盐分胁迫对植物的影响及植物耐盐机理研究进展

盐分是影响植物生长的一个重要环境因素。总结了盐分胁迫对植物生长发育影响的研究进展,从氧自由基产生、膜脂过氧化、离子伤害、渗透伤害和有毒物质积累等方面系统分析了盐胁迫对植物的伤害机理,并综述了植物对盐分胁迫的适应机制,总结了主要的抗盐生理指标。     

棉花耐盐机理与盐害控制研究进展

综述了棉花耐盐机理、耐盐性鉴定方法和盐害控制技术的研究进展。棉花耐盐机理与一般植物存在着较大的差异,对盐分胁迫下的植株体内离子分布、细胞膜结构和稳定性以及渗透压调节作用等方面进行了探讨,总结了运用传统育种和现代生物技术改良和提高棉花耐盐性方面取得的进展。此外,提出了从棉花品种、栽培技术、种子引发技术和土壤改良等方面盐碱地植棉的综合技术体系。     

棉花盐害的控制技术及其机理

棉花是耐盐作物,但土壤耕层中积累过多的盐离子会通过离子毒害、渗透胁迫和引起营养失衡等机制导致盐害。控制棉花盐害的途径主要有两条,一是提高棉花自身的耐盐性,另一方面是躲避或减轻盐胁迫。本文评述了提高棉花耐盐性和躲避或减轻盐胁迫的途径、原理和方法,提出在工程措施改良盐碱地的基础上,综合运用适宜品种、水肥运筹、种子处理及地膜覆盖和诱导根区盐分差异分布等农艺措施是现阶段控制盐碱地棉花盐害的有效途径。     

伽师县种植作物土壤有机质与盐分的相关性分析

为提高伽师县不同耕作土壤施肥的精度、减少浪费、降低盐分含量及轮流种植作物等方面提供科学依据。采用野外取样、GPS定位、统计分析和空间分析方法,在SPSS 17.0 和ArcGIS 9＋的支持下,研究不同耕作土壤有机质与盐分之间进行相关性分析。研究结果表明：（1）种植甜瓜土壤各层有机质平均含量高于种植玉米和种植棉花土壤。（2）不同耕作土壤不同土层中各盐离子变异系数的差异比较明显,有机质与盐离子具有不同程度的相关特征。其中,种棉土壤中有机质与K+＋Na+、Mg2+盐离子呈显著正相关,其余都是呈显著负相关;种植甜瓜土壤有机质与Cl-、Mg2+盐离子呈显著正相关,其余都是呈显著负相关;种植玉米土壤中有机质与SO42-、K+＋Na+、Mg2+盐离子呈显著正相关,其余都是呈显著负相关。（3）种植棉花土壤的盐分含量从表层到底层呈逐渐增加趋势;种植甜瓜土壤的盐分含量分别为表层含量高,中层和底层的盐分含量差异不大;种植玉米土壤的盐分含量呈先增加后减少的趋势。     

盐分胁迫对海陆杂交棉及亲本生长发育的影响

以海陆杂交棉及其亲本为材料，采用完全随机区组设计研究了盐分胁迫对海陆杂交棉生长发育及生理特性的影响。结果表明，盐分胁迫下海陆杂交棉及其亲本生长及干物质积累都存在不同程度的下降趋势，但杂交棉表现出较强的抗盐性。盐分胁迫下杂交棉根／冠比显著提高及其渗透明显高于双亲是其表现出抗盐性的主要原因。中度盐分胁迫（５ｍｓ·ｃｍ－１）能促进海陆杂交棉及陆地棉的生殖生长，特别是对杂交棉。此特性在盐地棉花生产上可加以利用。     

盐胁迫对棉花幼苗子叶超氧化物歧化酶(SOD)活性的影响

棉花幼苗子叶 SOD 活性在细胞内的分布是细胞溶质部分活性最高。其次是线粒体,再次是叶绿体。各细胞器 SOD 活性对盐分的敏感程度不同,依次是叶绿体>线粒体>细胞溶质部分。在盐分胁迫初期,棉花幼苗子叶能够维持较高 SOD 活性,但随着盐胁迫强度的增加,棉花幼苗子叶 SOD 活性下降和膜透性增加,幼苗表现出盐害症状,SOD 活性下降比膜透性增加出现的早。轻度盐分胁迫随时间延长,鲁棉6号的子叶 SOD 活性有一定增加,表明棉花幼苗具有一定的耐盐能力。耐盐性不同的两个品种在 SOD 活性和细胞质膜透性变化上有差异,并对 SOD 作为棉花抗盐碱育种指标进行讨论。     

