The effect of potassium chloride on ion dynamics and – budget in a slightly acidic forest soil

In a laboratory study, KCI- a neutral salt - equivalent to 300kg K/ha and 272 kg CI/ha was applied to the surface of undisturbed columns of a forest soil (Terra Fusca Rendzina) under steady state unsaturated flow conditions (1.0 cm/day). The effluent of the five soil columns was collected daily, and pH, cation- and anion concentrations were measured. Most of the applied K ions were retained in the top 10cm of the soil and moved in decreasing amounts further down the column. Among the cations studied Ca⁺⁺, Mg⁺⁺, and Na⁺ were lost from the system, K⁺, NH₄, Fe⁺⁺⁺, Mn⁺⁺, H⁺, and Al⁺⁺⁺ were retained. Nitrate and sulfate concentrations in the leachates showed a temporary decrease when CI passed through the columns. This decrease was accompanied with a decrease in pH. CI^?, NO₃^?, and SO₄^? exhibited leaching losses. Besides these anions, HCO₃^? played an important role.     

Etude de la nutrition potassique du sorgho I‐ incidence du remplacement du potassium par le sodium sur la teneur en cations des feuilles

Abstract

Grain sorghum plants were grown in nutritive solution culture under variable potassium concentrations from 0.5 to 6.0 meq/l, Na replacing K in deficient solutions. Leaves were analysed for K⁺, Na⁺, Ca⁺⁺ and Mg⁺⁺.

Potassium deficiency has no effect on the total amount of cations, but the decrease of K in deficient leaves is correlated with an increase of Na⁺, Ca⁺⁺ and Mg⁺⁺. Evidence of antagonism between K and divalent cations in given, but, in the most deficient leaves, magnesium instead of calcium balances for the diminution of potassium.     

Adsorption sur les argiles de deux lipopolysaccharides rhizosphériques

The adsorption with time has been measured of two well characterized lipopolysaccharides onto aqueous suspensions of a montmorillonite, a kaolinite and an illite at one fixed polymer-clay ratio. The clays were prepared in the Fe⁺⁺⁺ or Ca⁺⁺ forms by washing with FeCl₃ or CaCl₂ followed with water. The competitive sorption of the two polymers was measured also in the presence of an equal concentration of a protein or a basic amino-acid. Sorption of the polymers by themselves was approximately proportional to the external areas of the three clays and independent of the exchangeable cation. The presence of the protein inhibited completely the adsorption of both polymers onto the Ca⁺⁺ clays, but usually enhanced sorption onto the Fe⁺⁺⁺ clays. Sorption in the presence of the amino-acid differed both for each polymer and according to the form of the clay. Possible reasons for the various sorption patterns are discussed.     

Diltiazem influence on calcium and aluminum absorption by roots of three sorghum cultivars

Calcium (Ca⁺⁺) (10 mM) and Al⁺⁺⁺ (10 mM) ions were applied unilaterally in agar to primary roots of sorghum [Sorghum bicolor (L.) Moench.]. Both Ca⁺⁺ and Al⁺⁺⁺ caused unilateral growth “inhibitions and induced root curvature in cv Funk G522DR, SC574, and SC283 (acid soil stress sensitive, tolerant, and tolerant, respectively). Diltiazem (0.1 mM) [3‐(acetyloxy)‐5‐[2‐(dimethylamino)ethyl]‐2,3‐dihydro‐2‐(4‐methoxyphenyl)‐l‐5‐benzothiozepin‐4 (5H)‐one] inhibited Ca⁺⁺ absorption in Funk G522DR and SC283 but only partially influenced Ca⁺⁺ absorption by roots of SC574. Aluminum ion absorption by roots was inhibited in SC283 and SC574 but not in Funk G522DR.     

