Spatial distribution characteristics of fine roots of Populus euphratica in a desert riparian forest

The soil-plant system is a very important subsystem of the soil-plant-atmosphere continuum (SPAC). The water uptake by plant roots is an important subject in the research on water transport in this SPAC and is also the most active study direction in the fields of ecology, hydrology and environment. The study of the spatial distribution pattern of fine roots of plants is the basis of constructing a water absorption model of plant roots. Our study on the spatial distribution pattern of fine roots of Populus euphratica in a desert riparian forest shows that the density distribution of its root lengths can be expressed horizontally as a parabola. The fine roots are concentrated within the range of 0–350 cm from the tree trunk and their amount accounts for 91.9% of the total root mass within the space of 0–500 cm. In the vertical direction, the density distribution of the fine root lengths shows a negative exponential relation with soil depth. The fine roots are concentrated in the 0–80 cm soil layer, accounting for 96.8% of the total root mass in the 0–140 cm soil layer. __________ Translated from Chinese Journal of Ecology, 2007, 26(1): 1–4 [译自: 生态学杂志]     

Construction of cDNA Library from Populus euphratica

1 Introduction Populus euphratica is a salt tolerant tree species, which is mainly distributed in the desert regions in northwest China (Wei 1993). Moreover, it is the only large tree species, which can survive and develop into forest in these arid and saline-alkali areas. P. euphratica forest plays a very important role in restraining the expansion of desert, maintaining ecological environment in west China, protecting the biological diversity and raising the local people抯 living standard…     

不同水分条件下胡杨和新疆杨苗期叶绿素变化

在不同水分条件下,应用SPDA-502叶绿素测定仪测定了胡杨和新疆杨苗木旺盛生长期的叶绿素含量.结果表明:(1)在7月和8月,不同水分处理下胡杨和新疆的叶绿素含量变化存在差异,7月胡杨叶绿素含量随着水分降低呈现增长趋势,而新疆杨叶绿素含量表现出先升后降再升高的趋势.8月叶绿素的含量变化是随着水分的减少2个树种都呈现先升...     

胡杨叶片不同叶形的分形特征研究

通过测定阿拉尔地区胡杨相同叶形及不同叶形的叶片叶脉的分形特征,对胡杨叶片的分形特征进行了研究。结果表明:胡杨叶片存在柳形、卵状菱形和鸡爪形等3种叶形;同一株胡杨相同叶形的成熟未老叶片在统计意义上具有相似的分形特征;同一株胡杨不同叶形的成熟未老叶片的分形特征不同。     

Nighttime transpiration of Populus euphratica during different phenophases

Evidence exists of nighttime transpiration and its potential impact on plant/water relations for species in a diversity of ecosystems. However, relevant data related to typical desert riparian forest species remains limited Accordingly, we measured sap flow velocity of Populus euphratica using the heat ratio method between 2012 and2014. Nocturnal stem sap flow was separated into nighttime and stem refilling using the ‘‘forecasted refilling'method. Nighttime transpiration was observed for each phenophase. The highest value was during the full foliation period but lowest during leaf expansion and defoliation periods. The contribution of nighttime transpiration to daytime transpiration was an average of 15% but this was comparatively higher during the defoliation period. Relationships between nighttime transpiration, vapor pressure deficits, and air temperatures were more closely associated than with wind speed in all phenophases. Moreover, we found that nighttime transpiration linearly correlated to vapour pressure deficit during the first and the full foliation periods, but nighttime transpiration showed exponential correlations to air temperatures during the same phenophases. Additionally, environmental drivers of transpiration were significantly different between nighttime and daytime(P \ 0.05). Driving forces behind nighttime transpiration were characterized by many factors, and integrated impacts between these multiple environmental factors were complex. Future studies should focus on these integrated impacts on nighttime transpiration, and the physiological mechanisms of nighttime transpiration should be investigated, given that this could also influence its occurrence and magnitude during different phenophases.     

