Salt Tolerance in the Triticeae: The Contribution of the D Genome to Cation Selectivity in Hexaploid Wheat

Inorganic cation concentrations were measured in shoots of hexaploidbread wheat (Triticum aestivum L.) and its presumed ancestorsgrown at 100 mol m^–3 external NaCl. Aegilops squarrosaand T. aestivum had high K/Na ratios while T. dicoccoides andAe. speltoides had low K/Na ratios. T. monococcum although havinga high K/Na ratio, had the highest total salt load of the fivespecies tested. The effect of the D genome (from Ae. squarrosa)was further investigated in seedlings of synthetic hexaploidwheats, and was again found to improve cation selectivity. Differentresponses were obtained from root and shoot tissue in this experiment.One synthetic hexaploid and its constituent parents were grownto maturity at 100 mol m^-3 NaCl and the yields recorded. Despitecomplications due to increased tillering in the stressed hexaploid,it was possible to show that the addition of the D genome enhancedyield characteristics in the hexaploid wheat. An experimentwith synthetic hexaploids derived from the tetraploid wheatvariety "Langdon" and several Ae. squarrosa accessions revealeddifferences in vegetative growth rates between the differentsynthetic hexaploids in the presence or absence of 150 or 200mol m^–3 external NaCl. The possibility of transferringsalt tolerance genes from Ae. squarrosa to hexaploid wheat usingsynthetic hexaploids as bridging species is discussed. Key words: Salt stress, wheat, D genome, Aegiops squarrosa, synthetic hexaploids     

Salt Tolerance in the Triticeae: K/Na Discrimination in Synthetic Hexaploid Wheats

Ion concentrations were measured in the leaves of synthetichexaploid wheats and their parents growing in saline hydroponicculture. The synthetic hexaploids contained genomes from a tetraploidwheat (Triticum diccocum, T. durum, T. araraticum or T. timopheevi)and from a diploid species (T. monococcum, T. urartu, T. boeoticumor Aegilops squarrosa). Leaf Na concentrations were low, andK concentrations high, in Ae. squarrosa, T. araraticum and allof the synthetic hexaploids, but high in T. dicoccum and T.durum. At low salinities leaf Na concentrations were particularlyhigh in T. durum in comparison with the other species. Theseresults suggest that the enhanced K/Na discrimination character,originally found in Ae. squarrosa and BBAADD genome hexaploidwheats, is also present in diploid wheat and in GGAA genometetraploid wheats. It is suggested that this character has beenlost in the evolution of the BBAA genome tetraploid wheats. Key words: Salt, ion transport, A genome, Triticum spp     

Salt Tolerance in the Triticeae: K/Na Discrimination in Aegilops Species

Inorganic ion concentrations were measured in the leaves ofAegilops species growing in 50 or 75 mol m^–3 NaCl (+2.5or 3.75 mol m–3 CaCl₂). The low leaf Na and high leafK concentrations characteristic of the enhanced K/Na discriminationcharacter, originally found in Aegilops squarrosa and in hexaploidwheat, were also found in other Aegilops species containingthe D genome, but not in Ae. ventricosa. The S genome diploidAegilops species (section Sitopsis) all lacked the enhancedK/Na discrimination trait, as did the C genome species Ae. caudataand the N genome species Ae. uniaristata. Most of the U genomespecies (section Polyeides), except Ae. biuncialis, Ae. kotschyiand Ae. variabilis, also exhibited the trait. Examination ofamphiploid hybrids suggested that the trait was dominant incrosses involving Ae. squarrosa or Ae. umbellulata with otherspecies in which the trait was absent. Key words: Salt, ion transport, D genome, Aegilops spp     

Salt Tolerance in the Triticeae: Ion Discrimination in Rye and Triticale

When rye and triticale accessions were grown in saline hydroponicculture they exhibited the low Na and high K concentrationsin their leaves which are characteristic of the enhanced K/Nadiscrimination trait originally found in the D genome of wheat.This trait was not consistently improved by the presence ofthe D genome in octaploid triticale or in D genome substitutionlines of hexaploid triticale. The presence of the rye genomedid not significantly affect anion concentrations within theleaves. At high salt concentrations (250 mol m^–3 NaCl+12.5mol m^–3 CaCl₂) the triticales were more tolerant thanthe rye accessions or a DDRR-genome tetraploid, with two triticalelines being almost as salt-tolerant as barley. Key words: Salt, ion transport, R genome, rye (Secale cereale L.)     

