盐胁迫下水稻叶绿体中Na+、Cl-积累导致叶片净光合速率下降

研究了0-200mmol/L的NaCl胁迫下耐盐性不同的水稻品种Pokkali(耐盐）和Peta(盐敏感）根系,叶片和叶绿体中Na^ ,K^ 和Cl^-含量的变化及其与叶片光合作用的关系。结果表明：随着NaCl胁迫时间和浓度的增加,供试2个品种在根,叶片和叶绿体中Na^ ,Cl^－含量增加,K^ 含量下降。耐盐品种体内Na^ ,Cl^－含量增加或K^ 含量减少的幅度小于盐敏感品种。在200mmol/L的NaCl胁迫下盐敏感品种根,叶片和叶绿体中的Na^ /K^ 分别是耐盐品种的208％,308％和297％。与Na^ 相比,耐盐品种根系对K^ 吸收和向叶片运输的选择性（SK,Na)较强。但在经过0,100和200mmol/L的NaCl处理后2个品种叶绿体中的Na^ /K^ 均高于叶片（SK,Na均小于1）。盐胁迫下水稻叶绿体中Na^ ,Cl^-含量和Na^ /K^ 与叶片净光合速度呈极显著负相关。     

不同抗盐性小麦叶鞘的Na+/K+选择性

以200mmol／LNaCl处理耐盐小麦（Triticum aestivum L．）品种DK961和盐敏感小麦品种LM153d后,DK961叶鞘中Na^＋含量和叶片中K^＋含量均显著高于LMl5,这造成DK961叶片中Na^＋／K^＋比显著低于LM15。即DK961的叶鞘以其较LM15更强的限制Na^＋、推动K^＋向叶片运输的能力来保持叶片相对较低的Na^＋／K^＋比,即叶鞘在小麦抗盐性中可能起重要作用。     

盐胁迫下盐地碱蓬体内无机离子含量分布特点的研究

用不同浓度NaCl溶液处理盐地碱蓬（Suaeda salsa)植株后,测定并比较老叶、幼叶及根部的无机离子含量和对K的选择性,叶片及根部的Na^ 、Cl^-含量随盐度的增加而升高,且累积趋势相似,盐胁迫下根部Na^ 、Cl^-及总离子含量（K^ 、Na^ 、Ca^2 ,NO3^-,Cl^-)明显低于叶片,说明盐地碱蓬地盐胁迫下,以叶片优先积累大量离子（如Na^ ,Cl^-) 为其适应特征。NaCl处理下,叶片的K^ ,Ca^2 含量低于对照,但随盐度的增加保持相对稳定,而根部K^ 含量,K/Na比、对K的选择性则高于叶片,这对盐胁迫下地上部的K^ 亏缺有一定补偿作用。低盐度处理（100mmol/LNaCl)促进NO3^-的吸收,另外随盐度的增加,叶片渗透势下降,渗透调节能力增强,幼叶渗透势低于老叶,但渗透调节能力相同。     

盐胁迫下盐桦生理响应的变化分析

对组织培养获得的盐桦（Belula halophila）苗在盐胁迫下的生理指标和解剖结构进行了分析,结果显示,随着盐浓度的增加,植物叶片相对含水量逐渐降低;脯氨酸（Pro）含量逐渐增加;叶片丙二醛（MDA）含量和过氧化氢酶（CAT）活性大小存在相关性,在50～200mmol／L盐胁迫下,植物的CAT活性是递增的,200mmol／LNaCl处理时达到最高,同时叶片MDA含量在50～200mmol／L盐处理时变化不明显;CAT活性在300mmol／LNaCl处理时突然降低,此时叶片MDA含量大;植物叶片和根的离子含量测定表明,在盐胁迫下K^＋／Na^＋比值逐渐降低,叶片中K^＋含量始终高于Na^＋含量;石蜡切片和扫描电镜发现盐桦茎、叶中有晶体状物质存在,通过X-ray分析表明这种晶体含有C,O,Ca元素,相关的细胞成分化学实验进一步确定其结晶体的成分。     

