Ameliorative effect of potassium on mice and tomato subjected to sodium salinization

Rice (Oryza sativa L. cv. Yamabiko) and tomato (Lycopersicon esculentum Mill cv. Saturn) plants subjected to Na-salinization (NA: 80 mmol( + ) kg^-1 Na) in hydroponics were grown after the addition of K at five concentrations (K1: 10, K2: 20, K3: 30, K4: 40, K5: 50 mmol( + ) kg^-1). The effect of K on their growth was analyzed in terms of transpiration, cation uptake, and transport. A similar tendency for the above parameters was obtained in both species. The addition of 10 mmol( + ) kg^-1 K improved the growth by decreasing the content of Na and increasing the K content of the plants. The growth of the plants, however, was reduced along with the increase of the K concentration and became comparable to that of NA at K5. The total cation content increased with the increase of the K concentration, which was due to the increase of the K content.

A close relationship was observed among the osmotic potential of the solution, cumulative transpiration, and dry weight for both species among the K treatments.

Addition of K suppressed the uptake of other cations by rice and tomato in the order of Na>Mg>Ca, with a very small suppression for Ca and Mg. The depression of Na uptake by K could be due to the antagonism between the two cations.

In rice, the addition of K resulted in a decrease of the uptake concentration (UC) of Na and an increase of that of K, but did not bring about any changes in the UC of Ca and Mg. It was worth noting that K1 and K2 led to a higher UC of Na than NA in tomato, while the trend of the UC of K, Ca, and Mg was similar to that in rice. The transport of Na and Ca to the tops of rice was not affected by the addition of K, while that of Mg increased by K addition. In tomato, the transport of all the cations was promoted by the increase of the K concentration.     

Differences in short-term responses of rice and tomato to sodium salinization and supplemental potassium and calcium

Short-term (72 h) responses of the water and nutritional status to Na-salinization were investigated in rice (Oryza sativa L. cv. Koshihikari) and tomato (Lycopersicon esculentum Mill cv. Saturn). The short-term effect of supplemental K and Ca to the nutrient solution on the water status and absorption and transport of ions in the plants was also investigated. In both species, Na salinity resulted in the deterioration of the water status of tops and in nutritional imbalance. However, in rice, it was possible to prevent the deterioration of the nutrient status by enhancing the transport of cations, especially K, while tomato could maintain an adequate water status by inhibiting the water loss associated with transpiration. On the other hand, the water status in rice and the nutritional status in tomato markedly deteriorated by high Na level in the solution. Supplemental K and Ca could not ameliorate th.e water status in both species, and even worsened the status in rice. In rice, a close relationship was observed between the osmotic potential (OP) of the solution, water uptake and water content. The water status of rice, therefore, seemed to depend on OP of the solution. Supplemental K and Ca, on the other hand, were effective in the amelioration of the nutritional status. In tomato, supplemental Ca could improve the nutritional balance by suppressing the transport of Na and enhancing that of the other cations in avoidably the deterioration of the water status. Thus, the differences in the responses of the water and nutritional status of rice and tomato to high Na salinization and to supplemental K and Ca were evident in a short-term study and supported a similar tendency observed in a long-term study.     

Effect of K-type and Ca-type artificial zeolites applied to high sodic soil on the growth of plants different in salt tolerance

Abstract

The present study aimed to investigate the effects of K-type and Ca-type artificial zeolites on the growth and water and element absorptions of kidney bean (Phaseolus vulgaris L.), tomato (Lycopersicon esculentum Mill), maize (Zea mays L.) and beet (Beta vulgaris L.) in high sodic soil. Tottori sand dune soil, which was used as a control, was converted to high sodic soil mixed with salts. Each type of zeolite was mixed into the high sodic soil at rates of 0, 1, 2 and 5%. The results showed that kidney bean, tomato and maize died in high sodic soil 25–27 days after transplanting (DAT), whereas beet survived, although its growth was extremely suppressed at 26 DAT. The addition of Ca-type zeolite improved growth in all of the tested plants. Even 4 DAT the growth of beet was improved by recovery of water absorption, and growth of tomato was improved by recovery of Ca and K absorptions and cation balance, and restriction of Na absorption. Growth of kidney bean and maize improved at 11 or 13 DAT by recovery of water absorption and Ca and K absorptions. After 4 DAT, water absorption and P and K absorptions of beet were highly recovered compared with those of the other plants; beet growth improved to a large degree. The ameliorative effect of 5% Ca-type zeolite was lower than that of 2% in tomato, maize and beet because the excessive uptake of Ca restricted P transport from root to shoot, and high electrical conductivity of the soil solution restricted water uptake. Even 1% K-type zeolite addition suppressed growth of beet at 4 DAT, and the addition of 2% or 5% of K-type zeolite suppressed the growth of tomato and maize 11 or 13 DAT. Higher concentrations of HCO^? ₃ and CO^2? ₃, and pH of the soil solution of K-type zeolite treatments might inhibit water absorption by roots.     

