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1.
Effects of NaCl on growth in vitro and contents of sugars, free proline and proteins in the seedlings and leaf explants of Nicotiana tabacum cv. Virginia were investigated. The fresh and dry mass of the seedlings decreased under salinity. These growth parameters in leaf explants decreased at 50 mM NaCl and increased up to 150 mM NaCl and then decreased at higher level of salinity. Free proline content in both seedlings and leaf explants increased and polysaccharide content decreased continuously with increasing of NaCl concentration. Reducing sugars, oligosaccharides, soluble sugars and total sugars contents in both seedlings and leaf explants decreased up to 150 mM NaCl and then increased at higher concentrations of NaCl.  相似文献   

2.
Longan species (Dimocarpus longan Lour.) exhibit a high agronomic potential in many subtropical regions worldwide; however, little is known about its responses to abiotic stress conditions. Drought and salinity are the most environmental factors inducing negative effects on plant growth and development. In order to elucidate the responses of longan to drought and salinity, seedlings were grown under conditions of drought and salt stresses. Drought was imposed by suspending water supply leading to progressive soil dehydration, and salinity was induced using two concentrations of NaCl, 100 and 150 mM in water solution, for 64 days. Data showed that salt concentrations increased foliar abscisic acid (ABA) and only 150 mM NaCl reduced indole-3-acetic acid (IAA) and increased proline levels. NaCl treatments also increased Na+ and Cl? content in plant organs proportionally to salt concentration. Drought increased leaf ABA but did not change IAA concentrations, and also increased proline synthesis. In addition, drought and salt stresses reduced the photosynthesis performance; however, only drought decreased leaf growth and relative leaf water content. Overall, data indicate that under severe salt stress, high ABA accumulation was accompanied by a reduction of IAA levels; however, drought strongly increased ABA but did not change IAA concentrations. Moreover, drought and high salinity similarly increased (or maintained) ion levels and proline synthesis. Data also suggest that ABA accumulation may mitigate the impact of salt stress through inducing stomatal closure and delaying water loss, but did not mediate the effects of long-term drought conditions probably because leaves reached a strong dehydration and the role of ABA at this stage was not effective to detain leaf injuries.  相似文献   

3.
B. Demmig  K. Winter 《Planta》1986,168(3):421-426
Concentrations of four major solutes (Na+, K+, Cl-, proline) were determined in isolated, intact chloroplasts from the halophyte Mesembryanthemum crystallinum L. following long-term exposure of plants to three levels of NaCl salinity in the rooting medium. Chloroplasts were obtained by gentle rupture of leaf protoplasts. There was either no or only small leakage of inorganic ions from the chloroplasts to the medium during three rapidly performed washing steps involving precipitation and re-suspension of chloroplast pellets. Increasing NaCl salinity of the rooting medium resulted in a rise of Na+ und Cl- in the total leaf sap, up to approximately 500 and 400 mM, respectively, for plants grown at 400 mM NaCl. However, chloroplast levels of Na+ und Cl- did not exceed 160–230 and 40–60 mM, respectively, based upon a chloroplast osmotic volume of 20–30 l per mg chlorophyll. At 20 mM NaCl in the rooting medium, the Na+/K+ ratio of the chloroplasts was about 1; at 400 mM NaCl the ratio was about 5. Growth at 400 mM NaCl led to markedly increased concentrations of proline in the leaf sap (8 mM) compared with the leaf sap of plants grown in culture solution without added NaCl (proline 0.25 mM). Although proline was fivefold more concentrated in the chloroplasts than in the total leaf sap of plants treated with 400 mM NaCl, the overall contribution of proline to the osmotic adjustment of chloroplasts was small. The capacity to limit chloroplast Cl- concentrations under conditions of high external salinity was in contrast to an apparent affinity of chloroplasts for Cl- under conditions of low Cl- availability.Abbreviation Chl chlorophyll  相似文献   