种植耐盐植物对滨海盐碱地土壤盐分的影响

为了揭示不同耐盐植物根际土壤与对照之间的盐分差异,通过大田试验研究了田菁、苜蓿、苏丹草、碱蓬4种耐盐植物不同生长时期各土层可溶性盐分和盐分离子的测定分析,研究了4种耐盐植物根际土壤与对照土壤中的可溶性盐分和主要盐分离子的运移特征。结果表明：种植耐盐植物对表层土壤具有明显的脱盐效果,其中田菁对表层及0～80 cm土层的脱盐效果最好。10月份时耐盐植物处理表层土脱盐效果顺序为田菁＞苏丹草＞苜蓿＞碱蓬;0～80 cm整体各处理的脱盐顺序为田菁＞苜蓿＞苏丹草＞碱蓬。 HCO3-、Cl-和SO42-均在对照的0～10 cm土层中含量最高,耐盐植物根际土壤0～10,10～20 cm土层中Na＋和Cl-含量要显著低于对照土壤的含量。种植耐盐植物后,根际土壤中可溶性Ca2＋含量增加,使更多的Na＋被取代后将其移除到耕层以下,说明种植耐盐植物处理对Na＋的移除效果比较明显。     

NaCl胁迫对两优培九幼苗离子含量的影响

3种浓度的NaCl胁迫杂交水稻两优培九幼苗4d后，根和地上部分的相对含水量明显下降。功能叶片中的游离脯氨酸和可溶性总糖含量以及幼苗根、茎、叶中的Na＋含量、Na＋／K＋、Na＋／Ca^2＋和Na＋／Mg^2＋与对照相比，随着盐处理浓度的增大而增大，K＋、Ca^2＋和Mg^2＋的含量则相反。试验结果表明，在盐胁迫下两优培九幼苗主要利用产生游离脯氨酸和可溶性糖等有机渗透调节物质来维持地上部分的渗透平衡；从离子平衡角度发现，两优培九幼苗在根部通过避Na＋机制来保持较高的Na＋／K＋以减轻盐胁迫对地上部分的伤害，在茎和功能叶片中则通过保持细胞中较高的K＋水平以减轻盐胁迫的伤害。     

不同盐碱胁迫对棉花离子组稳态及Na~+相关基因表达影响

【目的】维持细胞内离子稳态是作物重要的耐盐机制之一。研究不同盐碱胁迫下棉花离子组响应特征和耐盐基因表达的差异,为深入认识棉花耐盐机理和提高棉花耐盐性提供依据。【方法】以鲁棉研24号为试验材料,在盆栽控制条件下设置3种盐碱胁迫类型(盐胁迫、碱胁迫和复合盐碱胁迫)和2个梯度水平(低盐碱和高盐碱),并以无盐碱胁迫处理为对照。测定棉花植株干物质质量以及根系形态指标根长、根表面积和根体积。采用电感耦合等离子体原子发射光谱仪(ICP-AES)测定棉花各器官P、Na、K、Ca、Mg等13种元素含量,并采用实时荧光定量聚合酶链式反应技术测定了耐盐相关基因Gh DFR1、GhSOS1、GhNHX1和GhAKT1的相对表达量。【结果】1)不同盐碱胁迫显著抑制棉花生长,复合盐碱胁迫棉花生长抑制率(48.7%～57.9%)显著高于盐胁迫(27.6%～49.9%)和碱胁迫(21.2%～35.5%)。盐胁迫和复合盐碱胁迫下,棉花地上部和根系生长均显著受抑制,地上部干物质质量、根长、根表面积和根体积显著降低;而碱胁迫对根系的抑制作用相对较小。2)3种盐碱胁迫下,棉花体内Na含量显著增加;各器官Mo含量也均显著增加,叶片和根系N含量降低。3)盐胁迫下,棉花Ca、Mg、Fe、Mn、Zn吸收受抑制,通过促进这些离子以及P、K的转运,维持体内离子平衡。4)碱胁迫下,除Ca、Mg、Fe、Mn、Zn以外,P的吸收也受到抑制,但K的吸收以及P、K、Ca、Mg、Fe、Mn、Zn向地上部转运受到促进。5)复合盐碱胁迫尤其是高盐和pH值环境下,主要营养元素吸收均受抑制,Ca、Mg、Zn、Mn、Fe转运能力降低。6)盐胁迫下,Gh SOS1和GhAKT1基因相对表达量显著增加,在碱胁迫和复合盐碱胁迫下呈先增后降趋势;3种盐碱胁迫下,表现为碱盐复合盐碱胁迫。GhNHX1基因相对表达量随土壤盐碱度增加先增后降,表现为盐碱复合盐碱。【结论】复合盐碱胁迫由于高盐度和pH叠加效应显著抑制棉花生长和离子吸收,制约P、K、Ca、Mg、Zn、Mn、Fe向地上部转运,使棉花K、Na离子调控能力下降导致离子失衡。     

