胡杨(Populus euphratica Oliv.)根繁殖特征

以新疆塔里木河中游河岸北部河漫滩的胡杨幼林带为对象,从克隆生态学的角度,采用挖掘法、高压冲洗法及断根胁迫实验,研究了胡杨在资源异质环境中的风险分担、资源觅食与保持功能以及根源性克隆生长形态特征。结果表明:胡杨的地下根分枝类型为单轴型,同一生长方向2水平根的夹角平均约为180°,水平根与垂直根的夹角为90°～100°,水平根和垂直根的空间构型近似T形;基株的胚根周长>分株的次根周长;水平根呈侧圆台形,胡杨的2水平根之间存在着养分的传递。

Cloning of plasma membrane H^+-ATPase gene in Populus euphratica Oliv.

For this paper, the plasma membrane （PM） H^＋-ATPase gene has been cloned from Populus euphratica Oliv. through a ho- mology based strategy. The isolated 3,210 bp cDNA contains a single 2,862 bp open reading frame （ORF） which encodes a putative H^＋-ATPase protein of 953 amino acid residues, with a significant homology to plasma membrane H^＋-ATPase of Prunus persica, Phaseolus vulgaris, Sesbania rostrata and Daucus carota. The predicted protein has a molecular weight of 104,553 Da. The copy number analysis revealed multiple copies of the PM H^＋-ATPase in the P. euphratica genome after digestion of their genomic DNA by the restriction enzymes EcoRI, NdeI, FbaI and Bg/Ⅱ, and Southern blot.

Evapotranspiration of a Populus euphratica Oliv. forest and its controlling factors in the lower Heihe River Basin,Northwest China

Evapotranspiration(ET) within an ecosystem is crucial for the water-limited environment that currently lacks adequate quantification in the arid region of Northwest China, mainly covered by phreatophytes, such as the Populus euphratica Oliv. tree and the Tamarix ramosissima Ledeb. shrub species. Accordingly, ET was measured for an entire year using eddy covariance(EC) in P. euphratica stands in the lower Heihe River Basin, Northwest China. During the growing season,the total ET was 850 mm, with a mean of 4.0 mm/d, which is obviously more than that observed at tree-level and standlevel scales, which was likely due to the different level of soil evaporation induced by irrigation via water conveyance.Factors associated with ET fall into either environmental or plant eco-physiological categories. Environmental factors account for at least 79% variation of ET, and the linear relationship between ET and the groundwater table(GWT) revealed the potential water use of P. euphratica forests under the non-water stress condition with the GWT less than 3 m deep.Plant eco-physiological parameters, specifically the leaf area index(LAI), have direct impact on the seasonal pattern of ET, which provides a valuable reference to the wide-area estimates of ET for riparian forests by using LAI. In conclusion,P. euphratica forests have high water use after water conveyance, which may be the result of long-term adapting to local climates and limited water availability.

Effects of temperature on flowering phenological traits of Populus euphratica Oliv. and Populus pruinosa Schrenk populations, Xinjiang, China

The aims of this study were to explore the interspecific differences of Populus euphratica Oliv.and Populus pruinosa Schrenk populations and the intraspecific differences of males and females within the same species in flowering phenological traits,and the effects of temperatures on flowering phenological traits in different growth years(2001–2003 and 2013–2015).The results showed that P.euphratica population flowered earlier than P.pruinosa population.Moreover,flowering phenological period of population,number of days of flowering phenological period per population,number of days of flowering phenological period per plant and average number of days of flowering period per plant of P.euphratica population were less than those of P.pruinosa population.The differences between male and female within the same species indicated that the flowering periods of males P.euphratica and P.pruinosa populations were earlier than those of female plants.For both species,flowering phenological traits were significantly and negatively correlated with the average temperatures in previous ten days,previous one month and previous three months of flowering.Both species are sensitive to temperature changes and adjust to the changes by advancing the start of flowering and prolonging the duration of flowering.