4.
To elucidate the osmotic adjustment characteristics of mangrove plants, inorganic ion and organic solute contents of intermediate leaves were investigated in 3-month-old Kandelia candel (L.) Druce seedlings during 45 days of NaCl treatments (0, 200, and 500 mM NaCl). The contents of Na+, Cl, total free amino acids, proline, total soluble sugars, pinitol and mannitol increased to different degree by salinity, whereas, K+ content decreased by salinity compared with control. NaCl treatment induced an increase of inorganic ion contribution while a decrease of organic solute contribution. It was concluded that accumulating a large amount of inorganic ions was used as the main osmotic adjustment mechanism under salinity treatment. However, accumulation of organic osmolytes might be considered to play much more important role in osmoregulation under severe salinity (500 mM NaCl) than under moderate salinity (200 mM NaCl), thus the damage caused by high toxic ions (Na+ and Cl) concentration in K. candel leaves could be avoided.  相似文献   

5.
Nitric oxide (NO) is a plant signaling compound known to mitigate key physiological processes and salicylic acid (SA) is considered to be a signaling molecule that plays a key role in growth, development, and defense responses in plants under stress conditions. This work investigated the effects of sodium nitroprusside (SNP, a donor of NO) and SA on salt-tolerance of cotton (Gossypium hirsutum L.) seedlings by examining growth, photosynthetic performance, total osmoregulation substance content, antioxidative enzymes and H+-ATPase enzyme subjected to 100 mM NaCl. Addition of 100 mM NaCl inhibited the growth and photosynthetic parameters of cotton seedlings, and dramatically increased the electrolyte leakage, the plant contents of proline, lipid peroxidation (malondialdehyde), hydrogen peroxide (H2O2) and Na. Furthermore, antioxidant enzyme activities were restrained. Foliar applications of 0.1 mM SNP or/and 0.1 mM SA led to increase in the growth rate and photosynthesis, including photosystem II, net photosynthetic rate and transpiration rate, improvement of reactive oxygen species-scavenging enzymes activities and reduction of H2O2 accumulation in cotton seedlings induced by NaCl. In addition, membrane transport and function were facilitated by decreasing leaf electrolyte leakage, improving ion absorption and activating the osmotic-regulated substances metabolic. Further investigation also showed that SNP and SA alleviated the inhibition of H+-ATPase in plasma membrane induced by NaCl. The present study showed that foliar application of SNP and SA alone mitigated the adverse effect of salinity, while the combined application proved to be even more effective in alleviating the adverse effects of NaCl stress.  相似文献   

6.
Effect of grain soaking presowing in 1 mM salicylic acid (SA) and NaCl (0, 50, 100, 150 and 200 mM) on barley (Hordeum vulgare cv Gerbel) was studied. Increasing of NaCl level reduced the germination percentage, the growth parameters (fresh and dry weight), potassium, calcium, phosphorus and insoluble sugars content in both shoots and roots of 15-day old seedlings. Leaf relative water content (RWC) and the photosynthetic pigments (Chl a, b and carotenoids) contents also decreased with increasing NaCl concentration. On the other hand, Na, soluble sugars, soluble proteins, free amino acids including proline content and lipid peroxidation level and peroxidase activity were increased in the two plant organs with increasing of NaCl level. Electrolyte leakage from plant leaves was found to increase with salinity level. SA-pretreatment increased the RWC, fresh and dry weights, water, photosynthetic pigments, insolube saccharides, phosphorus content and peroxidase activity in the stressed seedlings. On the contrary, Na+, soluble proteins content, lipid peroxidation level, electrolyte leakage were markedly reduced under salt stress with SA than without. Under stress conditions, SA-pretreated plants exhibited less Ca2+ and more accumulation of K+, and soluble sugars in roots at the expense of these contents in the plant shoots. Exogenous application (Grain soaking presowing) of SA appeared to induce preadaptive response to salt stress leading to promoting protective reactions to the photosynthetic pigments and maintain the membranes integrity in barley plants, which reflected in improving the plant growth.  相似文献   