Growth and Ca,Mg, K,and P uptake by triticale,wheat, and rye at four al levels

This study was conducted to determine relationships between Al toxicity and mineral uptake of triticale (X Triticosecale, Wittmack), wheat (Triticum aestivum L.), and rye (Secale cereale L.). Two culti‐vars of each species were grown in 1/5‐strength Steinberg solution with 0, 3, 6, or 12 ppm Al added. The solutions were adjusted to pH 4.8 at transplanting and were not adjusted thereafter. The plants were grown in a growth chamber for 19 days before harvesting to determine nutrient solution pH, dry weights, and Al, Ca, Mg, K, and P levels in plants. Increasing Al concentration reduced the final pH of solutions. The addition of 12 ppm Al severely reduced the growth and increased Al concentration of plant tops. The Al levels in roots generally increased with increments of added Al up to 6 ppm. Increasing Al decreased the uptake of Ca, Mg, and P by plant tops more than that of K. Regression analyses indicated that Al toxicity was associated with increasing K/Ca + Mg equivalent ratios and decreasing P concentration in plant tops. Differences between species were: higher Al concentration in rye than wheat with 6 and 12 ppm Al, higher translocation of Ca from roots to tops in wheat than in rye and Mg in triticale and wheat than rye; K/Ca + Mg equivalent ratios associated with 50% reduction in top growth followed the order: triticales > tolerant wheat > sensitive wheat > rye. Differences in mineral uptake associated with Al toxicity in wheat were more indicative of differential Al sensitivity in wheat than in triticale and rye which have higher internal Al tolerance.     

Lime and phosphorus interactions on growth and nutrient uptake by upland rice,wheat, common bean,and corn in an Oxisol

Liming and phosphorus (P) applications are common practices for improving crop production in acid soils of the tropical as well as temperate regions. Four greenhouse experiments were conducted on an Oxisol (clayey, kaolinitic, isothermic, Typic Haplustox) to evaluate response of liming (0,2, and 4 g/kg) and P application (0, 50, and 175 mg P/kg) in a factorial combination on growth and nutrient uptake by upland rice (Oryza sativa L.), wheat (Triticum aestivum L.), common bean (Phaseolus vulgaris L.), and corn (Zea mays L.). Phosphorus application significantly (P<0.01) increased dry weight of tops of all the four crop species as well as dry weight of roots of wheat and corn. Liming significantly (P<0.01) improved growth of common bean and corn but had significant negative effects on rice growth. Maximum dry weight of tops of rice and wheat was obtained at 175 mg P/kg without lime. Maximum dry weight of tops in common bean was obtained at 4 g lime/kg with 175 mg P/kg of soil. In all the crops, increasing levels of applied P significantly increased nutrient uptake. With some exceptions, increasing levels of lime tend to reduce uptake of P, zinc (Zn), copper (Cu), manganese (Mn), and iron (Fe) and increase the uptake of calcium (Ca) and magnesium (Mg) in all the crop species. Decrease in potassium (K) uptake, due to high lime, is probably due to antagonistic effects of Ca and Mg and reduced micronutrients uptake is probably due to increased soil pH resulting in decreased availability of these elements to plants. Therefore, in these types of acid soils, one should avoid over liming.     

