction in cell size. These effects were associated with a decrease in the number of conducting vessels and an increase in the number of woody fibers.
ABSTRACT
Chickpea (Cicer arietinum L.) is one of the main pulse crops of Pakistan. The yield of chickpea is affected by a variety of biotic and abiotic factors. Due to their environmentally friendly nature, different nanoparticles are being synthesized and applied to economically important crops. In the present study, Trichoderma harzianum has been used as a stabilizing and reducing agent for the mycosynthesis of zinc oxide nanoparticles (ZnO NPs). Before their application to control Fusarium wilt of chickpea, synthesized ZnO NPs were characterized. X-ray diffraction (XRD) analysis revealed the average size (13 nm) of ZnO NPs. Scanning electron microscopy (SEM) indicated their spherical structure, and energy dispersive X-ray analysis (EDX) confirmed the oxide formation of ZnO NPs. Transmission electron microscopy (TEM) described the size and shape of nanoparticles, and Fourier transform infrared (FTIR) spectroscopy displayed the presence of reducing and stabilizing chemical compounds (alcohol, carboxylic acid, amines, and alkyl halide). Successfully characterized ZnO NPs exhibited significant mycelial growth inhibition of Fusarium oxysporum, in vitro. In a greenhouse pot experiment, the priming of chickpea seeds with ZnO NPs significantly increased the antioxidant activity of germinated plants and they displayed 90% less disease incidence than the control. Seed priming with ZnO NPs helped plants to accumulate higher quantities of sugars, phenol, total proteins, and superoxide dismutase (SOD) to create resistance against wilt pathogen. These nanofungicides were produced in powder form and they can easily be transferred and used in the field to control Fusarium wilt of chickpea.
ABSTRACT
The reduction of herbicide use and herbicide-resistant weeds through allelopathy can be a sustainable strategy to combat the concerns of environmental degradation. Allelopathic crop residues carry great potential both as weed suppressers and soil quality enhancers. The influence of sorghum crop residues and water extracts on the weed population, soil enzyme activities, the microbial community, and mung bean crop productivity was investigated in a two-year experiment at the Student Research Farm, University of Agriculture Faisalabad. The experimental treatments comprised two levels of sorghum water extract (10 and 20 L ha-1) and two residue application rates (4 and 6 t ha-1), and no sorghum water extract and residues were used as the control. The results indicated that the incorporation of sorghum water extract and residue resulted in significant changes in weed dynamics and the soil quality indices. Significant reduction in weed density (62%) and in the dry weight of weeds (65%) was observed in T5. After the harvest, better soil quality indices in terms of the microbial population (72-90%) and microbial activity (32-50%) were observed in the rhizosphere (0-15 cm) by the same treatment. After cropping, improved soil properties in terms of available potassium, available phosphorus soil organic matter, and total nitrogen were higher after the treatment of residue was incorporated, i.e., 52-65%, 29-45%, 62-84%, and 59-91%, respectively. In the case of soil enzymes, alkaline phosphatase and dehydrogenase levels in the soil were 35-41% and 52-77% higher, respectively. However, residue incorporation at 6 t ha-1 had the greatest effect in improving the soil quality indices, mung bean productivity, and reduction of weed density. In conclusion, the incorporation of 6 t ha-1 sorghum residues may be opted to improve soil quality indices, suppress weeds, harvest a better seed yield (37%), and achieve higher profitability (306 $ ha-1) by weed suppression, yield, and rhizospheric properties of spring-planted mung beans. This strategy can provide a probable substitute for instigating sustainable weed control and significant improvement of soil properties in the mung bean crop, which can be a part of eco-friendly and sustainable agriculture.