滨海盐土覆盖植棉抑盐机理及效果

棉花耐盐性受土壤盐分和水分含量的双得影响，试验表明棉花在氯化钠浓度为１．２％以下的水溶液和土壤溶液中能正常出苗，受到抑制的盐分浓度为１．４～１．７％，以此土壤含盐量和土壤含水量换算成土壤溶液含盐量对棉花发芽影响结果相似。因此，中度盐渍化土可以通过保水抑盐措施，植棉利用。地膜和盖草抑盐效果明显，其作用是：保持土壤水分，虽然使土壤溶液盐不变的情况下低于耐盐指标，控制水分蒸发避免盐份在表土层聚积造成植物     

Ionic Homeostasis and Expression of Na+ Related Genes of Cotton under Different Salt and Alkali Stresses

[Objective] Maintaining intracellular ion homeostasis is one of the important salt-tolerant mechanisms of crops. This study aims to analyze differences in response characteristics of cotton ionome and salt-tolerant gene expression under different saline-alkali stresses, which provides a basis for understanding the mechanism of salt tolerance and improving salt tolerance of cotton. [Method] Using Lumianyan 24 as the experimental material, three kinds of salt and alkali stress types (salt stress, alkali stress, and mixed salt-alkali stress) and two concentration gradients (low and high concentrations) were set under pot cultivation conditions. Meanwhile, non-saline-alkali stress treatment was set as control. The dry matter weight of cotton plants and root morphological parameters including root length, root surface area, and root volume were measured in this study. The concentrations of 13 elements such as P, Na, K, Ca and Mg in different organs of cotton plants were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The relative expressions of salt tolerance related genes GhDFR1, GhSOS1, GhNHX1 and GhAKT1 were determined by the quantitative real-time polymerase chain reaction method. [Result] 1) Salt and alkali stresses significantly inhibited cotton growth. The growth inhibition rate of cotton under mixed salt-alkali stress treatments (48.7%–57.9%) was significantly higher than that under salt stress (27.6%–49.9%) and alkali stress (21.2%–35.5%) treatments. Under salt stress and mixed salt-alkali stress treatments, both shoot and root growth of cotton were significantly inhibited, dry matter weight, root length, root surface area and root volume were significantly reduced, while root growth was less inhibited under alkali stress treatments. 2) Under three types of saline-alkali stresses, Na content and Mo content in different organs of cotton plant increased significantly, but N content in leaves and roots decreased. 3) Under salt stress treatments, the uptake of Ca, Mg, Fe, Mn and Zn in cotton was inhibited, and the ion balance was maintained by promoting the transport of these ions and P, K. 4) In addition to Ca, Mg, Fe, Mn and Zn, P uptake was also inhibited under alkali stress treatments, but K uptake and P, K, Ca, Mg, Fe, Mn and Zn transport were promoted. 5) Under mixed salt-alkali stress treatments, especially under high salinity and pH conditions, most of nutrients uptake was inhibited, and the transport capacity of Ca, Mg, Zn, Mn and Fe was reduced. 6) The relative expression of GhSOS1 and GhAKT1 genes increased significantly under salt stress treatments, but increased first and then decreased under alkali stress and mixed salt-alkali stress treatments. The relative expression levels of GhSOS1 and GhAKT1 genes under three types of saline-alkali stresses were alkali＞salt＞mixed saline-alkali stress. With the increase of soil salinity and pH value, the relative expression of GhNHX1 gene increased first and then decreased. The expression levels of GhNHX1 gene were salt＞alkali＞mixed salt-alkali stress. [Conclusion] Due to high salinity and pH value, mixed salt-alkali stress significantly inhibits cotton growth and ions uptake, which restricts the transport of P, K, Ca, Mg, Zn, Mn and Fe. The decrease of K and Na regulation ability leads to ions imbalance.     