胡杨根蘖繁殖能力及其规律

文章通过对胡杨林的调查,阐述了胡杨的根蘖繁殖能力及规律。     

胡杨引种与嫁接技术研究

以山西省北部风沙区为胡杨引种试验区,以新疆北部的石河子和南部的库尔勒为种源地,进行引种和种源对比试验,以群众杨和旱柳为砧木进行胡杨炮捻嫁接繁育试验。结果表明：根据栽植成活率和生长量,石河子为适宜种源;群众杨和胡杨的亲和力很高,嫁接成活率最高达81%,平均成活率69.5%,群众杨是胡杨嫁接繁育的适宜砧木;炮捻嫁接扦插成活后,在封垄高度达到25 cm,垄内水分充足,地温和气温很高的第2年7月,形成自生根系。     

胡杨杂交育种研究初报

运用母本花粉提取液处理柱头以克服胡杨为父本的杂交不亲和性,并进行离体子房,胚珠培养,结果表明,母本花粉提取液处理柱头能有效克服杂交障碍,而离体子房朋翻粑培养能解决授粉后种子未成熟蒴果就脱落而得不到杂种植株的问题。此外,文章还对胡杨杂种苗微体繁殖技术进行了研究,并选出适宜的诱导不定芽培养基和生根培养基配方。     

胡杨抗盐机理初探

对两年生胡杨（Ｐ．ｅｕｐｈｒａｔｉｃａＯｌｉｖｅ）和胡杨的杂种（密叶杨（Ｐ．ｔａｌａｓｉｃａＫｏｍ）×（胡杨＋白柳（ＳａｌｉｘａｌｂａＬ））实生苗进行５０ｍＭ和２００ｍＭ氯化钠（ＮａＣｌ）溶液的盐胁迫试验。得出胡杨的四种耐盐机制：（１）减少叶片的数量和面积；（２）叶柄肉质化（叶面积随盐胁迫的增加而减少）；（３）茎和叶片的斥盐性（高盐处理时，胡杨叶片中Ｎａ＋和Ｃｌ＋的含量只有胡杨杂种的三分之一）；（４）选择吸收Ｋ＋和Ｃａ２＋以抵抗盐离子的毒性，并保持膜的完整性（胡杨茎中Ｃａ２＋的含量随着盐处理浓度的增加而增加，叶片中Ｋ＋的含量却保持不变）。     

水培胡杨抗盐特性的研究*

1987和1989年,利用1、2年生胡杨苗,在水培条件下,通过电导率仪控制培养液浓度,对受盐害苗木进行了分析。研究结果表明,几种盐对苗木危害的排序是:Na_2CO_3>NaHCO_3>NaCl>CaSO_4>MgSO_4>以NaCl为主的盐渍皮。CaSO_4对苗木没有毒害作用。1年生苗比2年生苗受盐害后症状明显,但总的趋势是一致的。蒸馏水催根苗木,在蒸馏水中加盐后死亡浓度是:Na_2CO_3 0.05％、NaHCO_3 0.07％、NaCl 0.17％、CaSO_4 0.7％、MgSO_4 1.9％、以NaCl为主的盐渍皮3.5％。0.1％相应盐水催根苗在盐水培养液中加盐后,抗盐极限提高到:NaCl1.1％、MgSO_4 3.5％、NaCl为主的盐渍皮3.7％。说明胡杨幼苗经过抗盐处理后,可以显著地提高抗盐害能力。     

Genetic diversity of Populus euphratica populations in northwestern China determined by RAPD DNA analysis

Five Populus euphratica Oliver populations in northwestern China were analyzed using RAPD DNA markers to determine genetic diversity among and within populations. One hundred-and-five polymorphic bands were observed, ranging in size from 250 bp to 1700 bp, using 10 primers. Only one population on the north side of the Tianshern Range had a unique band common to all individuals that was not found in individuals from populations in the Tarim River valley. Intra-population genetic diversity was high in two populations along the Tarim River and low in the other three populations. There was no significant correlation between genetic distances and geographic distances. The result of correspondence analysis shows that the individuals from the three populations with low genetic diversity are isolated from each other. The result of cluster analysis based on genetic distance shows that the population in the Tianshern Range is genetically distant from the other populations. These results suggest that the Tianshern Range population was genetically isolated from the other populations.     

