Meiotic chromosome preparation techniques of pollen mother cells for laser micro-dissection in Populus spp.

In order to isolate meiotic chromosomes of Populus species meiotic chromosome preparation techniques of pollen mother cells for laser micro-dissection were studied. Pollen mother cells at diakinesis ofPopulus canadensis Moench were used as samples. Two methods were used to prepare meiotic chromosomes： in the first, cell suspensions were dropped on polyethylene-naphthalate or polyester membrane slides which had just been incubated at -20~C; in the second method, cell suspensions were also dropped on polyethylene-naphthalate or polyester membrane slides, but spread with the aid of high temperatures. The cells did not completely spread by the first method and chromosomes at diakinesis could not be individually distinguished. In contrast, well-spread diakinesis chromosomes were obtained by the second method, where chromosomes, connected with their nucleolus, were successfully isolated with the laser micro-dissection system. As well, we discuss the prospect of applications of laser micro-dissection in cytogeneties and molecular genetics in Populus species.

Direct Regeneration of Plants Derived from in vitro Cultured Shoot Tips and Leaves of Poplar （Populus×euramericana ＇Neva＇）

The purpose of the present study was to establish a regeneration procedure for Populus × euramericana ＇Neva＇ by using in vitro shoots tips and leaves. For sterilization, 0.1% （w/v） mercuric chloride （HgCl2） solution for 8 to 10 min was the optimal treatment for this poplar cultivation. The effects of benzyladenine （BA） and α-naphthaleneacetic acid （NAA） added to Murashige and Skoog （MS） medium were tested on organogenesis. The highest regeneration rate and numbers of shoots/explant from shoot tips （96.7%, 9.8） and leaves （90.0%, 8.7） were obtained on the half-strength MS medium supplemented with 0.5 mg/L BA and 0.1 mg/L NAA. The optimal medium for in vitro rooting of shoots was on a half-strength MS medium containing 1 mg/L indolebutyric acid （IBA） with the highest rooting frequency （93.3%） and numbers of roots/explant （8.2）. For acclimatization, in vitro rooted plantlets were transferred to plastic cups containing vermiculite and peat （1： 1）. After acclimatization, transplanted plantlets grew well in a shade house. Therefore, we believe that this efficient plant regeneration protocol especially by leaf explants is very important for in vitro clonal propagation of Populus×euramericana ＇Neva＇.

The effect of number of joints on bending properties of laminated lumber made from poplar (Populus nigra)

Connection plays an important role in structural components and end jointing is one of the most common connections in structural applications. This study was designed to investigate some mechanical properties （MOE and MOR） of solid wood samples manufactured from poplar （Populus nigra）, joined together through end jointing. As well, we studied combinations of lumber manufactured from 10-mm veneer, using a polyvinyl acetate adhesive. The results show that non-jointed lumber （control samples） have better bending properties （MOE and MOR） than jointed specimens and lumber made from laminated layers. On the whole, side-by- side joints have a negative effect on the MOR and MOE of laminated products, which is more pronounced in the MOR. By increasing the number of joints, the properties of combination of three-ply, i.e., bending strength and modulus of elasticity, decreased.

Somaclonal variations as a mean for obtaining regenerants with different growth rates in poplar (<i>Populus ×berolinensis</i>Dipp.)

Adventive regenerants of Populus × berolinensis Dipp. were obtained on 1/2 MS salts with sucrose, vitamins, BA, TDZ and NAA using stem, petiole and leaf explants. They differed from each other in plantlet dimensions. More than 50 clones were produced from initial regenerants by excision and rooting of apexes and lateral shoots. Differences in stem length and thickness were observed between 200 field plants produced from in vitro plantlets. Differences in stem length were conditioned mainly due to different number of internodes and not by internodes’ lengths. Plants grown from cuttings excised from highest and smallest plants retained the abilities of mother plants to grow with different rates. It is concluded that somaclonal variability can be used for selection of fast growing poplar plants which are necessary for industrial plantations. These plants can be used for this purpose without the limitations existing for transgenic plants.

Transformation of Poplar (Populus)with tPA Gene

In this study, tPA gene(human tissuetype plasminogen activator gene) was remolded with the leader sequence removed and an artificially synthesized sequence containing the initiator (ATG) added. Using the binary vector strategy,we first inserted the remolded tPA gene into the Ti-derived plasmid, PGA643 and then transferred,in a triparental mating system,the plasmid into a strain of Agrobacterium tumefaciens,A281, that contained vir-DNA.Finally poplar cells were transformed with A. tumefaciens using leaf discus method. The transformed cells were selected in culture containing kanamycin and in siyu hybridization.Successful generation of transgenic poplar was demonstrated by molecular hybridization in the cultivated plants and detection of tPA gene product.