K^＋营养对NaCl胁迫下盐地碱蓬生长及叶片液泡膜V—H^＋—ATP和V—H^＋—PPase活性的影响

对溶液培养的盐地碱蓬（Suaeda salsa L.)幼苗进行不同浓度NaCl胁迫并改变培养液中K^ 浓度,以了解K^ 营养对NaCl胁迫下盐地碱蓬幼苗生长及叶片液泡膜V－H^ -ATPase、V－H^ -PPase活性的影响。提高培养液K^ 浓度可明显增加盐胁迫下碱蓬植株的鲜重、干重,促进盐地碱蓬叶片及根部组织K^ 积累。盐地碱蓬叶片液泡膜V－H^ -ATPase至少由A、B、C、D、E及c亚基组成,其表达量在缺K^ 处理（12μmol/L K^ )下随盐胁迫浓度的增加而减小,而在正常K^ （6mmol/L)培养下则随盐胁迫浓度的增加而增加;盐地碱蓬叶片液泡膜V－H^ -PPase分子量为72kD,在缺K^ 和正常K^ 供应情况下,V－H^ -PPase均有较高表达。V－H^ -ATPase及V－H^ -PPase活性变化与其亚基表达量变化基本成正相关。结果表明：K^ 对盐生植物碱蓬的耐盐性有重要作用,盐胁迫下,K^ 可能参与了V－H^ -ATPase和V－H^ -PPase活性调控。     

硅改善盐胁迫下库拉索芦荟生长和离子吸收与分布

Si2．0mmol／L处理明显缓解NaCl 100、200mmol／L胁迫120d对库拉索芦荟（Aloevera）生长的抑制作用。Si可显著降低NaCl胁迫下芦荟植株中的Na^＋和Cl^-含量,提高K^＋含量,从而显著降低K^＋／Na^＋,促进根对K^＋的选择性吸收（ASK,Na）和K^＋向地上部的选择性运输（TSK,Na）,以维持植株体内的离子稳态。根系和叶片横切面的X-射线能谱微区分析结果进一步证实了这一结果。Si改善盐胁迫下芦荟对K^＋的选择性吸收和运输的机制之一是通过显著提高盐胁迫下芦荟根细胞质膜H^＋ATPase、液泡膜H^＋-ATPase和液泡膜H^＋-PPase的活性。     

甘氨酸甜菜碱增强青菜抗盐的作用

通过对青菜（Brassica chinensis L.)叶面喷施甜菜碱,发现其易于为叶片所吸收并运至其他部位,一定浓度范围内的甜菜碱可明显增强青菜对盐胁迫的抗性,甜菜碱可显降低盐胁迫下叶和根中Na^ 的累积,这种降低主要是根系对Na^ ,K^ 的选择性吸收能力增强所致,盐胁迫下甜菜碱导致根系质膜H^ -ATPase活性提高了45.1%,据此推测甜菜碱降低植株中Na^ 累积很可能部分由于促进根系质膜的主动排Na^ 过程,另外,甜菜碱对抗盐性的增强还体现有对叶片质膜和叶绿素的稳定作用和对脯氨酸合成的促进。     

盐胁迫下氯丙嗪和LaCl3对稻苗K^＋、Na^＋、Cl^—吸收转运的影响

研究了氯丙嗪（CPZ）和LaCl3预处理阻碍Ca^2 。CaM信使系统传导后,盐胁迫下稻苗体内Na^ 、K^ 和Cl^-含量及吸收转运的变化。结果表明：CPZ和LaCl3预处理后,盐胁迫下稻苗对K^ /Na^ 的选择性吸收下降,致使稻苗K^ 含量减少、Na^ 含量增加,Na^ /K^ 比值显著增加;并且稻苗地上部Cl^-含量也显著增加,盐胁迫处理稻苗2d后解除盐胁迫,改用蒸馏水培养,在蒸馏水中加入CPZ或LaCl3时,稻苗中含有较高的Na^ ,即CPZ和LaCl3抑制稻苗将体内Na^ 排出体外的能力,上述结果表明,盐胁迫下,Ca^2 .CaM信使系统可能参与稻苗对K^ 、Na^ 和Cl^-的吸收转运以适应盐胁迫。     

