Salt Tolerance in the Triticeae: Solute Accumulation and Distribution in an Amphidiploid derived from Triticum aestivum cv. Chinese Spring and Thinopyrum bessarabicum

An amphidiploid derived by colchicine treatment of a hybridbetween Triticum aestivum cv Chinese Spring and Thinopyrum bessarabicumwas found to be more salt tolerant than the wheat cultivarsChinese Spring, Kharchia and Ciano 79 in terms of survival andgrain yield at 250 mol m^–3 NaCl. Tolerance was relatedto the ability of the amphidiploid to exclude Na and Cl fromthe shoots, and particularly from the young leaves, developinginflorescence and grain. There was no relationship between thesalt tolerance of the different species and varieties testedand changes in the concentrations of other solutes. The amphidiploiddid not inherit the high glycinebetaine concentrations characteristicof the wheatgrass parent. Amphidiploids produced from crossesbetween Thinopyrum species and wheat may be useful as stress-resistantnew crops. Key words: Salt stress, solute accumulation, Thinopyrum, Triticum     

Salt Tolerance in the Triticeae: Salinity-induced Changes in the Leaf Solute Composition of Some Perennial Triticeae

Changes in the leaf solute composition of a number of perennialTriticeae in response to salinity are described. There was variationboth within and between species in the extent of Na and Cl accumulationin the leaves. In almost all cases leaf nitrate concentrationsdecreased substantially and orthophosphate concentrations increasedin response to salinity. There was no overall decrease in arange of soluble nitrogen-containing compounds nor in totalnitrogen. In Thinopyrum scirpeum there was an inverse relationshipbetween proline and glycinebetaine contents of different tissues,with proline levels higher in older leaves. Concentrations ofboth compounds were higher in salt-stressed plants. Key words: Triticeae, salinity, leaf solute composition     

Salt Tolerance in the Triticeae: Leymus sabulosus

Elymus dahuhcus, Leymus giganteus, L. angustus, L. sabulosusand, to a lesser extent, L. triticoides, were found to tolerate200 mol m^–3 NaCl in solution culture. Elymus dahuricusdiffered from the Leymus species in its ion-uptake characteristics,showing a greater uptake of Cl and Na and a greater loss ofK from the shoots. In a more detailed experiment on Leymus sabulosusit was found that transpiration rates altered rapidly in responseto changes in external salinity whereas the accumulation ofNa and Cl in the leaves exhibited a lag of several days. Insalt stressed L. sabulosus Cl partially replaced the high levelsof nitrate found in the leaves of control plants. Glycinebetainelevels increased in the leaves from 8.0 mol m^–3 plantsap in the controls to 28 mol m^–3 plant sap at 250 molm^–3 NaCl. Key words: Salt stress, Transpiration, Solute accumulation, Leymus     

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.)     

Salt Tolerance in the Triticeae: K/Na Discrimination in Barley

Concentrations of ions were measured in the youngest fully-expandedleaves of Triticum aestivum, T. durum, Hordeum vulgare, H. spontaneum,Secale cereale, and Aegilops squarrosa accessions grown in hydroponicculture in the presence of salt (NaCl+CaCl₂). Triticum aestivum,Secale cereale, and Ae. squarrosa had the low leaf Na and highleaf K concentrations typical of plants which contain the enhancedK/Na discrimination character originally found in Ae. squarrosa.T. durum and the Hordeum species did not have this character.The better growth of H. vulgare than of T. durum with similarsalt concentrations in the youngest fully-expanded leaves maybe a result of better compartmentation of Na, Cl, and K betweendifferent tisssues or between different compartments withincells. The enhanced K/Na discrimination character was expressedin disomic addition lines of H. vulgare chromosomes in Triticumaestivum. The H. vulgare variety Herta and its slender mutantboth had similar leaf cation concentrations, although they differedin growth rate when grown at 60 mol m^–3 NaCl. H. vulgareand T. durum seedlings grown in the absence of monovalent cationsaccumulated more ²²Na in their shoots than seedlings of otherspecies when incubated in 1.0 mol m^–3 NaCl labelled with²²Na. Key words: Salt, ion transport, I genome, barley, wheat     

Multidisciplinary approach to genome analysis in the diploid species,Thinopyrum bessarabicum and Th. elongatum (Lophopyrum elongatum), of the Triticeae