Trunk volume estimation of irregular shaped Populus euphratica riparian forest using TLS point cloud data and multivariate prediction models

Background: Trunk volume(Vt) is an essential parameter for estimating forest stand volume, biomass, and carbon sequestration potential. As the dominant tree species in desert riparian forests, Euphrates poplar(Populus euphratica) has a high proportion of irregularly shaped tree trunks along the Tarim River, NW China, where the habitat is very fragile owing to long-term water stress. This causes uncertainty in estimation accuracy as well as technical challenges for forest surveys. Our study aimed to acquire P. euphratica Vtusing terrestrial laser scanning(TLS) and to establish a species-specific Vtprediction model.Methods: A total of 240 individual trees were measured by TLS multiple-station in 12 sampling plots in three sections along the lower reaches of the Tarim River. Vtwas calculated by a definite integration method using trunk diameters(Di) at every 0.1-m tree height obtained from TLS, and all data were split randomly into two sets:70% of data were used to estimate the model parameter calibration, and the remaining 30% were used for model validation. Sixteen widely used candidate tree Vtestimation models were fitted to the TLS-measured Vtand tree structural parameter data, including tree height(H), diameter at breast height(DBH), and basal diameter(BD). All model performances were evaluated and compared by the statistical parameters of determination coefficient(R^(2)),root mean square error(RMSE), Bayesian information criterion(BIC), mean prediction error(ME), mean absolute error(MAE), and modeling efficiency(EF), and accordingly the best model was selected.Results: TLS point cloud reflection intensity(RI) has advantageous in the extraction of data from irregular tree trunk structures. The P. euphratica tree Vtvalues showed obvious differences at the same tree height(H). There was no significant correlation between Vtand H(R^(2)=0.11, P < 0.01), which reflected the irregularity of P. euphratica trunk shape in the study area. Among all the models, model(14): Vt=0.909DBH1.184H0.487BD0.836(R^(2)=0.97, RMSE=0.14) had the best prediction capability for irregularly shaped Vtwith the highest R^(2), BIC(-37.96), and EF(0.96), and produced a smaller ME(0.006) and MAE(1.177) compared to other models. The prediction accuracy was 93.18%.Conclusions: TLS point cloud RI has a potential for nondestructively measuring irregularly shaped trunk structures of P. euphratica and developed Vtprediction models. The multivariate models more effectively predicted Vtfor irregularly shaped trees compared to one-way and general volume models.

Analysis on the change of water potential of Populus euphratica Oliv.and P.Russkii Jabl under different irrigation volumes in temperate desert zone

The measurement of plant water potential is considered to be a direct approach to confirming the irrigation time in present irrigation systems.In this current study,two shelter forests species in the Junggar Basin (Central Asia),Populus euphratica and P.Russkii Jabl,were studied.We monitored leaf water potential (ψl),stem water potential (ψs) and soil water potential (ψsoil) under different irrigation conditions.The characteristics of the variation in leaf and stem water potential (ψl and ψs) of P.euphratica and P.Russkii Jabl,as well as the impact of soil water potential (ψsoil) on the leaf and stem water potential (ψl and ψs) under different irrigation conditions were discussed.Our results showed the following.(1) With increased irrigation,the intensity of drought stress on P.euphratica and P.Russkii Jabl decreased.(2) The intensity of drought stress experienced was less for P.Russkii Jabl than for P.euphratica under the same irrigation conditions.(3) The more intense the drought,the less sensitive was P.Russkii Jabl,but the more sensitive was P.euphratica,and vice versa.(4) For the P.euphratica community the soil water potential (Ψsoil) at 60 cm depth responded to variation in irrigation more strongly than at 30 and 90 cm depths.For the P.Russkii Jabl community the soil water potential (ψsoil) in the shallow surface layer responded to irrigation variation more strongly than that in deep layers.(5) In the event of relatively sufficient soil water,predawn stem water potential (ψpds) of plant was a reasonable indicator reflecting soil water potential (ψsoil).(6) The water demand of P.euphratica and P.Russkii Jabl shelter forests can be met with different irrigation policies:large volume and less frequency for P.euphratica but small volume and more frequency for P.Russkii Jabl.

