北美鹅掌楸漂白药剂的选择

采用几种常见的氧化型和还原型漂白剂对变色北美鹅掌楸木材进行漂白试验,对漂后试材进行目测观察及测色仪测定色度指数比较其漂白效果.试验结果表明,对于北美鹅掌楸木材的一般漂白,氧化型漂白剂优于还原型漂白剂.在考虑环保和对材面纤维的影响等因素的条件下,低浓度过氧化氢对漂白对象有很好的漂白效果,较佳的工艺条件为:H2O2质量分数6％,pH值为9,5 ～10.0,Na2SiO3质量分数0.4％,温度70℃,时间60～ 90 min.     

The ultrastructure of intercellular passageways in vessels of yellow poplar (Liriodendron tulipifera,L.) part I: Vessel pitting

Summary The newly matured intervessel pit membranes of yellow poplar contain distinct openings. With increasing age the membranes become progressively occluded with incrustations which obstruct the small openings. Openings were not detected in the vessel-to-ray parenchyma and vessel-to-fiber pit membranes at any age.Paper No. 3478 of the Journal Series of the N. C. State University Agricultural Experiment Station, Raleigh, N. C.     

不同栽培林龄和轮次的杨树人工林土壤理化性质

采用空间代替时间的方法,构建了不同栽培林龄和轮次的杨树人工林试验样地,测定了土壤主要物理化学性质.结果表明,不同栽培轮次土壤密度值表现为1轮11年生＞2轮9年生,随着林龄增加,土壤密度呈逐渐下降趋势,表现为2轮3年生＞2轮6年生＞2轮9年生,且各样地之间呈显著差异;土壤饱和持水量、毛管持水量、毛管孔隙度和总孔隙度在各样地之间的变化无明显差异,而土壤非毛管孔隙度的变化则呈显著差异,在不同林龄样地上呈极显著差异.试验结果还显示,表层0～10 cm土壤中各养分元素的含量都对应地高于10～ 30 cm土层的含量,而pH值则呈相反的变化趋势;在不同栽培轮次和林龄的杨树人工林样地上对应土层土壤养分元素无明显的变化规律.     

鹅掌楸属种及杂种的SSR分子鉴定

以不同种源的鹅掌楸、北美鹅掌楸和不同组合的杂交鹅掌楸为试验材料,对176对SSR引物进行初筛、复筛,最后筛选出1对物种特异性SSR引物。该引物在鹅掌楸群体中特异性扩增出190bp的产物,在北美鹅掌楸群体中特异性扩增出180bp的产物,在杂交鹅掌楸群体中特异性扩增出180bp和190bp2种产物。该引物对鹅掌楸种间鉴别准确率达100%。     

Provenance Performance of Liriodendron tulipifera in South Africa

Four provenances of Liriodendron tulipifera were imported from the United States in 1973. Test plantings were made in three forest regions of South Africa, with major trials being established in one of the regions. The resulting provenance rankings show a classical clinal variation pattern with the southernmost United States source exhibiting the best growth rate. All sources tested appear to be equally sensitive to rat and buck damage.     

两种层积处理方式对北美鹅掌楸种子4种内源激素物质含量变化的影响

应用酶联免疫吸附法(ELISA)测定了低温层积和低温裸层积两种种子层积处理方式对北美鹅掌楸种子4种内源激素物质IAA、GA3、ZR和ABA的含量变化情况.研究结果表明,两种种子处理方式均对北美鹅掌楸种子的4种内源激素物质含量变化有影响.经层积处理后,北美鹅掌楸种子中的生长促进物质IAA和GA3含量较未经层积处理的对照种子内源激素含量有显著的提高,而其种子中的萌发抑制物质ABA的含量比未经层积处理的对照降低,特别是其种子中的IAA/ABA和GA3/ABA的比值显著增加.     