Nitrate Effects on Growth of the First Four Main Stem Leaves of a Range of Temperate Cereals and Pasture Grasses

The effects of different applied NO₃^– concentrations onextension growth and final length and area of leaves 1–4of five cereals and six pasture grasses of temperate originwere examined. Increased applied NO₃^– in the range 0.1–0.5.0mol m^–3 caused decreased duration of growth but increasedgrowth rate and final length of leaves 2–4 of the cerealsAvena saliva, Hordeum vulgare, Secale cereale, x Triticosecaleand Triticum aestivum. For all cereals, increased NO₃^–resulted in increased area of leaves 1–4. Pasture grasseswere supplied either 0.5 or 50 mol m^–3 NO₃^–. Increasedapplied NO₃^– (0.5–5.0 mol m^–3) resulted indecreased duration of growth and increased growth rate and finalarea of leaves 1–4 of Bromus wiltdenowii, leaves 2–4ofFestuca arundinaceae and leaves 3 and 4 of Lolium muitiflorum.In addition, length of leaves 3 and 4 of B. witidenowii increasedwith increased NO₃^–. Increased NO₃^– resulted inincreased area of leaves 2–4 of Dactylis gtomerata andLolium perenne and leaves 3 and 4 of Phalaris aquaiica but hadno effect on extension growth of all three species. Avena sativa L, oat, Hordeum vulgare L, barley, Secale cereale L, rye, x Triticosecale Wittm, triticale, Triticum aestivum L, wheat, Bromus willdenowii Kunth, prairie grass, Dactylis gtomerata L, cocksfoot, Festuca arundinaceae Shreb, tall fescue, Lolium multijlorum Lam, Italian ryegrass, Lolium perenne L, perennial ryegrass, Phalaris aquatica L, nitrate, leaf extension, leaf expansion     

Nitrate Effects on Growth of the First Four Main Stem Leaves of a Range of Temperate Cereals and Pasture Grasses

The effects of different applied NO₃^– concentrations onextension growth and final length and area of leaves 1–4of five cereals and six pasture grasses of temperate originwere examined. Increased applied NO₃^– in the range 0.1–50mol m^–3; caused decreased duration of growth but increasedgrowth rate and final length of leaves 2–4 of the cerealsAvena saliva, Hordeum vulgare, Secale cereale x Triticosecaleand Triticum aestivum. For all cereals, increased NO₃^–resulted in increased area of leaves 1-4. Pasture grasses weresupplied either 0.5 or 50 mol m^–3; NO₃^–. Increasedapplied NO₃^– (0.5–50 mol m^–3) resulted indecreased duration of growth and increased growth rate and finalarea of leaves 1–4 of Bromus willdenowii leaves 2–4of Festuca arundinaceae and leaves 3 and 4 of Lolium multiflorum.In addition, length of leaves 3 and 4 of B. willdenowii increasedwith increased NO₃. Increased NO₃ resulted in increased areaof leaves 2–4 of Daciylis glomerata and Lolium perenneand leaves 3 and 4 of Phalaris aquatica but had no effect onextension growth of all three species. Avena saliva L., oat, Hordeum vulgare L., barley, Secale cereaie L., rye, x Triticosecale Wittm, triticale, Triticum aestivum L., wheat, Bromus willdenowii Kunth, prairie grass, Dactylis glomerata L., cocksfoot, Festuca arundinaceae Shreb, tall fescue, Lolium multiflorum Lam, Italian ryegrass, Lolium perenne L, perennial ryegrass, Phalaris aquatica L, nitrate,, leaf extension, leaf expansion     

An immunochemical approach to species relationship in Triticum and some related species

Summary An immunological reaction, precipitation in gel, was produced using a rabbit antiserum directed to a specific protein constantly present in bread wheats (T. aestivum, genome AABBDD), but absent in durum wheat (T. durum Desf., genome AABB). This protein was isolated in the soluble-protein fraction of bread wheat caryopses by combined biochemical and immunological techniques.The availability of such a specific anti-bread wheat serum made possible the analysis of a series of varieties and species of wheat and of some closely related (Secale, Aegilops) and less closely related (Hordeum, Haynaldia) taxa to determine whether the protein was present or absent. Hordeum vulgare, Haynaldia villosa, Triticum monoccocum and Triticum turgidum gave a negative result, while positive results were obtained in T. aestivum, T. timopheevi, T. zhukovskyi, Secale cereale, Aegilops speltoides, Ae. mutica, Ae. comosa, Ae. caudata, Ae. umbellulata, Ae. squarrosa, and also in the artificial amphiploids (Ae. speltoides x T. monococcum) and (Ae. caudata x T. monococcum).It is concluded that these results agree closely with the classification of Triticum proposed by MacKey in 1966. The investigated protein not only permits the differentiation of T. aestivum from T. turgidum, but also T. turgidum from T. timopheevi at tetraploid level and T. monococcum from all the diploid species of Aegilops.     