Establishment of in vitro culture of Populus euphratica Olivier

The purpose of our study was to establish a regeneration system for micropropagation of Populus euphratica Olivier. On the basis of an analysis of plant leaf mineral nutrients, a special medium was proposed, called MP2. In optimizing media for in vitro plant cultures including MS, B5 and MP2 media we employed hormones, auxin IAA, cytokine benzyladenine （BAP） and gibberellic acid （GA） in our factorial experiments on media. Adventitious shoots were derived from cuttings of adult plants taken from Xingii- ang, west China, on selected media with MP2^＋ 0.5 mg·L^-1BA＋0.1 mg·L^-1 NAA. The shoots were elongated on a medium with 0.25 mg·L^-1 BAP, 0.1 mg·L^-1NAA and 2 mg·L^-1 GA and were then rooted on a medium with 0.2-0.5 mg·L^-1 IBA. All the media were incorporated with 30 g·L^-1 sucrose and an adjusted pH at 6.3.

胡杨(Populus euphratica)在额济纳绿洲三种生境内的根蘖繁殖特性

以额济纳荒漠绿洲胡杨根蘖幼苗为研究对象,通过对绿洲内胡杨分布的3种主要生境内根蘖幼苗的调查,得出如下结论。近年来绿洲内胡杨种群的更新几乎完全依赖于无性繁殖更新,种子萌发产生的幼苗在调查地内没有发现。河岸沙丘地及胡杨林下地的根蘖幼苗中,3龄幼苗所占比重最大,龄级越小的根蘖苗在群落中的数量越少;在河水漫灌后的林间空地,2龄幼苗的数量最多。水漫灌后的林间空地中根蘖幼苗密度显著大于其余两生境内根蘖幼苗密度,同时该生境内每段胡杨根系萌生出的不定芽也大于另两生境。随着龄级增加,未枯枝根蘖幼苗的比率逐渐减小。根蘖幼苗的萌发点分布于土层30cm以内的根系上,分布深度大于30cm的根系不能萌发出根蘖幼苗。

NaCl胁迫下胡杨(Populus euphratica)和群众杨(P.popularis)抗氧化能力及耐盐性

在盐浓度逐渐提高的胁迫条件下，对抗盐的胡杨（Populuseuphratica）和盐敏感的群众杨（Ppopularis35-44）1年实生苗木叶片中Na^＋、Cl^-水平、O2^-产生速率以及抗氧化酶：超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）的动态变化以及抗盐性进行了研究。结果表明，在盐浓度不断提高的胁迫条件下，群众杨叶片中Na^＋、Cl^-浓度持续增加，盐胁迫18d时，群众杨叶中Na^＋、Cl^-含量分别达到对照的17．8和14．6倍，此时O2^-产生速率也达到最高水平。而在盐胁迫期间，群众杨叶片SOD活性没有明显提高，CAT活性维持在对照水平以下，只有APX和GR活性在盐胁迫13—18d，即盐害症状出现前才有所上升，属于典型的盐害反应。胡杨与群众杨明显不同：在盐胁迫初期，胡杨叶片Na^＋、Cl^-含量虽然没有明显的变化，但胡杨叶片中O2^-产生速率在盐胁7d时明显提高，SOD、APX、CAT活性也都先后相应上升，表明胡杨能响应盐胁迫并上调SOD、APX和CAT等保护酶类，降低盐诱导的膜脂过氧化，从而减少了电解质外渗，最终提高了树木的抗盐性。

