Genotypic Variation in Nutrient Selectivity in Populus under NaCl Stress

We used a salt-resistant poplar genotype Populus euphratica and two salt-sensitive genotypes, Populus 'popularis 35-44' (P. popularis) and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) to examine genotypic differences in nutrient selectivity under NaCl stress. One-year-old seedlings of P. euphratica and one-year-old hardwood cuttings of P. popularis were used in a short-term study (24 hours), while in a long-term study, up to 4 weeks, two-year-old seedlings of P. euphratica and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) were compared. In the short-term study, K+ concentration in the xylem sap ([K+]xylem) of P. euphratica significantly increased after salt stress was initiated, and maintained 1-2 fold higher than control levels during the period of salt stress (24 hours). Xylem Ca2+ and Mg2+ concentrations ([Ca2+]xylem, [Mg2+]xylem) in P. euphratica resembled the pattern of K+ despite a lesser magnitude in elevation. However, [K+]xylem, [Ca2+]xylem and [Mg2+]xylem in P.     

Overexpression of the ThTPS gene enhanced salt and osmotic stress tolerance in Tamarix hispida

Trehalose is a non-reducing disaccharide with high stability and strong water absorption properties that can improve the resistance of organisms to various abi-otic stresses.Trehalose-6-phosphate synthase (TPS) plays important roles in trehalose metabolism and signaling.In this study,the full-length cDNA of ThTPS was cloned from Tamarix hispida Willd.A phylogenetic tree includ-ing ThTPS and 11 AtTPS genes from Arabidopsis indicated that the ThTPS protein had a close evolutionary relationship with AtTPS7.However,the function of AtTPS7 has not been determined.To analyze the abiotic stress tolerance function of ThTPS,the expression of ThTPS in T.hispida under salt and drought stress and JA,ABA and GA3 hormone stimu-lation was monitored by qRT-PCR.The results show that ThTPS expression was clearly induced by all five of these treatments at one or more times,and salt stress caused par-ticularly strong induction of ThTPS in the roots of T.hispida.The ThTPS gene was transiently overexpressed in T.his-pida.Both physiological indexes and staining results showed that ThTPS gene overexpression increased salt and osmotic stress tolerance in T.hispida.Overall,the ThTPS gene can respond to abiotic stresses such as salt and drought,and its overexpression can significantly improve salt and osmotic tolerance.These findings establish a foundation to better understand the responses of TPS genes to abiotic stress in plants.     

荒漠河岸林2种典型植物的耐盐性比较

在新疆尉犁县的天然荒漠河岸林里,选择了3个土壤盐度不同的样地,测定了胡杨和柽柳叶片的脯氨酸含量、K+/Na+、氯离子(Cl-)含量、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量等5个生理指标,并利用模糊数学隶属函数法对二者的耐盐性进行了综合评价.结果表明:随着土壤盐胁迫的增强,胡杨叶片的脯氨酸含量总体上呈增加趋势...     

7种园林地被植物耐盐性研究

应用不同NaCI水溶液处理法,比较研究了华南地区栽培的7种常见地被植物幼苗在盐胁迫条件下的存活率、盐害指数、叶绿素荧光参数、根和叶的K＋浓度、Na＋浓度、K＋／Na＋值、叶片相对电导率和相对含水量等指标,并运用隶属函数值对其植物耐盐性进行综合评定。结果表明：在7种参试植物中,小蚌兰Rhoeospathacea和鸢尾Ir...     

半红树植物杨叶肖槿幼苗耐盐性研究

温室内对半红树植物杨叶肖槿幼苗进行7个盐度(5、8、11、14、17、20、23 g·kg-1)的胁迫处理,并对各处理下杨叶肖槿的生长量、生物量、生理指标和光合速率进行测定,结合生理指标进行适应度分析.结果表明:杨叶肖槿的苗高、地径、叶片数、根、茎、叶干质量及总生物量随着盐度的上升均呈下降趋势,在盐度为5、8 g·kg...     