Summary The J and E genome species of the Triticeae are invaluable sources of salt tolerance. The evidence concerning the phyletic relatedness of the J genome of diploid Thinopyrum bessarabicum and the E genome of diploid Th. elongatum (=Lophopyrum elongatum) is discussed. Low level of chromosome pairing between J and E at different ploidy levels, suppression of J-E pairing by the Ph1 pairing regulator that inhibits homoeologous pairing, complete sterility of the diploid hybrids (JE), karyotypic divergence of the two genomes, differences in total content and distribution of heterochromatin along their chromosomes, and marked differences in gliadin proteins, isozymes, 5S DNA, and rDNA indicate that J and E are distinct genomes. Well-defined biochemical markers have been identified in the two genomes and may be useful in plant breeding. The level of distinction between J and E is comparable to that among the universally accepted homoeologous genomes A, B, and D of wheat. Therefore, the J and E genomes are homoeologous and not homologous, although some workers continue to call them homologous. The previous workers' data on chromosome pairing in diploid hybrids and/ or karyotypic differences in the conventionally stained chromosomes do not provide sufficient evidence for the proposed merger of J and E genomes (and, hence, of the genera Thinopyrum and Lophopyrum) specifically and for establishing genome relationships generally. Extra precautions should be exercised before changing the designation of an established genome and before merging two genera. A uniform, standardized system of genomic nomenclature for the entire Triticeae is proposed, which should benefit cytogeneticists, plant breeders, taxonomists, and evolutionists.Cooperative investigations of the USDA-Agricultural Research Service and the Utah Agricultural Experiment Station, Logan, UT 84322, USA. Approved as Journal Paper no. 3832     

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: 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     

Biochemical and molecular diagnostics of Thinopyrum bessarabicum chromosomes in Triticum aestivum germ plasm

Thinopyrum bessarabicum (2n=2x=14, JJ) is a self-fertile salt-tolerant grass species, and its hybridization with Triticum aestivum to achieve the transfer of this attributes has been promoted. For the detection of alien introgression, development of diagnostic markers of Th. bessarabicum chromosomes in the wheat background has emerged as an important aspect in our intergeneric hybridization program. Six proteins/isozymes-high-molecular-weight glutenins, superoxide dismutase, grain esterase, β-amylase, glutamate oxaloacetate transaminase and α-amylase —were identified as positive markers for detecting the presence of Th. bessarabicum chromosomes in the advanced backcross derivatives of T. aestivum/Th. bessarabicum//n^* T. aestivum. Fluorescent in situ hybridization further enabled the detection of complete and translocated arms of Th. bessarabicum chromosomes in the T. aestivum background. These diagnostic markers served for tentatively characterizing a distinct set of Th. bessarabicum disomic additions to wheat (2n=44) and have facilitated establishing the homoeology of these added chromosomes.     

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     

Solute Accumulation In Plant Cells IV. Effects of Ammonium lons on Growth and Solute Content

Procedures previously described were used to study growth andsolute content of aseptically cultured carrot explants as affectedby supplementary salts in the medium. The salts chosen (KC1,KNO₃, NH₄,Cl, and NH⁴,NO₃) contrasted, with appropriate controls,the effects due to nitrate and ammonium. Growth was measuredin terms of fresh weight, the number and average size of cells:solute concentrations were recorded for total solutes, sugars,soluble nitrogen compounds, and the electrolytes K⁺, Na⁺, C1^–,NO^–₃, and organic acids. The time-response curves of thecultures were traced at a fixed concentration of the added saltsand the effects due to the concentration of the supplementarysalts were tested after a fixed time period, For the same nitrogensource the concentrations of metabolites and solutes in cellswere very similar despite some clonal differences in their growth.When cells in a nitrate medium were small and dividing, thecultures had a low osmotic value, contained K⁺ as the principalcation balanced by organic acid, had relatively low sugar content,and their enriched total nitrogen content emphasized proteinrather than soluble nitrogen compounds. Later, as the cellsbecame older and larger, salts (K⁺, organic anions, Cl^–)contributed substantially to their increased osmotic value butthey accumulated sugar as their main, osmotically active solute,and the ratio of soluble to protein nitrogen declined as proteinsynthesis progressed. The extra nitrogen supplied by the additionalpotassium nitrate contributed more to protein and caused potassium,organic acids, and sugars to accumulate to higher levela. Supplementaryammonium salts required that more sugar be metabolized to organicnitrogen compounds (e.g. glutamine), contributed more to solublethan to protein nitrogen, and sharply reduced. both the osmoticvalue of the cells and the potassium linked to organic anions.The selectivity of the growing cells for K⁺ over Na⁺ and theirdiscrimination. between alkali cations (Ka⁺+Na⁺) and halides(C1^–) were relaxed in the presence of ammonia. Attentionis drawn to the implications of these results for the accumulationof solutes, organic and inorganic, by dividing and enlargingcells.     