杂种鹅掌楸扦插苗营养元素含量的分布

本文利用不同浓度的外源激素处理杂种鹅掌楸的扦插繁殖幼苗,并通过烘干法、凯氏法、原子吸收等方法,对扦插繁殖幼苗的根、茎、叶3个器官生物量及其营养元素进行测定。结果表明:不同浓度的外源激素(处理1:IBA50gkg-1+NAA300gkg-1;处理2:IBA50gkg-1+NAA300gkg-1)处理插穗后,根、茎、叶的生物量均有一定程度的提高。在所有的扦插苗中,其根、茎、叶内的含C量差异不大,但茎内的N、P、K、Ca含量较根、叶的少。方差分析结果表明:不同浓度外源激素处理的同一器官后,其C/N及P、K、Ca的含量没有明显的差异;而同一浓度外源激素处理不同器官之间的4种营养元素的含量有显著或极显著的差异。并且扦插生根苗体内营养元素含量较低,在大田栽培时,应及时施肥补充营养,以提高幼苗生长适应能力。图1表4参12。     

北美鹅掌楸种子老化过程中的生理生化变化

应用人工加速老化的方法对北美鹅掌楸种子进行了老化处理试验,试验结果表明:北美鹅掌楸种子浸出液的相对电导率与其的SOD酶活性和CAT酶活性呈负相关,与MDA含量呈正相关;北美鹅掌楸种子经人工老化处理后,其种子膜脂的过氧化作用加强,膜的结构和功能遭到破坏。     

北美鹅掌楸LtCHS基因的克隆及生物信息学与组织表达特征分析

【目的】鹅掌楸属花色种间差异较大,是研究木本植物花色形成与调控机制的较理想材料。查尔酮合成酶基因( CHS)是黄酮类化合物生物合成途径中的关键基因,与植物花色形成密切相关,同时又是研究科以下系统发育的理想基因,种间进化差异较大,因此 CHS基因用于研究鹅掌楸属花色差异形成机制有较强的可行性。本研究克隆北美鹅掌楸的查尔酮合成酶基因,并对其进行生物信息学及组织表达分析,以期为鹅掌楸属树种花色的形成和调控机制研究提供参考。【方法】以北美鹅掌楸的花芽为材料,采用同源克隆和 RACE 技术克隆查尔酮合成酶基因( LtCHS),并进一步扩增该基因的基因组序列。对该基因进行生物信息学分析。采用半定量 RT-PCR 方法分析 LtCHS基因在鹅掌楸属种间及不同组织中的表达水平。【结果】获得2个查尔酮合成酶基因： LtCHS1与LtCHS2。LtCHS1基因的 cDNA全长875 bp,包含1个702 bp的ORF,其基因组DNA ( gDNA)只含有1个外显子,没有内含子,编码233个氨基酸,蛋白质分子量为71.88 kDa,等电点为5.09。LtCHS2基因的 cDNA 全长1457 bp,包括1个1185 bp的 ORF,其 gDNA含有2个外显子和1个内含子,编码394个氨基酸,蛋白质分子量为120.0 kDa,等电点为4.97。2个基因的组织表达分析结果显示,LtCHS 基因不仅在同一树种不同组织间存在差异,而且在种间也存在表达差异。LtCHS1基因仅在北美鹅掌楸中表达,LtCHS2基因在鹅掌楸中表达,在杂交鹅掌楸中二者均有表达。【结论】获得的2个 LtCHS基因属于同一基因家族,但执行不同功能。二者在种间表达存在差异可能与鹅掌楸属花色形成有关。结合鹅掌楸属种间花色特征,可初步推测,LtCHS1基因与 LtCHS2基因可能分别调控不同类型花青素的合成。     

杂种马褂木在北京地区的生长与适应表现

杂种马褂木生长快、树干挺直、叶形奇特、冠形优美,在园林绿化、农田防护林、速生丰产林建设方面具有广阔的发展前景,有重要的生态、经济效益。为筛选适合北京地区生长的杂种马褂木优良家系,特对其生长发育动态规律及适应表现进行试验观察。在6个供试家系中,以家系TC02表现较好。     