额济纳绿洲胡杨(Populus euphratica)酚类物质含量和分布及其与土壤水分的关系

采用分光光度法测定了额济纳绿洲胡杨（Populus euphratica）的披针形叶、卵圆形叶、嫩枝、枝（D〈5mm）、枝（5～10mm）、主干树皮、根（D〈2mm）、根（2～5mm）和根（5～10mm）9类器官中的总酚、黄酮和缩合单宁含量。结果表明，总酚含量较高的器官为皮（27．93mg／g），叶、根、枝中总酚含量分别为17．64mg／g（两类叶均值）、16．72mg／g（三类根均值）、12．19mg／g（三类枝均值）；黄酮含量较高的器官为皮（51．30mg／g），叶、根、枝中黄酮含量分别为28．45mg／g（两类叶均值）、39．99mg／g（三类根均值）、23．67mg／g（三类枝均值）；根中缩合单宁含量较高，三类根均值为22．10mg／g，皮、叶、枝中缩合单宁含量分别为8．41mg／g、4．03mg／g（两类叶均值）、4．47mg／g（三类枝均值）。披针形叶和卵圆形叶中酚类物质含量没有显著性差异（P〉0．05）；随着枝不断成熟，嫩枝、枝（D〈5mm）、枝（5～10mm）中酚类物质逐渐减少；随着根直径减少，根中缩合单宁逐渐增加，细根（D〈2mm）中的缩合单宁含量最高（25．95mg／g）。分析胡杨各器官中酚类物质含量与土壤水分的关系，结果表明卵圆形叶中酚类物质含量与土壤水分含量成显著负相关关系（P〈0．05，总酚：r=-0．949；黄酮：r=-0．923；缩合单宁：r=-0．944）。研究揭示了极端干旱地区胡杨各器官中酚类物质的变化规律，及其与环境因子的相互作用关系。

胡杨(Populus euphratica)径向生长日变化特征分析

利用树木径向生长测定仪、自动气象站和土壤水分自动监测仪,在黑河下游胡杨河岸林内,同步监测了胡杨径向生长日变化和太阳辐射、气温、空气相对湿度及主要根系层土壤水分动态等环境因子.结果表明:胡杨径向生长日变化呈抛物线形,每日16:00～20:00时达到最低值点,随后逐步上升至翌日06:00～09:00时达到最高值点,完成一个由收缩期、膨胀恢复期和生长期3阶段构成的日变化周期;不同季节,胡杨径向生长变动幅度存在较大差异.就监测样树而言,不同胡杨个体,胸径越大,日净生长量越大.对各环境因子统计表明,胡杨径向生长日变化与总辐射、气温和土壤体积含水率呈负相关关系,与空气相对湿度呈正相关关系.各环境因子对胡杨径向生长影响存在延时滞后作用,特别是土壤水分条件.

胡杨(Populus euphratica)叶片呼吸作用对地下水埋深的响应

土壤水分条件能够改变叶片呼吸作用,进而影响叶片、个体及生态系统的碳平衡。在内蒙古自治区额济纳旗境内,根据地下水埋深度的差异建立了干旱和湿润2块样地,并对其中生长的胡杨(Populus euphratica)叶片的呼吸作用特性进行了观测。结果表明,干旱样地胡杨叶片的相对含水量(RWC)和单位质量氮含量(Nmass)显著低于湿润样地,但叶片单位面积氮含量(Narea)和比叶面积(SLA)差异不显著。叶片暗呼吸速率(Rn)和光下线粒体呼吸速率(RL)均随地下水埋深的降低而升高,其中地下水埋深度的变化对RL影响更加明显。光对叶片暗呼吸速率具有抑制作用,其抑制程度在11%—57%变化。光对暗呼吸的抑制程度同Rubisco酶的最大氧化速率(vo)呈负相关。湿润样地胡杨叶片光合速率(A)同光下线粒体呼吸速率的比值(A/RL)显著高于A同Rn的比值(A/Rn),而在干旱样地2者间差异不显著。胡杨叶片呼吸速率和光对暗呼吸抑制作用对地下水埋深的响应可能同细胞抗旱对能量和物质需求的增加有关。此外,叶片A/R比值不仅受到光照条件的影响,同时受到水分条件的调控。

胡杨(Populus euphratica)盐相关基因的克隆

以 2年生胡杨实生苗为研究材料 ,通过用 119mmol L的NaCl溶液浇灌处理 1h ,分别收集NaCl处理前后的细嫩白根设立对照样品与处理样品 ,分离mRNA。用抑制性扣除杂交技术建立胡杨盐处理的cDNA扣除文库 ,并以cDNA阵列杂交技术用32 P标记探针进行杂交 ,共筛选 6 72个有效克隆 ,从中确认 3个探针进行了序列分析 ,其中 1个为盐抑制表达基因片段 ,2个为盐诱导表达基因片段。分析表明 ,1个盐诱导表达基因片段为 1含 188氨基酸开放阅读框的EST ,该EST具有 10 79个核苷酸。该结果与我们早先检测到的

