Application of polygene polymerization for insect-resistant poplar breeding

A major goal of poplar breeding is to obtain new insect-resistant poplar varieties through genetic engineering.However,engineering poplars with only a single insect-resistant gene has limitations,such as narrow insecticidal bands and the rapid development of insect tolerance to the gene.To expand insecticidal bands,delay the development of insect tolerance,and improve the insect resistance of transgenic poplars,polygene polymerization is increasingly being applied to cultivate insect-resistant poplars.In the present study,we discuss polygene polymerization,applications of the polygene combination strategy,the current state of research on transgenic poplar with multiple insect-resistant genes,including existing problems,and future research directions.We provide reference data to aid the cultivation and utilization of new polygenic insect-resistant poplar varieties.

Importance of oxygen-containing functionalities and pore structures of biochar in catalyzing pyrolysis of homologous poplar

Biochar and bio-oil are produced simultaneously in one pyrolysis process,and they inevitably contact and may interact,influencing the composition of bio-oil and modifying the structure of biochar.In this sense,biochar is an inherent catalyst for pyrolysis.In this study,in order to investigate the influence of functionalities and pore structures of biochar on its capability for catalyzing the conversion of homologous volatiles in bio-oil,three char catalysts(600C,800C,and 800AC)produced via pyrolysis of poplar wood at 600 or 800℃or activated at 800℃,were used for catalyzing pyrolysis of homologous poplar wood at 600℃,respectively.The results indicated that the 600C catalyst was more active than 800C and 800AC for catalyzing cracking of volatiles to form more gas(yield increase by 40.2%)and aromatization of volatiles to form more light or heavy phenolics,due to its abundant oxygen-containing functionalities acting as active sites.The developed pores of the 800AC showed no such catalytic effect but could trap some volatiles and allow their further conversion via sufficient aromatization.Nevertheless,the interaction with the volatiles consumed oxygen on 600C(decrease by 50%),enhancing the aromatic degree and increasing thermal stability.The dominance of deposition of carbonaceous material of a very aromatic nature over 800C and 800AC resulted in net weight gain and blocked micropores but formed additional macropores.The in situ diffuse reflectance infrared Fourier transform spectroscopy characterization of the catalytic pyrolysis indicated superior activity of 600C for removal of -OH,while conversion of the intermediates bearing C=O was enhanced over all the char catalysts.

Factors affecting poplar wetwood characteristics

Wet wood is an abnormal phenomenon in growing trees,which adversely affects growth,subsequent wood processing and economic values of wood products.In this study,the influences of factors such as clones,afforestation methods,site conditions and climate conditions on the characteristics of poplar wetwood were studied through field investigations in 27 clones from 48 sample plots in 28 counties.Results showed that the incidences of wetwood were almost 100%in all plots.Ratios of wetwood area among the48 plots differed from 15.1 to 90.2%.Wetwood area ratios,moisture contents and pH differed significantly between the 27 clones.Wetwood area ratios of the clones ranged from18.7 to 62.3%.Ratios of wetwood areas were positively correlated with wet wood moisture content and pH,tree age,and negatively correlated with pH of sap wood.The repeatability of wet wood area ratios was 0.52,moderately controlled by genetics.Wetwood moisture content and pH were highly controlled by genetics,indicated by the repeatability of 0.91 and 0.89,respectively.There were significant differences in wetwood area ratios,moisture content and pH between different site conditions,afforestation methods,and geographical regions.Sloping land had the lowest wetwood area ratios and moisture content among four types of sites.Afforestation by direct seeding and rooted cuttings had the lowest wetwood area ratios and moisture content,respectively.In the three geographical regions,the Yellow River Basin had the lowest wetwood values of all three factors.

Study on Insect-resistant Transgenic Cotton Harbouring Double-gene and Its Resistance to Insect Pests

By using the method of pollen tube pathway, the synthesized GFM CryIA gene and modified CpTI gene were transfered into the elite cotton( Gossypium hirsutun L. ) varieties(lines). Through the field and lab identifications, the insect-resistant transgenic plants were obtained. PCR analysis indicated that both the synthesized GFM CryIA gene and modified CpTI gene presented positive reaction. In R1 the boliworm resistance of each transformant was different, and the insect-resistance of R3 of ZGK9708 was stable.