Segregation of AFLP Markers in A ( Populus tomentosa× P. bolleana) ×P. tomentosa Carr. BC_1 Family

To investigate the levels of polymorphisms and Mendelian segregation ratio in clone “TB01” (P. tomentosa×P. bolleana) ×clone “LM50” (P. tomentosa) BC 1 population at the entire genome level, amplified fragment length polymorphisms (AFLPs) analysis was conducted for both parents and 120 progenies. Forty one pairs of selective primers were used to detect 2?707 bands, of which 712 (26.4%) were polymorphic. Chi\|square tests were performed to examine if the observed genotypic frequencies of AFLP loci deviated from expected 1∶1 Mendelian segregation ratio ( P <0.01) in BC 1 population. Among the 712 loci 571 (80.2%) fit to Mendelian 1∶1 segregation ratio, corresponding to DNA polymorphisms heterozygous in one parent and a null in the other. The result shows that the AFLP markers are very suitable for fingerprinting and genetic mapping in the Chinese white poplar (Populus tomentosa Carr.).

An electron microscopic-cytochemical localization of plasma membrane Ca^(2+)-ATPase activity in poplar apical bud cells during the induction of dormancy by short-day photoperiods

Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face （cytoplasmic side） of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-punlping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy developlnent in poplar.

A Global Analysis of Temperature Effects on Populus Plantation Production Potential

The genus Populus contains some of the most economically important tree species and hybrids in the world. We compared productivity of short and long-rotation poplar plantations using published data from 23 countries to determine if climate, particularly temperature, had any effect on the observed patterns of productivity. We discovered that climate factors (related to temperature) and clone origin (pure species or hybrids) slightly influenced productivity of long rotation forests more than short rotation plantations. While long rotation plantation productivity exhibited positive correlations with increasing temperature during winter and decreasing heat during summer, short rotation plantations showed weak positive relationship among productivity and increasing yearly temperature and the number of hot days. It was apparent that short rotation plantations productivity was less dependent on regional climatic variables or origin of clone. However, it appears that overall, regardless of the system, Populus species are generally adapted to a range of climatic conditions where they are planted.

An improved draft genome sequence of hybrid Populus alba×Populus glandulosa

Populus alba × P.glandulosa clone 84 K,derived from South Korea,is widely cultivated in China and used as a model in the molecular research of woody plants because of hi gh gene transformation efficiency.Here,we combined63-fold coverage Illumina short reads and 126-fold coverage PacBio long reads to assemble the genome.Due to the hi gh heterozygosity level at 2.1% estimated by k-mer analysis,we exploited TrioCanu for genome assembly.The PacBio clean subreads of P.alba × P.glandulosa were separated into two parts according to the similarities,compared with the parental genomes of P.alba and P.glandulosa.The two parts of the subreads were assembled to two sets of subgenomes comprising subgenome A(405.31 Mb,from P.alba)and subgenome G(376.05 Mb,from P.glandulosa) with the contig N50 size of 5.43 Mb and 2.15 Mb,respectively.A high-quality P.alba × P.glandulosa genome assembly was obtained.The genome size was 781.36 Mb with the contig N50 size of 3.66 Mb and the longest contig was 19.47 Mb.In addition,a total of 176.95 Mb(43.7%),152.37 Mb(40.5%)of repetitive elements were identified and a total of 38,701 and 38,449 protein-coding genes were predicted in subgenomes A and G,respectively.For functional annotation,96.98% of subgenome A and 96.96% of subgenome G genes were annotated with public databases.This de novo assembled genome will facilitate systematic and comprehensive study,such as multi-omics analysis,in the model tree P.alba X P.glandulosa.

