Comprehensive Overview of Populus simonii Research in the Recent Years

As an important ecological tree species in northern China, Populus simonii plays a crucial role in maintaining ecological balance and promoting environmental sustainability. The academic community has conducted a series of in-depth studies on this species, covering key areas such as genomics, survival mechanisms, and genetic breeding. Through the analysis of the genomic structure and function of P. simonii, we have not only revealed the molecular basis for its adaptation to harsh environments but also identified key genes that promote its growth and resistance to pests and diseases. Furthermore, exploring the survival mechanisms of P. simonii has deepened our understanding of its stress resistance traits, including how it effectively copes with abiotic stresses such as drought, salinization, and heavy metal pollution. In genetic breeding, significant progress has been made through the application of modern biotechnology, improving the growth rate and wood quality of P. simonii and enhancing its environmental adaptability and disease resistance. These research findings have not only enriched our knowledge of the biological characteristics of P. simonii but also provided a solid scientific foundation for its application in ecological restoration, forestry production, and environmental management.

Foraging behavior of parasitoid chalcid to the essential oil from bark of Populus pseudo-simonii P. nigra and Quadraspidiotus gigas

采用四臂式嗅觉仪测定了长棒四节蚜小蜂（Pteroptrix longgiclava(Girault)(Hymenoptera:Aphelinidae))和黄胸扑虱蚜小蜂（Encarsia gigas(Tshumakova)(Hymenoptera:Aphelinidae)),对健康的小青×黑杨（Populus pseudo-simonii×P.nigra)树皮、被杨圆蚧（Quadraspidiotus gigas(Thiem & Gerneck)）危害的杨树皮、杨圆蚧1齿固定若虫的虫体和介壳的挥发油的趋性反应。测定结果表明：被杨圆蚧危害后的小青×黑杨树皮和杨圆蚧1龄因定若虫的介壳对长棒四节蚜小蜂和黄胸扑虱蚜小蜂成虫具有较大的吸引力。3－7μL介壳挥发油和5－9μL受害杨树皮挥发油对长棒四节蚜小蜂的寄主搜寻行为具有较强的引导作用。虫体的挥发油对小蜂的寄生定位也起到了一定的引诱作用。两种小蜂对健康树皮的挥发油几乎没有反应。图4表1参20。

Two novel eukaryotic translation initiation factor 5A genes from Populus simonii×P.nigra confer tolerance to abiotic stresses in Saccharomyces cerevisiae

The role of plant eIF5A proteins in multiple biological processes, such as protein synthesis regulation, translation elongation, mRNA turnover, programmed cell death and stress tolerance is well known. Toward using these powerful proteins to increase stress tolerance in agricultural plants, in the present study, we cloned and characterized PsneIFSA2 and PsneIFSA4 from young poplar （P. simonii × P. nigra） leaves. The deduced amino acid sequences of PsneIF5A2 and PsneIF5A4 were 98 % similar to each other, and they are orthologs of eIF5A 1 in Arabidopsis. In a subcellular localization analysis, PsneIF5A2 and PsneIF5A4 proteins were localized in the nucleus and cytoplasm, qRT-PCR analysis showed that PsneIF5A2 and PsneIF5A4 were transcribed in poplar flowers, stem, leaves, and roots. In addition, they were also induced by abiotic stresses. Transgenic yeast expressing PsneIF5A2 and PsneIF5A4 had increased salt, heavy metal, osmotic, oxidative tolerance. Our results suggest that PsneIF5A2 and PsneIF5A4 are excellent candidates for genetic engineering to improve salt and heavy metal tolerance in agricultural plants.