Selecting the Technology of Sodium Silicate Modified Poplar with the Highest Performance by Fuzzy Orthogonal Method

Sodium silicate modification can improve the overall performance of wood.The modification process has a great influence on the properties of modified wood.In this study,a new method was introduced to analyze the wood modification process,and the properties of modified wood were studied.Poplar wood was modified with sodium silicate by vacuum-pressure impregnation.After screening using single-factor experiments,an orthogonal experiment was carried out with solution concentration,impregnation time,impregnation pressure,and the cycle times as experimental factors.The modified poplar with the best properties was selected by fuzzy mathematics and characterized by SEM,FT-IR,XRD and TG.The results showed that some lignin and hemicellulose were removed from the wood due to the alkaline action of sodium silicate,and the orderly crystal area of poplar became disorderly,resulting in the reduction of crystallinity of the modified poplar wood.FT-IR analysis showed that sodium silicate was hydrolyzed to form polysilicic acid in wood,and structural analysis revealed the formation of Si-O-Si and Si-O-C,indicating that sodium silicate reacted with fibers on the wood cell wall.TG-DTG curves showed that the final residual mass of modified poplar wood increased from 25%to 67%,and the temperature of the maximum loss rate decreased from 343℃ to 276℃.The heat release and smoke release of modified poplar wood decreased obviously.This kind of material with high strength and fire resistance can be used in the outdoor building and indoor furniture.

Genetic Transformation of NGc Insect-resistant Gene in Hi-Ⅱ Maize

In order to promote the research of transgenic insect-resistant maize,the target gene were transferred into maize material Hi-Ⅱ by Agrobacterium-mediated genetic transformation of maize embryos,and maize plants with CryNGc insect-resistant genes were cultured by explant infection,co-culture and differentiation screening to study the genetic expression and resistance of exogenous genes in the offspring.The results showed that the infection effect was the best when the size of young maize embryo was 1.2-1.8 mm.Ten positive transformed plants with CryNGc insect-resistant genes were successfully obtained,and the transformation efficiency was 1.428‰.

Function identification of miR159a,a positive regulator during poplar resistance to drought stress

Drought seriously affects the growth and development of plants.MiR159 is a highly conserved and abundant microRNA family that plays a crucial role in plant growth and stress responses.However,studies of its function in woody plants are still lacking.Here,the expression of miR159a was significantly upregulated after drought treatment in poplar,and the overexpression of miR159a(OX159a)significantly reduced the open area of the stomata and improved water-use efficiency in poplar.After drought treatment,OX159a lines had better scavenging ability of reactive oxygen species and damage of the membrane system was less than that in wild-type lines.MYB was the target gene of miR159a,as verified by psRNATarget prediction,RT-qPCR,degradome sequencing,and 5′rapid amplification of cDNA ends(5′RACE).Additionally,miR159a-short tandem target mimic suppression(STTM)poplar lines showed increased sensitivity to drought stress.Transcriptomic analysis comparing OX159a lines with wild-type lines revealed upregulation of a series of genes related to response to water deprivation and metabolite synthesis.Moreover,drought-responsive miR172d and miR398 were significantly upregulated and downregulated respectively in OX159a lines.This investigation demonstrated that miR159a played a key role in the tolerance of poplar to drought by reducing stomata open area,increasing the number and total area of xylem vessels,and enhancing water-use efficiency,and provided new insights into the role of plant miR159a and crucial candidate genes for the molecular breeding of trees with tolerance to drought stress.

Experimental Study of Mode-I and Mode-II Interlaminar Fracture Characteristics of Poplar LVL

Fracture is a common failure form of poplar laminated veneer lumber(LVL).In the present work,we performed an experimental study on the mode-I along-grain interlaminar fracture,mode-I cross-grain interlaminar fracture,and mode-II interlaminar fracture of poplar LVL.We investigated stress mechanisms,failure modes,and fracture toughness values of the different fracture types.The experimental results revealed that the crack in the mode-I along-grain interlaminar fracture specimen propagated along the prefabricated crack direction,and the crack tip broke.The mode-I cross-grain interlaminar fracture specimen had cracks in the vertical direction near the prefabricated crack.In the mode-II interlaminar fracture specimen,cracks appeared along the initial prefabricated crack direction.The load–displacement curves of these three specimens were linear in the early stage of loading.With the increase in the load,a nonlinear segment appeared before crack propagation and a descending segment appeared after crack propagation.The nonlinear segments of the mode-I along-grain interlaminar fracture and mode-II interlaminar fracture were very short,and cracks expanded quickly after their initiation,resulting in brit-tle fracture.The nonlinear segment of the mode-I cross-grain interlaminar fracture was long,resulting in plastic failure.The average toughness values of the mode-I along-grain interlaminar fracture,mode-I cross-grain inter-laminar fracture,and mode-II interlaminar fracture were 15.43,270.15,and 39.72 MPa·mm^(1/2),respectively.

