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1.
Sorghum bicolor L. Moench, RS 610, was grown in liquid media salinized with NaCl, KCl, Na2SO4, K2SO4 or with variable mixtures of either NaCl/KCl or Na2SO4/K2SO4 at osmotic potentials ranging from 0 to -0.8 MPa. The purpose was to study the effects of different types and degrees of salinity in growth media on growth and solute accumulation. In 14-day-old plants the severity of leaf growth inhibition at any one level of osmotic potential in the medium increased according to the following order: NaCl < Na2SO4 < KCl = K2SO4. Inhibition of growth by mixtures of Na+ and K+ salts was the same as by K+ salts alone. Roots responded differently. Root growth was not affected by Na+ salts in the range of 0 to -0.2 MPa while it was stimulated by K+ salts. The major cation of leaves was K+ because S. bicolor is a Na+-excluder, while Na+ was the major cation in roots except at low Na+/K+ ratios in media. Anions increased in tissues linearly in relation to total monovalent cation, but not with a constant anion/cation ratio. This ratio increased as the cation concentrations in tissues increased. Sucrose in leaf tissue increased 75 fold in Chloride-plants (plants growing in media in which the only anion of the salinizing salts was Cl?) and 50 fold in Sulphate-plants (the only anion of the salinizing salts was SO42-). Proline increased 60 and 18 fold in Chloride- and Sulphate-plants, respectively, as growth media potentials decreased from 0 to -0.8 MPa. The concentrations of both sucrose and proline were directly proportional to the amount of total monovalent cation in the tissue. Sucrose concentrations began increasing when total monovalent cations exceeded 100 μmol (g fresh weight)?1 (the monovalent cation level in non-stressed plants), but proline did not start accumulating until monovalent cation concentrations exceeded 200 μmol (g fresh weight)?1. Therefore, sucrose seemed to be the solute used for osmotic adjustment under mild conditions of saline stress while proline was involved in osmotic adjustment under more severe conditions of stress. Concentrations of inorganic phosphate, glucose, fructose, total amino acids and malic acid fluctuated in both roots and leaves in patterns that could be somewhat correlated with saline stress and, sometimes, with particular salts in growth media. However, the changes measured were too small (at most a 2–3 fold increase) to be of importance in osmotic adjustment.  相似文献   

2.
Potato plants grown in vitro were subjected to different salt stresses by providing the salts NaCl, Na2SO4, MgCl2 and MgSO4 in different concentrations up to 300 mM. Salinity greatly affected the survival and the rooting of the plants. Shoot and root growth decreased with increasing salt concentrations. Under mild stress conditions, i.e. in conditions where the plant is able to adapt to the stress, the observed decrease was dependent upon the salt used. Under severe stress conditions, however, the decrease of the shoot and root growth was independent of the nature of the ions.  相似文献   

3.
Abstract

Puccinellia festucaeformis (Host) Parl.: germination and early growth on different salt substrates. Germination behaviour of Puccinellia festucaeformis seeds and early growth of seedlings at different experimental conditions was analysed. The following growth substrates were utilized: NaCl, KCl, KNO3, MgCl2, MgSO4, Na2SO4, NaNO3, CaCl2 at the decreasing concentrations of 0.50, 0.25, 0.12, 0.06M. Caryopses were allowed to imbibe and grow at alternating temperatures (10°-20°C or 20°-30°C) in the dark for 3 days. Seedling were grown for 15 days, at controlled light and temperature conditions, in the same nutrient substrates as those used for the germination experiments.

The germination experiments showed a high tolerance to salts up to 0.25M solution and for the whole range of MgSO4 concentrations. High growth temperatures increased the depressive effects of salt concentrations. Seedling growth was highly reduced when salt concentration was higher than 0.12M. High salt tolerance - maximum shoot and root growth - was showed by seedling allowed to grow on 0.50M MgSO4.