公路绿化植物油松(Pinus tabulaeformis)和小叶杨(Populus simonii)对重金属元素的吸收与积累

对内蒙古西部公路绿化植物油松(Pinustabulaeformis)、小叶杨(Populussimonii)及其根际土壤中重金属元素(Cd、Hg、Pb、Cu、Zn、Ni、Cr)和类金属元素(As和Se)含量以及根际土壤重金属(Cu、Zn、Pb、Ni和Cr)形态、土壤pH值进行了测定。对比分析了公路沿线不同绿化植物及其不同器官对重金属元素的吸收与积累特征。结果表明:绿化植物根际土壤对重金属元素的吸附及污染程度以Cd为最高。随原子序数的递增,小叶杨和油松两种植物的根部和茎叶两种营养器官中重金属的含量均表现出“N”字形变动趋势。而且重金属元素在不同植物不同器官中的含量具有Zn>Cu>Ni,Cr,As,Pb>Cd>Hg的基本规律。小叶杨茎叶对重金属元素Cr、Ni和Pb的富集能力较根部为强,油松茎叶对重金属元素Cr、Ni、Cu和Pb的富集能力较根部为强。绿化植物根际土壤重金属元素有效态占总量百分比的大小序列为Zn>Pb>Ni、Cr>Cu,与重金属元素在不同植物不同器官中的含量大小序列Zn>Cu>Ni、Cr、As、Pb>Cd>Hg并非趋于一致。公路绿化植物对根际土壤中重金属元素的吸收和积累与重金属元素有效态所占的比例有关。

Pb胁迫对欧美杂交杨(Populus deltoides×Populus nigra)生物量分配格局及其Pb富集特性的影响

采用速生树种修复重金属污染土壤的方法近年来受到越来越多关注,但已有结果存在很大不确定性。为了解杨树在不同Pb胁迫条件下生长响应和Pb富集效果,以长江上游两种典型土壤(酸性紫色土和钙质紫色土)为栽培介质,采用盆栽试验方法,研究了不同Pb浓度处理下(CK:0mg·kg-1;T1:200mg·kg-1;T2:450mg·kg-1;T3:2000mg·kg-1)欧美杂交杨(Populus deltoides×Populusnigra)生物量生产与分配格局以及Pb吸收、富集特性。两种土壤条件下杨树各器官生物量及总生物量均表现出随Pb胁迫程度的增加而降低的趋势,Pb胁迫条件下杨树生物量分配格局在钙质紫色土中表现为茎>粗根>叶>细根。相同浓度Pb处理条件下,单株杨树总生物量均表现为钙质紫色土大于酸性紫色土。随着Pb处理浓度的增大,杨树各器官Pb含量及积累量显著增加。Pb胁迫使杨树对Pb的富集系数逐渐增大而耐性系数逐渐减小。T3处理条件下杨树对Pb的富集系数在酸性紫色土中较大,且各处理条件下杨树对Pb的耐性系数均为酸性紫色土中较大。这些结果表明,高浓度Pb胁迫条件下酸性紫色土中的欧美杂交杨表现出较好的吸收和富集Pb的特性,这为Pb污染土壤的生物修复提供了一定的科学依据。

镉胁迫对欧美杂交杨(Populus deltoides×Populus nigra)光合作用与生物量生产的影响

采用盆栽实验研究了生长在四川盆地典型Cd污染冲积土和紫色土上的欧美杂交杨(Populus deltoides×Populus nigra)对国家土壤环境质量标准中Cd浓度梯度(0、0.3、1.0、2.0 mg/kg)的光合响应和生物生产量。Cd处理显著降低紫色土上生长的杨树叶绿素a和叶绿素总量,增加气孔导度与胞间CO2浓度,增加凋落叶生物量,降低茎生物量、根生物量和单株总生物量。但是,Cd处理对冲积土上生长的杨树叶绿素特征、光合生理指标和生物量生产并无明显差异。尽管同一生长基质上不同Cd处理间杨树光合生理指标与生物量生产均有一定程度的影响,但紫色土上生长的杨树生理和生长特征均显著低于冲积土上生长的杨树。这些结果表明,自然条件国家土壤环境质量标准内,Cd污染并不对杨树生长构成较大威胁,而生长土壤基质的选择可能对杨树的栽培更为重要。这为Cd污染土壤区域城市森林建设和速生丰产林建设提供了一定的科学依据。