PtrDJ1C,an atypical member of the DJ-1 superfamily,is essential for early chloroplast development and lignin deposition in poplar

The nuclear-encoded factors and the photosynthetic apparatus have been studied extensively during chloroplast biogenesis.However,many questions regarding these processes remain unanswered,particularly in perennial woody plants.As a model material of woody plants,poplar not only has very significant value of research,but also possesses economic and ecological properties.This study reports the Populus trichocarpa DJ-1C(PtrDJ1C)factor,encoded by a nuclear gene,and a member of the DJ-1 superfamily.PtrDJ1C knock-out with the CRISPR/Cas9 system resulted in different albino phenotypes.Chlorophyll fluorescence and immunoblot analyses showed that the levels of photosynthetic complex proteins decreased significantly.Moreover,the transcript level of plastid-encoded RNA polymerase-dependent genes and the splicing efficiency of several introns were affected in the mutant line.Furthermore,rRNA accumulation was abnormal,leading to developmental defects in chloroplasts and affecting lignin accumulation.We concluded that the PtrDJ1C protein is essential for early chloroplast development and lignin deposition in poplar.

Evaluation of Water Transfer Capacity of Poplar with Pectinase Treated under the Solar Interface Evaporation

Poplar wood,which was used as the absorption material for the solar-driven interfacial evaporation,was treated for 3 days,6 days and 9 days with the pectinase,and then was simulated for photothermal evaporation test at one standard solar radiation intensity(1 kW⋅m^(−2)).The effects of pectinase treatment on cell passage and water migration capacity of poplars were analyzed by the mercury intrusion porosimetry,the scanning electron microscope and fractal theory.It was found that the pit membrane and the ray parenchyma cells of poplar wood were degraded and destroyed after pectinase treatment.Compared with the untreated poplar wood,the evaporation rate of three sections of the specimen was changed.Especially the evaporation rate of radial and tangential direction was significantly increased.At the same time,based on the experimental data and fractal dimension deduction,fractal characteristics could be found in that the structure of poplars treated with pectinase.The porosity decreased with the increase of the fractal dimension in a certain range.It was shown that it is feasible to evaluate solar-driven water migration capacity by using fractal theory.

杨树无性系表型性状及ISSR分子标记遗传多样性分析

【目的】综合表型性状及分子标记多样性分析探明供试的62个杨树无性系的遗传多样性,为杨树进一步遗传改良奠定基础。【方法】选取地径、苗高、叶面积、叶长、叶宽、叶柄长、叶绿素、侧枝数、叶厚、单株总叶片、叶片干质量、叶片含水率等12个表型性状和ISSR分子标记对杨树无性系个体间进行遗传多样性分析,利用PopGen 32、SPSS 16.0及NTsys 2.10e等软件分别计算多样性指数、进行表型性状间的方差分析以及对各无性系进行UPGMA法聚类分析。【结果】侧枝数、单株叶片数、叶片干质量、叶面积以及地径的变异系数均达到了10%以上,叶柄长、叶长、苗高的变异系数也达到了8%以上的水平。利用5条ISSR引物检测到62份杨树无性系多态性谱带百分率平均为89.04%,基因多样度平均为0.4074,Shannon多样性指数(I)平均为0.5304。采用UPGMA法构建的形态和分子标记聚类图将供试材料聚成的类群均有家系内聚为一类的趋势,但也存在较大的差异;表型性状聚类分析主要是根据叶片的相关性状相似度越高的被聚为一个类群;分子标记聚类主要呈现出亲缘关系越近的无性系越容易聚为一个类群的聚类规律。【结论】供试的杨树无性系间表型性状分化程度高,具有丰富的遗传多样性,研究结果为杨树种质资源的改良、种质创新及多元化开发利用提供科学依据。