The Partitioning of Nitrate Assimilation Between Root and Shoot of a Range of Temperate Cereals and Pasture Grasses

Nitrate reductase activity (NRA, in vivo assay) and nitrate(NO^-₃) content of root and shoot and NO^-₃ and reduced nitrogencontent of xylem sap were measured in five temperate cerealssupplied with a range of NO^-₃ concentrations (0·1–20mol m^–3) and three temperate pasture grasses suppliedwith 0·5 or 5 0 mol m^–3 NO^-₃ For one cereal (Hordeumvulgare L ), in vitro NRA was also determined The effect ofexternal NO^-₃ concentration on the partitioning of NO^-₃ assimilationbetween root and shoot was assessed All measurements indicatedthat the root was the major site of NO3 assimilation in Avenasatwa L, Hordeum vulgare L, Secale cereale L, Tnticum aestivumL and x Triticosecale Wittm supplied with 0·1 to 1·0mol m^–3 NO^-₃ and that for all cereals, shoot assimilationincreased in importance as applied NO^-₃ concentration increasedfrom 1.0 to 20 mol m^–3 At 5.0–20 mol m^–3 NO3,the data indicated that the shoot played an important if notmajor role in NO^-₃ assimilation in all cereals studied Measurementson Lolium multiflorum Lam and L perenne L indicated that theroot was the main site of NO^-₃ assimilation at 0.5 mol m^–3NO^-₃ but shoot assimilation was predominant at 5.0 mol m^–3NO^-₃ Both NRA distribution data and xylem sap analysis indicatedthat shoot assimilation was predominant in Dactylis glomerataL supplied with 0.5 or 5.0 mol m^–3 NO^-₃ Avena sativa L., oats, Hordeum vulgare L., barley, Secale cereale L., rye, x Triticosecale Wittm., triticale, Triticum aestivum L., wheat, Dactylis glomerata L., cocksfoot, Lolium multiflorum Lam., Italian ryegrass, Lolium perenne L., perennial ryegrass, nitrate, nitrate assimilation, nitrate reductase activity, xylem sap     

The Effect of Growth in D2O on the Metabolism of Winter Rye

The metabolism of winter rye seedlings (Secale cereale, L. ev.Winter) cultured in 99.8 per cent D₂O was investigated. Comparedwith water-grown seedlings, the protein content was much lowerin the D₂O-cultured seedlings and the pattern of incorporationof [³H]leucine and [³H]phenylalanine into protein was substantiallydifferent. Seedlings cultured in D₂O incorporated [³H]thymidineinto DNA, but did not take up [³H]uridine. The results suggestthat some of the toxic effects of D₂O culture on higher plantscan be attributed to a partial block of protein synthesis.     

Growth Analysis of Solution Culture-grown Winter Rye, Wheat and Triticale at Different Relative Rates of Nitrogen Supply

At low nitrogen (N) supply, it is well known that rye has ahigher biomass production than wheat. This study investigateswhether these species differences can be explained by differencesin dry matter and nitrogen partitioning, specific leaf area,specific root length and net assimilation rate, which determineboth N acquisition and carbon assimilation during vegetativegrowth. Winter rye (Secale cereale L.), wheat (Triticum aestivumL.) and triticale (X Triticosecale) were grown in solution cultureat relative addition rates (R_N) of nitrate-N supply rangingfrom 0.03–0.18 d^-1and at non-limiting N supply under controlledconditions. The relative growth rate (R_W) was closely equalto R_Nin the range 0.03–0.15 d^-1. The maximalR_W at non-limitingnitrate nutrition was approx. 0.18 d^-1. The biomass allocationto the roots showed a considerable plasticity but did not differbetween species. There were no interspecific differences ineither net assimilation rate or specific leaf area. Higher accumulationof N in the plant, despite the same relative growth rate atnon-limiting N supplies, suggests that rye has a greater abilityto accumulate reserves of nitrogen. Rye had a higher specificroot length over a wide range of sub-optimal N rates than wheat,especially at extreme N deficiency (R_N=0.03–0.06 d^-1).Triticale had a similar specific root length as that of wheatbut had the ability to accumulate N to the same amount as ryeunder conditions of free N access. It is concluded that thebetter adaptation of rye to low N availability compared to wheatis related to higher specific root length in rye. Additionally,the greater ability to accumulate nitrogen under conditionsof free N access for rye and triticale compared to wheat maybe useful for subsequent N utilization during plant growth.In general, species differences are explained by growth componentsresponsible for nitrogen acquisition rather than carbon assimilation.Copyright 1999 Annals of Botany Company Growth analysis, nitrogen, nitrogen productivity, partitioning, specific root length, Secale cereale L.,Triticum aestivum L., X Triticosecale, winter rye, winter wheat, winter triticale.     