植物耐盐机理与耐盐植物选育研究进展*

文中结合对植物耐盐生理基础的讨论，综述了耐盐植物，尤其是耐盐树木的选育研究进展。植物对盐分胁迫的反应和适应是一个复杂的生理过程，既有蛋白质、核酸、碳水化合物等结构和能量物质的代谢，还有酶、激素等生长调节物质的合成与激话。在这一系列的反应过程中包含着离子交换与逆向运输，信号刺激与传递．基因活化与合成，其中渗透调节起着关键作用；在渗透调节过程中，离子如K^ 、Ca^2 等在浓度和时空上的变化对渗透调节的启动，调节速率和调节能力都有着重要作用。此外，脯氨酸、脯氨酸甜菜碱、甘氨酸甜菜碱等作为可配伍溶质在调节渗透势变化、整合盐分离子方面有着无可代替的作用。Ca^2 |作为第二信使的一个重要组成部分．在胁迫信号传递方面的功能正受到日益重视。激素如ABA在渗透调节和胁迫基因的诱导方面发挥了重要作用。胁迫基因目前主要是指渗透调节基因。首先在细菌中被发现，后来在高等植物中也相继分离克隆出来。有许多不同的方法用来选育耐盐植物，包括选、引、育等常规育种方法和基因工程，突变体育种等生物工程方法。它们各有特点．都发挥了各自的作用。对植物耐盐机理有限的认识以及高等植物结构与功能的高度复杂性制约着耐盐植物选育工作的进展。     

Stable carbon isotope discrimination: an indicator of cumulative salinity and boron stress in Eucalyptus camaldulensis

Saplings of Eucalyptus camaldulensis Dehn. Clone 4544, irrigated with water of differing salinities (2 to 28 dS m-1) and boron concentrations (1 to 30 mg l-1), integrated the history of these stresses through the discrimination of stable isotopes of carbon in leaf and woody tissues. Carbon isotope discrimination (delta) was reduced primarily by salinity. Decreases in discrimination in response to boron stress were detected in the absence of salinity stress, but the decreases were significant only in leaf tissues with visible boron injury. Sapwood core samples indicated that salinity- and boron-induced reductions in delta increased with increasing tree age. Absolute values of delta varied with location of leaf or wood tissue, but relative effects of salinity on the relationship between delta and transpiration efficiency (W) were similar. In response to increasing salinity stress, relative decreases in delta paralleled relative decreases in biomass and both indices yielded similar salt tolerance model parameters. The strong correlations between delta, tree fresh weight, leaf area and W suggest that delta is a useful parameter for evaluating salt tolerance of eucalyptus     

Gas exchange, water relations and osmotic adjustment in Phillyrea latifolia grown at various salinity concentrations

Leaf gas exchange, water relations and osmotic adjustment were studied in hydroponically grown Phillyrea latifolia L. plants exposed to 5 weeks of salinity stress (0, 80, 160, 240 and 320 mM NaCl) followed by 5 weeks of treatment with half-strength Hoagland solution. Whole-plant relative growth rate and root/shoot and lateral/structural root ratios were also evaluated. Net CO2 assimilation rate, stomatal conductance and transpiration rate were markedly decreased by all of the salt treatments. Growth was also strongly depressed by all salt treatments, especially lateral root growth. Leaf water potential decreased soon after salinity stress was imposed, whereas there was a lag of several weeks before leaf osmotic potential decreased in response to the salt treatments. After 5 weeks of salinization, leaf turgor of salt-treated plants was similar to that of controls. Although Na+ + Cl- contributed little to the salt-induced changes in osmotic potential at full turgor (Psi(piFT)), the contributions of K+, mannitol (Man) and glucose (Glc) to Psi(piFT) markedly increased as external salinity increased. Salt accumulation was negligible in the youngest leaves, which mostly accumulated soluble carbohydrates and K+; in contrast, old leaves served as storage sinks for Na+ and Cl-. Photosynthetic performance of salt-treated plants fully recovered once salt was leached from the root zone, with the recovery rate depending on the severity of the salt stress previously experienced by the plants. Recovery of gas exchange occurred even though the leaves still had a salt load similar to that detected in leaves at the end of the 5-week salinity period, and had markedly lower concentrations of K+ and soluble carbohydrates than control leaves. We conclude that salt-induced water stress primarily controlled gas exchange of salt-treated P. latifolia leaves, whereas the salt load in the leaves did not cause irreversible damage to the photosynthetic apparatus.     