7.
This research was conducted to screen various treatments of selenium (Se) and/or salicylic acid (SA) to mitigate signs of salinity on soybean. Seedlings were treated with three concentrations of Se (0, 25 and 50 mg l?1), two concentrations of SA (0 and 0.5 mM) and/or two concentrations of NaCl (0 and 100 mM). Se and/or SA had significant enhancing and alleviating effects on the chlorophyll a (Chl a) and carotenoid contents as well as, Chl a/b in the treated plants, but had adverse effects on the Chl b concentrations. The limiting effects of salinity on leaf area and dry mass were significantly eased by the Se and/or SA among which 25 mg l?1 Se and combined treatment of 50 mg l?1 Se and SA were the most effective. The utilization of Se and/or SA led to the improved proline and Mg contents, compared to the control. The supplemented Se and/or SA, especially the mixed ones, resulted in a significant decrease in Na/K ratios. Se and/or SA had significant inducing effects on enzymatic (peroxidase, catalase and superoxide dismutase) and non-enzymatic (ascorbate) antioxidant system. On the basis of the obtained results, it could be stated that the foliar utilization of Se in combination with SA may be used to relieve the signs of salinity stress.  相似文献   

8.
Carthamus tinctorius L., rich in antioxidant compounds, is a herbal medicine. Biochemical mechanisms of adaptation to salinity stress in safflower are still poorly understood at the cellular level. For this purpose, callus cultures of four different genotypes of safflower were used in this study to evaluate changes in their biochemical (ionic content, proline, and glycine betaine), total phenolics content (TPC), total flavonoids content (TFD), antioxidant responses (2,2-diphenyl-1-picrylhydrazyl: DPPH assay and carotenoid content), and lipid peroxidation (malon dialdehyde content: MDA) under salinity stress. The calluses derived from hypocotyls were exposed to in vitro salt stress at different concentrations of sodium chloride (0, 100, 200, and 300 mM). A reducing trend was observed in K+ and carotenoid reserves of the calluses with increasing NaCl concentration while an increasing trend was observed in Na+ content, proline, MDA, TPC, TFD, and DPPH activity under the same conditions. Callus glycine betaine content was found to decrease in the medium containing 100 mM NaCl but increased beyond this concentration up to 300 mM NaCl. Positive and significant correlations were recognized between DPPH and total phenolics as well as DPPH and total flavonoid contents, demonstrating that phenolics are the main contributors to the potential antioxidant activity of safflower at the cellular level. Overall, the salt-tolerant genotypes of Mex.2-137 and Mex.2-138 were found capable of being processed for the production of secondary metabolites via NaCl elicitation.  相似文献   

9.
外源GSH对盐胁迫下番茄幼苗生长及抗逆生理指标的影响   总被引:5,自引:0,他引:5  
采用营养液栽培法,研究外源谷胱甘肽(GSH)对NaCl胁迫下番茄幼苗生长、根系活力、电解质渗透率和丙二醛(MDA)、脯氨酸(Pro)、可溶性糖含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响,为利用外源物质减轻盐胁迫伤害提供理论依据。结果显示:(1)NaCl胁迫显著抑制了番茄幼苗的生长、根系活力和SOD、POD、CAT活性,提高了电解质渗透率及MDA、Pro、可溶性糖含量;(2)外源喷施GSH能够诱导NaCl胁迫下番茄幼苗叶片抗氧化酶SOD、POD、CAT活性上调,电解质渗透率及MDA含量下降,Pro和可溶性糖含量恢复至对照水平;(3)外源喷施还原型谷胱甘肽抑制剂(BSO)使NaCl胁迫下番茄幼苗的根系活力以及抗氧化酶SOD、POD、CAT活性下降,脯氨酸含量提高;(4)喷施GSH可诱导BSO和NaCl共处理番茄植株的根系活力、SOD、POD、CAT活性提高,MDA和Pro含量降低。研究表明,外源GSH可通过提高促进盐胁迫下番茄幼苗植株渗透调节能力及清除活性氧的酶促系统的防御能力、降低细胞膜脂过氧化程度、保护膜结构的完整性,从而有效缓解NaCl胁迫对番茄幼苗生长的抑制,提高其耐盐性。  相似文献   