Transgenic Poplar Plants for the Investigation of ABA-Dependent Salt and Drought Stress Adaptation in Trees

Important functions of the plant hormone abscisic acid (ABA) in stress reactions, growth and photosynthetic processes are extensively studied in the model plant Arabidopsis thaliana. This paper investigates the importance of Moco-sulphurase ABA3 and aldehyde oxidase (AO) on ABA-biosynthesis in Populus × canescens. ABA3 is essential for activation of the molybdenum enzymes AO and xanthine dehydrogenase (XDH). AO itself catalyzes the last step in ABA-biosynthesis. Generation of transgenic poplar plants altered in ABA3 and AO-activity using RNAi knock down and overexpression was performed. Whereas RNAi-AO plants show a specific loss of AO activity, the RNAi-ABA3 plants has a strongly reduced activity of both molybdenum enzymes: AO and XDH. Constructs of AO and ABA3-promoters fused to β-glucuronidase provide the basis to investigate transcriptional regulation of ABA-biosynthetic processes under stress conditions. Application of high salt concentrations and different drought stress intensities does change the endogenous AO or XDH neither on the side of transcription nor on protein activity. On phytohormone level however, water loss leads to increased ABA-amounts regardless of whether transgenic or wildtype plants are studied. Salt application resulted in higher ABA-levels in all analyzed plant lines. The down regulation of AO in the two different RNAi-plant lines strongly prevented a wildtype-like increase of ABA-levels. Whereas the WT plants accumulated up to 6000 ng ABA g-1 FW-1 after 16 h of salt stress exposure, plants of the RNAi lines revealed a markedly lower increase of only up to 2000 ng ABA g-1 FW-1. Opposing to these observations, ABA-levels increased during drought without any influence by the RNAi-effect. These results revealed that although stresses did not result in a visible increased AO-activity, ABA-production was influenced by AO and ABA3 at least under salinity.

Early differentiation in biomass production and carbon sequestration of white poplar and its two hybrids in Central Iran

We assessed the potential of white poplar（Populus alba L.） and its inter-sectional hybridization with euphrates poplar（P. euphratica Oliv.） for carbon storage and sequestration in central Iran. Trials were established at planting density of 2,500 trees per hectare in block randomized design with three replicates. After 6 years, we measured the above-ground biomass of tree components（trunk, branch, bark, twig and leaf）, and assessed soil carbon at three depths. P. alba 9 euphratica plantation stored significantly more carbon（22.3 t ha-1） than P. alba（16.7 t ha-1） and P. euphratica 9 alba（13.1 t ha-1）.Most of the carbon was accumulated in the above-ground biomass（61.1 % in P. alba, 72.4 % in P. alba 9 euphratica and 56.0 % in P. euphratica 9 alba）. There was no significant difference in soil carbon storage. Also, biomass allocation was different between white poplar P. alba and its inter-sectional hybridization. Therefore, there was a yield difference due to genomic imprinting, which increased the possibility that paternally and maternally inherited wood production alleles would be differentially expressed in the new crossing.

糠醇-环氧植物油复合改性毛白杨木材的物理力学性能

【目的】采用糠醇-环氧植物油复合改性方法,改善糠醇改性降低木材韧性的问题,促进其在建筑结构领域的应用。【方法】将环氧大豆油和环氧亚麻油2种环氧植物油以不同添加量与糠醇溶液复配制备浸渍液,采用满细胞法处理毛白杨木材,获得不同环氧植物油添加量的糠醇-环氧植物油复合改性材。利用扫描电镜(SEM)和傅里叶红外光谱(FTIR)探究糠醇、环氧植物油在木材细胞结构中的分布规律,揭示其化学反应关系。分析复合改性材的力学性能变化,优选适宜增韧剂添加量。【结果】复合改性材SEM观察并结合其增重率和密度测试结果(显著增加)证明,糠醇树脂和环氧植物油可浸渍到木材细胞结构中。FTIR分析表明,环氧植物油与糠醇发生开环反应。与糠醇改性材相比,环氧大豆油添加量为20%(质量分数,下同)时,复合改性材气干/吸水饱和的弦向和体积湿胀率降低幅度最大,分别降低36.9%、20.0%和35.9%、30.7%,且抗湿胀系数(ASE)最大;环氧亚麻油添加量为40%时,复合改性材气干/吸水饱和的弦向和体积湿胀率降低幅度最大,分别降低52.5%、65.6%和41.5%、46.0%,且ASE最大,环氧植物油加入能够显著提高糠醇改性材的尺寸稳定性。环氧大豆油和环氧亚麻油添加量为20%时,复合改性材的抗弯强度(MOR)和静态硬度提高幅度最大,与糠醇改性材相比,分别提高17.9%、25.3%和30.0%、25.1%。环氧大豆油和环氧亚麻油添加量为40%时,复合改性材的抗弯弹性模量(MOE)提高幅度最大,与糠醇改性材相比,分别提高22.7%、21.1%。与其他力学性能相比,环氧植物油对糠醇改性材的韧性提高幅度最大。环氧大豆油和环氧亚麻油添加量为40%时,复合改性材的冲击韧性分别提高88.7%、59.8%。环氧植物油添加可显著提高糠醇改性材的MOE、MOR和静态硬度,改善其韧性下降问题。【结论】环氧植物油添加量20%的复合改性材物理力学性能最优。环氧植物油与糠醇发生开环反应,其长柔性脂肪链引入糠醇树脂链中可改善糠醇改性降低木材韧性的问题,且可进一步提高其物理力学性能。