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 Xingjiang, west China, on selected media with MP2 0.5 mg·L-1 BA 0.1 mg·L-1 NAA. The shoots were elongated on a medium with 0.25 mg·L-1 BAP, 0.1 mg·L-1 NAA 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.     

胡杨幼苗黑星病初步研究

对发生于新疆吉木萨尔是胡杨上的黑星病进行了调查研究，经鉴定该病是由山杨黑星孢菌[(Fusicladium tremulas (Fr.)Aderh]引起。病害的发病程度与品种有关，不同胡杨品种的感病程度依次为：胡杂1号＞胡杂3号＞胡杂4号＞胡杂2号＞胡杂5号；苗高、地径及叶甲数量与感病指数之间无显著相关性。     

塔里木河流域胡杨群落特征分析

为进一步保护塔里木河流域胡杨林,对该流域胡杨群落物种种类及数量组成特征、群落高度级物种组成性状进行研究,结果表明:胡杨群落中具有明显的分层性,其结构较简单,最主要的分层为乔木层、灌木层、草本层。塔里木河上游胡杨群落物种数量特征为灌木层>乔木层>草木层,中游为草本层>灌木层>乔木层,下游为灌木层>乔木层>草本层。中游群落中所含的物种个体最多,密度最大;其次是上游;下游所含物种最少,密度最小。     

应用一元材积表法测定胡杨林分蓄积量

通过标准地每木调查,结合一元材积表测定计算胡杨林的林分蓄积量,结果显示:胡杨的一元材积方程为V=0.000484469d2.011854,将各径阶相应单株平均材积按径阶大小顺序排列成表即为一元材积表;4块样地林分平均直径分别为:15.1、15.0、13.7、15.9cm,在株数累积分布曲线上所对应的株数累积百分数的位置...     

胡杨嫩枝不同嫁接技术效果分析

以胡杨为砧木,采用芽接和枝接方式就嫁接繁殖胡杨技术进行了试验研究,结果表明:选择2年生、地径0.7～1.2cm的胡杨是胡杨嫁接繁殖的优良砧木;而"T"型芽接是最佳的嫁接方式,其平均成活率可达90%以上;5月下旬、6月初为胡杨芽接的适宜时期,适时嫁接成活率高达95%,一般可保证成活率在80%以上。     

塔里木盆地胡杨群落结构特征研究

塔里木盆地胡杨群落植物种类少,植被结构简单,构成了典型的荒漠河岸林景观。群落的生活型以高位芽植物为主,地面芽植物次之,该群落叶的性质以小型叶、单叶、革质、非全缘为主,群落垂直结构单一,地上成层明显,可分为乔木层、灌木层和草本层,乔木层→灌木层→草本层物种多样性依次递增,优势种胡杨种群的年龄结构属稳定型。     

Structural Characteristics and Eco-adaptability of Heteromorphic Leaves of Populus euphratica

The microstructural and ultrastructural traits of three kinds of typical leaves of Populus euphratica Olive, including lanceolate, broad-ovate and dentate broad-ovate leaves, were studied by using electron microscope and optical microscope. The re- sults showed that with the leaves changing from lanceolate shape to dentate broad-ovate shape, their structure obviously tended to be xeromorph: developed palisade tissue, undeveloped spongy tissue, thick cutin layer and sunken stomas. The amount of mitochondria tended to be increased, and the shape of chloroplasts varied from regular spindle to irregular rotundity or oval. The leaves were cov- ered with wax without cilium, and the stomas on the upper and lower epidermis of the leaves opened unevenly. The stomas on the lower epidermis were deeper than those on the upper epidermis under the scanning electron microscope. The results implied that the structural characteristics of the diversiform-leaves of P. euphratica are related to its eco-adaptability.     

胡杨耐盐分子机制研究进展

胡杨耐盐机制的研究涉及植物生理、生化及分子生物学等方面。本文对胡杨耐盐分子机理方面的研究进行了综述,探究了胡杨cDNA基因文库的构建,渗透调节物质,盐离子代谢,以及膜系统稳定性等对耐盐所起的作用。阐述了胡杨耐盐研究的重要性及意义。