10.
Salinity is a major yield-reducing factor in coastal and arid irrigated rice production systems. Rice seedlings (Oryza sativa cv. Tarom Atri) were exposed to different NaCl concentrations for 8 days after germination. Plants height, fresh and dry weight, relative water content, pigment and carbohydrate content, photosynthetic efficiency and lipid peroxidase and antioxidant enzyme activity of rice seedlings grown under salt stress were investigated. Seedling grown under 25and 50 mM salt were shorter than the control. They could, however, develop their secondary leaves. Seedlings grown in the nutrient solution supplied with 100 and 200 mM extra salt could not develop their secondary leaves. Fresh weight ofseedlings grown under salt stress reduced up to 42.2% of the non-treated seedlings. Chlorophylls and carotenoids contents decreased significantly in the salt-treated seedlings. Carotenoid contents in NaCl-treated seedlings were decreased to 39.3%. No significant changes occurred in the photochemical efficiency of control and stressed plants. Increasing concentrations of NaCl resulted in increase and decrease of Na+ and K+ ions, respectively. NaCl salinity caused an increase in both peroxide content and lipid peroxidation. Seedlings which recovered for 24 h showed lower peroxide and malondialdehyde content.  相似文献   

11.
The interactive effects of salinity stress (40, 80, 120 and 160 mM NaCl) and ascorbic acid (0.6 mM), thiamin (0.3 mM) or sodium salicylate (0.6 mM) were studied in wheat (Triticum aestivum L.). The contents of cellulose, lignin of either shoots or roots, pectin of root and soluble sugars of shoots were lowered with the rise of NaCl concentration. On the other hand, the contents of hemicellulose and soluble sugars of roots, starch and soluble proteins of shoots, proline of either shoots or roots, and amino acids of roots were raised. Also, increasing NaCl concentration in the culture media increased Na+ and Ca2+ accumulation and gradually lowered K+ and Mg2+ concentration in different organs of wheat plant. Grain soaking in ascorbic acid, thiamin or sodium salicylate could counteract the adverse effects of NaCl salinity on the seedlings of wheat plant by suppression of salt stress induced accumulation of proline.  相似文献   

12.
Salt stress perturbs a multitude of physiological processes such as photosynthesis and growth. To understand the biochemical changes associated with physiological and cellular adaptations to salinity, two lettuce varieties (Verte and Romaine) were grown in a hydroponics culture system supplemented with 0, 100 or 200 mM NaCl. Verte displayed better growth under 100 mM NaCl compared to Romaine, but both genotypes registered relatively similar reductions in growth under 200 mM NaCl treatment. Both varieties showed differences in net photosynthetic activity in the absence of salt and 8 days after salt treatment. These differences diminished subsequently under prolonged salt stress (14 days). Verte showed enhanced leaf proline and restricted total cations especially Na+, lesser malondialdehyde (MDA) formation and lignification in the roots under 100 mM NaCl salinity. Membrane damage estimated by electrolyte leakage increased with elevated salt concentrations in roots of both varieties, but Verte had significantly lower electrolyte leakage relative to Romaine under 100 mM NaCl. Moreover, Verte also accumulated greater levels of carotenoids under increasing NaCl concentrations compared to Romaine. Taken together, these findings suggest that the greater tolerance of Verte to 100 mM NaCl is related to the more restricted accumulation of total cations and toxic Na+ in the roots and enhanced levels of antioxidative metabolites in root and leaf tissue.  相似文献   

13.
Rice (Oryza sativa L.) seedlings were grown under NaCl stress. The leaf growth of resistant cv. Damodar was less affected than that of the susceptible cv. Jaya. The leaf protein content showed no distinct cultivar or age dependent differences under NaCl salinity. There was a significant increase in chlorophyll (Chl) and carotenoid (Car) contents of 25-d-oldseedlings of both cv. Jaya and cv. Damodar. However, Chl and Car content of 15-d-old seedlings of cv. Jaya decreased and that of cv. Damodar increased, under NaCl stress. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

