盐分胁迫条件下甜菜碱对小麦幼苗体内Na^＋,K^＋和Cl^—的含量及 …

以抗盐品种茶淀红和盐敏感品种中国春等两种小麦为实验材料,研究甜菜碱对盐分胁迫条件下小麦幼苗Ｎａ＾＋、Ｋ＾＋、Ｃｌ＾－的吸收、分配的影响。结果表明：外源甜菜碱能够在一定程度上限制幼苗对Ｎａ＾＋、Ｋ＾＋、Ｃｌ＾－的吸收、分配的影响。结果表明：外源甜菜碱能够在一定程度上限制幼苗对Ｎａ＾＋、Ｃｌ＾－的吸收,阻滞其向地上部分运输的数量和速度,同时提高体内Ｋ＾＋含量、向上运输效率,降低地上部分对Ｎａ＾＋、Ｋ＾     

NaCl胁迫对黄瓜幼苗体内K+、Na+和Cl-分布的影响

采用营养液水培,以2个耐盐性不同的黄瓜品种为材料,研究了不同浓度NaCl处理下幼苗植株体内K 、Na 和Cl-在器官间的区域化分布及其吸收和运输特性的变化。结果表明:NaCl胁迫下,黄瓜植株体内K 含量下降,Na 和Cl-含量升高,变化幅度随NaCl浓度的升高而增大;不同器官间,茎中Na 和Cl-含量最高,上位叶中Na 和Cl-含量最低、K 含量下降幅度最小。与耐盐性较弱的“津春2号”相比,耐盐性较强的“长春密刺”根向茎运输的SK,Na值较高,根系对Na 的截留作用较强,茎向上位叶运输的SK,Na和SCl,Na值均较高,叶片中K 含量下降幅度较小,K/Na和Cl/Na比值均较高,功能叶中盐分离子尤其是Na 积累较少,植株生物量较高。说明根系对Na 的截留能力较强且向上位叶运输Na 的选择性较低,是“长春密刺”耐盐性较强的主要原因之一。     

NaCl胁迫下黄瓜幼苗体内K+、Na+和Cl-分布及吸收特性的研究

采用营养液水培法,研究了不同浓度NaCl胁迫对黄瓜幼苗不同器官K 、Na 和Cl-含量的影响。结果表明,NaCl胁迫下黄瓜植株体内K 含量下降,Na 和Cl-含量升高,变化幅度随NaCl浓度的增加而增大;NaCl处理4 d后,各器官中K 含量下降幅度剧增,叶片中Na 和Cl-含量快速升高;3种离子在器官间呈区域化分布,Na 主要积累在根和茎部,K 和Cl-主要积累在茎部,而且K 的含量下降幅度由根向叶递减。在低浓度NaCl胁迫或高浓度NaCl短期胁迫下,黄瓜植株对K 的吸收选择性以及向地上部运输的选择性提高,离子区域化分布的能力增强,有利于避免离子代谢紊乱,减轻NaCl胁迫的伤害。可见,离子在器官水平的区域化分布是黄瓜植株耐盐性的重要机理之一。     

盐胁迫条件下杨树盐分与甜菜碱及糖类物质变化

以抗旱耐盐性强的胡杨（Populus euphratica) 和非抗盐的群众杨（P.popularis 35-44'）为实验材料,研究了盐胁迫条件下盐分与甜菜碱,还原糖,蔗糖以及水溶性糖等细胞相容溶质的动态变化,两种杨树在盐处理期间表现出明显差异;群众杨下部叶片首先表现出盐害症状,处理后两周苗木上部叶片也出现盐害并脱落,而胡杨在试验期间仅下部叶片发黄脱落,盐处理15天后落叶量仅为16％,群众杨盐害症状的出现主要是由叶片中盐离子的大量累积所致。与之比较,胡杨拒吸Na^ 的能力及控制Cl^-转运的能力均优于群众杨。另外,胡杨的耐盐性强于群众杨也与其有机溶质的变化有关,受到盐胁迫后胡杨根叶中甜菜碱浓度显著提高,在处理后15天达到最高值,特别是叶片中甜菜碱的浓度提高了243倍,达到1899．8umol/L,根中甜菜碱含量也增加了9倍,此外,盐处理后胡杨叶和根中的还原糖,水溶性糖和蔗糖含量均呈明显上升趋势,分别在第4天和第15天达到峰值,与胡杨相反,耐盐性弱的群众杨在盐胁迫期间,叶中甜菜碱和糖含量并无显著提高,根中糖分水平还明显降低,由此可以得出结论,胡杨渗透调节能力高于群众杨,是其耐盐性强的重要生理基础之一。     

