ABSTRACT
Flax (Linum usitatissimum) is an important oilseed and medicinal plant that numerous breeding lines andcultivars have been produced by plant breeders up to now. The present study was conducted to evaluate thebiochemical factors changes affected by NaCl oxidative stress in different genotypes of flax. For this purpose,an experiment was conducted as a factorial arrangement based on a completely randomized design with threereplications in greenhouse conditions. The experimental factors included three genotypes (Tabare, Golchin,and 375Ha) as the first experimental factor and salinity stress (120 mM NaCl) time course at three levels (0,24, and 48 hours after salinity treatment) as the second factor. The measured biochemical factors in the leafwere catalase, guaiacol peroxidase, malondialdehyde, hydrogen peroxide, proline, and superoxide dismutase(SOD). The results showed that salinity stress had a significant effect on the content of measured biochemicalparameters. The levels of catalase, guaiacol peroxidase, hydrogen peroxide, and proline were statisticallysignificant in the tolerant flax genotypes. Furthermore, the interaction of genotype and time after applyingstress had a significant effect on the catalase, hydrogen peroxide, and proline content. The amount of catalaseand proline in the 24 hours after stress was more than the 48 hours, indicating the key role of these factors at thebeginning of the stress. On the other hand, the amount of guaiacol peroxidase and SOD increased significantlyin 48 hours after stress. Generally, the content of the antioxidant factor increased significantly under salinitystress, especially in 375Ha tolerant genotype. This indicates the importance of these enzymes in salt stresstolerance in order to more accurately evaluate the genotypes sensitive and tolerant to the flaxseed in the seedlingstage. These results confirmed the slat tolerance of 375Ha genotype in the seedling stress and therefore can bea promising line for regions with slat stress conditions.
ABSTRACT
Objective: Based on the transcriptome sequencing results of Lycium barbarum under different concentrations of NaCl stress, the bHLH transcription factor family members of Lycium barbarum were identified by bioinformatics method. Methods: The bHLH family genes were screened by transcriptome sequencing of leaf and root samples of Lycium ruthenicum Murr. under NaCl stress. Results: The physicochemical properties, conserved domain, gene structure, cell location and phylogenetic development of these genes were analyzed by bioinformatics method. The results showed there were 89 bHLH family of Lycium ruthenicum. under NaCl stress. Their physicochemical properties were different, of which 71.90% proteins were weakly acidic and they were hydrophilic protein. The bHLH family of Lycium ruthenicum contained two conserved domains, which were located in the alkaline amino acid region of N and the helical ring and spiral region of C, respectively. The subcellular localization prediction of these bHLHs were mainly in the nucleus and extracellular. Phylogenetic analysis showed that 89 bHLH genes were divided into 20 subgroups, among which the 3 subgroup contained the most abundant bHLH members,including 11 bHLH proteins; the 7, 11, 13, 22 subgroups had only 1 member, respectively. In the other subgroups, the range was between 2 and 8. Conclusion: There are 89 members of bHLH transcription factor family in Lycium barbarum under NaCl stress, and most of the bHLH family proteins are weakly acidic, belonging to hydrophilic proteins, which can be divided into 20 subgroups.
ABSTRACT
Abstract The viability of Lactobacillus bulgaricus in freeze-drying is of significant commercial interest to dairy industries. In the study, L.bulgaricus demonstrated a significantly improved (p < 0.05) survival rate during freeze-drying when subjected to a pre-stressed period under the conditions of 2% (w/v) NaCl for 2 h in the late growth phase. The main energy source for the life activity of lactic acid bacteria is related to the glycolytic pathway. To investigate the phenomenon of this stress-related viability improvement in L. bulgaricus, the activities and corresponding genes of key enzymes in glycolysis during 2% NaCl stress were studied. NaCl stress significantly enhanced (p < 0.05) glucose utilization. The activities of glycolytic enzymes (phosphofructokinase, pyruvate kinase, and lactate dehydrogenase) decreased during freeze-drying, and NaCl stress were found to improve activities of these enzymes before and after freeze-drying. However, a transcriptional analysis of the corresponding genes suggested that the effect of NaCl stress on the expression of the pfk2 gene was not obvious. The increased survival of freeze-dried cells of L. bulgaricus under NaCl stress might be due to changes in only the activity or translation level of these enzymes in different environmental conditions but have no relation to their mRNA transcription level.
Subject(s)
Enzymes/metabolism , Freeze Drying , Lactobacillus/drug effects , Lactobacillus/radiation effects , Sodium Chloride/metabolism , Gene Expression Profiling , Glycolysis/drug effects , Glycolysis/radiation effects , Lactobacillus/enzymology , Lactobacillus/physiology , Microbial Viability/drug effects , Microbial Viability/radiation effectsABSTRACT
Objective: To find get the method of alleviating salinity damage to Coptis chinensis under NaCl stress by studying the seed generation and seedling physiological nature. Methods: Several physiological indexes such as germination vigor, germination rate, germination index, and vigor parameters of C. chinensis were measured after treated by 5-aminolevulinic acid (ALA) under salt stress (NaCl with the concentration of 100 mmol∙L-1 NaCl). And other parameters such as memberane permeability, H2O2 content, production rate of superoxide anion, contents of soluble surge, soluble protein, free proline, and malondialdehyde (MDA), and activities of superoxide (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were also measured. Results: The seed germination indexes of C. chinensis under NaCl stress have an obvious inhibition. But after the treatment of ALA, germination indexes were all increased. The results also showed that the treatment of exogenous ALA obviously increased the contents of soluble sugars, free proline, and soluble protein, decreased the contents of MDA, H2O2, and production rate of superoxide anion. Meanwhile, the results also indicated that ALA could improve the activities of SOD, POD, CAT, and APX. Conclusion: Exogenous ALA with appropriate concentration could significantly alleviate the damages to the seeds and seedlings of C. chinensis under NaCl stress and promote the salt resistance of the seeds and seedlings through improving the germination indexes and activities of anti-oxidase, decreasing the memberane permeability, and so on.