RESPONSES OF GRAFTED WATERMELON ONTO DIFFERENT GOURD SPECIES TO SALINITY STRESS

The watermelon cultivar ‘Crimson Tide’ was grafted onto three different rootstocks and grown under saline conditions to investigate effects of salinity on grafted and non-grafted watermelon. One Cucurbita maxima and 2 Lagenarai siceraria landraces (Skp and Brecik) were used as rootstock. Plants were irrigated with two different saline solutions [0.5 (control) and 8.0 dS m^?1] by two days interval at the first 15 days of experiment and one day interval at the last 15 days of experiment. The experimental design was randomized block. Each treatment was replicated three times with three plants. Grafted plants had higher plant growth parameter than non-grafted plant under saline conditions. Reduction in shoot dry weight was 41% in non-grafted plants while it was varied from 22% to 0.8% in grafted plants under saline conditions. Accumulation of sodium (Na⁺) was higher in non-grafted plants than grafted one. Calcium (Ca⁺⁺) and magnesium (Mg⁺⁺) concentration were higher in all grafted plants than non-grafted plants. Non-grafted plants had higher K⁺ concentration than other treatments under saline conditions. Ratios of Ca⁺⁺/Na⁺, K⁺/Na⁺ and Mg⁺⁺/Na⁺ were significantly affected by salt treatments and positively correlated with plant growth parameters. The ratios were lower in non-grafted plants than grafted plants under saline conditions.     

外加盐对凉粉草胶溶液的耐盐性和分子链刚性度的影响

在有盐环境下贮藏和加工凉粉草胶必须了解其多糖分子对盐的敏感性,该文绘制了凉粉草胶多糖在不同离子强度NaCl、KCl、MgCl₂和CaCl₂溶液中的Huggins'图,分别计算其分子链在这4种离子溶液中的耐盐度S、链刚性度B等值,结果发现：凉粉草胶多糖在4种离子溶液中,其耐盐性由强到弱的顺序为:K⁺>Na⁺>Mg⁺⁺>Ca⁺⁺,其分子链的构象在4种离子溶液中由柔到刚的顺序为:K⁺>Na⁺>Mg⁺⁺>Ca⁺⁺,这说明凉粉草胶多糖适合在KCl溶液中贮藏和加工。与其他多糖分子链在NaCl溶液中的B值比较后发现,凉粉草胶多糖的分子链构象较海藻酸钠要刚,较黄原胶要柔,这说明凉粉草胶比黄原胶更适合在NaCl溶液中贮藏和加工。     

pH and solubility of aluminium in acidic forest soils: a consequence of reactions between organic acidity and aluminium alkalinity

Data from two Podzol O and E horizons, sampled in 1-cm layers at 13 points within 2 m × 2 m plots, were used to test the hypothesis that the composition of hydrogen ions (H) and aluminium (Al) adsorbed to the solid-phase soil organic matter (SOM) determines pH and Al solubility in organic-rich acidic forest soils. Organically adsorbed Al was extracted sequentially with 0.5 m CuCl₂ and organically adsorbed H was determined as the difference between total acidity titrated to pH 8.2 and Al extracted in 0.5 m CuCl₂. The quotient between fractions of SOM sites binding Al and H (N_Al/N_H) is shown to determine the variation in pH and Al solubility. It is furthermore shown that models in which pH and Al solubility are linked via a pH-dependent solubility of an Al hydroxide and in which cation exchange between Al³⁺ and Ca²⁺, rather than cation exchange between Al³⁺ and H⁺, is the main pH-buffering process cannot be used to simulate pH or Al solubility in O and E horizons. The fraction of SOM sites adsorbing Al increased by depth in the lower O and throughout the E horizon at the same magnitude as sites adsorbing H decreased. The fraction of sites binding the cations Ca²⁺ + Mg²⁺ + K⁺ + Na⁺ remained constant. It is suggested that a net reaction between Al silicates (proton acceptors) and protonated functional groups in SOM (proton donors) is the long-term chemical process determining the composition of organically adsorbed H and Al in the lower part of the O and in the E horizon of Podzols. Thus, in the long term, pH and Al solubility are determined by the interaction between organic acidity and Al alkalinity.     

Predicting cation exchange equilibria in soil containing three heterovalent cations

Theoretical cation exchange equilibria relationships in a soil for a ternary system containing Na⁺, Ca²⁺ and Mg²⁺ are presented. The solid phase activity coefficients of cations for the three binary systems (i. e., Na⁺ – Ca²⁺, Na⁺ – Mg²⁺ and Ca²⁺ – Mg²⁺) were used to calculate the Wilson parameters. Adsorbed phase activity coefficients of Na⁺, Ca²⁺ and Mg²⁺ corresponding to their equivalent fractions on the adsorbed phase of A horizon of a Camborthid for the ternary system (i. e., Na⁺ – Ca²⁺ – Mg²⁺) were evaluated, using these Wilson parameters. Using the values of activity coefficients of adsorbed Na⁺, Ca²⁺ and Mg²⁺ in a ternary soil system and of thermodynamic equilibrium constants for the binary systems, the multiple linear regression relationships between the equivalent fractions of Na⁺, Ca²⁺ and Mg²⁺ on the adsorbed phase and their mole fractions in the equilibrium solution were obtained. The amounts of adsorbed phase cations so predicted showed a fair agreement with those observed experimentally in a ternary system.     