北美鹅掌楸不同种源在闽北山区的生长表现及评价

在福建省洋口国有林场,对从美国引进的北美鹅掌楸3个种源进行苗期试验并建立测定林,在6年生时对测定林进行调查和分析测定。方差分析结果表明,不同种源苗高、地径的差异均达到0.05显著水平;6年生时树高、胸径和单株材积平均值分别达6.41 m、10.94 cm和0.03561 m3,与本地乡土速生落叶树种南酸枣比较,生长性状表现相当,能较好适应闽北地区的生长。各种源间树高、胸径和材积生长量差异均不显著,但在个体水平上仍存在较大的差异,树高、胸径、材积个体水平的变异系数都约为相对应指标种源水平的4倍,从优良种源的292株个体中选择了10株优良的个体作为杂交育种或无性系利用的繁殖材料。     

北美鹅掌楸实生苗苗期生长性状变异分析

对引进繁育的北美鹋掌楸实生苗的高、地径、叶片宽、叶片长和叶全长等性状进行了调查分析,研究结果表明,该树种在济南地区能健壮生长;种源内及种源闻实生苗高、地径生长量及叶相关性状均表现出较大变异,苗高和叶片长生长量变异达到显著水平,加拿大多伦多种源较为优异;在山东进行引种繁育北美鹅掌楸,需进行种源及个体选择;苗期苗高是进行早期筛选的理想指标。     

Variations in organic acid exudation and aluminum resistance among arbuscular mycorrhizal species colonizing Liriodendron tulipifera

Aluminum (Al) in acidic soils is toxic to plants, affecting growth, water uptake and nutrient assimilation. Aluminum resistance in some plant species and genotypes has been ascribed to organic acid exudation from roots and arbuscular mycorrhizal (AM) fungal symbiosis. We investigated variation among several AM species in altering Al resistance of Liriodendron tulipifera L. and evaluated AM influence on organic acid production as a potential Al resistance mechanism. Growth, nutritional responses and rhizosphere organic acid profiles were assessed for seedlings in association with Acaulospora morrowiae Spain & Schenck, Glomus claroideum Schenck & Smith, G. clarum Nicol. & Schenck or Paraglomus brasilianum (Spain & Miranda) Morton & Redecker and non-mycorrhizal seedlings exposed to 0, 50 or 200 microM Al. Plants colonized by G. clarum had the greatest biomass, least Al and most phosphorus (P) in leaf tissues and exuded malate and citrate into the rhizosphere at rates that complexed 99% of delivered Al in all treatments. Other AM fungi did not confer significant Al resistance on L. tulipifera and did not maintain citrate and malate exudation in response to Al exposure. This study illustrates functional diversity among AM fungal species in conferred Al resistance to plants and highlights the potential importance of fungal diversity in ecosystem responses to environmental stresses.     

不同温度、时间层积处理对北美鹅掌楸种子发芽影响

通过7种不同温度、不同时间的层积处理研究其对北美鹅掌楸种子发芽的影响。结果表明：低温层积处理能显著促进北关鹅掌楸的种子萌发。在2℃、层积处理时间为60d的条件下种子发芽效果最好，种子绝对发芽率为86．84％，发芽速度最快；在2～12℃变温层积处理56d的条件下，种子绝对发芽率为80.71％，种子发芽较快。在7℃，层积处理时间为30d的条件下种子发芽效果最差，种子绝对发芽率为62．29％。     

假植对北美鹅掌楸生长量的影响分析研究

通过对北美鹅掌楸苗木立即定植和假植后定植的苗木高、枝下高、胸径和材积生长量进行了对比分析显示：假植对北美鹅掌楸苗木的高、枝下高、胸径和材积生长量影响极显著,其平均生长量分别是立即定植的北美鹅掌楸苗木相应平均生长量的69．16％、66．12％、62．63％和29．84％。北美鹅掌楸不宜假植,移苗后最好立即栽植。     

杨村新无性系木材物理力学性质的研究

研究了7个杨树新无性系和I－69杨的木材物理力学性质。结果表明，杨木新无性系的物理力学性质等主要指标均属于小至甚小级，无性系间物理力学性质差异显著，据此可用木材物理力学性质因子选育优良无性系。尽管新无性系的生长速度超过I－69杨，但由于其某些强度指标低于I－69杨，8年生的速生材尚不能完全替代11年生的I－69杨使用，因此不能作为建筑结构材使用。     

End-use related physical and mechanical properties of selected fast-growing poplar hybrids (Populus trichocarpa × P. deltoides)