盐胁迫对不同抗盐性小麦叶片荧光诱导动力学的影响

以不同抗盐性小麦为材料,研究了NaCl胁迫对叶片叶绿素。荧光诱导动力学的影响。指出150 mmol/L NaCl使小麦幼苗生长降低,叶绿素含量下降,同时使光系统Ⅱ的潜在光化学活性和原初光能转化率降低,使光反应受到抑制。     

Thinopyrum bessarabicum: biochemical and cytological markers for the detection of genetic introgression in its hybrid derivatives with Triticum aestivum L.

Summary Thinopyrum bessarabicum (2n = 2x = 14, JJ) with its unique property of salt tolerance provides a potential means for the transfer of this important and complex trait into cultivated wheat through intergeneric hybridization. To accomplish this, diagnostic markers for detecting the presence of Th. bessarabicum chromosomes in a wheat background have to be established. The C-banded karyotype of Th. bessarabicum distinctly identifies individual Th. bessarabicum chromosomes and separates them from those of Triticum aestivum. Also, seven protein/isozymes, i.e., malate dehydrogenase, high-molecular-weight glutenin, Superoxide dismutase, grain esterase, glutamate oxaloacetate transaminase, -amylase and -amylase, were identified as being positive markers specific to Th. bessarabicum; these were also expressed in the T. aestivum/Th. bessarabicum amphiploid. These diagnostic biochemical markers could be useful in detecting and establishing homoeology of Th. bessarabicum chromosomes in T. aestivum/Th. bessarabicum intergeneric hybrid derivatives.     

Synthesis and cytological characterization of trigeneric hybrids involving durum wheat,Thinopyrum bessarabicum,and Lophopyrum elongatum

Summary In an attempt to transfer genes for salt tolerance and other desirable traits from the diploid wheatgrasses, Thinopyrum bessarabicum (2n=2x=14; JJ genome) and Lophopyrum elongatum (2n=2x=14; EE genome), into durum wheat cv Langdon (2n=4x=28; AABB genomes), trigeneric hybrids with the genomic constitution ABJE were synthesized and cytologically characterized. C-banding analysis of somatic chromosomes of the A, B, J, and E genomes in the same cellular environment revealed distinct banding patterns; each of the 28 chromosomes could be identified. They differed in the total amount of constitutive heterochromatin. Total surface area and C-banded area of each chromosome were calculated. The B genome was the largest in size, followed by the J, A, and E genomes, and its chromosomes were also the most heavily banded. Only 25.8% of the total chromosome complement in 10 ABJE hybrids showed association, with mean arm-pairing frequency (c) values from 0.123 to 0.180 and chiasma frequencies from 3.36 to 5.02 per cell. The overall mean pairing was 0.004 ring IV + 0.046 chain IV + 0.236 III + 0.21 ring II + 2.95 rod II + 20.771. This is total pairing between chromosomes of different genomes, possibly between A and B, A and J, A and E, B and J, B and E, and J and E, in the presence of apparently functional pairing regulator Ph1. Because chromosome pairing in the presence of Ph1 seldom occurs between A and B, or between J and E, it was inferred that pairing between the wheat chromosomes and alien chromosomes occurred. The trigeneric hybrids with two genomes of wheat and one each of Thinopyrum and Lophopyrum should be useful in the production of cytogenetic stocks to facilitate the transfer of alien genes into wheat.     

Zinc Accumulation and Tolerance in Solanum nigrum are Plant Growth Dependent

Zinc tolerance, accumulation, and organic acid production by Solanum nigrum, a known Zn accumulator, was studied during pre- and post-flowering stages of development. The plants, when challenged with Zn concentrations lethal to plantlets, showed an increase in tolerance from pre-flowering to post-flowering, which was accompanied by a reduction of Zn translocation to the aerial plant parts. Treatment with Zn induced a differential response in organic acids according to the plant organ and developmental stage. In the roots, where Zn concentrations were similar in pre- and post-flowering plants, a general decrease in organic acid in pre-flowering roots contrasted with the increase observed in post-flowering plants. In the stems, Zn induced a generalized increase in organic acids at both growth stages while in the leaves, a slight increase in malic and shikimic was observed in pre-flowering plants and only shikimic acid levels were significantly increased in post-flowering plants. This work shows that Zn accumulation and tolerance in S. nigrum vary during plant development – an observation that may be important to improve the efficiency of phytoremediation approaches. Furthermore, the data suggest the involvement of specific organic acids in this response.     