Phosphate adsorption by Na−, Mg− and Ca−saturated soil clays

Phosphate adsorption by the homoionic clay (Na, Ca, Mg) of three soils with widely varying mineralogy obeyed the Langmuir isotherm. The Langmuir constants b and k were a function both of the nature of the dominant clay mineral present and of the saturating cations following the order: Ca⁺⁺ ? Mg⁺⁺ ? Na⁺. This order was in agreement with those predicted by the diffuse double layer theory. The sample having montmorillonite when saturated with sodium, exhibited a negative adsorption of phosphorus which changed to a large positive adsorption in the presence of 0.1 N NaCl; It was concluded that the exchangeable cations influenced the extent of P adsorption by controlling the accessibility of the edge clay surfaces to phosphate ions.     

Sorption of primisulfuron on soil, and inorganic and organic soil colloids

Inorganic and organic soil colloids are responsible for the sorption of many pesticides. We studied the sorption of the herbicide primisulfuron [methyl 2 N‐[[[[[4,6‐bis(difluoromethoxy)‐2‐pyrimidinyl]amino]carbonyl]amino]sulfonyl]benzoate] on Fe³⁺‐, Al³⁺‐, Ca²⁺‐ and Na⁺‐exchanged montmorillonite, soil organic matter (H⁺‐ and Ca²⁺‐saturated), amorphous iron oxide, and three soils in aqueous media. The sorption on soils was negatively correlated with pH. Ca²⁺‐ and Na⁺‐exchanged montmorillonites are ineffective in the sorption of primisulfuron. The sorption on Fe³⁺‐ and Al³⁺‐exchanged montmorillonite is rapid and follows the Freundlich equation. Fourier transform infrared (FT‐IR) and X‐ray powder diffraction studies of the Fe³⁺‐ and Al³⁺‐montmorillonite samples after the interaction with primisulfuron in chloroform solution suggest that primisulfuron is adsorbed and degraded in the interlayer. Humic acid is more effective in the sorption than is Ca humate, suggesting that the pH of the suspension (3.5 for humic acid and 6.0 for Ca humate) has a strong influence on the sorption of primisulfuron. Experiments on amorphous iron oxide indicate similar pH dependence. Infrared spectra indicate that the protonation of the pyrimidine nitrogen moiety of herbicide and subsequent hydrogen bonding with the surface hydroxyls of Fe oxide is the mechanism acting in the primisulfuron sorption.     

不同白榆品系对滨海盐碱地的改良效果及盐分离子的分布与吸收

为揭示不同白榆(Ulmus pumila L.)品系对滨海盐碱地土壤盐分的改良作用及盐分离子在土壤-白榆系统中的分布与吸收特征,筛选适宜在滨海盐碱地造林的耐盐白榆品系,以中度盐渍化生境下4年生的6种白榆品系(1,5,28,30,46,105号)为试验材料,采用野外取样与室内测试相结合的方法,研究了Na+、K+、Ca2+、Mg2+等盐离子在土壤及白榆品系各器官(根、茎、叶)中的分布特征。结果表明:(1)白榆可降低滨海盐碱地土壤中盐离子及全盐含量,不同白榆品系较对照的土壤全盐含量降低了55.0%～63.1%,30号白榆降幅最大。(2)不同白榆品系将Na+、K+、Ca2+、Mg2+优先积累到叶中,且叶中维持较高的K+/Na+、Ca2+/Na+、Mg2+/Na+比值,不同白榆品系通过建立新的离子平衡以适应盐胁迫环境。(3)不同白榆品系的离子吸收选择性系数均为SK,NaSCa,NaSMg,Na,其对K+的吸收选择性大于对Ca2+、Mg2+吸收选择性;种内差异导致不同白榆品系对Na+、K+、Ca2+、Mg2+吸收选择能力不同,28号白榆根系对K+的吸收性最强,5号白榆根系对Ca2+、Mg2+的吸收性最强。     

Effects of Supplemental Calcium on Ion Accumulation,Transport and Plant Growth of Salt Sensitive Brassica Rapa Landrace