自然干旱后不同系号杨树湿心材的特征

以2017年造林材料为对象,比较不同系号杨树湿心材在大旱前和大旱后的变化差异。结果表明:干旱前和干旱后所有系号杨树的湿心材长度比例均呈显著正态分布。所有系号均存在湿心材现象,且整体上湿心材比较严重。杨树径生长由于干旱受到了严重抑制,但随着直径的增加及干旱的影响,湿心材长度比例继续增大,木芯含水率略有下降,干旱会减轻湿心材的危害。不同材料湿心材的pH差异不显著,均为弱碱性,江汉平原主栽的4个品种插干造林生长速度有一定优势,但湿心材相比带根造林更为严重一些。对连续2 a的湿心材特征进行相关分析,发现湿心材主要特征之间存在极显著正相关。

菌丝体-杨木颗粒多孔复合材料的制备及保温阻燃性能研究

石油基高分子多孔材料的大量使用导致了严重的塑料污染(“白色污染”)。在这项工作中,采用了一种绿色可持续的合成策略,通过在杨木颗粒上接种培养真菌菌丝体,使其生长贯穿整个颗粒,最终制备出了一种菌丝体-杨木颗粒多孔复合材料。结果表明,多孔复合材料具有较低的密度(0.165 g·cm^(-3))、较高的孔隙率(82.7%)和疏水性(接触角:131.8°),并展示出优异的力学性能(压缩强度2.39 MPa;杨氏模量9.79 MPa)。另外,多孔复合材料还具有较低的导热系数(0.066 W/mK)和优异的阻燃性能(氧指数为28.4%)。这项研究工作展示了一种简捷和清洁环保的菌丝体-杨木颗粒多孔复合材料制备方法,对农林生物质高值化利用具有重要的参考价值。

基于AE-BP模型的杨木胶合板应力损伤识别

【目的】利用声发射(AE)技术对应力损伤全过程中的杨木胶合板进行无损检测,并利用BP神经网络对AE检测结果进行识别,以提高胶合板损伤检测精度。【方法】以市场占有量较高的托盘用杨木胶合板作为研究对象,在联合AE和应力损伤试验过程中,提取6个AE特征参数,利用声发射RA-AF联合分析法区分杨木胶合板产生裂纹的类型,采用K-均值聚类分析方法确定损伤演化程度和AE特征参数之间的对应关系,利用BP神经网络建立损伤识别模型,并对识别网络进行测试训练。【结果】AE信号幅度和上升时间可有效地表征杨木胶合板应力损伤从微裂纹萌生、产生宏观裂纹至完全断裂的损伤演化过程;通过RA-AF联合分析发现:杨木胶合板在应力损伤试验第一阶段主要为剪切破坏损伤,第二、三阶段主要为拉伸破坏损伤;通过K-均值聚类分析发现损伤类型与AE峰值频率之间的存在较强对应关系,可有效的表征不同的损伤类型:在31 kHz内为基体开裂,在31~100 kHz内为脱胶分层,大于100 kHz为纤维断裂;构建AE-BP神经网络模型对应力损伤类型训练样本的拟合优度是95.94%,测试集的拟合优度是98.89%,模型总拟合优度是96.51%,网络训练效果较好。【结论】在应力承载AE监测过程中,通过构建AE-BP模型,可对杨木胶合板产生的未知损伤进行有效检测并准确识别。