Growth and nutrient uptake of tomato in response to application of saline water,biological fertilizer,and surfactant

The importance of using low-quality water, such as saline waters, for food production has been increased in the recent decades. An experiment was conducted to evaluate the effect of diluted seawater (electrical conductivity (EC) of 6 dS m^?1) on growth and nutrient uptake of tomato. We examined if surfactant (0, 1, 2, 4 mg L^?1) and biological fertilizer (compost tea + arbuscular mycorrhizal fungi propagules) have potential to alleviate the adverse effects of salinity on tomato plant. Salinity stress significantly reduced all plant growth parameters. Under salinity stress, nitrogen (N) and potassium (K) contents in tomato shoot were lower, while phosphorus (P), sodium (Na), and calcium (Ca) contents were higher than non-salinized plants; showing ionic imbalance in this condition. Biological fertilizer improved root weight in saline condition. Under salinity stress surfactant application at the rate of 1 mg L^?1 helped tomato plants to maintain their ionic balance, especially declining Na uptake, and improved plant growth.     

Function of sodium and potassium in growth of sodium-loving Amaranthaceae species

We observed that the growth of three Amaranthaceae species was promoted by sodium (Na), in the order dwarf glasswort (Salicornia bigelovii Torr.) >> Swiss chard (Beta Burgaris L. spp. cicla cv. Seiyou Shirokuki) > table beet (Beta vulgaris L. spp. vulgaris cv. Detroit Dark Red). In the present study, these Na-loving plants were grown in solutions containing 4 mol m^?3 nitrate nitrogen (NO₃-N) and 100 mol m^?3 sodium chloride (NaCl) and potassium chloride (KCl) under six Na to potassium (K) ratios, 0:100, 20:80, 40:60, 60:40, 80:20 and 100:0, to elucidate the function of Na and K on specific characteristics of Na-loving plants. The growth of dwarf glasswort increased with increasing Na concentration of the shoot, and the shoot dry weight of plants grown in 100:0 Na:K was 214% that of plants grown at 0:100. In Swiss chard and table beet, growth was unchanged by the external ratio of Na to K. The water content was not changed in Swiss chard or table beet by the external Na to K ratio. These observations indicate that both Na and K have a function in osmotic regulation. However, dwarf glasswort could not maintain succulence at 0:100; therefore, Na has a specific function in dwarf glasswort for osmotic regulation to maintain a favorable water status, and the contribution of K to osmotic regulation is low. NO₃-N uptake was promoted by Na uptake in dwarf glasswort and Swiss chard. NO₃-N uptake and transport to shoots was optimal at 100:0 in dwarf glasswort and at 80:20 in Swiss chard. These functions are very important for the Na-loving mechanism, and the contribution of K was lower in dwarf glasswort than in Swiss chard.     

Physiological responses of canola and weld mustard to salinity and contrasting calcium supply

Growth, ion balance, water relations and leaf photosynthesis of canola (Brassica napus L., cv. Excel) and wild mustard (Brassica kaber L. C. Wheeler) grown under a mixture of sodium and magnesium sulphate salts were examined using a hydroponic system in a growth chamber. Wild mustard was less salt tolerant than canola, based on the growth responses. Salinity caused large accumulation of sodium (Na) and magnesium (Mg) ions, but reduced calcium (Ca) and potassium (K) concentrations in the shoots and roots. Water potential, osmotic potential, transpiration, stomatal conductance and hydraulic conductance decreased to a greater extent in canola than in wild mustard, indicating salinity imposed a smaller osmotic effect on the wild species. Calcium addition improved the growth of wild mustard more than canola but it had no effect on water relations. The growth reduction in these species under salt stress resulted from a combination of ion toxicity, insufficient nutrient ion availability and altered water relations. Supplemental Ca improved growth by reducing Mg and increasing Ca content in plant tissues, ameliorating salinity‐associated ion toxicity to photosynthesis, and possibly through an indirect effect on cell growth.     