Germination and growth condition of Puccinellia festucaeformis is discussed in relation to the ecological features of this species and to its possible importance as bioindicator of MgSO4 rich natural substrates.  相似文献   

4.
The effects of sea salts, NaCl, KCl, MgCl2, MgSO4, and CaCl2, on the growth of protoplast cultures of two mangrove species, Sonneratia alba and Avicennia alba, were investigated using 96-well culture plates. Plants of these two species naturally grow at the seaward side of a mangrove forest. Cotyledon protoplasts of S. alba showed halophilic nature to NaCl, KCl, and MgCl2 at low concentrations (10–50 mM) when cultured in Murashige and Skoog’s (MS) medium containing 0.6 M mannitol. CaCl2 at a concentration higher than 25 mM was inhibitory to cell growth. On the other hand, in protoplast culture of A. alba suspension cells, which were induced from cotyledon tissues, in the modified amino acid (mAA) medium containing 1.2 M sorbitol, tolerance to NaCl, MgCl2 and MgSO4 were observed at a wide range of concentrations up to 400 mM. CaCl2 was always inhibitory for cell divisions in A. alba, but stimulatory for spherical enlargement of cells. However, no difference in cell enlargement was observed among other salts. Similarity and difference in reactivity to salts between protoplasts and suspension cells from our previous studies were discussed in relation to the site of salt tolerance or halophilic adaptation within mangrove cells. For protoplast cultures, the site(s) for response of S. alba and A. alba are located in the cytoplasm and/or the cell membrane.  相似文献   

5.
In order to identify physiological components that contribute to salinity tolerance, we compared the effects of Na+, Mg2+ and K+ salts (NaCl, Na2SO4, MgCl2, MgSO4, KCl and K2SO4), Ca2+ (CaSO4), mannitol and melibiose on the wild type and the single-gene NaCl-tolerant mutants stl1 and stl2 of Ceratopteris richardii. Compared with gametophytic growth of the wild type, stl2 showed a low level of tolerance that was restricted to Na+ salts and osmotic stress. stl2 exhibited high tolerance to both Na+ and Mg2+ salts, as well as to osmotic stress. In response to short-term exposure (3 d) to NaCl, accumulation of K+ and Na+ was similar in the wild type and stl1. In contrast, stl2 accumulated higher levels of K+ and lower levels of Na+. Ca2+ supplementation (1.0 mol m?3) ameliorated growth inhibition by Na+ and Mg2+ stress in wild type and stll, but not in stl2. In addition, under Na+ stress (175 mol m?3) wild-type, stll and stl2 gametopbytes maintained higher tissue levels of K+ and lower levels of Na+ when supplemented with Ca2+ (1.0 mol m?3). stl2 gametophytes were extremely sensitive to K+ supplementation. Growth of stl2 was greater than or equal to that of the wild type at trace concentrations of K+ but decreased substantially with increasing K+ concentration. Supplementation with K+ from 0 to 1.85 mol m?3 alleviated some of the inhibition by 75 mol m?3 NaCl in the wild type and in stl1. In stl2, growth at 75 mol m?3 NaCl was similar at 0 and 1.85 mol m?3 K+ supplementation. Although K+ supplementation above 1.85 mol m?3 did not alleviate inhibition of growth by Na+ in any genotype, stl2 maintained greater relative tolerance to NaCl at all K+ concentrations tested.  相似文献   

6.
Tadano T  Baker JH  Drake M 《Plant physiology》1969,44(11):1639-1644
The effect of addition of Ca salts on accumulation of K from 5 mN KCl or K2SO4 solutions was found to depend on whether Ca was added as Cl or SO4 salt. Chloride as well as K uptake was increased when Ca and Cl concentrations in culture solutions were increased. Pre-treatment of roots with CaCl2 stimulated subsequent K uptake from K2SO4 solutions as compared to pre-treatment with distilled water but pre-treatment with CaSO4 did not. The results indicate that addition of Ca salts to KCl or K2SO4 solutions increased anion uptake and the effect of the addition of the Ca salts on K uptake was in part the result of increased anion uptake and not entirely a direct effect of Ca.  相似文献   