杉木施肥引发基因表达响应机制的转录组分析

【目的】从基因表达水平上,研究施肥引起杉木基因表达变化规律,为杉木施肥理论与MAS育种实践,提供科学依据。【方法】以开化1年生的杉木无性系开6扦插苗为研究对象,4种施肥处理,每处理三个重复,采用Illumina HiSeq4000高通量测序技术进行测序,对测序结果进行无参转录组分析。【结果】1)转录组测序共产生clean reads5.0E+07 nt到7.1E+07 nt,总拼接长度724341090 nt,通过Trinity组装,获得了74288个unigenes(基因),然后将组装序列在6个数据库(Nr,Swiss-prot,eggNOG,KEGG,Pfam,GO)进行BLASTX分析,获取功能注释信息;2)韦恩图揭示基因对不同施肥处理的响应是:在-P-N1-VS-WT比较组中,未施肥处理,有4650个特异表达基因,其中包含了若干耐性基因,其它比较组也获得了相应的结果。杉木施肥诱导一些基因的开启和上调,同时也导致一些基因表达的关闭或下调;不同处理间的表达差异基因数在不同施肥组间变化很大,显著差异表达基因从施磷与对照比较组的429个到施磷与施氮比较组的4942;3)差异表达极显著基因的热聚类分析结果,揭示同一比较组,不同处理间基因表达是互补的关系:同一基因要么高表达,要么低表达;4)GO富集与分类显示施肥对杉木影响显著的基因主要定位在叶绿体、细胞骨架、细胞膜、细胞核、细胞质上;5)GO富集分析的结果表明施氮(磷)肥,不仅可以促进氮(磷)的吸收与代谢,而且也能促进磷(氮)的吸收与代谢;6)对施磷肥与氨酰基-tRNA大分子化合物合成的生理生化过程进行了分析。基于以上研究结果:今后可对转录组分析获得的重要基因进行研究,其结果可用于指导杉木施肥和杉木营养遗传育种MAS选择。【结论】RNA-seq高通量测序技术,对于研究非模式植物(包括基因组比较大的针叶树)施肥分子机制,是一种快速而简便的方法。研究结果表明,施肥不仅激活了与N、P的吸收、转运和利用有关的基因表达,还下调了与生长发育和光合作用有关的基因表达。施肥促使杉木的生长发育向着适应环境、竞争资源和生长发育的方向发展。     

盐胁迫下11个树种生理特性及其耐盐性研究

以11个树种实生幼苗为材料,用不同浓度(0、3、5、8、10 g·kg-1)NaCl溶液进行浇灌处理,研究了盐胁迫下各树种的生理特性,并运用隶属函数法对其耐盐性进行综合评定,结果表明:(1)随着盐胁迫浓度的增加,各树种的叶绿素含量下降,脯氨酸含量增加,可溶性糖含量和质膜透性在树种间差异较大;(2)盐处理后,不同部位(根、茎和叶)Na 含量明显增加,K 含量随树种不同表现各异,K /Na 比值均呈下降趋势,且根中Na 含量明显比叶中的高;(3)日本丁香、银水牛果、榆桔和三裂叶漆的耐盐碱能力较强,豆梨、欧洲荚蒾、沃氏金链花及鹰爪豆具有中高度耐盐碱能力,而金雀儿、甜桦和光叶漆稍差,具有中度耐盐性.本研究为11个树种耐盐性标准的制订及其推广应用提供了理论依据.     