Effect of chromium VI on mineral element composition of bush beans

Bush beans (Phaseolus vulgaris L. cv Contender) were grown on perlite with nutrient solution and 0, 1, 2.5 and 5 ppm levels of Na₂CrO₄ Significant decrease of top growth and chlorosis in trifoliated leaves were observed for 2.5 and 5 ppm Cr, with Cr concentrations (μg/g) in tops:≥ 12.1, in roots:≥ 509.9. Cr decreased K, Na, Mg and Fe concentrations, and increased P and Mn concentrations in roots. In tops decreased N, K, Na and Fe concentrations and increased Mn and Ca concentrations were observed, Translocation of P, Zn, Cu and Fe was inhibited; Ca and Mn translocation was generally enhanced. P/Fe ratio was increased up to 60% in chlorotic plants, indicating a shift from Fe²⁺ to Fe³⁺.     

The effect of paclobutrazol on the growth and uptake of Ca and K by apple seedlings 1

Abstract

Addition of paclobutrazol (PP333) at 0.2 ppm to a nutrient solution in which 11‐month‐old apple seedlings were growing reduced terminal growth, fresh weight increase (FWI), transpiration and Ca and K uptake per seedling. Total root surface area was not affected by PP333 treatment. Reduced Ca uptake preceded the reduction in transpiration and FWI. In the case of K these changes were parallel. This may indicate that different mechanisms were responsible for reduced Ca and K uptake in PP333‐treated plants. At the conclusion of the experiment control and treated plants were absorbing similar amounts of Ca per unit of FWI. At the same time the amount of K uptake per unit of FWI was significantly lower in treated than control plants.     

MODULATION OF MACRONUTRIENTS UPTAKE AND TRANSLOCATION IN Mn-TREATED RICE IN EARLY STAGES OF VEGETATIVE GROWTH

The effect of increasing manganese (Mn) concentrations on calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), and phosphorus (P) absorption and translocation was studied in rice (Oryza sativa L. cv. Safari), before and after the end of mobilization of seed reserves. Rice plants were grown over a 15-, 21-, and 28-day period in nutrient solutions containing Mn concentrations varying between 0.125 and 32 mg L^?1. It was found that increasing Mn concentrations in the nutrient solution was coupled to an increasing net uptake, total shoot accumulation, and root and shoot contents of this metal during all the experimental periods. Concerning the translocation rates, in 15-day-old plants a decrease was found after the 2 mg L^?1 Mn treatment, but from the 21st day onward an increase was found until the highest treatment. The modulating action of Mn in macronutrient accumulation displayed different patterns among the experimental periods. In the root tissues of 15-day-old plants, Ca decreased significantly until the 2 mg L^?1 treatment and Na increased. In the shoots, the contents of P and Na decreased, but K and Mg showed significant increases. Until the 32 mg L^?1 Mn treatment, the ratio between root and shoot concentrations of K and Mg decreased in these plants. A similar pattern was also found for Ca until the 2 mg L^?1 Mn treatment. That ratio increased for Na. Plant total amount of Ca sharply decreased. Shoot total amount of Na and P also decreased, but the pattern of Ca increased until the 2 mg L^?1 Mn treatment. The concentrations of K increased in the root tissues 21 days after germination, but the levels of Ca, Mg, Na, and P decreased. In the shoots, the concentrations of Ca and Mg decreased significantly. Until the 32 mg L^?1 Mn treatment, the ratio between root and shoot concentration of Na and P increased, whereas those of Ca and Mg decreased. An increase was found for the plant and shoot total amount of Ca, K, and Mg until the last Mn treatment, but an opposite trend was found for Na and P. Additionally, until the 32 mg L^?1 Mn treatment, an increase was found for the proportions of Ca and Mg translocated to the shoot, but an opposite trend was detected for P. It was concluded that before and after the end of the mobilization of seed reserves, the net uptake rate of Ca is reversed, and, moreover, a similar trend is shown for the net translocation of Mg. A major implication of this process is the alteration of the related pattern for shoot accumulation. Eventually a different selectivity of the K⁺:Na⁺ ratio is also developed in the roots.     