Transformation of Tobacco with Two AP1 Genes Isolated from Poplar( Populus simonii × Populus nigra)

[ Objective ] This study aimed to analyze the functions of AP1 gene from Populus simonii × Populus nigra and to lay the theoretical foundation for shortening the breeding cycle of forest trees and investigating the flowering mechanism in poplar. [ Method] Plant expression vectors of AP1 genes were constructed and transformed into tobacco leaf disks with Agrobacterium-mediated method. Transgenic tobacco plants were identified by PCR. [ Result] AP1 genes were integrated into the genome of tobacco. Transgenic tobacco plants all presented an early flowering phenotype compared with wild-type tobacco. [ Conclusion] AP1 genes could promote early flowering in transgenic tobacco plants, which provided theoretical basis for molecular regulation of flowering in poplar.

Phenotypic variation among five provenances of Populus simonii in northern China

We investigated phenotypic variation ofPopulus simonii from five provenances in northern China. Our results show that significant differences exist between plants of different provenances in morphological and physiological traits, except for leaf-stalk length and the number of leaf margins. The coefficient of variation for all traits ranges from 14.77% to 81.49%. The mean phenotypic coefficient of differentiation （VST） is 47.1%, which means that the variation within provenances is the major source for phenotypic variation in P. simonii. Given our cluster analysis of provenances based on an average linkage computing method, the five provenances ofP. simonii investigated could be divided into three groups. Our results provide a theoretical basis for genetic resource conservation and provenance selection of natural P. simonii in northern China.

Pharmacological potential of Populus nigra extract as antioxidant,anti-inflammatory,cardiovascular and hepatoprotective agent

Objective:To evaluate antioxidant,anti-inflammatory,hepatoprotective and vasorelaxant activities of Pupulus nigra flower buds ethanolic extract.Methods:Antioxidant and anti-inflammatory activities of the extract were assessed using respectively the ABTS test and the animal model of carrageenan-induced paw edema.Protection from hepatic toxicity caused by aluminum was examined by histopathologic analysis of liver sections.Vasorelaxant effect was estimated in endothelium-intact and-nibbed rings of porcine coronary arteries precontracted with high concentration of U466I9.Results:The results showed a moderate antioxidant activity(40%),but potent anti-inflammatory activity(49.9%)on carrageenan-induced mice paw edema,and also as revealed by histopathologic examination,complete protection against AlCl_3-induced hepatic toxicity.Relaxant effects of the same exlracl on vascular preparation from porcine aorta precontracted with high concentration of U466I9 were considerable at 10^(-1)g/L,and comparable(P>0.05)between endothelium-intact(67.74%,IC_(50)0.04 mg/ml.)and-rubbed(72.72%,IC_(50)=0.075 mg/ml,)aortic rings.Conclusions:The extract exerted significant anti-inflammatory,hepatoprotective and vasorelaxant activities,the latter being cndothelium-independent believed to be mediated mainly by the ability of components present in the extract to exert antioxidant properties,probably related to an inhibition of Ca^(2+)influx.

Emissions of saturated C6-C10 aldehydes from poplar (Populus simonii×P. pyramidalis ‘Opera 8277’) cuttings at different levels of light intensity

Aldehydes play an important role in atmospheric chemistry and plant direct and indirect defense against environmental stresses.In this study,the emissions of saturated C6-C10 aldehydes from Populus simonii × P.pyramidalis ＇Opera 8277＇ cuttings were examined by using a gas chromatography/mass spectrometry（GC/MS） technique at three levels of light intensity（400,800 and 1 200 μmol·m-2·s-1）.A positive correlation between the emissions of these aldehydes and light intensity was found.Moreover,nordi-hydroguaiaretic acid（NDGA）,a special inhibitor of lipoxygenase（LOX）,significantly inhibited the emissions of C6-C9 aldehydes at three levels of light intensity,but did not influence the emission of decanal（C10）.The emissions of C6-C10 aldehydes in NDGA treated poplar cuttings,exhibited the same positive correlation with light intensity.The results indicated that LOX pathway contributes to the emissions of C6-C9 aldehydes,whereas some pathways regulated by light intensity might be a universal mechanism for emissions of C6-C10 aldehydes.