罗布麻对不同浓度盐胁迫的生理响应

利用网室盆栽实验,研究不同浓度的NaCl（100-400mmol·L^-1）胁迫对罗布麻（Apocynum venetum）生长及生理特性的影响。结果表明,100mmol·L^-1NaCl处理显著降低了罗布麻植株的鲜重,但对其干重影响不大;随着盐浓度继续增加,罗布麻鲜重和干重显著下降。在盐胁迫下,罗布麻叶片内的丙二醛含量、电解质渗漏率、根部和地上部Na^＋的含量明显增加,K^＋的含量随着盐离子浓度的增加而降低。盐胁迫显著降低了地上部Ca^2＋的含量,而对根部Ca^2＋的含量没有影响。植株K^＋/Na^＋和Ca^2＋/Na^＋比值随着盐胁迫强度的增加而降低。盐胁迫显著促进了罗布麻根部对K^＋和Ca^2＋的选择性吸收及对K^＋的选择性运输。当NaCl浓度小于或等于200mmol·L^-1时,随着盐离子浓度的增加,罗布麻叶片内的脯氨酸和可溶性糖积累显著增加,而当NaCl浓度大于200mmol·L^-1时,这2种有机溶质含量显著下降。总体上,罗布麻通过积累无机离子、合成有机溶质及维持较高的K^＋、Ca^2＋选择性吸收和运输来适应一定浓度（≤200mmol·L^-1NaCl）的盐胁迫。     

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。     

Characterization and use of polyclonal antibody to Na+,K+-ATPase: immunocytochemical localization in salt glands of the duck

The amount of Na+,K+-ATPase of the avian salt gland increased concomitantly with plasma membrane surface area during salt feeding of ducklings (adaptation), and both enzyme content and membrane surface area decreased upon return to fresh water (deadaptation). In a further study of the enzyme, a marker for plasma membrane biogenesis, polyvalent antibodies were raised to the denatured alpha-subunit of the purified ATPase. Antisera did not inhibit enzymatic activity but immunoprecipitated the phosphorylated intermediate of the alpha-subunit. Furthermore, the alpha-subunit, which was not glycosylated, was immunoprecipitated from homogenates of tissue slices metabolically labelled with [35S]-methionine, using antisera raised against either duck salt gland or dog kidney alpha-subunit. The former antisera also recognized the alpha-subunit in the brain, heart, kidney, liver, intestine and skeletal muscle of the duck. Immunocytochemistry with the antisera raised to the duck salt gland alpha-subunit revealed reaction at basolateral as well as apical plasma membrane in the duck salt gland principal cells, with essentially no deposits on peripheral cells, fibroblasts, erythrocytes, endothelial cells and neural elements. Within the principal cells, immunolabelling was also detected on small vesicles, multivesicular bodies and lysosomes; deposits on extracellular debris and vesicles in the lateral and lumenal spaces were also apparent. The labelling patterns were qualitatively but not quantitatively similar in salt glands of control, adapted and deadapted ducklings, and are discussed in the context of a model for plasma membrane biogenesis and turnover in which degradative events may play a major role.     

盐胁迫下杨树根际系统盐分离子分布特性

在温室条件下,采用盆栽根箱培养的方法研究盐胁迫下I 69杨(PopulusdeltoidesBartr.cv.'Lux')和NL 1381杨〔PopulusdeltoidesBartr.cv.'Lux'×P.euramericana(Dode)GeninierCL'I 45 51'〕根际、非根际土壤盐分分布特征。盐处理浓度共设3个水平:CK(NaCl0g kg)、处理A(NaCl1g kg)和处理B(NaCl2g kg),采用完全随机设计。结果表明,2个杨树无性系根际水溶性K+亏缺,水溶性Na+、Ca2+和Mg2+富集。K+的亏缺率及Na+的富集率随NaCl处理浓度的增大而减小,Ca2+和Mg2+的富集率在非盐渍条件下最低,处理A达最高,处理B较处理A略有下降。在盐胁迫下,无性系NL 1381杨根际土壤Na+的浓度和电导率均低于无性系I 69杨,可以有效减轻盐分对根系的渗透胁迫,相对而言具有较强的抗盐性。     

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。     

Intracellular Na+ and K+ contents of Zygosaccharomyces rouxii mutants defective in salt tolerance