Nitrate Stimulation of Mobilization of Seed Reserves in Temperate Cereals: Importance of Water Uptake

Relationships between nitrate (NO^-₃) supply, uptake and assimilation,water uptake and the rate of mobilization of seed reserves wereexamined for the five main temperate cereals prior to emergencefrom the substrate. For all species, 21 d after sowing (DAS),residual seed dry weight (d.wt) decreased while shoot plus rootd.wt increased (15–30%) with increased applied NO^-₃concentrationfrom 0 to 5–20 mM . Nitrogen (N) uptake and assimilationwere as great with addition of 5 mM ammonium (NH⁺₄) or 5 mMNO^-₃but NH⁺₄did not affect the rate of mobilization of seedreserves. Chloride (Cl^-) was similar to NO^-₃in its effect onmobilization of seed reserves of barley (Hordeum vulgare L.).Increased rate of mobilization of seed reserves with additionalNO^-₃or Cl^-was associated with increases in shoot, root and residualseed anion content, total seedling water and residual seed watercontent (% water) 21 DAS. Addition of NH⁺₄did not affect totalseedling water or residual seed water content. For barley suppliedwith different concentrations of NO^-₃or mannitol, the rate ofmobilization of seed reserves was positively correlated (r >0.95)with total seedling water and residual seed water content. Therate of mobilization of seed reserves of barley was greaterfor high N content seed than for low N content seed. Seed watercontent was greater for high N seed than for low N seed, 2 DAS.Additional NO^-₃did not affect total seedling water or residualseed water content until 10–14 DAS. The effects of seedN and NO^-₃on mobilization of seed reserves were detected 10and 14 DAS, respectively. It is proposed that the increasedrate of mobilization of seed reserves of temperate cereals withadditional NO^-₃is due to increased water uptake by the seedlingwhile the seed N effect is due to increased water uptake bythe seed directly. Avena sativa L.; oat; Hordeum vulgare L.; barley; Secale cereale L.; rye; xTriticosecale Wittm.; triticale; Triticum aestivum L.; wheat; nitrate; seed; germination; seed reserve mobilization     

The presence of the enhanced K/Na discrimination trait in diploid Triticum species

Summary A number of accessions of the three species of diploid wheat, Triticum boeoticum, T. monococcum, and T. urartu, were grown in 50 mol m^-3 NaCl+2.5 mol m^-3 CaCl₂. Sodium accumulation in the leaves was low and potassium concentrations remained high. This was not the case in T. durum grown under the same conditions, and indicates the presence in diploid wheats of the enhanced K/Na discrimination character which has previously been found in Aegilops squarrosa and hexaploid wheat. None of the accessions of diploid wheat showed poor K/Na discrimination, which suggests that if the A genome of modern tetraploid wheats was derived from a diploid Triticum species, then the enhanced K/Na discrimination character became altered after the formation of the original allopolyploid. Another possibility is that a diploid wheat that did not have the enhanced K/Na discrimination character was involved in the hybridization event which produced tetraploid wheat, and that this diploid is now extinct or has not yet been discovered.     