杨叶枯病病原菌生物学特性、防治药剂筛选及杨树抗病性评价

为防治杨树叶枯病,利用单因素试验,对中荷64杨(P.×euramericana cv.‘N3016’)上分离获得的链格孢菌(Alternaria alternata)进行了生物学特性及室内防治药剂筛选研究,并开展了不同品种杨树抗叶枯病综合评价。结果表明:链格孢菌菌丝生长的适宜培养基为马铃薯蔗糖琼脂培养基,适宜碳源为玉米粉,适宜氮源为酵母提取物,适宜培养温度范围为25~30℃,适宜pH为8,光照条件对菌丝生长影响不大,致死温度为52℃。采用生长速率法进行室内防治药剂筛选,结果显示,选用的5种生物制剂防治效果优于2种化学药剂,各药剂抑制作用排序从大到小依次为哈茨木霉(3亿菌落/g)、枯草芽孢杆菌(100亿芽孢/g)、质量分数为10%的多抗霉素、质量分数为3%的中生菌素、质量分数为2%的宁南霉素、质量分数为50%的多菌灵、质量分数为75%的百菌清,将哈茨木霉(3亿菌落/g)和枯草芽孢杆菌(100亿芽孢/g)作为防治链格孢菌的适宜药剂。选用7个黑杨派品种杨树,利用模糊数学隶属度函数法,开展了杨树抗叶枯病综合评价,确定中荷64杨为高感品种,中辽1号杨和欧美杨177为中感品种,渤丰1号杨、渤丰3号杨、辽育3号杨和欧美杨111为高抗品种。

杨木旧材高温作用后力学性能试验研究

依托新疆玉儿滚军垦旧址保护项目,采用火灾后未过火原木制作杨木旧材的标准无疵小试样,考虑温度、恒温时间两种因素高温处理试样并进行抗拉、抗压力学性能试验,探究木材顺纹和横纹方向上的主要力学性能演化规律。在试验基础上,建立了顺纹杨木旧材抗压本构模型。试验结果表明:高温处理后,顺纹木材抗压强度整体下降幅度为15%~30%,横纹木材抗压强度整体下降幅度为20%~50%;顺纹木材和横纹木材的抗拉强度均显著下降,为25%~62%。建立的本构模型曲线与试验结果相比,误差在10%以内,可适用于相应木材力学性能分析。

杨树溃疡病拮抗菌防治机制研究进展

随着杨树栽植面积不断扩大,杨树溃疡病发生趋重,对树木造成严重损害。杨树溃疡病主要防治手段为化学药剂,但环境污染和病原菌耐药性等问题越发严重,需开发无污染且防治有效的技术或策略。以植物根际微生态组学为研究手段,可获得提升植物抗病能力的有益微生物。这些拮抗菌能够抑制溃疡病原菌的生长且无环境污染,具有很好的生物防治潜力。鉴于此,本综述主要探讨拮抗菌对防治杨树溃疡病的作用方式,包括通过养分水分竞争和分泌抑菌物质抑制病原菌生长,提高植物抗病性抵御病原菌侵染,以及提高宿主自身的活性氧耐受性等机制。未来利用多组学手段,将微生物培养与宏基因组学、代谢组学充分结合,进一步探究拮抗菌的协同作用机制,将有助于开发高效、稳定、环保的微生物菌剂;同时,寻找合适的纳米材料作为载体,构建能最大限度发挥拮抗菌功能的菌剂体系,也是未来生物控制剂研发的重要方向之一。

五个杨树品种生长、光合生理及根尖离子流速特性比较分析

通过比较不同品种杨树(Populus)的生长、光合生理及根尖离子流速特性差异,为速生适应性强品种的早期选育提供参考。以渤丰3号杨(P.×euramericana‘Bofeng 3’)、渤丰1号杨(P.×euramericana‘Bofeng 1’)、西雄1号杨(P.×euramericana‘Xixiong 1’)、中雄7号杨(P.×euramericana‘Zhongxiong 7’)和中雄4号杨(P.deltoides×P.suaveolens cl.‘Zhongxiong 4’)5个杨树品种1年生苗为研究对象,于正常培养条件下的试验开始和试验结束(30 d)时分别测定株高、地径等生长指标,并于10、20、30 d时分别测定幼苗的叶片数量、单叶面积、叶长、叶宽、瞬时净光合速率(P_(n))、胞间CO_(2)摩尔浓度(C_(i))、气孔导度(G_(s))、蒸腾速率(T_(r))、叶绿素相对含量以及根尖K^(+)、Ca^(2+)、H^(+)流速等指标,经过30 d的正常管理,5个品种的株高生长量之间的差异达到显著水平,由高到低依次为中雄4号杨、西雄1号杨、渤丰3号杨、中雄7号杨、渤丰1号杨;其中光合特性指标和蒸腾速率渤丰1号杨均表现为最大,中雄4号杨均表现为最小,但是中雄4号杨的单叶面积((57.49±2.37)cm^(2))、总叶面积((1721.10±28.59)cm^(2))、单株净光合速率((17863.10±910.21)μmol·m-2·s-1)和水分利用率((3.15±0.06)μmol·mmol^(-1))均表现为最大,且K^(+)外排流速最慢,为(62.68±0.45)pmol·cm^(-2)·g^(-1),Ca^(2+)内流流速最快,为(-74.24±1.29)pmol·cm^(-2)·g^(-1),而渤丰1号的单株净光合速率((8539.70±164.64)μmol·m-2·s-1)和水分利用率((2.64±0.07)μmol·mmol^(-1))最小,且K^(+)外排流速((130.81±1.71)pmol·cm^(-2)·g^(-1))最快,Ca^(2+)内流流速((-34.43±0.84)pmol·cm^(-2)·g^(-1))最慢。综上所述,5个杨树品种中,中雄4号杨总叶面积、单株净光合速率、水分利用率最高,蒸腾速率最小,根尖K^(+)外排流速最慢,Ca^(2+)内流流速最快,植物体内K^(+)、Ca^(2+)离子含量最多,H^(+)最活跃,株高生长表现最好,可能具有潜在的较强环境适应能力,适宜种植的范围更广。