ABSTRACT
Objective: To investigate the effect of NaCl stress on growth and physiological-biochemical characteristics of Stellaria dichotoma amdits mechanism. Methods: In this study, one-year-old S. dichotoma was cultivated in pot at four NaCl levels (0.2%, 0.3%, 0.4%, and 0.5%) and the plant growth parameters and physiological-biochemical characteristics were determined. Results: NaCl stress had no significant effect on S. dichotoma growth at 0.3% NaCl. However, NaCl stress significantly inhibited the growth of S. dichotoma at 0.4% NaCl or above, and this inhibition was greater at higher concentration. The activities of SOD, POD, and CAT increased first and then decreased as NaCl concentration increased; The content of MDA and proline significantly increased as NaCl concentration increased, while membrane permeability and soluble protein content significantly decreased as NaCl concentration increased. Conclusion: S. dichotoma has osmotic stress resistance ability and reactive oxygen scavenging capacity at light NaCl stress, which causes S. dichotoma growth no inhibited at a certain extent NaCl stress.
ABSTRACT
The regulation of proline accumulation in seedlings of rice (Oryza sativa L. cv. Badami) was investigated. The increasing concentration of NaCl from 0.5 to 2.5 % progressively increased the proline content in rice. Proline accumulation caused by NaCl was related to protein proteolysis, an increase in OAT, P5CS, P5CR activity, a decrease in PDH activity. The maximum increase in proline content was recorded at 2.5 % NaCl concentration as compared to control and other concentrations of NaCl. The highest significant activity of proline synthesizing enzymes, D1-Pyrrolline-5-carboxylate synthetase, D1-Pyrrolline-5-carboxylate reductase and Ornithine-d-aminotransferase with a lowest activity of proline hydrolysis enzymes; Proline dehydrogenase were also recorded at 2.5 % salinity over control and other concentrations of NaCl with a in-significant increase in the activity of D1-Pyrrolline-5-carboxylate synthetase and Ornithine-d-aminotransferase at 0.5 % concentration of NaCl over control. Externally the addition of 300mg MnCl2, 220 ml-1 ½ strength Hoagland solution, having 1% NaCl, was seen to increase a 893.9 % in proline content of this variety as compared to control.
ABSTRACT
Objective: To investigate the effects of exogenous nitric oxide (NO) on the physiology of the seed germination and seedling growth of Silybum marianum under NaCl stress. Methods: The seeds of S. marianum were treated by sodium nitro prusside (SNP) at the concentration of 0.05-0.60 mmol/L under 0.7% NaCl stress. Some physiological indexes were measured, such as germination energy, germination rate, germination index, and vigor index of the seeds, and contents of malondialdehyde (MDA), photosynthetic pigment, osmosis substances, and the activities of the protective enzymes in leaves. Results: The seed germination and seedling growth of S. marianum were obviously inhibited under NaCl stress. Soaking seeds with 0.05-0.60 mmol/L SNP could alleviate the damage of NaCl stress. Under this treatment, the contents of photosynthetic pigment (including chlorophyll a, chlorophyll b, total chlorophyll, and carotinoid) and osmosis substances (including soluble sugar, soluble protein, and proline), and the activities of protective enzymes (including SOD, POD, and CAT) in the leaves were significantly increased, while the MDA content in the leaves was decreased. Conclusion: Soaking seeds with 0.05-0.60 mmol/L SNP could promote the salt resistance of the seeds and seedlings of S. marianum. The different cultivars of S. marianum differ in the sensitivity to SNP. The optimal concentration of SNP for the seed soaking of S. marianum with white and black skins is 0.10 and 0.40 mmol/L, respectively.
ABSTRACT
OBJECTIVE: To study the changes in physiological indices reflecting resistance to environmental stress and volatile constituents of Lysimachia nummularia Aurea. METHODS: Different concentrations (150, 200, 250 and 300 mmol · L-1) of NaCl solution was used to treat young Lysimachia nummularia Aurea to investigate the effect of saline stress on the seedling growth. The changes of physiological indices including soluble sugars, proline, SOD and so on were assayed. Volatile constituents were analyzed by head space solid-phase microextration (HS-SPME) coupled with gas chromatography-mass spectrometry (GC/MS). RESULTS: With increasing stress intensity, the contents of soluble proteins declined, those of soluble sugars increased gradually, the content of proline reached the maximum value when saline stress intensity was 250 mmol · L-1, and the contents of chlorophyll a and b decreased firstly and rose later above 250 mmol · L-1. MDA content and SOD activity rose gradually under saline stress with increasing stress intensity. POD activity was significantly lower under the saline stress than the control group. CAT activity rose firstly and rapidly declined later. The volatile constituents of L. nummularia fluctuated after saline stress. CONCLUSION: L. nummularia has relatively higher saline resistance by means of active accumulating osmoregulation substances such as soluble sugars, soluble proteins and enhancing capability of antioxidase.