Effects of Low Temperature on the Development and Morphology of Rye (Secale cereale) and Wheat (Triticum aestivum)

Seedlings of Secale cereale cv. Rheidol and Triticum aestivumcv. Mardler were grown at shoot/root temperatures of 20/20 °C,20/8 °C and 8/8 °C. During vegetative growth both cerealsproduced leaves, tillers and roots in a defined pattern, ata species-specific rate which was linearly related to the temperatureof the shoot meristem. Thus, plant development could be standardizedon a temperature x time (°C d) basis despite contrastinggrowth-temperature treatments. When compared at a similar developmentalstage, the cooling of whole plants or of plant roots resultedin an increase in the d. wt: f. wt ratio of both shoot and roottissues, a decrease in the length of both the longest shootand root, and the development of broader and thicker leaves.Although the effects of temperature on developmental characteristicscould be accurately predicted by an empirical relationship,the effects on morphological characteristics could not. Development, phyllochron, rye, Secale cereale cv. Rheidol, temperature, thermal time, Triticum aestivum cv. Mardler, wheat     

Zinc-induced Vacuolation in Root Meristematic Cells of Cereals

In the absence of Zn, vacuolar volume fractions of root meristematiccells of Secale cereale L. cv. K2, Triticum aestivum L. cv.Chinese Spring and Oryza sativa L. cv. IR34 were 5.64 x 10^–2,2.17 x 10^–2 and 1.63 x 10^–2 µm³ vacuole µm^–3tissue, respectively. A 4-d exposure to a subtoxic concentrationof zine (0.2 µg Zn cm^–3) induced a 2.93-fold anda 6.78-fold increase in the total vacuolar volume fraction inOryza and Triticum, respectively, whereas no significant increasewas observed for Secale. It is proposed that this Zn-inducedvacuolation represents a compartmentalization mechanism. Theinitial total vacuolar volume fraction in Secale was greaterthan that for Oryza and Triticum and this may enable compartmentalizationof the metal soon after the onset of treatment so reducing itscytotoxic effects. These findings are similar to those observedin contrasting cultivars of Festuca rubra L. Triticum aestivum L, Secale cereale L, Oryza sativa L, zinc, root meristem, vacuolation     

Poly(A) polymerase in Dormant Embryos of Triticum durum

Triticum durum‘Cappelli’ has a ‘relative’dormancy which can be broken by dry after-ripening at room temperature.The breakage of dormancy in the embryos of T. durum , is accompaniedby a decline in content and a different degree of synthesisof poly(A)⁺RNA. This work studies the activity of poly(A) polymerase(E.C. 2.7.7.19), the enzyme which permits polyadenylation. Anincrease in the activity of this enzyme in parallel with theenhanced rate of germination is revealed. Since poly(A) polymeraseactivity is the same in dormant and non-dormant dry embryos,it seems that the activity of the enzyme is not involved inthe breakage of dormancy. The use of cycloheximide and cordycepinshows the presence of enzymes with different origins: a storedenzyme and one bound to a long lived mRNA, present in dormantand non-dormant embryos, plus an enzyme bound to newly synthesizedmRNA which is mainly active in non-dormant embryos. Since dormancycould be the result of an interaction between hormones, thiswork analyses the effects of GA₃and ABA on poly(A) polymerase.GA₃enhanced poly(A) polymerase activity only in dormant embryoswhile ABA inhibited this activity only in non-dormant embryos.Cycloheximide applied to excised wheat embryos represses thestimulatory and inhibitory effects of GA₃and ABA, respectively.The hormone action on poly(A) polymerase activity is thus dependenton de novo protein synthesis. Results using cordycepin suggestthe presence of a stored mRNA for poly(A) polymerase, togetherwith hormonal regulation of enzyme activity at a translationallevel. Copyright 1999 Annals of Botany Company Triticum durum , wheat, dormancy breakage, poly(A) polymerase, GA₃, ABA, germination.     

The Occurrence of Endogenous Rhythms in the Coleoptiles in Various Cereal Genera

The rate of growth of the coleoptiles was determined from photographstaken by infra-red radiation. CO₂ output was measured by meansof an infra-red gas analyser. The rhythm of CO₂ output from the coleoptile of Avena was inducedby a change from red light to darkness. It has a period of about24 hours and agrees in timing with the growth-rate rhythm previouslyrecorded. Some degree of rhythmicity in the growth-rate was found in Triticumvulgare (var. ‘Eclipse’) and in Secale cereale (var.Petkus). Very slight indications of rhythmicity were found inTriticum spelta and in Hordeum vulgare. Negative results wereobtained with Oryza sativa and with Zea mays. Where rhythmicityin the coleoptile is less strongly developed, the peaks comecloser together, the interval being about 18–20 hours.Cereals cannot be sharply separated into two groups accordingto the presence or absence of rhythmicity in the coleoptile.Of the genera examined, the most marked endogenous rhythms occurin Avena. It is doubtful if the ability of the coleoptile toexhibit an endogenous rhythm has any beneficial effect on thedevelopment of the seedling. Under normal conditions of germinationinduction of the rhythm would not occur.     