盐胁迫条件下杨树盐分与甜菜碱及糖类物质变化

以抗旱耐盐性强的胡杨（Populus euphratica）和非抗盐的群众杨（P. popularis‘35-44’）为实验材料,研究了盐胁迫条件下盐分与甜菜碱、还原糖、蔗糖以及水溶性糖等细胞相容溶质的动态变化。两种杨树在盐处理期间表现出明显差异：群众杨下部叶片首先表现出盐害症状,处理后两周苗木上部叶片也出现盐害并脱落。而胡杨在试验期间仅下部叶片发黄脱落,盐处理15天后落叶量仅为16%。群众杨盐害症状的出现主要是由叶片中盐离子的大量累积所致。与之比较,胡杨拒吸Na+的能力及控制Cl-转运的能力均优于群众杨。另外,胡杨的耐盐性强于群众杨也与其有机溶质的变化有关。受到盐胁迫后胡杨根叶中甜 菜碱浓度显著提高,在处理后15天达到最高值,特别是叶片中甜菜碱的浓度提高了243倍,达到1*!899.8 μmol/L,根中甜菜碱含量也增加了9倍。此外,盐处理后胡杨叶和根中的还原糖、水溶性糖和蔗糖含量均呈明显上升趋势,分别在第4天和第15天达到峰值。与胡杨相反,耐盐性弱的群众杨在盐胁迫期间,叶中甜菜碱和糖含量并无显著提高,根中糖分水平还明显降低。由此可以得出结论,胡杨渗透调节能力高于群众杨,是其耐盐性强的重要生理基础之一。     

NaCl胁迫对2个菊属野生种幼苗体内K+、Na+和Cl-分布及生长的影响

采用营养液水培,研究了不同浓度NaCl处理下耐盐性不同的2个菊属物种幼苗的生长变化及体内K+、Na+、Cl-在器官间的区域化分布和吸收、运输特性,以揭示其耐盐差异机制。结果表明,NaCl胁迫下,2个物种的新生叶面积比率减小,受害叶面积比率增加,叶电解质外渗率增加;大岛野路菊受胁迫影响较轻。2个物种体内Na+和Cl-含量随NaCl浓度的升高而增大,且地上部的Na+、Cl-积累量大于根系,成熟叶是2个物种Na+、Cl-积累的主要器官。新生叶、茎的K+含量也随NaCl浓度的升高而增加。与耐盐性强的大岛野路菊相比,NaCl胁迫下萨摩野菊各器官积累的Na+和Cl-量均显著高于前者,其生长对其体内含有的Na+和Cl-比大岛野路菊更为敏感。除高盐胁迫下的根以外,大岛野路菊各器官的K+/Na+均显著高于萨摩野菊。大岛野路菊根向茎运输的SK,Na值远高于萨摩野菊,茎向中位成熟叶运输的SK,Na值较低,高盐胁迫时茎向上位新生叶运输的SK,Na值较高。说明NaCl胁迫下大岛野路菊对Cl-、Na+的累积能力弱、维持K+、Na+平衡的能力强,且根系对Na+的截留能力强,茎向上位新生叶运输Na+的选择性较低,是其耐盐性强的主要原因,而茎向中位成熟叶运输Na+的选择性较高是其对盐胁迫的适应。多元回归分析结果还表明,Cl-对萨摩野菊的影响强于Na+。     