14.
Salt stress causes extensive losses to agricultural crops, including wheat, throughout the world and has been the focus of wide research. Though, information is scarce on the potential of ancient wheat relatives in tackling this major limiting factor. Thus, six hulled tetraploid wheat genotypes (HW) were compared to a free-threshing durum wheat genotype (FTW) under different NaCl concentrations, ranging from 0 to 150 mM, at early growth stages in a sand culture experiment. Salt stress induced significant declines in the leaf chlorophyll (Chl) a, Chl b, total Chl, and carotentoid contents; the extent of the declines was greater in FTW compared to HW. Mean leaf proline (3.6-fold) and Na+ (1.58-fold) concentrations and Na+/K+ (2.48-fold) drastically increased with 150 mM of NaCl; the magnitude of the increases was greater in HW compared to FTW. While the carotenoids concentration decreased with progressive salinity both in HW and FTW, the activities of antioxidant enzymes, i.e., catalase, ascorbate peroxidase, and peroxidase were reduced in FTW, but remained unchanged in HW. The above responses to 150 mM NaCl were associated with a significant decrease in shoot dry mass of FTW and lack of significant changes in that of HW. Findings of the present study could help pave the way for further studies on physiological and molecular mechanisms of salt tolerance in these durum wheat relatives.  相似文献   

15.
The salt-sensitive humid tropical biodiesel crop, Jatropha curcas, was subjected to a 28-day exposure to salinity (0, 50, 100, and 200 mM NaCl), and activities of antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX), the rate of lipid peroxidation, stomatal conductance, mineral contents, and chlorophyll (Chl) content were compared to corresponding characteristics of J. cinerea, a related wild species of saline-dry areas. Biomass production decreased under the influence of 50 mM NaCl in both species, and the reduction was larger in J. curcas than in J. cinerea at the higher NaCl concentrations. In both species, stomatal conductance and transpiration decreased, leaf temperature and Na+ concentration increased under salt treatment; salinity effect was stronger in J. curcas. Chl degradation was enhanced only in J. curcas. In both Jatropha species, SOD, CAT, and POX activities increased with salinity. J. curcas showed the higher antioxidant activity than J. cinerea. Lipid peroxidation was observed only in J. curcas at concentrations above 100 mM NaCl, partially due to a greater reduction in stomatal conductance and/or the poor ROS-scavenging system. Thus, J. cinerea had more favorable characteristics to adapt to saline environments, and young J. curcas plants could adapt to salt-affected land if soil salinity was moderate (about 50 mM NaCl in solution).  相似文献   

16.
Six-months-old, uniform sized seedlings of two citrus rootstocks; Cleopatra mandarin (Citrus reshni Hort. ex Tan) and Troyer citrange (Poncirus trifoliata × Citrus sinensis) were irrigated with half-strength Hoagland nutrient solution containing 0, 40 or 80 mM NaCl for 12 weeks. Shoot height, leaf number and fresh weights of the seedlings, and relative chlorophyll contents, chlorophyll fluorescence yields (Fv/Fm), net photosynthetic and respiration rates in the leaves decreased with the increase in salinity level in the irrigation water. The decrease was greater in Troyer citrange as compared to Cleopatra mandarin. The concentrations of sugars i.e. fructose, glucose and sucrose in the leaves of Cleopatra mandarin and both leaves and roots of Troyer citrange decreased with the increase in salinity level. However, the concentrations in the roots of Cleopatra mandarin increased with the increase in salinity level. Free proline content in the leaves of Troyer citrange and root tissue of Cleopatra mandarin also increased with the increased salinity level. Among the polyamines, spermine titer increased in the leaves of both rootstocks as a response to salinity treatments. Na+ concentrations were higher in leaf and root tissue of Cleopatra mandarin, while that of Cl were higher in Troyer citrange.  相似文献   