Association Analysis of the Growth of Black Poplar (Populus Nigra L.) Under Contrasting Nitrogen Levels

The European black poplar(Populus nigra L.)has been used as a germplasm resource for the breeding of new poplar varieties around the world.The identification and screening of its high nitrogen use efficiency genotypes could enable the breeding of new resource-efficient poplar varieties.The accessions were screened using MALDI-TOF MS genotyping technology for ammonium transporter(AMT)and nitrate transporters(NRT)genes against phenotypic data for seedling height and ground diameter traits,in both low and high nitrogen environments.Allele re-sequencing of seven genes related to root development was carried out using the minisequencing method.By cluster analysis,101 accessions of black poplar were divided into 4 populations,and it was concluded that Central Europe is the origin of the evolution of low-nitrogen and high-efficiency populations of European black poplar.Association study between SNP typing and seedling height and ground diameter traits showed that there were significant correlations between four SNP loci and growth traits under the contrasting N levels.We found that SNP3 and SNP4 in the PttAMT1;3 gene were significantly associated with seedling height traits,and that SNP2 and SNP7 in the PttAMT1;2 and PttAMT1;5 genes,respectively,were significantly associated with ground diameter traits.Thus,considerable allelic diversity is present within the candidate genes studied and can be utilized to develop functional markers to select for poplars with improved growth under N stress conditions.

No consistent daily variation in DNA methylation detected in Populus nigra leaves by methylation-sensitive amplification polymorphism analysis

DNA methylation, an epigenetic mechanism used by cells to control gene expression, has an important biological role in plant development and environmental fitness. Since plant DNA methylation is closely related to environmental conditions, variation during the day is expected. Here, in genetically identical plants of Populus nigra clone N46, DNA methylation changes in leaves over a 24 h period were detected using the methylation-sensitive amplification polymorphism method. The results showed different DNA methylation patterns in mature poplar leaves: not only in individuals at the same time, but also in samples at each of the six time during the day. In addition, night samples had a higher percentage of methylation than in morning samples. However, no statistically significant differences were found among the samples gathered at different times. Similar results were obtained for three other P. nigra clones with different genetic backgrounds. Real time qPCR showed that the DNA methyltransferase genes Pt-MET1 and Pt-SOM1 involved in CG DNA methylation in poplar were stable over a 24 h period in leaves of P. nigra N46 compared with circadian-controlled genes. That could be part of the reason that methylation of CCGG sites is stable in those leaves. That DNA methylation differed even in genetically identical plants indicates the specificity of DNA methylation changes in their genomes. No statistically significant differences in methylation changes were found between day and night, suggesting that DNA methylation is more stable than expected and is unlikely to be involved in circadian regulation in plants.

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.

Control Mechanisms and Simulation of <i>Populus simonii</i>Leaf Unfolding

Populus simonii Carr., one of the main poplar tree species, is cultivated widely in Northeast and Northwest China in protection and timber forests. Plant phenology plays an important role in timber production by controlling the growing period (i.e., the period between the leaf unfolding and the leaf turning yellow). It is important to understand this control mechanism and to improve the accuracy of the simulation of leaf unfolding phenology for P. simonii in order to determine accurately the timber production of P. simonii plantations. In this study, based on phenological observation data from 10 agricultural meteorological stations in Heilongjiang Province, China, model simulation was employed to determine the control mechanism of leaf unfolding of P. simonii. Furthermore, the predicting effects of nine phenology-simulating models for P. simonii leaf unfolding were evaluated and the distribution characteristics of P. simonii leaf unfolding in China in 2015 were simulated. The results show that P. simonii leaf unfolding is sensitive to air temperature;consequently, climate warming could advance the P. simonii leaf unfolding process. The phenological model based on air temperature could be better suited for simulating P. simonii leaf unfolding, with 76.7% of the calibration data of absolute error being less than three days. The performance of the models based solely on forcing requirements was found superior to that of the models incorporating chilling. If it was imperative that the chilling threshold is reached, the south of the Yunnan, Guangdong, and Guangxi provinces would be unsuitable for planting P. simonii. In this regard, the phenology model based on the chilling threshold as necessary condition was indicated a more reasonable model for the distribution characteristics of P. simonii leaf unfolding.