7.
R E Dehl 《Biopolymers》1973,12(10):2329-2334
The effects of two salts, MgCl2 and MgSO4 on the wide-line nmr spectrum of D2O in oriented, undernatured collagen fibers have been examined at four different D2O contents. MgCl2 was found to decrease the nmr doublet splitting, as compared with equal quantities of pure D2O while the major effect of MgSO4 was to inhibit the adsorption of D2O without significantly affecting its nmr spectrum. The results, together with a few observations of KCl and LiCl solutions, indicate that even fairly high concentrations of salt have only small effects on the nmr spectrum of D2O in fibrous collagen. It is considered unlikely that either “two-state” or “structured-water” models can satisfactorily account for the D2O-nmr doublet spectrum or the effects of salts on it, over the entire range of observed D2O content.  相似文献   

8.
Atriplex prostrata was grown for one month in nutrient solutions with NaCl, KCl, Na2SO4, and K2SO4 (at osmotic potentials of 0, –0.75, –1.00, and –1.50 MPa). Plants treated with K2SO4 had less glycinebetaine at –1.0 and –1.50 MPa than those treated with Na+ salts, probably due to the inhibitory effects of K+ on glycinebetaine accumulation.  相似文献   

9.
Summary In contrast with the toxicities of sulfate and chloride salts added to substrates, the anions SO4 and C1 were not injurious when accumulated without leaf burning by cotton and tomato plants from atmospheres enriched with SO2 or HC1 gases. The foregoing results are discussed in terms of cationenzyme interactions which appear to represent at least a major cause of salt toxicity. Although anions are largely unreactive with enzymes it has long been observed that chloride salts in soil solutions are far more toxic than sulfate salts. Five of seven species have shown nearly equal growth repressions on substrates with 100 me/1 of C1 salts versus 200 me of SO4 salts, each added as 50 per cent Na. The ion activities of the two solutions were equal and the sum of cations in the plant saps were similar. The osmotic differentials (average about 10 atm) between the expressed tissue fluids and these substrate solutions were remarkably uniform within species. It is projected that the downward transport of salts via the phloem provides for root concentrations which supply ions to the xylem and thereby control the uptake of substrate salts.  相似文献   

10.
Application of cross-protection is expected to improve the thermotolerance of yeasts to enhance their ethanol production at high temperature. In this study, the effects of eight kinds of inorganic salts on the thermotolerance and ethanol production at high temperature in Pichia kudriavzevii were investigated. P. kudriavzevii showed strong thermotolerance and the ability to produce ethanol at high temperature, and higher ethanol production of P. kudriavzevii was observed at high temperature (37–42 °C) compared with that at 30 °C. Inorganic salt stresses induced obvious cross-protection of thermotolerance in P. kudriavzevii. The presence of 0.1 mol/L KNO3 or Na2SO4 or 0.2 mol/L NaCl, KCl, NaNO3, K2SO4 or MgCl2 increased the yeast biomass in YEPD medium at 44 °C to 2.72–3.46 g/L, obviously higher than that in the absence of salt stress (2.17 g/L). The addition of NaCl, KCl, NaNO3, KNO3, Na2SO4, K2SO4, CaCl2 and MgCl2 significantly increased the ethanol production of P. kudriavzevii in YEPD fermentation medium at 44 °C by 37–58%. KCl and MgCl2 exhibited the best performance on improving the thermotolerance and ethanol production, respectively, of P. kudriavzevii. A highly significant correlation (P?<?0.01) was obtained among ethanol production, biomass and glucose consumption, suggesting the important role of thermotolerance and glucose consumption in enhanced ethanol production. The combination of NaCl, KCl and MgCl2 had a synergistic effect on the improvement of thermotolerance and ethanol production at high temperature in P. kudriavzevii. This study provides some important clues for improving ethanol production of thermotolerant yeasts at high temperature.  相似文献   