This study focused on physical and mechanical properties of fast-growing poplar clones in relation to potential end uses with high added value. A total of 14 trees from three different clones, all P. trichocarpa × deltoides (T×D) hybrids, were felled in a poplar plantation in Lille (Belgium): six ‘Beaupré’, four ‘Hazendans’ and four ‘Hoogvorst’. Growth rate was found to have no significant influence on the physical mechanical properties. Although the investigated clones are genetically closely related, important variations in physical and mechanical properties were observed. Specific features such as spatial distribution of tension wood and dimensional stability are the main quality factors. It was concluded that ‘Beaupré’ is suitable for a wide range of high value added applications, such as plywood or construction wood. ‘Hazendans’ and ‘Hoogvorst’ will need adapted technology in processing. Further research is needed to characterize clonally induced variation in properties and to assess adequate processing strategies for multiclonal poplar stands.     

Changes in the physical and chemical properties of six Japanese softwoods caused by lengthy smoke-heating treatment

The effects of prolonged smoke-heating treatments on wood quality were investigated. Six Japanese softwoods were smoke-heated for 100 and 200h at a temperature of 75° ± 5°C, which was recorded inside the log. After smoke heating, wood quality, including moisture content, amounts of chemical components, relative degree of crystallinity (RDC) of cellulose, and sapwood color were examined. Moisture content decreased as a result of smoke heating, especially in sapwood, leading to a uniform distribution of moisture content within a log. Almost no difference was found in the amounts of chemical components between the control woods and the woods that were smoke-heated for 100h. However, in the wood that was smoke-heated for 200h, the amounts of holocellulose decreased, suggesting that thermal deterioration and/or degradation of hemicelluloses had occurred. We assume that the increase in RDC was caused by smoke heating with the crystallization of cellulose and/or thermal degradation of hemicelluloses. Almost no differences were found in sapwood color between the control woods and the woods that were smoke-heated for 100h. In the wood that was smoke-heated for 200h, however, L*decreased, whereas a* and b* increased. As a result, E*ab, showing the total color change, increased, resulting in a deeper color. These results suggest that thermal degradation of hemicelluloses was caused by smoke heating for over 100h. Therefore, smoke heating of softwood logs using a commercial-scale kiln should not exceed 100h.     

Changes in chemical characteristics of bamboo (Phyllostachys pubescens) components during steam explosion

Chemical changes in cell wall components of bamboo internode during steam explosion process were analyzed to investigate self-binding mechanism of binderless board from steam-exploded pulp. More than 30% of xylose on initial mass, which is a major hydrolyzate of bamboo hemicelluloses, was lost after steam explosion treatment. Bamboo lignin is characterized by the presence of ester- and/or ether-linked p-coumaric acid to lignin. The content of phenolic hydroxyl groups of lignin isolated from steam-exploded pulp was characterized 2.3 times higher than those of the extract-free bamboo internode due to the cleavage of β-O-4 linkages. Alkaline nitrobenzene oxidation of the bamboo lignin gave vanillin, syringaldehyde and p-hydroxybenzaldehyde as major products. The content of p-hydroxybenzaldehyde decreased after steam explosion treatment, indicating the cleavage of ester- and/or ether-linked p-coumaric acid. The total yield of erythronic and threonic acids in ozonation products of the extract-free bamboo internode lignin was 268 mmol (200 g lignin)⁻¹, while those of lignins in the steam-exploded pulp and powdery fraction were 96 and 129 mmol (200 g lignin)⁻¹, respectively, suggesting the significant cleavage of β-O-4 linkages during steam explosion treatment. The cleavage of β-O-4 linkages was also confirmed by ¹H- and ¹³C-NMR spectroscopic observations.     

杨树黄叶病害症状及侵染性研究初报

在野外详细调查和定量测试基础上,对杨树黄叶病害症状进行了描述,修改了过去对杨树黄叶病害症状描述中的"叶脉保持绿色"、"叶片变薄"和"丛枝"等不确切说法。进行了病树枝条的硬枝、嫩枝扦插,病接穗嫁接、病苗换土盆栽、病树移植、病苗造林及病树自然恢复现象观测等试验,连续跟踪观测3 a未发现杨树黄叶病害具有侵染性。