Genotype-Dependent Differential Responses of Three Forage Species to Calcium Supplement in Saline Conditions

Salt toxicity comprises of osmotic and ionic components both of which can severely affect root and shoot growth. In many crop species, supplemental calcium (Ca) reduces the inhibition of growth typical of exposure to salt stress. The objective of this study was to compare whole plant growth and physiological responses to interactive effect of salinity and Ca level on three forage species [African millet (AM), tall wheat grass (TW), and perennial ryegrass (PR)] differing in tolerance to sodium chloride (NaCl) salinity. Plants were grown under glasshouse condition and supplied with nutrient solution containing 0, 100, and 250 mM NaCl supplemented with 0.5, 5, or 10 mM calcium chloride (CaCl₂). Plant growth, ionic concentration, water relations, and solute (proline and glycinebetaine) concentrations of the plants were determined two weeks after the salinity treatments. At 100 mM NaCl, there was a moderate reduction in dry matter (DM) production of all three species. A drastic decrease in DM occurred at 250 mM NaCl. Supplemental Ca reduced the adverse effects of salinity on all three species. The TW showed higher shoot and root growth in 100 and 250 mM NaCl than AM and PR. It also showed the highest DM at 5 and 10 mM Ca supplement. The shoot and root DM of TW increased by about 45 and 15%, respectively compared to the control. Chemical analysis indicated that in TW, Ca restricted both uptake and transport of sodium (Na) from root to shoot. It also increased Ca and potassium (K) concentrations in both organs. The transport of K and Ca from root to shoot of AM and PR were decreased by NaCl, but were restored with increasing Ca in the medium. The opposite occurred for Na. In PR, more K uptake was observed in shoot at 250 mM NaCl with 10 mM Ca supplement. The sap osmotic potential (Ψ_S) was the highest in TW at 10 mM Ca in the presence of 250 mM NaCl. Contribution of various solutes to the difference in Ψ_S among the species from the control and 250 mM salt treatment differed greatly. Supplemental Ca induced decline in the leaf Ψ_S of TW which was predominately due to K, glycinebetaine, Na and proline accumulation. Addition of 10 mM Ca to the growth medium maintained a low Na and a high K level. Accumulation of glycinebetaine and proline in leaf contributed the NaCl tolerance of TW. The presented results suggest that supplement Ca, not only improved ionic relations but also induced plant ability in production of compatible solutes (glycinebetaine and proline) and osmotic adjustment. Accordingly, genotype dependent capacity could be found using supplemental Ca.     

Influence of pH on growth and nutrient uptake by crop species in an Oxisol

Abstract

Crop growth in Oxisols is known to be limited by high soil acidity and low levels of basic cations. Five greenhouse experiments were conducted to evaluate the effects of soil pH on the growth and nutrient uptake of upland rice (Oryza sativa L.), wheat (Triticum aestivum L.), corn (Zea mays L.), common bean (Phaseolus vulgaris L.), and cowpea (Vigna unguiculata L. Walp.). Six levels of soil pH (4.1, 4.7, 5.3, 5.9, 6.6, and 7.0) were achieved by addition of various levels of CaCO₃. Crop species responded differently to pH, reflecting the genetic diversity among species. Higher dry matter accumulation in roots and tops of rice, corn, and cowpea was observed at acidic pH ranges indicating that these species are tolerant to soil acidity. However, increasing soil pH enhanced dry matter accumulation in roots and tops of wheat and common bean, reflecting their intolerance to soil acidity. In all of the crop species, uptake of calcium (Ca) and magnesium (Mg) decreased with a decrease in soil pH. Overall uptake of zinc (Zn), manganese (Mn), and iron (Fe) in all species increase with a decrease in soil pH. Higher pH in an Oxisol might induce micronutrient deficiencies; therefore, one has to avoid overliming. In general, increasing soil pH decreased the uptake of nitrogen (N), phosphorus (P), and potassium (K) in rice, but uptake of these elements increased in wheat, corn, and common bean. In order to achieve the full genetic potential of any given species on an Oxisol, one needs to consider the species tolerance to soil acidity and its nutrient demand.     