ABSTRACT

Effects of three supplemental calcium (Ca⁺⁺; 2.5, 5.0, and 10 mole m^?3) concentrations on ion accumulation, transport, selectivity, and plant growth of salt-sensitive species, Brassica rapa ‘Sani’ in saline medium were investigated. Supplemental Ca⁺⁺ in the presence of 125 mol m^?3 sodium chloride (NaCl) did not improve the dry weight and leaf area indicating no role played by Ca⁺⁺ in the alleviation of salinity induced growth inhibition. However, calcium chloride (CaCl₂) did significantly affect sodium (Na⁺), potassium (K⁺), and Ca⁺⁺ contents of roots and shoots. The ion contents of shoots were significantly greater than those of roots per g dry weight, indicating ion transportation to shoots is greater than ion accumulation in roots. Use of CaCl₂ in 125 mol m^?3 NaCl reduced the Na⁺ content but increased K⁺ and Ca⁺⁺ contents in shoots. Sodium contents in shoots differed among the supplemental Ca⁺⁺ treatments indicating the role of CaCl₂ in Na⁺ ions transportation. Calcium content in shoots declined significantly in the control treatment (0 CaCl₂) but increased significantly in 10 mol m^?3 CaCl₂. The root also showed the effects of Ca⁺⁺ on the reduction of Na⁺ content and the increase of K⁺ and Ca⁺⁺ content. Unexpectedly, 5 mol m^?3 CaCl₂ induced the highest Na⁺ content in roots at 16 days after treatment. Supplemental CaCl₂ application influenced the K⁺ or Ca⁺⁺ selectivity over Na⁺ in two ways, ion accumulation at roots and transport to shoots. However, high CaCl₂ treatments allowed greater Ca⁺⁺ selectivity over Na⁺ than low CaCl₂. Likewise, high supplemental CaCl₂ showed higher K⁺ selectivity over Na⁺ than low CaCl₂. A marked increase in K⁺ versus Na⁺ selectivity for the transport process occurred at 10 mol m^?3 CaCl₂ treatments. The roots and shoots exhibited higher K⁺/Na⁺ and Ca⁺⁺/Na⁺ ratios in high CaCl₂ treatment than in low. The results are discussed in context to supplemental Ca⁺⁺ concentrations, ions accumulation, transportation and selectivity of salt sensitive Brassica rapa cultivar.     

Distribution of Manganese(Ⅱ) Chemical Forms on Soybean Roots and Manganese(Ⅱ) Toxicity

Distribution of chemical forms of manganese(Ⅱ)(Mn(Ⅱ))on plant roots may affect Mn(Ⅱ)absorption by plants and toxicity of Mn(Ⅱ)to plants at its high level.The chemical forms of Mn(Ⅱ)on soybean roots were investigated to determine the main factors that affect their distribution and relationship with Mn(Ⅱ)plant toxicity.Fresh soybean roots were reacted with Mn(Ⅱ)in solutions,and Mn(Ⅱ)adsorbed on the roots was differentiated into exchangeable,complexed,and precipitated forms through sequential extraction with KNO_3,EDTA,and HCl.The exchangeable Mn(Ⅱ)content on the roots was the highest,followed by the complexed and precipitated Mn(Ⅱ)contents.Mn(Ⅱ)toxicity to the roots was greater at pH 5.5 than at pH 4.2 due to the larger amount of exchangeable Mn(Ⅱ)at higher pH.The cations Al~(3+),La~(3+),Ca~(2+),Mg~(2+),and NH_4~+competed with Mn(Ⅱ)for cation exchange sites on the root surfaces and thus reduced exchangeable Mn(Ⅱ)on the roots,in the order Al~(3+),La~(3+)Ca~(2+),Mg~(2+)NH_4~+.Al~(3+) and La~(3+) at 100μmol L~(-1) decreased exchangeable Mn(Ⅱ)by 80%and 79%,respectively,and Ca~(2+) and Mg2+at 1 mmol L~(-1) decreased exchangeable Mn(Ⅱ)by 51%and 73%,respectively.Organic anions oxalate,citrate,and malate reduced free Mn(Ⅱ)concentration in solution through formation of complexes with Mn(Ⅱ),efficiently decreasing exchangeable Mn(Ⅱ)on the roots;the decreases in exchangeable Mn(Ⅱ)on the roots were 30.9%,19.7%,and 10.9%,respectively,which was consistent with the complexing ability of these organic anions with Mn(Ⅱ).Thus,exchangeable Mn(Ⅱ)was the dominant form of Mn(Ⅱ)on the roots and responsible for Mn(Ⅱ)toxicity to plants.The coexisting cations and organic anions reduced the exchangeable Mn(Ⅱ)content,and thus they could alleviate Mn(Ⅱ)toxicity to plants on acid soils.     