改进的CTAB法提取胡杨(Populus euphratica)总DNA

以胡杨幼叶为材料,对影响胡杨DNA提取质量的主要因子进行研究,以期建立适宜胡杨DNA提取的优化反应体系,结果表明,在胡杨基因组DNA提取过程中,CTAB缓冲液中增加EDTA的用量及添加完异丙醇沉淀时间是影响胡杨基因组DNA提取的最主要因子。

盐分对胡杨(Populus euphratica)幼苗生长和离子平衡的影响

基于控制试验研究了盐分(Na Cl)处理60 d对胡杨(Populus euphratica)幼苗生长和各器官矿质离子吸收、分布和运输的影响。结果表明:(1)盐分对幼苗生长有显著的抑制作用。与对照相比,轻度(50 mol·L^(-1))、中度(100 mol·L^(-1))和重度(200 mol·L^(-1))盐分处理的幼苗株高生长速率、叶面积及各器官生物量分别减小了约30%、50%和80%。幼苗通过改变生物量分配策略,提高根冠比增加对资源的获取和减少体内水分散失,以增强其耐盐性。(2)盐分改变了幼苗对离子的选择性吸收和运输。与对照相比,各盐分处理显著提高了幼苗器官对Na^+和Cl-的吸收,抑制了Ca^(2+)、Mg^(2+)和K^+由根向茎、茎向叶选择性运输、降低了幼苗器官对Ca^(2+),K^+,Mg^(2+)的吸收,导致器官离子平衡遭到破坏。幼苗将较多的Na^+积累在叶片,增大了地上和地下的渗透势差,这是胡杨幼苗抵御盐分胁迫的一个有效方式。(3)重度盐胁迫下幼苗增强对Ca^(2+)、Mg^(2+)和K^+的选择性运输,避免高盐胁迫对幼苗更大的伤害。

基于无人机的胡杨(Populus euphratica)结构参数获取技术研究

快速准确获取森林结构参数具有重要的科学意义。通过使用大疆精灵4 Pro无人机通过倾斜摄影测量和正射摄影测量方式获取塔里木河下游胡杨林样地的冠层高度模型,提出一种自适应窗口最大值算法来分析处理,获取了研究区胡杨(Populus euphratica)的树高、冠幅和株数等结构参数。最后,使用地面实测数据对以上结构数据进行精度评价。结果表明:(1)自适应窗口最大值算法计算效果优于传统的固定窗口最大值算法。(2)倾斜摄影测量方式获取的树高、冠幅和株数精度均优于正射摄影测量方式。(3)倾斜摄影测量获取的结构数据与实测值比较,树高、冠幅和株数R2分别为0.9002,0.8403和0.9405,均方根误差分别是0.4457、0.6815和4.2500,证明使用消费级无人机可以有效获取单木尺度森林结构参数。

基于生物量的塔里木河下游胡杨(Populus euphratica)生态服务价值评估

胡杨是塔里木河下游荒漠河岸林的重要组成部分,研究塔里木河下游胡杨生物量及生态服务价值变化特征,可以为塔里木河下游生态输水的效益评估提供科学依据。以塔里木河下游胡杨为研究对象,采用实地调查采样与遥感解译分析相结合的方法,评估了不同年份胡杨地上生物量特征,并结合遥感方法提取不同年份胡杨面积,估算了不同年份胡杨的生态服务价值。结果表明:(1)胡杨主要分布在离河道0—700 m的范围内,此范围内的生物量占总生物量的90%以上;在离河道700 m以外,胡杨的生物量不足10%。英苏断面胡杨平均生物量最高,阿拉干断面次之,依干不及麻与喀尔达依断面胡杨生物量较低。(2)2000年,胡杨单位面积平均生态服务价值为78.96元/hm^2,2010年为177.14元/hm^2,2016年为313.55元/hm^2;胡杨总服务价值在2000年为43.24×10~4元,2010年为93.00×10~4元,2016年为184.27×10~4元。(3)2016年胡杨的有形服务价值为22.74×10~4元,无形服务价值为161.53×10~4元,胡杨的无形生态服务价值为有形生态服务价值的7.1倍。生态输水对胡杨生物量与服务价值具有显著的影响,输水效益十分显著。