Growth and nutrient composition of tomato and cucumber seedlings as affected by sodium chloride salinity and supplemental calcium

The effect of three levels of salinity (2.0,4.0, and 8.0 mS/cm) on growth and ion composition of tomato and cucumber seedlings was examined with and without addition of 7.4 meq/L calcium chloriode (CaCl₂). The corresponding sodium/calcium (Na/Ca) ratio of the irrigation solution were 4.0 and 1.8 at salinity level 4.0 mS/cm, and 12 and 4.8 at salinity level 8.0 mS/cm. Seedlings growth of tomato and cucumber was generally reduced with increasing salinity level. Cucumber was more salt‐sensitive than tomato. Shoot and root dry weight of cucumber was increased by decreasing Na/Ca ratio at 4.0 mS/cm salinity. Sodium and chloride (Cl) accumulation was increased and Ca was decreased in salinized plants. Reducing Na/Ca ratio under saline condition reduce the accumulation of Na in tomato roots. The effect of salinity on the uptake of nitrogen (N), phosphorus (P), potassium (K), Na, Ca, chloride (Cl), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) in the root and shoot was also determined.     

Effects of saline nutrient solutions on the growth and accumulation of mineral elements in some tomato cultivars

Abstract

Tomato cultivars were grown in a saline nutrient culture system to investigate growth and fruiting responses in relation to the application of 3 mM potassium (K), 1.5 mM phosphorus (P), and 10 mM calcium (Ca). The deleterious effects of salinity on tomato stem growth and fruit yield were ameliorated following the addition of K, P, and Ca to the nutrient solution. Potassium levels in tomato leaves were increased 4‐fold compared to control plants in the presence of applied K. The use of K resulted in an increase in Na content, however, a comparatively low level of sodium (Na) was obtained in treatments receiving K, Ca, and P. Calcium content was greater than sufficiency levels in all treatments, whereas magnesium (Mg) declined with the increase in salinity. The amount of P in tomato leaves was increased 4–5 fold when the nutrient solution was supplemented with 1.5 mM P. Correlation of vegetative parameters, such as stem height and leaf growth to salinity, revealed no significant responses, however commercial parameters such as total soluble solids and fruit weight correlated significantly with the saline nutrient treatments.     

The uptake of nutrients by sunflower plants (Helianthus annum) growing in a continuous flowing culture system,supplied with nitrate or ammonium as nitrogen source

Sunflower plants (Helianthus annuus) were grown in a continuous flow nutrient system, in which nitrogen was supplied, under controlled pH conditions, in either the NO₃-or NH₄-form. Nutrient uptake and distribution, as well as dry matter production of the plants, was followed over the growth period. The results obtained may be summarized as follows: 1. At all stages in development, growth was somewhat greater in the plants of the NO₃-treatment, but the difference between the two treatments was not large. The similarity in the behaviour of plants in the two nitrogen treatments is discussed in relation to the maintenance of a high pH in the nutrient medium. 2. The mean rates of uptake of Ca, Mg, K, and Na, expressed per unit root length, were all higher in the NO₃-fed plants. For P, the mean rate of uptake was higher in the NH₄-fed plants. 3. The levels of K, Ca, Mg, and Na, per unit dry weight, were higher in the NO₃-fed plants, but for P the converse was true. 4. The higher uptake of Ca and Mg by NO₃-fed plants was reflected in the higher concentrations of these elements in the leaves. In the case of K, accumulation occurred in the roots. 5. From the results of selected harvests, it was found that total nitrogen uptake was higher in the NO₃-fed plants.     

Response of two sorghum genotypes to soil lime and sodium chloride amendments

Abstract

Salinity affects plants by interaction between sodium (Na) and calcium (Ca). Two sorghum (Sorghum bicolor) genotypes ('Hegari’ and ‘NB‐9040') were studied for the Na x Ca interaction in a soil amended with 2% calcium carbonate (CaCO₃) and with 0, 12.3, 24.6, and 36.9 mmol sodium chloride (NaCl)/kg soil. The two genotypes were similar in their response to soil NaCl in their shoot and root growth but differed in response to lime. The salinity‐tolerant Hegari was suppressed by high Ca concentration in the soil, mainly in the low‐NaCl treatments, and responded by a lower concentration of potassium (K) and magnesium (Mg) in the leaves, which was associated with leaf‐chlorosis. Since Na uptake was reduced by Ca, the main effect of salinity on plant growth was by the accumulation of chloride (Cl) in the leaves.     