电解质种类和浓度影响磷酸根解吸的机理研究

本文研究了吸附性阳离子、电解质浓度和组成影响几种矿物和土壤吸附态磷的解吸的机理。结果表明,吸附性阳离子影响磷酸根解吸与离子桥有关。桥接静电场愈强,被束缚磷的释放就愈困难。电解质阳离子对磷酸根解吸的影响则取决于其对表面负电荷的屏蔽效应。阳离子电价高,屏蔽作用大,磷解吸就少。电解质浓度影响吸附态磷的解吸主要与表面电位的变化有关。当pH>PZC值时,提高电解质浓度降低表面负电位,从而减少磷的吸附;当pH<PZC时,提高电解质浓度则降低表面正电位,促进磷的解吸。磷酸根解吸盐效应零点(P_PZSE)值一般都介于土壤或矿物样品吸附磷酸根前后测得的两个PZC值之间。不同浓度电解质溶液中磷解吸量之差与吸附层电位变化量(△ψ_x)呈正相关。     

Effects of the sodium and calcium concentrations on the in vitro growth of Atriplex halimus L. plantlets

The objective of this work is to analyse the sodium (Na⁺) and calcium (Ca⁺⁺) importance in the in vitro morphogenesis of a halophile species the Atriplex halimus. The experiments have been made on plantlets coming from a seed population collected in a natural area (Algeria). Twenty medium, all different by their sodium chloride (NaCl) and calcium chloride (CaCl₂) content, have been tested. For five Na⁺ concentrations, four [Na⁺]/[Ca⁺⁺] ratios have been tested. The [Na⁺]/[Ca⁺⁺] ratio has a significant effect on the studied criteria (stem length, longest root length and leaf number). The ratio equal to two is the one which gives the lowest values and the ratio equal to one (for the same [Na⁺] quantity and a double quantity of [Ca⁺⁺]) gives the strongest ones. A new doubling of the [Ca⁺⁺] (ratio equal to 0.5) induces a decrease of the values. These results are remarkable if we take into account the low cation concentrations used in the experiments. The morphogenetical events observed here will be explained when results about cation ratios inside the plant and the enzyme activity will have been obtained.     

Ten years of precipitation chemistry in Haifa,Israel

Rain event samples have been collected in Haifa, Israel, for nine hydrological years 1981 to 1990. Precipitation amount, pH, SO₄ ⁼, NO₃ ^?, Cl^?, NH₄ ⁺, Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺ and alkalinity of rainwater samples were recorded. The sampling and analysis program was based on WMO recommendations for background networks. The sampling was performed manually, and the analysis was based on wet chemistry for ions and atomic absorptions for metals. Data of 187 rain samples showed that the average pH was 5.3±1.1∶ 26% of the rain events were below pH of 5.6 and 23% above pH of 7.0. Some simple chemical mass-balance considerations indicate that natural sources, sea salt and soil carbonates are the main contributors to rain chemistry. However, the presence of low pH events observed over the years suggests that the impact of anthropogenic emissions may overwhelm the buffering capacity of the alkaline aerosol.     

Evaluating the fraction of electrically associated cations on surfaces of soil particles by extrapolation of strong-field Wien effect measurements in dilute suspensions

Purpose

For agricultural production and environment protection, it is cations loosely bound to the soil particles that have a great significance in short-term processes of adsorption–desorption, exchange, and transport. It is beneficial to be able to evaluate the fractions of these cations in order to correctly predict potential pollution of soils by heavy metals and availability of plant nutrients.

Materials and methods

The homionic suspensions of yellow-brown soil (YB) and black soil I (BI) saturated with Na⁺ and Ca²⁺ and three subsamples of black soil II (BII) saturated with Ca²⁺ and Cd²⁺ were prepared to determine the electrical conductivity (EC) of the suspensions. On the basis of electrical conductivity vs. field strength (EC-E) curve, the fraction of electrically associated cations on surfaces of soil particles was evaluated by extrapolation of strong-field Wien effect measurements in dilute suspensions.