11.
Soil salinity is a complex issue in which various anions and cations contribute to have a general adverse effect on plant growth. In the present study, effects of salinity from various salts including sodium chloride (NaCl), potassium chloride?+?sodium chloride?+?calcium chloride (KCl?+?NaCl?+?CaCl2), potassium sulfate?+?magnesium nitrate (K2SO4?+?Mg(NO3)2) at two electric conductivities (EC) of 2 and 4 dS m?1 of irrigation water, and a distilled water control were evaluated on coriander plants (Coriandrum sativum L.). At EC?=?2, all salts increased plant yield (shoot fresh weight) than control. Most growth traits including plant height, shoot fresh and dry weight, leaf SPAD value and vitamin C, leaf K, Mg and P concentrations were increased by K2SO4?+?MgNO3, and remained unchanged by KCl?+?NaCl?+?CaCl2 treatment (except reduced plant height). Leaf’s zinc concentration reduced by either treatment. Even sodium chloride at EC?=?2 showed some beneficial effects on leaf chlorophyll index, root fresh weight, leaf’s calcium and phosphorus concentration; however, most traits remained unchanged than control. Treatment of plants with NaCl or KCl?+?NaCl?+?CaCl2 at either EC increased the number of flowered shoots and leaf proline content than control. Most growth and quality traits including leaf minerals and vitamin C content were reduced by NaCl at EC?=?4; however, shoot fresh and dry weights remained unchanged than control. Plant root fresh weight increased by NaCl at EC?=?2 and decreased at EC?=?4 than control. At EC?=?4, shoot dry weight was increased and leaf Ca, P, Zn and Mn were decreased by KCl?+?NaCl?+?CaCl2, whereas shoot dry weight, leaf SPAD value and vitamin C content, leaf Mg and P were increased and leaf Zn was decreased by K2SO4?+?MgNO3 than control. The results indicate that in contrast to sodium chloride, the salinity effects of other salts can not be detrimental on coriander plant growth.  相似文献   

12.
Somatic embryogenesis in cacao is difficult and this species is considered as recalcitrant. Therefore, reformulation of culture media might be a breakthrough to improve its somatic embryogenesis. In cacao, acquisition of somatic embryogenesis competence involves three main stages: induction of primary callus, induction of secondary callus and embryo development. Screening for MgSO4 and K2SO4 concentrations for somatic embryo differentiation was conducted on three genotypes (Sca6, IMC67 and C151-61) at the three stages. The effect of these two salts in culture media appears to be most efficient at the embryo development stage. At this stage, high MgSO4 (24 mM) and K2SO4 (71.568 mM) in the culture media induced direct somatic embryos on staminodes and petals of the Sca6 and IMC67 genotypes. Media supplemented with 6.0 mM and 12.0 mM MgSO4 enabled high responsive of explants and produced high proportion of embryos. The positive effect of MgSO4 and K2SO4 on the acquisition of embryogenesis competence was further tested on seven cacao genotypes reputed as non embryogenic: SNK12, ICS40, POR, IMC67, PA121, SNK64 and SNK10. All these genotypes were able to produce somatic embryos depending on the MgSO4 concentration. Thus, our results showed that the recalcitrance of cacao to somatic embryo differentiation can be overcome by screening for the suitable MgSO4 or K2SO4 concentration. Studies of the influence of different K+/Mg2+ ratios (at normal sulphate concentration) on somatic embryo differentiation revealed that sulphate supply was the main factor promoting responsive explants and the proportion of embryos. Cysteine synthase isoforms showed patterns related to morphogenetic structures sustaining that sulphur supply and its assimilation improve somatic embryogenesis in cacao.  相似文献   