盐胁迫对四种基因型冬小麦幼苗Na+、K+吸收和累积的影响

以4种不同基因型冬小麦品种为试验材料,研究了盐胁迫下小麦幼苗的生长及Na^＋、K^＋和Cl^-的吸收、累积规律。结果表明,盐胁迫下小麦吸水困难,幼苗生长受抑;幼苗含水量、生物量及干物质量明显下降;Na^＋、Cl^-含量和单株累积量显著增加。K^＋含量和单株累积量则明显降低。Na^＋／K^＋比值随介质中的盐浓度的增加而升高。盐胁迫下各基因型冬小麦幼苗Na^＋、K^＋和Cl^-的单株累积量及其在地上部分和根系中的含量变化较大,说明小麦根系对Na^＋、K^＋和Cl^-的吸收存在基因型差异。盐处理下,暖型小麦NR9405对K^＋的选择吸收能力强,对Na^＋的吸收和累积少,植株体内的K^＋浓度较高,Na^＋／K^＋比值小;幼苗的生物量较大,耐盐性强。冷型小麦RB6对K^＋的选择能力差,对Na^＋的吸收和累积量大,幼苗的Na^＋／K^＋比值大,生物量小,耐盐性较差。低盐浓度下,Na^＋可作为渗透调节物质维持植物体内渗透平衡。高盐浓度下,Na^＋的过度吸收和累积可能是盐害的主要原因。维持体内较低的Na^＋水平和Na^＋／K^＋比值是小麦耐盐性的一个重要特征。     

干旱和NaCl胁迫下梭梭幼苗中甜菜碱含量和甜菜碱醛脱氢酶活性的变化（简报）

梭梭幼苗的甜菜碱含量和甜菜碱醛脱氢酶（BADH）活性随外界NaCl浓度的增加和干旱胁迫时间的延长而增加。干旱和NaCl促进旱生植物梭梭体内甜菜碱积累与BADH活性有关。     

多胺对盐胁迫下黄瓜 (Cucumis sativus L.)幼苗体内K+、Na+和Cl-含量及器官间分布的影响

采用营养液水培,选用耐盐性不同的两个黄瓜品种,研究了外源多胺（Put、Spd、Spm）对NaCl胁迫下黄瓜幼苗植株不同器官中K＋、Na＋和Cl-含量的影响。结果表明,NaCl胁迫后黄瓜植株体内K＋含量下降、Na＋和Cl-含量升高、K/Na比值降低,耐盐性较弱的“津春2号”体内离子含量变化幅度明显大于耐盐性较强的“长春密刺”;叶面喷施多胺抑制了K＋含量的降低,减少了Na^＋和Cl^-的积累,提高了K/Na比值及K^＋、Na^＋吸收和运输的选择性,可缓解盐胁迫的伤害,增加生物积累量,且Spd（亚精胺）的作用尤为明显。总之,外源多胺可通过调控盐胁迫下植株体内的离子平衡,提高黄瓜幼苗的耐盐性。     

盐胁迫下小麦体细胞杂种与亲本小麦幼苗的生长量和Na+、K+含量比较

对小麦体细胞杂种F6株系Ⅰ-1-3和其亲本小麦济南177的幼苗在不同NaC1浓度处理6d时的生长量和Na^ 、K^ 含量进行了比较。结果表明：盐胁迫下杂种的生长量明显高于亲本小麦。随着盐浓度的增加,杂种和亲本的叶、茎和根中Na^ 含量均增加,但杂种叶与茎的Na^ 含量显著低于亲本,而根的却高于亲本,这可能提示杂种根部液泡较亲本有较强的储Na^ 功能。受盐胁迫的杂种叶与茎中K^ 含量显著高于亲本,K^ ／Na^ 比值高。杂种的Na^ 净积累速率也高于亲本。可见杂种比亲本小麦有更强的耐盐性。     

Potassium‐induced decrease in cytosolic Na+ alleviates deleterious effects of salt stress on wheat (Triticum aestivum L.)