Pollen development and floral morphology of Populus pseudo-simonii

Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to mature pollen in the green-house. Meiosis of pollen mother cells was regularly applied and completed by a process of simultaneous cytokinesis. Pollen development was considerably asynchronous. The meiotic division was initiated at the bulgy middle position of the flower bud and proceeded towards the tip and base of the bud. The number and size of the nucleoli varied during pollen development and at most eight nucleoli formed in each daughter nucleus at the meiotic telophase, suggesting a paleopolyploid origin of the genus Populus. An association between floral morphology and pollen development was found and the ratio of width to length of flower buds or catkins presented an S-shaped curve related to pollen development as a function of time. The investigation on the pollen development and floral morphology ofP. pseudo-simonii is important for further cross breeding programs of the section Tacamahaca.

小青杨（populuspseud－simoni）生理生态特性的研究

在野外条件下，测定了小青杨树冠不同方向净光合速率和呼吸速率日进程呈双峰曲线形式，双峰出现在上午９时及下午１５时，低谷出现在１３时，即“午睡现象”，这与光照强度关系不大，而与环境因子有密切关系。小青杨树冠四个方向的光照强度都呈单峰曲线形式、温度也呈单峰曲线形式，但二者的峰值不同。树冠不同方向水分状况不同，饱和亏缺大者，水势较小，蒸腾强度也小。树冠不同方向，叶绿素含量不一，东面和北面叶绿含量较其他两面高，ａ／ｂ比值小于１。

杨树派间远缘杂种小胡杨(Populus simonii×P.euphratica)组培快繁体系的构建

小胡杨是小叶杨和胡杨远缘杂交选育出的抗旱、耐盐碱优良品种,但是其硬枝扦插生根率低,限制了其大面积推广种植。构建小胡杨组培快繁体系既可实现良种快繁,又可为其持续遗传改良奠定基础。本研究以小胡杨无菌苗为材料,分别利用完全随机区组和单因素试验设计筛选出叶片不定芽再生及生根的适合培养基,并初步探索了再生植株的移栽条件。结果显示,小胡杨叶片不定芽再生的最佳培养基为MS+0.4 mg/L6-BA+0.4 mg/L KT+30 g/L蔗糖+6 g/L琼脂(pH=5.8~6.0),叶片分化率可达(97.61±4.12)%,平均每个外植体产生(1.80±0.66)个不定芽;最佳生根培养基为1/2MS+0.3 mg/L IBA+30 g/L蔗糖+6 g/L琼脂(pH=5.8~6.0),生根率可达(98.67±0.13)%,接种9 d就可生根,接种30 d后,平均根长达(7.27±0.41)cm,平均苗高为(6.44±0.07)cm,单株叶片数达(10.47±0.35)片;将生根培养30 d的再生植株移栽到草炭土∶珍珠岩∶蛭石=3∶1∶1混合的基质中,15 d后成活率可达83.33%。小胡杨组培快繁体系的建立,为实现其无性系大规模繁殖提供了技术支持,同时也为继续开展小胡杨双二倍体诱导奠定了基础。