葡萄砧木耐盐性与丙二醛和脯氨酸关系的研究

采用水培法,对3个不同耐盐性葡萄砧木品种的1年生苗进行不同浓度的NaCl胁迫处理,研究叶片中丙二醛(MDA)和脯氨酸(Pro)含量的变化.结果表明,在NaCl胁迫下,不同耐盐性葡萄砧木品种的MDA和Pro含量变化不同.NaCl胁迫对高抗品种ZM01-1的MDA含量影响较小,MDA含量处于一个比较稳定的水平,而其它品种的MDA变化幅度大;NaCl胁迫下Pro含量呈波动式变化,在0.1%NaCl胁迫下高抗品种ZM01-1的Pro积累少,0.3%NaCl下ZM01-1的Pro积累多.研究认为可以把MDA含量的相对稳定作为葡萄耐盐性鉴定的辅助指标,而Pro不宜作为葡萄耐盐性鉴定指标.     

Analyses of Thinopyrum bessarabicum, T. elongatum, and T. junceum chromosomes using EST-SSR markers

Wild Thinopyrum grasses are important gene pools for forage and cereal crops. Knowledge of their chromosome organizations is pivotal for efficient utilization of this important gene pool in germplasm enhancement programs. Expressed sequence tags derived simple sequence repeat (EST-SSR) markers for Thinopyrum bessarabicum, T. elongatum, and T. junceum chromosomes were identified among amplicons produced from three series of wheat-Thinopyrum addition lines using 193 primer pairs designed from the Leymus EST unigenes. The homology of T. junceum chromosomes in 13 wheat addition lines was tentatively established to reveal that homologous groups 3, 4, 5, 6, and 7 were represented by HD3515, HD3505, AJDAj11, AJDAj1, and HD3508, whereas groups 1 and 2 were represented by AJADj7-AJDAj9 and AJDAj2-AJDAj4, respectively. AJDAj5 and AJDAj6 had complexly reconstituted T. junceum chromosomes that might have resulted from fusion or translocations of large chromosomal segments from two or more chromosomes, that is (1+5) and (2+5+1), respectively. The identified EST-SSR markers will be useful in comparative gene mapping, chromosome tracing, taxonomic studies, gene introgression, and cultivar identification.     

干旱和盐胁迫诱导甜菜叶中的甜菜碱醛脱氢酶的积累

应用双向免疫扩散方法测定表明,甜菜叶片的甜菜碱醛脱氢酶能与菠菜的甜菜碱醛脱氢酶抗体发生交叉反应。渗透势－０．６５￣－２．６ＭＰａ的甘露醇溶液或２００～３００ｍｍｏｌ／Ｌ的ＮａＣｌ溶液,诱导甜茶叶片甜菜碱醛脱氢酶积累明显增加。     

大豆耐盐机理及相关基因分子标记

大豆耐盐涉及多种生理代谢途径.耐盐大豆能够通过Cl-排除、控制Na 的吸收和转运、合成渗透调节物质、改变细胞膜膜脂组分及相关酶类的活性等多种形式来适应盐胁迫;野生大豆群体具有盐腺,从形态结构上适应盐逆境;大豆-根瘤菌共生体在盐胁迫下通过互作来提高整体的耐盐性.分子生物学技术应用于大豆耐盐研究,已获得了一些与耐盐相关基因连锁的分子标记.广泛搜集筛选大豆栽培种和野生种资源,利用分子生物学技术和基因工程提高大豆耐盐性,将成为未来大豆耐盐研究的主要内容.     

大豆耐盐机理及相关基因分子标记

大豆耐盐涉及多种生理代谢途径。耐盐大豆能够通过Cl-排除、控制Na+的吸收和转运、合成渗透调节物质、改变细胞膜膜脂组分及相关酶类的活性等多种形式来适应盐胁迫;野生大豆群体具有盐腺,从形态结构上适应盐逆境;大豆-根瘤菌共生体在盐胁迫下通过互作来提高整体的耐盐性。分子生物学技术应用于大豆耐盐研究,已获得了一些与耐盐相关基因连锁的分子标记。广泛搜集筛选大豆栽培种和野生种资源,利用分子生物学技术和基因工程提高大豆耐盐性,将成为未来大豆耐盐研究的主要内容。