Isolation of protoplasts from cereal leaves

Summary Mature leaves of Secale cereale cut into narrow strips and incubated for 18 h in a mixture of cellulase (Meicelase) and pectinase (Pectinol R10) produced quantities of protoplasts. Under the same conditions leaves of Triticum aestivum, Hordeum vulgare and Avena sativa also produce protoplasts but in lower yields. The wheat and rye protoplasts in culture appear to regenerate a cell wall but only a very small proportion undergo cell division.     

Effect of Sudden Salt Stress on Ion Fluxes in Intact Wheat Suspension Cells

Although salinity is one of the major problems limiting agriculturalproduction around the world, the underlying mechanisms of highNaCl perception and tolerance are still poorly understood. Theeffects of different bathing solutions and fusicoccin (FC),a known activator of plasma membrane ATPase, on plasma membranepotential (E_m) and net fluxes of Na⁺, K⁺and H⁺were studied inwheat suspension cells (Triticum aestivum) in response to differentNaCl treatments. E_mof cells in Murashige and Skoog (MS) mediumwas less negative than in cells exposed to a medium containing10 mM KCl + 0.1 m M CaCl₂(KSM) and to a basic salt medium (BSM),containing 1 m M KCl and 0.1 m M CaCl₂. Multiphasic Na⁺accumulationin cells was observed, peaking at 13 min after addition of 120m M NaCl to MS medium. This time scale was in good agreementwith net Na⁺flux changes measured non-invasively by moving ion-selectivemicroelectrodes (the MIFE system). When 120 m M NaCl was addedto all media studied, a quick rise of Na⁺influx was reversedwithin the first 20 min. In both 120 and 20 m M NaCl treatmentsin MS medium, net Na⁺efflux was observed, indicating that activeNa⁺transporters function in the plant cell response to saltstress. Lower external K⁺concentrations (KSM and BSM) and FCpre-treatment caused shifts in Na⁺fluxes towards net influxat 120 m M NaCl stress. Copyright 2000 Annals of Botany Company Sodium, potassium, proton, membrane potential, fusicoccin, salt stress, wheat, Triticum aestivum     

Kinetic parameters of Zn uptake by wheat are affected by the herbicide chlorsulfuron

Kinetic parameters of Zn uptake were determined for wheat plants(Triticum aestivum cvs Excalibur and Gatcher, and Triticum turgidumconv. durum cv. Durati) pre-grown at deficient or sufficientZn supply and with 0 or 4 mg m^-3 sulphonylurea herbicide chlorsulfuron(2-chloro-N-(((4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino)carbonyl)-benzenesulphonamide].Net Zn uptake generally showed a saturable response to increasingsolution Zn concentrations; this response fitted a modifiedMichaelis-Menten equation incorporating the C_min term (solutionconcentration when net uptake is     

Salt tolerance in a Hordeum marinum-Triticum aestivum amphiploid, and its parents

Growth, grain production, and physiological traits were evaluated for Hordeum marinum, Triticum aestivum (cv. Chinese Spring), and a H. marinum-T. aestivum amphiploid, when exposed to NaCl treatments in a nutrient solution. H. marinum was more salt tolerant than T. aestivum and the amphiploid was intermediate, both for vegetative growth and relative grain production. H. marinum was best able to 'exclude' Na(+) and Cl(-), particularly at high external NaCl. At 300 mM NaCl, concentrations of Na(+) (153 micromol g(-1) dry mass) and Cl(-) (75 micromol g(-1) dry mass) in the youngest fully-expanded leaf blade of H. marinum were, respectively, only 7% and 4% of those in T. aestivum; and in the amphiploid the Na(+) and Cl(-) concentrations were 39% and 36% of those in T. aestivum. Glycinebetaine and proline concentrations in the youngest fully-expanded leaf blade of plants exposed to 200 mM NaCl were highest in H. marinum (128 and 60 micromol g(-1) dry mass, respectively), lowest in T. aestivum (85 and 37 micromol g(-1) dry mass), and intermediate in the amphiploid (108 and 54 micromol g(-1) dry mass). Thus, salt tolerance of H. marinum was expressed in the H. marinum-T. aestivum amphiploid.