转抗虫基因107杨对根际和内源细菌群落的影响

为研究转抗虫基因对根际和内源细菌群落的影响,以转抗虫基因107杨田间对比试验林为对象,采用高通量测序技术对转基因株系和对照株系根际土壤细菌、树干韧皮部和根系内生细菌群落结构组成及多样性进行对比分析。结果显示:(1)土壤样品中有效序列平均在30000以上,杨树组织有效序列平均在300000以上。(2)转基因株系细菌物种组成与对照株系的极其相似,酸杆菌门与变形菌门为转基因和非转基因株系根际土壤的优势菌门,占比分别为16.6%和21.9%;蓝藻菌门和变形菌门为转基因和非转基因株系韧皮部的优势菌门,所占的比率分别为54.8%和59.2%;变形菌门为转基因和非转基因株系根部的优势菌门,所占的比率分别为40.7%和58.8%。(3)转基因和非转基因株系在细菌群落的丰富度和多样性上均没有表现出明显的差异,但不同部位之间差异显著。结果表明:转基因107杨没有对根际土壤和内生细菌造成显著影响,明确了转抗虫基因107杨不同部位细菌群落特征,为转抗虫基因107杨的生物安全评价提供了有益的参考。

株行距配置和无性系对杨树人工林碳储量的影响

为探究不同株行距配置和无性系对杨树人工林碳储量的影响,采用林木生物量直接收获法对13年生南林-895杨(NL-895)4种株行距配置(6 m×6 m、4.5 m×8.0 m、5 m×5 m、3 m×8 m)、南林-95杨(NL-95)和南林-797杨(NL-797)6 m×6 m株行距配置林分的碳储量进行了研究。结果表明:不同林分单株生物量存在显著差异(P<0.05),以6 m×6 m株行距配置模式的NL-895单株生物量最高(400.96 kg·株^(-1));4种株行距配置的NL-895林分的生物量不存在显著差异,但在6 m×6 m株行距配置林分中,NL-895和NL-95的生物量显著高于NL-797(P<0.05)。杨树人工林各器官的碳含量(质量分数)在39.79%~47.76%之间,表现为树干>树枝>根系>树叶;不同株行距配置林分的林木碳储量变异趋势与林分生物量相似,6 m×6 m株行距配置NL-895林分的林木碳储量最高,3 m×8 m株行距配置的NL-895林分的林木碳储量最低。不同无性系和株行距配置对杨树人工林土壤(0~100 cm)碳储量有一定影响但不显著,其碳储量约占杨树人工林碳储量的71.7%。同一无性系不同株行距配置林分的总碳储量存在显著差异(P<0.05),而同一株行距配置不同无性系林分总碳储量无显著差异。总体来看,6 m×6 m株行距配置的NL-895林分总碳储量最大(192.46 t·hm^(-2)),分别是4.5 m×8.0 m、5 m×5 m、3 m×8 m株行距配置林分的1.17、1.31、1.38倍。综上所述,在江苏省类似的立地条件下,建议选择NL-895、株行距6 m×6 m的均匀配置作为碳汇林营造的经营模式。