不同浓度NaCl对两个玉米品种Na+、K+、Ca2+含量的影响

比较不同耐盐性品种在NaCl胁迫下的离子含量的差异,为耐盐玉米的筛选提供理论依据。玉米耐盐品种‘郑单958’和盐敏感品种‘齐单1号’在含0%、0.2%、0.4%、0.6%、0.8%、1.0% NaCl的砂子中生长,分别测定根、茎和叶片中Na+、K+、Ca2+含量。NaCl胁迫下,Na+、K+、Ca2+含量在两个玉米品种间、NaCl浓度间差异均达到极显著水平。NaCl胁迫下,两个玉米品种根茎叶中Na+含量均增加,根中Na+含量增加的幅度大于茎和叶,‘郑单958’根中的Na+含量高于‘齐单1号’;K+、Ca2+含量随NaCl浓度的升高而降低。高盐胁迫下,‘郑单958’根中K+含量降低的幅度大于‘齐单1号’,而茎中K+含量降低的幅度小于‘齐单1号’;‘郑单958’茎和叶片中Ca2+含量降低的幅度小于‘齐单1号’。两个玉米品种在离子含量间表现出的差异非常明显,Na+、K+、Ca2+含量可以作为玉米耐盐性鉴定和筛选指标。     

盐胁迫下棉花K~+和Na~+离子转运的耐盐性生理机制

为了探究棉花的耐盐机制,以中棉所49、中棉所35和中51504为材料,研究了盐胁迫对棉花幼苗的生长及K+/Na+平衡生理的影响。结果表明,150 mmol·L-1 Na Cl处理对幼苗的生长具有明显抑制作用,降低了叶片的光合速率(Pn)、PSⅡ实际光量子产额(ΦPSII)和电子传递速率(ETR),增加了非光化学荧光猝灭系数(q N)。与中棉所49和中棉所35相比,中51504的干物质累积受盐胁迫影响最小,且保持较高的Pn、ΦPSII、ETR和q N值及较低的ETR/Pn值。盐胁迫提高了棉花组织中Na+的浓度,降低了K+的浓度;但中51504组织中保持了相对较低的Na+浓度和较高的K+浓度,维持了较高的K+/Na+比;通过非损伤微测技术(NMT)测定的离子流结果也表明,中51504的根系对Na+有较强的外排能力,而对K+有较强的保留和向地上部转运能力。能够有效地调节Na+和K+的跨膜转运进而维持K+/Na+平衡是棉花耐盐的重要生理机制之一。     

山菠菜胆碱单加氧酶基因对棉花的遗传转化和耐盐性表达

胆碱单加氧酶（CMO）是渗透保护剂甜菜碱生物合成的关键酶之一。以棉花（Gossypium hirsutium L.）泗棉3号的下胚轴切段为外植体，利用农杆菌介导法将克隆自山菠菜（Atriplex hortensis）的AhCMO基因导入其中，通过组织培养胚状体发生途径获得转基因再生植株。以0.5%卡那霉素对再生苗筛选后，PCR检测抗卡那霉素棉苗确认阳性转化株，Southern和Northern杂交结果进一步证实外源基因已导入棉花并得到表达。在温室盆栽条件下，于2片真叶期对转AhCMO基因棉花及其转化受体泗棉3号施加0.5%的NaCl胁迫，15 d后发现其光合作用和植株生长被显著抑制，非转基因棉花泗棉3号的株高、鲜重和光合速率分别降低了57.6%、65.6%和69.9%，而转AhCMO基因的棉株分别降低了37.3%、54.6% 和47.9%。转AhCMO棉花所受盐害程度显著小于非转基因的棉株，说明AhCMO基因的导入和表达提高了转基因棉花的耐盐性。     

Genetic variation in salt tolerance at the seedling stage in an interspecific backcross inbred line population of cultivated tetraploid cotton