NaCl胁迫对杨树插穗生长的影响

本研究选择小黑杨、迎春5号杨和中绥12号杨3个杨树品种在添加不同质量浓度NaCl溶液的基质中进行了扦插试验,调查生长情况,进行了统计分析。结果表明:随着NaCl溶液质量浓度的升高,3个杨树品种插穗的新梢长度、叶片数量、根数、根长、插穗地上及其地下部分鲜重和干重等均呈现出逐渐降低的趋势。品种间插穗新梢长度、叶片数量、根长、地上部分鲜重和干重、地下部分鲜重和干重差异达到极显著性水平(F值分别为12.88^(**)、10.91^(**)、22.96^(**)、148.60^(**)、27.01^(**)、29.40^(**)、31.55^(**)),NaCl溶液质量浓度间插穗新梢长度、叶片数量、根数、根长、地上部分鲜重和干重、地下部分鲜重和干重差异达到极显著性水平(F值分别为11.63^(**)、10.45^(**)、13.10^(**)、10.12^(**)、43.22^(**)、10.80^(**)、18.66^(**)、20.48^(**)),小黑杨插穗具有较强的耐盐(NaCl)性。

杨树人工林下辽东楤木高效栽培模式

为了提高杨树(Populus spp.)人工林下土地的利用率,解决辽东楤木(Aralia elata)发展缺乏土地问题,本项目将辽东楤木从山区引种到平原杨树人工林下栽植。通过研究不同郁闭度杨树林下辽东楤木的生长节律,不同株行距配置对春菜产量影响和温室反季节水培技术等,形成一整套杨树林下辽东楤木栽培模式。结果表明:1)郁闭度0.6以下的杨树林分,辽东楤木有较高的芽菜产量和较高的生长量,其中辽东楤木株行距1.0 m×1.2 m的配置方式单位面积鲜菜产量最高;2)在株行距4 m×6 m的杨树人工林下,辽东楤木可经营2个轮伐期,辽东楤木鲜菜年产量130 kg/667 m^(2)左右;3)温室反季节生产辽东楤木芽菜是一种可行且经济价值较高的生产方式,可产鲜菜10.0 kg/m^(2)。

章古台10个杨树品种抗烂皮病初报

为测试章古台地区现有10个杨树品种对杨树烂皮病的抗性,在室内模拟林间条件,采用烧伤接种法对10个杨树品种水培枝条进行病原菌接种实验。结果表明:在实验的10个杨树品种中,小青杨病斑发展速度快、危害最重;彰武小钻杨产生分生孢子角最多,传播病原菌能力强;健杨接种病原菌后病斑不发展、不产生分生孢子角,对杨树烂皮病的抗性最强。因此,可考虑健杨作为杨树更新品种,以提高林分的抗病性和生态稳定性。

科尔沁沙地南缘杨树不同品种旱作栽培表现研究

为了选择旱作条件下科尔沁沙地南缘适生杨树(Populus spp.)品种,敖汉旗于2007年对18个杨树品种进行沙地旱作栽培试验,2023年8月,采用样带法抽样,对单位面积蓄积量、枯梢病情指数、干部病害3个指标排序并赋分,按总得分由低到高确定选择先后顺序,最终选择黑林1号、白林3号、B6、白林2号(棱)为科尔沁沙地南缘适生品种。