13.
Dunaliella tertiolecta grew in a medium that contained MgSO4(MgSO4 medium), while this alga did not grow at all in mediathat contained MgCl2 or Mg(NO3)2. The growth in the MgSO4mediumwas inhibited in comparison with that in media that containedsodium salts, such as NaCl, NaNO3, and Na2SO4. The energy chargeobtained from measurements of levels of adenine nucleotidesby HPLC were almost constant in Na- and Mg-containing media(about 0.87), indicating that the failure of growth in MgCl2medium and Mg(NO3)2 medium was not directly related to.changesin the energy metabolism. K+ and Mg2+ were the dominant intracellularcations not only in Na-containing media (Na-media) but alsoin Mg-cohtaining media (Mg-media). The intracellular concentrationof Ca2+ was lower in Mg-media (1.6 mM) than that in Na-media(6mM). The concentrations of HPO42– in cells incubatedin Mg-media were lower (less than 60 mM) than those in Na-media(greater than 110 mM). By contrast, the intracellular concentrationof SO42– was higher in a MgSO4 medium (26 mM) than thatin a Na2SO4 medium (4 mM) which, at least, compensated by 40%for the decrease in HPO42–. The ability to grow in a MgSO4medium may be related to the high intracellular concentrationof SO42–. (Received September 20, 1990; Accepted March 22, 1991)  相似文献   

14.
Changes in the surface potential, the electrical potential difference between the membrane surface and the bulk aqueous phase were measured with the carotenoid spectral shift which indicates the change of electrical field in the membrane. Chromatophores were prepared from a non-sulfur purple bacterium, Rhodopseudomonas sphaeroides, in a low-salt buffer. Surface potential was changed by addition of salt or by pH jump as predicted by the Gouy-Chapman diffuse double layer theory.When a salt was added at neutral pH, the shift of carotenoid spectrum to shorter wavelength, corresponding to an increase in electrical potential at the outside surface, was observed. The salts of divalent cations (MgSO4, MgCl2, CaCl2) were effective at concentrations lower than those of monovalent cation salts (NaCl, KCl, Na2SO4) by a factor of about 50. Among the salts of monoor divalent cation used, little ionic species-dependent difference was observed in the low-concentration range except that due to the valence of cations. The pH dependence of the salt-induced carotenoid change was explained in terms of the change in surface charge density, which was about 0 at pH 5–5.5 and had negative values at higher pH values. The dependence of the pH jump-induced absorbance change on the salt concentration was also consistent with the change in the charge density. The surface potential change by the salt addition, which was calibrated by H+ diffusion potential, was about 90 mV at the maximum. From the difference between the effective concentrations with salts of mono- and divalent cations at pH 7.8, the surface charge density of (?1.9 ± 0.5) · 10?3 elementary charge per Å2, and the surface potential of about ?100 mV in the presence of about 0.1 mM divalent cation or 5 mM monovalent cation were calculated.  相似文献   

15.
Salinity remarkably inhibits NO3 - uptake but the mechanisms are not well understood. This study was addressed to elucidate the role of ionic and osmotic components of salinity on NO3 - influx and efflux employing classic kinetics involving a low affinity transport system (LATS) and a high affinity transport system (HATS). In the presence of KCl, NaCl, and Na2SO4 at 100 mM concentrations, in both LATS and HATS, Michaelis constant (Km) was similar for the three salts and maximum rate (Vmax) decreased as follows: KCl > NaCl > Na2SO4, compared to control indicating a non-competitive interaction with NO3 -. Unexpectedly, iso-osmotic solutions (osmotic potential Ψπ = -0.450) of polyethylene glycol (PEG, 17.84 %, v/v) and mannitol (100 mM) remarkably increased Km in both the LATS and the HATS, but Vmax did not change indicating a competitive inhibition. Under the PEG and mannitol treatments, Km and Vmax were higher than under the salt treatments. The salts increased slightly NO3 - efflux in the following order KCl > NaCl > Na2SO4. In contrast, mannitol strongly stimulated and the PEG inhibited NO3 - efflux. The obtained data reveal that salinity effects were not dependent on the anion type (Cl- versus SO4 2-) indicating a non-competitive inhibition mechanism between Cl- and NO3 -. In contrast, the cation types (K+ versus Na+) had a pronounced effect. The osmotic component is important to net NO3 - uptake affecting remarkably the influx in both LATS and HATS components of cowpea roots.  相似文献   