17.
Erythrina variegata Lam. seedlings were grown under low (100 mM NaCl) and high (250 mM NaCl) salinity. Seedlings exposed to high salinity for 10 d showed significant reduction in growth rate and biomass production while the root/shoot ratio increased. In contrast to pigment and protein contents, starch and saccharide contents increased in salt stressed seedlings. When the seedlings were subsequently sprayed with triacontanol (1 mg kg-1) the salinity effect was partially ameliorated and growth, biomass, chlorophyll and carotenoid contents increased.  相似文献   

18.
混合盐碱胁迫对青山杨渗透调节物质及活性氧代谢的影响   总被引:6,自引:0,他引:6  
为研究青山杨(Populus pseudo-cathayana × P. deltoides)对盐碱的适应能力,对青山杨2年生扦插苗进行不同盐度和碱度的28组胁迫处理.结果表明:随盐浓度增加,青山杨叶片的电解质外渗率、丙二醛和脯氨酸含量呈上升趋势,可溶性糖、SOD和POD活性先升后降.pH值升高使电解质外渗率、丙二醛和POD活性呈上升趋势,脯氨酸和可溶性糖含量先升后降,SOD活性上升趋势不明显.盐浓度低于100 mmol·L-1时,随pH值升高,各项生理指标的变化不明显,SOD具有较高的活性;盐浓度在200 mmol·L-1、pH 8.99以上时,其电解质外渗率在50%以上,POD活性和丙二醛含量大幅度增加,脯氨酸和可溶性糖含量下降,SOD活性较低.推断盐浓度>200 mmol·L-1、pH>8.99的盐碱条件不适宜青山杨的生长.  相似文献   

19.
The effects of NaCl on growth, contents of proteins and proline, and activities of catalase, peroxidase and polyphenol oxidase were investigated in seedlings and calli of Trigonella foenum-graecum L. and T. aphanoneura Rech. f. Seeds and hypocotyl explants were cultured on Murashige and Skoog medium supplemented with 0, 50, 100, 150 and 200 mM NaCl. Seed germination and the fresh and dry mass of the seedlings decreased significantly under salinity. In both species significant increases in protein content of seedlings over that of control were observed at 150 and 200 mM NaCl. Protein content in calli decreased at 200 mM NaCl over that of control. Protein content was higher in seedlings than in calli at all NaCl concentrations. Conversely, proline content was lower in seedlings than in calli at all the tested NaCl concentrations. NaCl caused changes in the activities of peroxidase, catalase and polyphenol oxidase in seedlings and calli.  相似文献   

20.
The drought tolerance of Salicornia brachiata seedlings was assessed by monitoring growth, nutrient uptake, electrolyte leakage, lipid peroxidation, and biochemical responses under drought conditions simulated with 0, 10, 20, and 30 % polyethylene glycol (PEG 6000). After 7 days of drought induction, plants were harvested for measurement of various parameters. The biomass decreased and the plant height remained unchanged with PEG treatment. The total plant water content (TWC%) decreased by 11 % at the highest concentration of PEG (30 %). The electrolyte leakage and lipid peroxidation of shoots increased by 17 and 5 %, respectively, in 30 % PEG-treated plants. K+ and Ca2+ contents of shoots increased in a dose-dependent manner. However, in roots K+ content decreased and Ca2+ content remained unaffected by PEG treatment. Mg2+ content increased at high concentrations of PEG (20–30 %) in shoots and decreased at the highest concentration of PEG (30 %) in roots. Total free amino acids, proline, and polyphenol contents increased progressively with increase in severity of the drought stress. Total sugar content and reducing sugar content increased in 10 and 20 % PEG-treated plants and decreased in 30 % PEG-treated plants. Our results suggest that proline and other free amino acids, sugars, and polyphenols are the main compatible solutes in S. brachiata for maintenance of osmotic balance, protection of cellular macromolecules, detoxification of the cells, and scavenging of free radicals under drought stress. A greater accumulation of compatible solutes also facilitates the maintenance of nutrient uptake and adequate tissue water status and protection of membranes under drought conditions in S. brachiata. The results from the present study suggest that S. brachiata can be used for restoration of arid and semiarid lands of coastal ecosystems.  相似文献   

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