• Accumulation of NaCl in soil causes osmotic stress in plants, and sodium (Na⁺) and chloride (Cl^?) cause ion toxicity, but also reduce the potassium (K⁺) uptake by plant roots and stimulate the K⁺ efflux through the cell membrane. Thus, decreased K⁺/Na⁺ ratio in plant tissue lead us to hypothesise that elevated levels of K⁺ in nutrient medium enhance this ratio in plant tissue and cytosol to improve enzyme activation, osmoregulation and charge balance.
• In this study, wheat was cultivated at different concentrations of K⁺ (2.2, 4.4 or 8.8 mm ) with or without salinity (1, 60 or 120 mm NaCl) and the effects on growth, root and shoot Na⁺ and K⁺ distribution and grain yield were determined. Also, the cytosolic Na⁺ concentration was investigated, as well as photosynthesis rate and water potential.
• Salinity reduced fresh weight of both shoots and roots and dry weight of roots. The grain yield was significantly reduced under Na⁺ stress and improved with elevated K⁺ fertilisation. Elevated K⁺ level during cultivation prevented the accumulation of Na⁺ into the cytosol of both shoot and root protoplasts. Wheat growth at vegetative stage was transiently reduced at the highest K⁺ concentration, perhaps due to plants' efforts to overcome a high solute concentration in the plant tissue, nevertheless grain yield was increased at both K⁺ levels.
• In conclusion, a moderately elevated K⁺ application to wheat seedlings reduces tissue as well as cytosolic Na⁺ concentration and enhances wheat growth and grain yield by mitigating the deleterious effects of Na⁺ toxicity.

     

砷对小麦生长和光合作用特性的影响

研究了水培条件下砷对小麦根系和地上部分生长速率、光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr)的影响.结果表明,随着营养液中砷浓度的提高,小麦根长生长量和地上部分生长量较对照减少;鲜重和砷的浓度呈显著负相关.在0～90mg/L 砷处理内,Pn、Gs、Tr都随砷的浓度的提高而降低;Ci呈先降低,后升高的变化.在As≤30 mg/L时Ci逐渐降低,气孔限制值Ls升高,使Pn下降,造成气孔性限制;而As>30 mg/L时,Ci升高,气孔限制值Ls下降,Pn降低,造成了非气孔性限制.叶片水分利用效率WUE和气孔限制值Ls在As≤30 mg/L时变化一致,都有所升高;但是当As>60 mg/L时,小麦趋于死亡,水分利用率降低.叶绿素含量在0～10mg/L As处理内,差异不显著,在较高砷浓度(As>30 mg/L)时叶绿素显著下降.这说明较低浓度的砷不会抑制小麦叶绿素的合成.砷主要是毒害小麦根系生长,造成植株体光合作用的气孔性限制和非气孔性限制出现,最终影响小麦的生长和发育.     

Nostoc, Microcoleus and Leptolyngbya inoculums are detrimental to the growth of wheat (Triticum aestivum L.) under salt stress

Background and aims

This study investigated the effect of cyanobacterial inoculants on salt tolerance in wheat.

Methods

Unicyanobacterial crusts of Nostoc, Leptolyngbya and Microcoleus were established in sand pots. Salt stress was targeted at 6 and 13 dS m^?1, corresponding to the wheat salt tolerance and 50 % yield reduction thresholds, respectively. Germinated wheat seeds were planted and grown for 14 (0 and 6 dS m^?1) and 21 (13 dS m^?1) days by which time seedlings had five emergent leaves. The effects of cyanobacterial inoculation and salinity on wheat growth were quantified using chlorophyll fluorescence, inductively coupled plasma-optical emission spectrometry and biomass measurements.

Results

Chlorophyll fluorescence was negatively affected by soil salinity and no change was observed in inoculated wheat. Effective photochemical efficiency correlated with a large range of plant nutrient concentrations primarily in plant roots. Inoculation negatively affected wheat biomass and nutrient concentrations at all salinities, though the effects were fewer as salinity increased.