Variable inhibition of iron uptake by oat phytosiderophore in five soybean cultivars

Abstract

Greenhouse experiment was conducted to evaluate the effect of arbuscular mycorrhizal fungi (AMF) on plant growth, and nutrient uptake in saline soils with different salt and phosphorus (P) levels. The following treatments were included in this experiment: (i) Soil A, with salt level of 16.6 dS m^?1 and P level of 8.4 mg kg^?1; (ii) Soil B, with salt level of 6.2 dS m^?1 and P level of 17.5 mg kg^?1; and (iii) Soil C, with salt level of 2.4 dS m^?1 and P level of 6.5 mg kg^?1. Soils received no (control) or 25 mg P kg^?1 soil as triple super phosphate and were either not inoculated (control) or inoculated with a mixture of AM (AM1) and/or with Glomus intraradices (AM2). All pots were amended with 125 mg N kg^?1 soil as ammonium sulfate. Barley (Hordeum vulgar L., cv. “ACSAD 6”) was grown for five weeks. Plants grown on highly saline soils were severely affected where the dry weight was significantly lower than plants growing on moderately and low saline soils. The tiller number and the plant height were also lower under highly saline condition. The reduced plant growth under highly saline soils is mainly attributed to the negative effect of the high osmotic potential of the soil solution of the highly saline soils which tend to reduce the nutrient and water uptake as well as reduce the plant root growth. Both the application of P fertilizers and the soil inoculation with either inoculum mixture or G. intraradices increased the dry weight and the height of the plants but not the tiller number. The positive effect of P application on plant growth was similar to the effect of AM inoculation. Phosphorus concentration in the plants was higher in the mycorrhizal plant compared to the non mycorrhizal ones when P was not added. On the other hand, the addition of P increased the P concentration in the plants of the non mycorrhizal plants to as high as that of the mycorrhizal plants. Iron (Fe) and zinc (Zn) uptake increased with AM inoculation. The addition of P had a positive effect on micronutrient uptake in soil with low level of soil P, but had a negative effect in soil with high level of soil P. Micronutrient uptake decreases with increasing soil salinity level. Inoculation with AMF decreases sodium (Na) concentration in plants grown in soil of the highest salinity level but had no effect when plants were grown in soil with moderate or low salinity level. The potassium (K) concentration was not affected by any treatment while the K/Na ratio was increased by AM inoculation only when plant were grown in soil of the highest salinity level.     

Effects of potassium nutrition on the absorption of sodium,calcium, and magnesium by intact tomato plants

Abstract

Tomato plants (cv. VF145 B 7879) were grown in a greenhouse by the water culture technique with six levels of K nutrition. The absorptions of Na, Ca, and Mg were not affected greatly by the K nutritional status of the intact tomato plants, except when the plants were extremely K deficient. The rates of absorption by the intact plants were slow initially when the plants were small, and then increased rapidly as the growth rates increased.

At the onset of K deficiency, the rate of growth and water use by the tomato plant decreased. A linear function of water use and plant size was obtained, indicating that water use was a function of plant size and hence a function of the plant's nutritional status.

Waterlogging, simulated by aeration cut‐off of the culture solution for two days, had only a small effect on water use, but concurrently interrupted the absorption of K, Ca, and Mg.     

Improvement in the Adaptation of Lygeum Spartum L. to Salinity In the Presence of Calcium

Lygeum spartum L. has been recently introduced in areas where salinity is high in soils. However, there are no studies about the physiological response of these plants to salt excess. The effect of sodium chloride (NaCl) on plant growth and water status was studied. Also, the effect of calcium (Ca) addition to salinity conditions was analyzed because of the coexistence of salinity and calcareous soils. Dry weight (DW), transpiration, and osmotic potential (Ψπ) decreased with elevated NaCl and were restored with Ca²⁺, whereas moderate salinity had no effect. Fresh weight (FW), water potential (Ψω), and root hydraulic conductance (L ₀) decreased with salinity; Ca²⁺ supply had an ameliorative effect at moderate salinity. Sodium (Na⁺) increased in leaf sap at high levels of NaCl and was decreased by Ca²⁺. Lygeum spartum showed a resistance to moderate salinity, but the effect of Ca²⁺ depends on salinity intensity. Thus, the role of Ca²⁺ in the tolerance to salinity was emphasized.