江汉平原杨树人工林连栽对林地土壤质量的影响

采用空间序列代替时间序列的方法，研究了连栽对江汉平原杨树人工林土壤理化性质、微生物数量变化及酶活性的影响。结果表明：与第1代林相比，第2代林土壤物理结构退化，土壤容重增大0．71％，土壤总孔隙度和毛管持水量分别降低0．41％和6．89％，土壤团聚体粒径分布的分形维数增大，土壤平均重量直径减小；土壤有机质、大量元素及微量元素等养分含量均有不同程度下降。连栽导致大量元素下降2．88％～12．20％，其中对N影响最大，K次之，P最小；连栽导致微量元素下降2．27％～53．37％，其中对Zn影响最大，其后依次是Cu、Fe、Mn和S；连栽对土壤微生物数量也有影响，随着连栽代数增加，土壤真菌、放线菌、细菌的数量分别下降34．38％、14．38％、56．63％；第2代林地土壤磷酸酶、脲酶、蔗糖酶、蛋白酶和过氧化氢酶较第1代林分别下降20．00％、11．54％、29．39％、50．00％和1．92％。

胡杨不同叶形光合特性、水分利用效率及其对加富CO_2 的响应

胡杨 (PopuluseuphraticaOliv .)叶形多变化 ,大致归纳为杨树叶 (卵圆形叶 )和柳树叶 (披针形叶 )两大类。在内蒙古额济纳旗胡杨林自然保护区 ,选择成年树同时具有卵圆形叶和披针形叶的标准株 ,将枝条拉至同一高度 ,通过活体测定 ,比较了其光合特征、水分利用效率及对CO2 加富的响应。结果表明 :在目前大气CO2 浓度下 ,当光强为 10 0 0 μmol·m-2 ·s-1时 ,卵圆形叶 (成年树主要叶片 ) (A)和披针形叶 (成年树下部萌条叶片 ) (B)的净光合速率(Pn)分别为 16 .40 μmolCO2 ·m-2 ·s-1和 9.38μmolCO2 ·m-2 ·s-1;水分利用效率 (WUE)分别为 1.5 2mmolCO2 ·mol-1H2 O和 1.18mmolCO2 ·mol-1H2 O ;A的光饱和点和补偿点分别为 16 0 0 μmol·m-2 ·s-1和 79μmol·m-2 ·s-1,B的相对应值则为 15 0 0 μmol·m-2 ·s-1和 16 8μmol·m-2 ·s-1。当CO2 浓度加富到 45 0 μmol·mol-1时 ,A的光饱和点升高了 15 0μmol·m-2 ·s-1,光补偿点降低了 36 μmol·m-2 ·s-1;而B的光饱和点降低了 2 72 μmol·m-2 ·s-1,光补偿点则升高了 32μmol·m-2 ·s-1。这表明 ,柳树叶的光合效率较低 ,以维持生长为主 ;随着树体长大 ,柳树叶难以维系其生长 ,出现杨树叶 ,杨树叶更能耐大气干旱 ,光合效率高 ,通过积累光合产物 ,

应用热脉冲技术对胡杨和柽柳树干液流的研究

应用热脉冲技术对干旱区胡杨(Populuseuphrtaicr)和柽柳(Tamarisspp.)树干液流速度进行了研究.结果表明:在正常生长状态下,胡杨树干单位面积液流通量为0 34L·cm-2·d-1,柽柳为0 15L·cm-2·d-1.树液流速的日变化表现出多峰形特征,在午后有短暂液流急速减小的现象,而晚上植物为了补充体内水分亏缺,保持一定的树液流量.随着胸径的增大,茎流速率和茎流量也随之增大.在生长季节胸径21cm和15cm的胡杨日平均耗水量23 3L和19 25L;基径5cm和4cm的柽柳日平均耗水量0 62L和0 37L.在生长季节(5～10月)胡杨总蒸腾量为3419 4L,柽柳仅为63 9L.

利用荧光SSR标记鉴别杨树品种

世界上天然杨树约100多种,我国有50多种。杨树作为重要造林树种,多用于水土保持、防风防沙和园林绿化,也是造纸、建筑及木材工业的重要经济树种。杨树易繁殖,生长速度快,生产周期短,在我国广泛栽培,我国也是世界上杨树人工林面积最大的国家（Carleetal.,2005）。我国杨树引种和育种的历史可追溯到新中国建立时期,杨树种质资源十分丰富,我国已培育了许多优良杨树品种（马常耕,1995）。随着育种技术的发展,新品种产生的速度与日俱增。然而,由于杨树品种繁多,形态相似,容易出现品种混淆。特别是近年来杨树种苗市场的迅速发展,为了追逐经济效益,杨树种苗市场上出现了以次充好。