Conclusions

The most likely explanation of these results is the sorption of nutrients to cyanobacterial extracellular polymeric substances, making them unavailable for plant uptake. These results suggest that cyanobacterial inoculation may not be appropriate for establishing wheat in saline soils but that cyanobacteria could be very useful for stabilising soils.     

The wheat (Triticum aestivum L.) leaf proteome

The wheat leaf proteome was mapped and partially characterized to function as a comparative template for future wheat research. In total, 404 proteins were visualized, and 277 of these were selected for analysis based on reproducibility and relative quantity. Using a combination of protein and expressed sequence tag database searching, 142 proteins were putatively identified with an identification success rate of 51%. The identified proteins were grouped according to their functional annotations with the majority (40%) being involved in energy production, primary, or secondary metabolism. Only 8% of the protein identifications lacked ascertainable functional annotation. The 51% ratio of successful identification and the 8% unclear functional annotation rate are major improvements over most previous plant proteomic studies. This clearly indicates the advancement of the plant protein and nucleic acid sequence and annotation data available in the databases, and shows the enhanced feasibility of future wheat leaf proteome research.     

Silicon absorption by wheat (Triticum aestivum L.)

Although silicon (Si) is a quantitatively major inorganic constituent of higher plants the element is not considered generally essential for them. Therefore it is not included in the formulation of any of the solution cultures widely used in plant physiological research. One consequence of this state of affairs is that the absorption and transport of Si have not been investigated nearly as much as those of the elements accorded 'essential' status. In this paper we report experiments showing that Si is rapidly absorbed by wheat (Triticum aestivum L.) plants from solution cultures initially containing Si at 0.5 mM, a concentration realistic in terms of the concentrations of the element in soil solutions. Nearly mature plants (headed out) 'preloaded' with Si absorbed it at virtually the same rate as did plants grown previously in solutions to which Si had not been added. The rate of Si absorption increased by more than an order of magnitude between the 2-leaf and the 7-8 leaf stage, with little change thereafter. This revised version was published online in June 2006 with corrections to the Cover Date.     

Proteomic analysis on salicylic acid-induced salt tolerance in common wheat seedlings (Triticum aestivum L.)

The influence of salicylic acid (SA) on the salt tolerance mechanism in seedlings of common wheat (Triticum aestivum L.) was investigated using physiological measurements combined with global expression profiling (proteomics). In the present study, 0.5mM SA significantly reduced NaCl-induced growth inhibition in wheat seedlings, manifesting as increased fresh weights, dry weights, and photosynthetic pigments, but decreased lipid peroxidation. Two-week-old wheat seedlings treated with 0.5mM SA, 250mM NaCl and 250mM NaCl+0.5mM SA for 3days were used for the proteomic analyses. In total, 39 proteins differentially regulated by both salt and SA were revealed by 2D PAGE, and 38 proteins were identified by MALDI-TOF/TOF MS. The identified proteins were involved in various cellular responses and metabolic processes including signal transduction, stress defense, energy, metabolism, photosynthesis, and others of unknown function. All protein spots involved in signal transduction and the defense response were significantly upregulated by SA under salt stress, suggesting that these proteins could play a role in the SA-induced salt resistance in wheat seedlings.     

Longitudinal distribution of growth substances in leaves of wheat (Triticum aestivum L.)

Summary The basal fifth of the lamina, containing most of the gibberellin of young leaves, was the only part of the lamina that elongated. When the base of the lamina stopped elongating the gibberellin apparently moved up the lamina, but the leaf sheath still contained some gibberellin and continued to elongate. Old, fully elongated, leaves contained most auxin and tryptophan in the apical fifth of the lamina that was dying; young leaves contained insignificant amounts of auxin. Leaves contained two cytokinins; generally most cytokinin activity occurred in the apical fifth of leaves. Cytokinin activity was also detected in guttation drops and in ethanolic washings from leaf tips.