ABSTRACT
The present study aims to evaluate the antioxidant and antimicrobial activity of essential oils (EO) extracted from safflower plants grown in the absence and presence of NaCl, 50 mM. Plants treated with 50 mM of NaCl showed decreases in root, stem, and leaf dry weight. Results of the essential oils showed that roots have a higher EO yield than leaves and stems. Salinity caused a decrease in this yield in roots and leaves but not in stems. The compounds identified in the EO extracted from these organs belong to seven chemical classes of which the dominant class is the sesquiterpene hydrocarbons. The chemotype of C. tinctorius EO is variable depending on the organ and the treatment. The safflower essential oils showed low antioxidant, antiradical, and iron-reducing activities compared to those of the positive control (BHT). In an antifungal activity test, only two strains, Aspergillus niger and Candida albicans, were found to be highly sensitive to these oils as they showed almost total inhibition of their growth. For antibacterial activity, safflower EOs showed significant antimicrobial activity against Bacillus subtilis, Bacillus cereus, and Xanthomonas campestris in both control and NaCl-treated plants: for these three strains, total inhibition of growth was noted at 50,000 ppm of EO in leaves and roots; whereas for stems, total inhibition was noted only for the third strain (Xanthomonas campestris). For other strains, this inhibition was variable and weak. Salt was found to have no effect on the activities of safflower EOs.
ABSTRACT
Physiological responses of Arabidopsis thaliana to the interaction of iron deficiency and nitrogen form were studied using plants grown in hydroponics. Thirty-three-day-old seedlings were submitted to four treatments for 7 days: NO 3 + 5 microM Fe; NO 3 + 0.1 microM Fe; NH 4 + 5 microM Fe and NH 4 + 0.1 microM Fe. Leaf growth and chlorophyll content were highest in NO 3 -fed, Fe sufficient plants, but were strongly diminished by Fe deficiency under nitric nutrition, and by ammoniacal nutrition independently of Fe regime. However, the leaves of NH 4 -fed plants presented a higher Fe content than those of Fe sufficient, NO 3 -fed plants. Thus, leaf chlorosis of NH 4 -fed in plant did not depend on Fe availability, and seemed to be due to another factor. Root acidification capacity and Fe-chelate reductase (FCR) activity were also dependent on N form. The medium was acidified under ammoniacal regime and alkalinized under nitric regime regardless of Fe level. FCR activity stimulation in response to Fe deficiency was observed only in NO 3- fed plants. In addition, both N form and Fe level induced antioxidant responses in rosette leaves. Ammoniacal regime increased both peroxidase expression and anthocyanin accumulation, whereas Fe deficiency enhanced superoxide dismutase expression.
Subject(s)
Arabidopsis/drug effects , Iron Deficiencies , Nitrogen/pharmacology , Anthocyanins/chemistry , Chlorophyll/chemistry , Electrophoresis/methods , FMN Reductase/chemistry , Hydrogen-Ion Concentration , Iron/chemistry , Nitrates/chemistry , Nitrogen/chemistry , Plant Leaves/drug effects , Quaternary Ammonium Compounds/chemistry , Time FactorsABSTRACT
The response of Damask rose to drought and the underlying mechanisms involved are not known. In this study, vegetative, propagated rose plants were grown under control and water-deficit conditions in a greenhouse at Taïf University, south-west of Saudi Arabia. Control plants were irrigated to field capacity (FC), while water-stressed plants were irrigated to either 50% FC (mild stress) or 25% FC (severe stress). After 60 days, leaf, stem and root fresh and dry weights (g plant-1), photosynthetic activity, leaf water potential (Ψw), leaf water content (WC), apoplastic water fraction (AWF), osmotic potential at full turgor (Ψs100) and turgor loss point (Ψs0), cell wall elasticity, osmotic adjustment (OA), and some solutes (K+, Ca2+, Cl-, proline and soluble carbohydrates) were evaluated. Water stress significantly decreased fresh and dry weights of R. damascena and all photosynthetic parameters, apart from leaf temperature, which increased. Severe water stress (25% FC) resulted in more negative Ψs100 and Ψs0 values than the mild water stress and control. The AWF did not significantly change in response to water stress. The leaf bulk modulus of elasticity (ε) increased from 2.5 MPa under well-watered conditions to 2.82 and 3.5 MPa under mild and severe water stress, respectively. R. damascena experienced OA in response to water stress, which was due to the active accumulation of soluble carbohydrates and, to a lesser degree, proline under mild stress, along with tissue dehydration (passive OA) under severe stress. Overall, we identified two important mechanisms of drought tolerance in R. damascena-osmotic and elastic adjustment-but they could not offer resistance to water stress beyond 25% FC.