Two of five Zygosaccharomyces rouxii mutants defective in salt tolerance, 152S (sat1) and 1717S (SAT3), were inviable in a nutrient medium (YPD) containing more than 1% NaCl. These two mutant cells contained significantly higher amounts of Na⁺ (298 μmol and 285 μmol per g cells of 152S and 1717S, respectively) but lower amounts of K⁺ (242 μmol and 176 μmol per g cells of 152S and 1717S, respectively) than three other mutants, 41S (sat2-1 [98 μmol Na⁺ and 326 μmol K⁺/g cells]), 197S (sat2-2 [103μmol Na⁺ and 336 μmol K⁺/g cells]), 1611S (SAT4 [139 μmol Na⁺ and 294 μmol K⁺/g cells]), as well as a wild-type strain, AN39 (61 μmol Na⁺ and 349 μmol K⁺/g cells), when cultured in YPD medium containing 0.8% NaCl. A KCl supplement, optimally 0.6 M, added to the medium somewhat restored the NaCl-hypersensitivity of 152S and 1717S with a concomitant decrease of intracellular Na⁺. This finding suggests that the NaCl-hypersensitive mutations are due to a defect in the Na⁺-regulating mechanism. The other three mutants showed weak responses to KCl in high NaCl-YPD. These five salt sensitive mutants and the wild-type strain retained the same levels of intracellular glycerol and arabitol when transferred into NaCl (5%)-YPD from YDP medium. This suggests that polyol accumulation is not the only mechanism of salt tolerance in Z. rouxii.     

Biochemical and immunochemical determination of (Na+ + K+)-ATPase content in subcellular fractions prepared from the avian salt gland: evidence for enzyme heterogeneity

Subcellular membrane fractions were prepared from the salt glands of osmotically-stressed ducklings. Two fractions were characterized biochemically with respect to (Na+ + K+)-ATPase, alkaline phosphodiesterase I, succinate dehydrogenase, esterase, and galactosyltransferase activities and immunochemically with respect to (Na+ + K+)-ATPase. The ratios of the estimates of the (Na+ + K+)-ATPase contents obtained biochemically and immunochemically from the two fractions differed by more than 2 X. The results are consistent with the presence of at least two molecular species of (Na+ + K+)-ATPase, unevenly distributed between the two fractions.     

Occlusion of Rb+ by detergent-solubilized (Na+ + K+)-ATPase from shark salt glands

Occlusion of Rb+ by C12E8-solubilized (Na+ + K+)-ATPase from shark salt glands has been measured. The rate of de-occlusion at room temperature is about 1 s-1, which is the same as for the membrane-bound enzyme. The amount of Rb+ occluded is 3 moles Rb+ per mole membrane-bound shark enzyme, whereas only about 2 moles Rb+ are occluded by the C12E8-solubilized enzyme.     

K+Nutrition and Na+Toxicity: The Basis of Cellular K+/Na+Ratios

The capacity of plants to maintain a high cytosolic K⁺/Na⁺ratiois likely to be one of the key determinants of plant salt tolerance.Important progress has been made in recent years regarding theidentification and characterization of genes and transportersthat contribute to the cytosolic K⁺/Na⁺ratio. For K⁺uptake,K⁺efflux and K⁺translocation to the shoot, genes have been isolatedthat encode K⁺uptake and K⁺release ion channels and K⁺carriersthat are coupled to either a H⁺or Na⁺gradient. Although thepicture is less clear for the movement of Na⁺, one pathway,in the form of non-selective ion channels, is likely to playa role in Na⁺uptake, whereas Na⁺efflux and compartmentationare likely to be mediated by H⁺-coupled antiport. In addition,several proteins have been characterized that play prominentroles in the regulation of K⁺and/or Na⁺fluxes. In this BotanicalBriefing we will discuss the functions and interactions of thesegenes and transporters in the broader context of K⁺nutritionand Na⁺toxicity. Copyright 1999 Annals of Botany Company Salinty, K⁺/N⁺ratio, transporter, membrane.     

Dynamic QTL analysis of the Na+ content,K+ content,and Na+/K+ ratio in rice roots during the field growth under salt stress

Rice (Oryza sativa L.) is seriously impacted by global soil salinization. To determine the quantitative trait loci (QTLs) related to salt tolerance in rice roots, F_2:3 and BC₁F_2:3 populations derived from a cross between the cv. Dongnong 425 of high quality and yield and the salt-tolerant cv. Changbai 10, were studied at different development stages. Two genetic linkage maps of F_2:3 and BC1F_2:3 populations were constructed. A 66 mM NaCl solution was used to irrigate the field and to analyze the dynamic QTL of some rice root traits. Using unconditional and conditional QTL mapping methods, 30 unconditional QTLs and 16 conditional QTLs related to the 6 root traits were detected on the 9 rice chromosomes during different developmental stages. Fourteen pairs of unconditional and conditional QTLs were detected at the identical developmental stage in the identical population. A number of QTLs were detected at different developmental stages, however, many did not appear at the last stage. Remarkably, qRKC1 appeared continuously at multiple stages in both the populations suggesting its key role in regulating the salt tolerance of rice roots.