Soil salinity reduces cotton growth, yield, and fiber quality and has become a serious problem in the arid southwestern region of the Unites States. Development and planting of salt-tolerant cultivars could ameliorate the deleterious effects. The objective of this study was to assess the genetic variation of salt tolerance and identify salt tolerant genotypes in a backcross inbred line (BIL) population of 142 lines from a cross of Upland (Gossypium hirsutum) × Pima cotton (G. barbadense) at the seedling growth stage. As compared with the non-saline (control) conditions, seedlings under the salinity stress (200 mM NaCl) showed a significant reduction in all the plant growth characteristics measured, as expected. Even though the two parents did not differ in salt response as measured by percent reduction, significant genotype variations in the BIL population were detected for all traits except for leaf number. Based on percent reduction of the traits measured, several BILs were more salt tolerant than both parents. The results indicate that transgressive segregation occurred during the process of backcrossing and selfing even though both parents were not salt tolerant during seedling growth. Coefficients of correlation between all the traits were significantly positive, indicating an association between the traits measured. The estimates of broad-sense heritability were 0.69, 0.46, 0.47, 0.43, and 0.49 for plant height, fresh weight of shoot and root, and dry weight of shoot and root, respectively, indicating that salt tolerance during cotton seedling growth is moderately heritable and environmental variation plays an equally important role. The overall results demonstrate that backcrossing followed by repeated self-pollination is a successful strategy to enhance salt tolerance at the seedling stage by transferring genetic factors from Pima to Upland cotton.     

冠菌素对棉花幼苗盐害的缓解效应

 以转基因抗虫棉(Gossypium hirsutum L.)中棉所45为材料,通过水培试验研究了冠菌素对盐胁迫下棉花萌发出苗和幼苗生长的影响。结果表明,盐胁迫严重抑制棉花种子萌发和幼苗生长,且对地上部的抑制程度大于对根系的抑制。盐胁迫对棉花萌发出苗和幼苗生长的抑制程度能被0.01 μmol·L^-1 的冠菌素缓解。苗期盐胁迫21 d内,冠菌素处理的棉花根、茎和叶的生物积累量较未施加冠菌素的盐处理增加1倍;活体组织化学原位检测结果显示,低浓度冠菌素处理降低盐胁迫诱导的主根H₂O₂含量。上述研究结果说明低浓度的冠菌素能提高棉花萌发出苗和苗期的耐盐性。     

棉属野生种旱地棉苏氨酸醛缩酶基因GarTHA的克隆及功能验证

盐胁迫是影响作物生长和发育的重要因素之一。一些棉属野生种具有较好的耐盐性, 是开展棉花耐盐性机制研究以及改良陆地棉耐盐性的重要资源。本研究基于cDNA-AFLP技术分离获得的旱地棉(Gossypium aridum)盐胁迫下差异表达片段序列信息, 经电子克隆技术和RT-PCR方法克隆了旱地棉苏氨酸醛缩酶基因cDNA全长, 命名为GarTHA (GenBank登录号为KC167360)。该cDNA全长为1 018 bp, 包含一个822 bp的完整ORF, 编码273个氨基酸残基, 蛋白质分子量为82.57 kD, 等电点为4.89。GarTHA基因与杨树PtTHA基因同源性最高, 为84.6%。为进一步验证其功能, 利用拟南芥逆境胁迫启动子rd29A构建植物表达载体, 将GarTHA基因的完整ORF转入拟南芥中, 获得转基因植株并进行了耐盐性鉴定。结果表明, 在盐胁迫下转基因拟南芥种子的发芽率明显高于野生型, 且转基因植株的根长显著高于野生型。说明GarTHA基因可能参与植物的盐胁迫反应, 从而提高植物抗逆性。     

Improved salt tolerance and seed cotton yield in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) by transformation with <Emphasis Type="Italic">betA</Emphasis> gene for glycinebetaine synthesis

Homozygous transgenic cotton (Gossypium hirsutum L.) plants that accumulated glycinebetaine (GB) in larger quantities were more tolerant to salt than wild-type (WT) plants. Four transgenic lines, namely 1, 3, 4, and 5, accumulated significantly higher levels of GB than WT plants did both before and after salt stress. At 175 and 275 mM NaCl, seeds of all the transgenic lines germinated earlier and recorded a higher final germination percentage, and the seedlings grew better, than those of the WT. Under salt stress, all the lines showed some characteristic features of salt tolerance, such as higher leaf relative water content (RWC), higher photosynthesis, better osmotic adjustment (OA), lower percentage of ion leakage, and lower peroxidation of the lipid membrane. Levels of endogenous GB in the transgenic plants were positively correlated with RWC and OA. The results indicate that GB in transgenic cotton plants not only maintains the integrity of cell membranes but also alleviates osmotic stress caused by high salinity. Lastly, the seed cotton yield of transgenic lines 4 and 5 was significantly higher than that of WT plants in saline soil. This research indicates that betA gene has the potential to improve crop’s salt tolerance in areas where salinity is limiting factors for agricultural productivity.