胡杨(Populus euphratica)异形叶叶片内源激素特征研究

通过野外调查结合室内分析,对胡杨异形叶叶片4种内源激素含量在胡杨不同个体发育阶段以及在树冠垂直空间的变化进行研究。结果表明:(1)胡杨不同发育阶段个体叶片平均叶形指数随着树龄的增大逐渐减小,且当植株树龄相差大于4年以上即存在显著差异;叶形指数均表现为从树冠底端到顶端逐渐减小,且顶端与底端存在显著差异。(2)胡杨成熟叶片IAA含量和IAA/ABA比值的变化趋势是随树龄的增加和树冠的增高而减小,而ZR、ABA含量和GA3/IAA,ZR/IAA比值的变化趋势则相反。研究认为,叶片内源激素含量随叶形的变化反映了胡杨适应干旱荒漠环境的生理调节。

不同土壤水盐条件下多枝柽柳(Tamarix ramosissima)对胡杨(Populus euphratica)幼苗的影响

目前胡杨更新困难,种群处于退化阶段,而与其生态位高度重叠的多枝柽柳却在扩张。为探讨多枝柽柳对胡杨生长的影响,本研究设置了3个水平的水分、盐分梯度,对胡杨进行了单种和混种的盆栽控制实验,通过测定胡杨幼苗的生长和存活状况,分析不同水、盐梯度下多枝柽柳如何影响胡杨生长。结果表明:(1)多枝柽柳伴生降低当年生胡杨幼苗的存活率,随着水分条件改善,胡杨存活率提高,而盐分对存活率没有显著的影响。(2)水分、盐分和伴生模式几个因子对胡杨的生长特征的影响存在显著的交互作用(P<0.05)。各水盐条件下,多枝柽柳会不同程度降低胡杨幼苗的株高、主根长和地上地下生物量,而根冠比增大。混种条件下,胡杨幼苗对水盐的响应更为敏感。(3)相对竞争强度对水盐环境有明显的响应(P<0.05),随水分条件改善,地上、地下相对竞争强度降低。多枝柽柳对胡杨的生长产生不良影响的机制是通过快速消耗土壤的水分,从而导致胡杨幼苗水分亏缺。土壤水分条件是胡杨和多枝柽柳幼苗共存的关键因素,在水分供给不足的情况下,对水分偏好的差异导致胡杨无法通过实生苗进行有效的更新从而加剧胡杨种群的衰退,而多枝柽柳更为耐旱的特性使其逐步占据河岸的生境。我们的研究结果强调了两个树种对环境因子的适应性差异决定了河岸带植被发育过程中植物-土壤的相互作用导致胡杨在演替过程中表现出的衰退现象。

极端干旱区淹灌对胡杨(Populus Euphratica)长势的影响——以叶尔羌河中、下游为例

【目的】加强塔里木河流域胡杨林的生态保护,维系胡杨林植被系统的多样性、稳定性和完整性。【方法】从样点、样带、整个补水区3个尺度,对胡杨长势、胡杨林密度、冠幅、株高、胸径及生理指标进行了调查和测定;分析了叶尔羌河中、下游荒漠河岸林胡杨的空间分布特征,以及距水源远近对胡杨林群落特征的影响。【结果】1)随着距生态闸距离的增大胡杨长势越差,且单位面积内(植)株(个)数胡杨树数量也呈下降趋势,到距离生态闸600 m处样方内仅有少量胡杨;树高、冠幅呈现出先增大后减少的趋势;叶河中游和下游距离300、450、600 m处胡杨高度分别较距150 m增加了50.1%和59.4%、46.2%和38.7%、47.6%和53.4%;胡杨胸径呈增加的态势;2)淹灌水随着补给量的减少,胡杨林密度减小;叶河中游和下游距离生态闸口150、300、450、600 m处胡杨密度分别是0.1、0.08、0.048、0.032和0.15、0.06、0.03、0.03株/m2;生态补水后,胡杨年轮宽度呈现出不同程度的增加,平均的增幅为46.63%。【结论】生态输水一定程度上缓解了胡杨的水分胁迫,使得胡杨生长环境得以好转。