Subject(s)
Droughts , Osmotic Pressure , Photosynthesis , Rosa , Cell Wall/physiology , Elasticity , Osmotic Pressure/physiology , Photosynthesis/physiology , Plant Leaves/physiology , Rosa/physiology , Water/metabolismABSTRACT
Arabidopsis thaliana plants (wild-type accessions Col and N1438) were submitted to a prolonged, mild salt stress using two types of protocols. These protocols allowed salt-treated plants to absorb nutrients either through a part of their root system maintained in control medium (split-rooted plants) or during episodes on control medium alternating with salt application (salt alternation experiment). Full-salt treatments (salt applied continuously to whole root system) resulted in severe (but non-lethal) growth inhibition. This effect was partly alleviated in split-rooted plants on mixed salt-control medium and in plants submitted to salt-control medium alternation. The activity of the various isoforms of superoxide dismutases (SODs) did not appreciably change with the treatments. The abundance of the mRNAs of the seven SOD genes present in Arabidopsis genome was determined using real-time polymerase chain reaction. The two protocols gave qualitatively identical results. The expression level was increased by full-salt treatments for some genes and diminished for other genes. However, the nature of these genes differed according to the accessions: the responses to salt of FSD1 and MSD were opposite in Col and N1438. In Col, salt treatments inhibited the expression of FSD1 and strongly stimulated that of CSD1 and MSD. In N1438, the stimulation by salt concerned FSD1 and CSD1 and MSD expression being inhibited. In both accessions, the expression of CSD2 and CSD3 was lowered by salt. For all genes, the treatments that mitigated stress partially restored SOD expression to control level. Thus, the changes in SOD transcript abundance accurately reflected the severity of the salt stress.
Subject(s)
Arabidopsis/drug effects , Sodium Chloride/pharmacology , Anions/metabolism , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis/metabolism , Base Sequence , Cations/metabolism , DNA Primers/genetics , Gene Expression/drug effects , Genes, Plant , Isoenzymes/genetics , Isoenzymes/metabolism , Plant Leaves/drug effects , Plant Leaves/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , RNA, Plant/genetics , RNA, Plant/metabolism , Salinity , Superoxide Dismutase/genetics , Superoxide Dismutase/metabolismABSTRACT
Seeds of Lactuca sativa L. 'Romaine' were subjected to priming treatments with UV-C radiation at 0.85 or 3.42 kJ m(-2). Seedlings obtained from both primed (Pr) and non-primed (NPr) seeds were grown in an hydroponic culture system supplemented with 0 (control) or 100 mM NaCl. After 21 days of NaCl treatment, root and leaf biomass, root lengths, leaf numbers, and leaf surface area were measured. Ions (Na(+) and K(+)) accumulation was determined in roots and leaves. Total phenolic compound and flavonoid concentrations, as well as antioxidant and antiradical activities were measured in L. sativa leaves. Salt stress resulted in a lower increase in fresh weight of roots and leaves, which was more pronounced in roots than in leaves, due to reduced root elongation, leaf number and leaf expansion, as well as leaf thickness. The lower increase in fresh weight was accompanied by a restriction in tissue hydration and K(+) ion uptake, as well as an increase in Na(+) ion concentrations in all organs. These effects were mitigated in plants from the UV-C primed seeds. The mitigating effect of UV-C was more pronounced at 0.85 than at 3.42 kJ m(-2). Salt stress also resulted in an increase in total phenolic compounds and flavonoid concentrations and in the total antioxidant capacity in leaves. The highest diphenylpicrylhydrazyl radical (DPPH) scavenging activity was found in the leaves of plants from both Pr seeds. Our results suggest that plants grown from seed primed by exposure to moderate UV-C radiation exhibited a higher tolerance to salinity stress.