Results and discussion

The maximum dissociation degree (α _max) of Na⁺ adsorbed on surfaces of yellow-brown soil and black soil I was about 0.21, which is approximately twice as much as those of Ca²⁺ (0.07–0.10) adsorbed on surfaces of two soils. The soil type was not the main factor in evaluating α _max, and the valence of the cations was. For divalent cations, α _max of Ca²⁺ and Cd²⁺ adsorbed on soil particles with different contents of organic matter descended in the order: top black soil II?>?bottom black soil II?>?OM-free bottom black soil II.

Conclusions

The relatively small fractions of electrically adsorbed cations—about 0.2 for Na⁺ and 0.1 for Ca²⁺ on yellow-brown and black soils particles indicated that even for the more loosely adsorbed Na⁺ ions, most of the cations in the double layers of soil particles were adsorbed strongly by other, more specific mechanisms and cannot be stripped off into the solution, which would increase its electrical conductivity in a strong applied field.

     

Nutrient uptake and yield of sweet pepper as affected by stage of development and N form

Uptake of NO₃ ^‐, NH₄ ⁺, P, K⁺⁺, Ca⁺⁺ and Mg⁺⁺, as influenced by the stage of plant development and three NO₃ ^‐: NH₄ ⁺ ratios (1: 0, 1: 1, and 0: 1), was determined for sweet pepper (Capsicum annuum L. cv. ‘California Wonder'). Uptake was highest during fruit development and immediately after fruit harvest, indicating that fruit removal promotes nutrient uptake. When NO₃ ^‐ and NH₄ ⁺ were supplied in equal concentrations, NO₃ ^‐ was absorbed more readily. Each increment in NH₄ ⁺ decreased the uptake of K⁺, Ca⁺⁺, and Mg⁺⁺ by fruit tissue, while no significant effect on the N and P content of the fruit was observed. Ammonium nutrition reduced plant dry weight and fruit yield in comparison to NO₃ ^‐. Results from this study suggest that NO₃ ^‐ is the preferred N form, and that fertilizer application should be scheduled according to specific physiological stages to maximize nutrient uptake. Nutrient content of vegetative tissue was not indicative of potential yield.     

Relationship between Callus Growth and Mineral Nutrients Uptake in Salt-Stressed Indica Rice Callus

ABSTRACT

One month old rice calli were exposed to 0, 50, and 100 mol m^?3 sodium chloride (NaCl) in the liquid LS basal medium supplemented with 2.5 mg L^?1 2,4-dichlorophenoxy acetic acid (2,4-D) and 0.5 mg L^?1 kinetin. Callus relative growth rate (RGR; fresh) of both cultivars indicated a progressive decrease; however, callus dry weight increased as the NaCl level increased in the culture medium. Salinity stress increased the callus sodium (Na⁺), manganese (Mn²⁺), and magnesium (Mg²⁺) contents while potassium (K⁺), calcium (Ca²⁺), and iron (Fe²⁺) contents decreased. ‘Basmati-385’ showed less reduction in callus RGR, K⁺, and Ca²⁺ contents and a larger increase in callus dry weight, Na⁺, Mn²⁺, and Mg²⁺ contents as compared to ‘Basmati-Karnal’. However, the reverse was true for Fe²⁺ contents. K⁺/Na⁺ and Ca²⁺/Na⁺ ratios generally decreased under salt stress. Overall, reduction in callus relative growth rate was found to be inversely correlated with decrease in K⁺, Ca²⁺, and Fe²⁺ uptake and directly correlated with increased Na⁺ and Mg²⁺ concentration in callus tissue.     

Effect of Exogenous Silicon on Ion Distribution of Tomato Plants Under Salt Stress

Seedlings of two tomato cultivars were exposed to 0, 50, or 100 mM sodium chlroide (NaCl) stress with or without silicon (Si) for 10 days, and leaf electrolyte leakage, root activity, plant growth, and ion sodium, potassium, calcium, and magnesium (Na⁺, K⁺, Ca²⁺, and Mg²⁺) contents were determined. No significant differences were observed in total biomass and the root/crown ratio of salt-stressed plants treated with exogenous Si, but leaf electrolyte leakage of both cultivars treated with 50 mM NaCl and Si was lower than that in the same salt treatment without Si. Root activities of both cultivars were significantly affected by treatment with NaCl and exogenous Si. Application of Si induced a significant decrease in Na⁺ content and increases in K⁺, Ca²⁺, and Mg²⁺ contents in leaves of plants treated with 50 mM NaCl, and consequently the K⁺/Na⁺ and Ca²⁺/Na⁺ ratios increased by at least two times. The effects of Si on the ion contents of the roots were not notable.