坝上地区退化小叶杨树干液流特征及对环境因子的响应

【目的】探究华北坝上地区退化和未退化小叶杨蒸腾耗水规律,合理配置生态用水,为小叶杨退化林的修复与重建提供理论参考。【方法】选取未退化、退化小叶杨为研究对象,利用热扩散探针(TDP)测定树干液流量,同时监测气象因子,研究两种小叶杨在不同天气下树干液流特征及其对环境因子的响应机制,分析生长旺季(7、8、9月)两种小叶杨树干液流与蒸腾量。【结果】(1)在不同天气条件下,退化和未退化小叶杨晴天树干液流速率大于雨天与阴天,晴天时两者差距最大,且未退化小叶杨树干液流的启动时间总是早于退化小叶杨;(2)生长季内两种小叶杨树干液流速率差异显著,未退化小叶杨蒸腾耗水量是退化小叶杨的3倍;(3)大气温度和光合有效辐射是影响小叶杨树干液流最主要的环境因子,未退化小叶杨对环境因子响应更敏感。【结论】退化小叶杨较低的蒸腾量难以维持正常生理所需,导致生理衰退,对环境因子变化的敏感性增加,进一步削弱了其应对未来干旱事件的能力。建议对已经发生退化的杨树林分进行更新改造。

转PsnNAC007高耐旱性小黑杨种质创制及其特性分析

小黑杨(Populus simonii×P.nigra)是东北地区速生、耐寒、材性优良的树种。为了创制适种范围广、耐旱性状明显改良的林木新种质,利用小黑杨为材料,以干旱胁迫关键响应因子PsnNAC007转录因子为对象,创制了小黑杨过表达OE-PsnNAC007转基因植株。对OE-PsnNAC007转基因植株的生长指标、干旱胁迫适应能力、净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))、导水率指标、细胞形态和木材组分进行分析。结果显示:与野生型小黑杨相比,转基因植株的生长情况无明显差异,而干旱胁迫成活率提高了26.15%。在干旱胁迫条件下,转基因植株气孔导度减小、蒸腾速率下降、水分利用效率明显提高,植株茎干的导水率损失显著减少。解剖学分析发现,PsnNAC007的过量表达导致植株茎干产生更多、更小的导管细胞,这种细胞特性有利于植株在干旱条件下维持水分连续高效的运输。木材组分分析发现,转基因植株茎干木质素沉积明显增强,构成纤维素、半纤维素的单糖含量均无明显变化。

自然群体小叶杨叶绿素荧光表型变异分析

【目的】通过对我国小叶杨叶绿素荧光表型的分析,多角度展示小叶杨叶绿素荧光表型的多样性,为相关的光合遗传机制的探究奠定基础。【方法】针对我国小叶杨叶绿素荧光参数的表型数据,通过聚类分析、表型可塑性和变异系数计算、动态拟合等方法来探究其变化规律。【结果】(1)在静态光照强度下(同一光强)对小叶杨4类荧光表型进行k均值聚类,最优聚类数目受光照强度影响显著。不同类别下,所研究的经过光系统Ⅱ的电子传递速率(ETR)、PSⅡ实际的光量子产量(Yield)、光化学猝灭系数(qP)、非光化学猝灭系数(qN)4个叶绿素荧光参数具有显著差异。(2)4个小叶杨荧光参数的表型可塑性指数和变异系数的计算结果显示:所选小叶杨群体在可变环境下具有丰富的表型可塑性,随光照强度的逐渐增强,ETR、Yield、qP的表型可塑性呈现出先减后增再减的整体变化趋势,而qN的表型可塑性整体呈下降趋势,这可能与各表型内部的遗传控制有关,也反映了不同表型对梯度光强的不同响应程度;ETR、Yield、qP的变异系数随光照强度的增加呈现出先下降后上升的趋势。qN的变异系数随光照强度的增加而逐渐减小,当光照强度达最大值时,所有类别样本的变异系数均小于0.1。(3)梯度光照强度下,小叶杨叶绿素荧光表型经聚类后可划分为2个大类,经生长方程拟合后可发现,不同类别样本的表型变异速率和最大(最小)值差别明显。【结论】小叶杨叶绿素荧光表型变异丰富,受光照强度的影响显著。通过聚类分析、表型可塑性及变异系数计算和生长方程拟合等方法可以有效地探究小叶杨叶绿素荧光表型的变化规律,为小叶杨遗传分析、光合作用机制挖掘奠定了基础,对小叶杨的培育提供了科学指导。