Responses of Prunus ferganensis,Prunus persica and two interspecific hybrids to moderate drought stress

Prunus ferganensis (Kost. & Riab) Kov. & Kost, a close relative of cultivated peach (Prunus persica (L.) Batsch.), is native to arid regions of central Asia. A distinguishing feature of P. ferganensis is its prominent, elongated, unbranched pattern of leaf venation. To determine whether the long-vein trait could be used as a marker in breeding for drought tolerance, we investigated the association between this trait and the leaf morphological and physiological parameters related to drought response in P. ferganensis, P. persica and two interspecific hybrids, one with the long-vein trait (BY94P7585) and one without (BY94P7589). The four genotypes were grafted onto "Guardian" peach rootstock and half of the plants were assigned to a drought treatment in which irrigation was limited to 25-50% of the evapotranspiration (ET) rate measured in the remaining well-watered plants, which were irrigated to runoff daily. The drought treatment reduced photosynthesis and leaf conductance by 49-83% and reduced total leaf area per plant by 17-24%, but generally did not affect mid-morning leaf water potential. Leaf gas exchange did not differ among genotypes in either treatment. Sorbitol accumulated in mature leaves in response to drought, but neither its amount nor its metabolism varied systematically with climatic adaptation among genotypes. Accumulation of transport sugars was highest in P. ferganensis, indicating that growth reduction may represent an important strategy for coping with drought in this species. Prunus ferganensis and the hybrids had higher ET than P. persica, and seemed to use water opportunistically, maintaining high gas exchange rates and consequently high ET when water was available, and avoiding low water potentials through stomatal closure as soil water declined. Leaf size (cm(2) leaf(-1)) and specific leaf area (cm(2) g(-1) dry mass) were lower in P. ferganensis and the hybrids than in P. persica. We conclude that the long-vein trait is not a reliable marker for drought tolerance, but leaf traits of P. ferganensis such as size and specific leaf area may be useful in P. persica breeding programs targeting drought tolerance.     

盐胁迫下比拉底白刺差异表达基因的转录组分析

[目的]为了挖掘比拉底白刺耐盐相关基因,对其盐胁迫下差异表达基因进行筛选分析。[方法]以比拉底白刺幼苗为材料,用200 mmol·L^-1 NaCl对幼苗处理7 d,并对胁迫处理和对照植株叶片进行转录组测序及生物信息学分析。[结果]有效序列组装共得到应答盐胁迫的168463条unigenes和196个差异表达基因。通过差异基因GO和KEGG功能聚类,分别获得64个GO功能小类和25条KEGG通路。进一步基因相互作用网络分析发现,转录调控、氧化还原以及抗逆相关基因在比拉底白刺应答盐胁迫中发挥重要作用,其中,筛选到3个重要的节点基因,分别是热激同源蛋白基因、L型凝集素类受体激酶基因和Win类蛋白基因。[结论]本研究获得了盐胁迫下比拉底白刺的差异表达基因及功能注释信息,有助于理解其耐盐的分子机制,为后续开发耐盐分子标记及通过基因编辑改良植物耐盐特性提供了科学依据。     

不同栽植密度下欧美杨叶片耐荫性与生物累积量的关系

为阐明不同栽植密度下欧美杨无性系树冠叶片耐荫性与生物累积量的关系,选择高密度(2 m×3 m)和低密度(2 m×5 m)栽植的不同亲本的5个欧美杨无性系为研究对象,测量了生物量、树冠结构、叶面积指数及光合参数。结果表明:(1)不同无性系对栽植密度有不同的反应;(2)具有较高生物量的欧美杨无性系树冠叶片在高、低栽植密度下均表现出较强的耐荫性特征;(3)树冠耐荫性在不同密度中表现出差异性,在低密度栽植中,树冠上层耐荫性与生物量和叶面积指数关系密切;在高密度栽植中,树冠上、下层叶片耐荫性与生物量和叶面积指数关系密切;(4)树冠耐荫性特征受亲本和环境的共同影响,由低密度到高密度,具有较高生物量的03-04-97、03-04-111、03-04-171树冠中下层叶片光补偿点和暗呼吸速率大幅度降低。该研究结果可为选择适合高密度栽植的欧美杨无性系提供数据和理论支持。     