16.
Certain inorganic salts like KNO3, KCl, K2SO4, Ca(NO3)2 and NH4NO3 extend longevity of cut carnation flowers. The effect of KNO3 was studied in some detail. There is an osmotic adjustment in response to KNO3 treatment. The osmotic concentration change occurred in the external as well as in the internal compartments. The osmotic concentration change in the external compartment is well correlated with extension of longevity. The effect of KNO3 on the sensitivity to ethylene, and its significance in delaying senescence is discussed.  相似文献   

17.
A study has been made on the mineral requirements of a strain ofAerobacter aerogenes for the production of valine. It was observed that K2HPO4 and MgSO4]. 7 H2O were required at concentrations of 0.1% and 0.05% respectively while the optimum level of each of the trace elements Fe and Mo was 1 μg/ml. NaCl, KCl and trace elements like Mn, Ni, Co, Cu and Zn had an adverse effect on the production of valine. The requirements for metals except Mg for growth of the organism and valine production are different.  相似文献   

18.
Response of sugarcane to different types of salt stress   总被引:2,自引:0,他引:2  
Summary Due to climatic conditions and prevailing water regime the yield and sucrose recovery in sugarcane are high in South Western India. However, excessive irrigation, poor drainage and luxuriant use of fertilizers have resulted in conversion of large fertile areas into saline lands. The salinity is due to the excess of Na+, Ca++, Mg++, SO4 and Cl ions. Individual salts of NaCl, Na2SO4, MgCl2 and MgSO4 were employed in culture experiments to study salt stress effect on sugarcane variety Co 740. It was observed that sulphate salinity was more toxic to sugarcane than the chloride one. Sulphate salts caused more inhibition of growth, chlorophyll synthesis, PEPCase activity, decreased the uptake of K+ and Ca++ ions but stimulated nitrate reductase. The stress did not result in proline accumulation in the sugarcane cultivar Co 740. The degree of toxicity of different ions in decreasing order in sugarcane cultivar Co 740 is SO4 >Na+>Cl>Mg++.  相似文献   

19.
The quinary system KCl-K2SO4-MgCl2-MgSO4-Mg(OH)2-H2O and associated eight systems K2SO4-MgSO4-Mg(OH)2-H2O, MgCl2-MgSO4-Mg(OH)2-H2O, KCl-MgCl2-Mg(OH)2-H2O, KCl-K2SO4-Mg(OH)2-H2O, MgSO4-Mg(OH)2-H2O, MgCl2-Mg(OH)2-H2O, K2SO4-Mg(OH)2-H2O and KCl-Mg(OH)2-H2O were investigated at 50° The solid phases of these systems were the new basic triple salt (NS salt B), MgCl2 · 3Mg(OH)2 · 8H2O, MgSO4 · 5Mg(OH)2 · 3H2O, carnallite, leonite, kieserite, hexahydrite, bischofite, potassium chloride, potassium sulfate and magnesium hydroxide and the crystallization fields of these salts in nine systems were determined.  相似文献   

20.
The main focus of this study was to determine the mechanism by which certain exogenous monovalent salts stimulate rates of net O2 evolution linked to oxaloacetate reduction in intact spinach chloroplasts. The influence of salts on the dicarboxylate translocator involved in the transport of oxaloacetate and on the activity and activation of the chloroplast enzyme NADP-malate dehydrogenase, which mediates electron transport to oxaloacetate, was examined. High concentrations of KCl (155 millimolar) increased the apparent Km for oxaloacetate but did not significantly alter the maximal velocity of uptake. Likewise, external salts (KCl, MgCl2, or KH2PO4) had minimal effects on the magnitude of light activation of NADP-malate dehydrogenase. In contrast, measurements of chloroplast NADP-malate dehydrogenase activity (after release by osmotic shock) showed a marked dependence on salt concentration. Rates were stimulated approximately 2-fold by both monovalent (optimally 75 millimolar) and divalent (optimally 20 millimolar) salts. It was inferred that the salt-induced increase in net rates of O2 evolution linked to oxaloacetate reduction is due, at least in part, to stimulation of NADP-malate dehydrogenase caused by monovalent cation permeability of the chloroplast inner envelope membrane.  相似文献   

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