盐分胁迫对公路护坡植物紫穗槐适应性的影响

本实验通过对公路两侧路肩及护坡回填土中的盐分程度和处理组不同浓度盐分的生长环境设定,对3年生紫穗槐的植物生理生化特性的数据分析,研究紫穗槐耐盐碱实际的应用效果。研究结果证实,盐分胁迫浓度的升高,对紫穗槐表现的蒸腾速率(Tr)、净光合速率(Pn)、K+含量等技术指标呈现下降趋势,而过氧化物酶(POD)活性、超氧化物歧化酶(SOD)、游离脯氨酸(Free Pro)、可溶性糖、Na+等多种物质含量呈明显升高。叶绿素总量、叶绿素a和b等含量随种植土中盐分浓度减小而呈对应减少。从分析各项指标数据得出紫穗槐3年生苗木对盐渍环境具有很强的适应性和良好的自我调节功能。     

PHYSIOLOGY OF WOODY PLANT UNDER SALT CONDITION

INTRODUCTIoNBccauscofthetvidespreadofsalinityinthct`or1d-plantsareincreasinglybeingsub-Jcctedtothcadverseconditions.Theimpactofcxccssivcsalinit)'onxvOodyplantSistvide-sprcadandcost-ald1ougl1rePOrtsontheseis-sucsarcnotasnumerousasthoseofagricuI-taralcrops(Alle11ctaI.l994).Sincclbrcstsarcanin1portantcomPoncntofthccontincntalccoIogY.-Fhc}pla}anil11portantrolci11stabi-Il,lllgdcgradatIol1i11so111ct'uInerablearcas.Solncsalttolcra11ttrccscangrot`ttclIinarcasx`llcrcagriculturaicropscalll1ot…     

Cloning of four DREB genes from Tibetan Sophora moorcroftiana and analysis of their expression during abiotic stress

Sophora moorcroftiana is an endemic, droughtresistant shrub that grows in Tibet and has some degree of resistance to salt, cold, heat, and drought. In the present study, four dehydration responsive element-binding(DREB) genes(Sm DREB1, Sm DREB2, Sm DREB and Sm DREB1) were isolated from S. moorcroftiana for the first time and their expression and proline content under abiotic stress were analyzed. Proline accumulated in seedlings under drought, salt, cold, and heat stress treatments. The four genes were variously expressed in response to the four abiotic stresses. Sm DREB1 was induced by drought, cold, and heat stresses; Sm DREB2 and Sm DREB4 were both induced by salt, cold, and heat stresses, whereas Sm DREB3 was induced by drought and heat stresses. Thus, these four genes may participate in conferring tolerance to these four abiotic stresses and are candidate genes for genetic engineering in the future.     

盐胁迫对尖果沙枣离子分布及渗透调节的影响

为了探讨尖果沙枣的耐盐机理,用NaCl处理尖果沙枣1年生幼苗,处理浓度为50、100、200、300和350 mmol/L,30 d后取样,测定其生理指标。结果表明:随NaCl浓度的增加,叶片膜透性呈增加趋势,叶片水势则有所降低,其中在低于300 mmol/L NaCl浓度下,叶片膜透性和水势的变化幅度不大,在300、350 mmol/L NaCl浓度时与对照呈极显著性差异(P<0.01);随NaCl浓度的增加,脯氨酸含量增加幅度较大,可溶性糖和可溶性蛋白含量均呈较缓的增加趋势,且分别在100 mmol/L和300 mmol/L NaCl浓度下达到最大值,与对照相比,各处理中的有机物质含量均有不同程度增加,其中在350 mmol/L NaCl浓度下的增幅最大;随NaCl浓度的增加,各器官中K 、Ca2 、Mg2 含量变化不大,叶片中K 、Mg2 含量大于茎部和根部,根部Ca2 含量最多,说明植物虽受到一定的伤害,但通过调节渗透调节物质的含量,降低水势,维持其生命代谢,因此,尖果沙枣具有较强的耐盐性。