Effects of Light Stress on Oxygen Evolution and Photochemical Energy Stor age of Hybrid Poplar Clones Determined by Photoacoustic Technique

The oxygen evolution, thermal dissipation, and photochemical energy storage of three hybrid poplar clones, namely the triploid clone B342, the diploid clone B11 [(Populus alba×P. glandulosa)×(P.tomentosa×P.bolleana)], and the triploid clone B346 [(P.tomentosa×P. bolleana)×(P. alba×P.glandulosa)], under light stress were studied using photoacoustics. The oxygen evolution signal and photochemical energy storage varied negatively with the pretreatment_PFD (photon flux density), whereas the thermal signal varied positively with the pretreatment_PFD. Photochemical energy storage was reallocated to PSⅡ more than to PSⅠ, while the photochemical energy storage in PSⅠ was more stable than that in PSⅡ when subjected to light stress. The inhibitors streptomycin (SM), dithiothreitol (DTT) and sodium fluoride (NaF) could all affect the oxygen evolution signal. Clones B11 and B342 were more resistant to light stress than clone B346.

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.

Growth variations and stability analyses of seven poplar clones at three sites in northeast China

Growth characteristics have complex inheritance patterns and genotype(G) by environment(E) interaction make predicting tree response to environmental changes difficult.In this study,the growth of seven poplar clones at three different sites was taken as the research focus,and heights and basal diameters were investigated in the second growing season.An ANOVA showed that all main effects,site,clone number and their interactions were highly significant in the overall F-tests.The coefficients of variation and repeatability of different traits ranged from 15.5 to 43.9%and from 0.549 to 0.912,respectively.AMMI(Additive Main Effects and Multiplicative Interaction) analysis results showed that genotype,environment and G × E interaction were significantly highly correlated.The stability analysis indicated that different clones showed different growth traits on different sites,which suggests that elite clones should be selected separately for different sites.Based on the growth traits,under a 10% selection rate,three clones were selected for different sites and the genetic gains of growth traits ranged from 4.7 to 11.2%.The three selected clones could be used to establish plantations in the future in different sites.

Temporal and spatial changes in Bt toxin expression in Bt-transgenic poplar and insect resistance in field tests

Extensive planting of Bacillus thuringiensis （Bt）-transgenic plants economically benefits society; how-ever, the potential risk they pose is receiving increasing attention. This study used enzyme-linked immunosorbent assay and fluorescence quantitative PCR （RT-PCR） to monitor the temporal and spatial dynamics of the expression of Bt toxic protein in a forest of 6- to 8-year-old trees of transgenic insect-resistant poplar 741 for three consec- utive years. The enrichment, distribution, and degradation of Bt toxic protein and the influence of transgenic poplars on the targeted insect population, Hyphantria cunea, were investigated. The content of CrylAc toxic protein dynamically changed in transgenic poplar. During the annual growth cycle, the content initially increased, then decreased in the long and the short branches of the crown and in the root system, peaking in August. During the study, the protein did not accumulate overtime. The mRNA transcription of gene CrylAc was almost consistent with the level of the protein, but transcription peaked in July. In the transgenic and control forestland, microscale levels of the CrylAc toxic protein were detected from the soil, but increased accumulation was not observed with the planting year of transgenic poplar. Meanwhile, Bt was isolated and detected molecularly from the soil in the experimental forestland. A systematic investigation of the density of H. cunea in the experimental transgenic poplar forest indi- cated that transgenic Pb29 poplar could resist insects to a certain degree. At peak occurrence of the targeted insects, the density of H. cunea in the experimental forest was significantly lower than in the nontransgenic poplar forest.

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.

中国杨树杂交育种研究进展

对我国 5 0余年杨属派内和派间杂交育种研究进行了综述。在众多的杨树杂交组合中 ,派内种间杂交以白杨派、黑杨派成就显著 ,派间杂交以青杨派与黑杨派杂交成果最为突出。从杂交方式看 ,有单交、双交、三交、回交等 ,以杂种作亲本进行再杂交能够获得显著杂种优势 ;从育种目标看 ,有速生、抗寒、抗旱、抗病虫、窄冠、生根等 ;从育种方法看 ,以常规人工杂交为主 ,将常规人工杂交与物理辐射、化学诱导等技术有机结合 ,能够创造出生产潜力较大的三倍体新品种。选育的杨树良种已在生产中产生了巨大的经济效益、生态效益和社会效益。最后 ,对目前我国杨树杂交育种中存在的主要问题以及应对策略进行了讨论。

转双抗虫基因741毛白杨的选择及抗虫性

用部分改造BtCrylAc基因与慈菇蛋白酶抑制剂 (API)基因构建的双抗虫基因表达载体 ,通过农杆菌介导法转化了 741毛白杨 [PopulusalbaL .× (P .davidianaDode +P .simoniiCarr .)×P .tomentosaCarr .]。本文报道了选择转化植株的条件。在含卡那霉素 (Km’)的生根培养基中初步选择到转化植株 ,PCR检测表明 80 %的植株呈现阳性反应。对初步选择的转基因植株用杨扇舟蛾 (ClosteraanachoretaFabricius)和舞毒蛾 (LymantriadisparLinnacus)幼虫进行饲虫试验。其结果按照死亡率划分了高、中、低和对照 4类昆虫死亡率的植株 ,并对这 4类的定期死亡率、生长发育的延迟性后效应等进行了比较研究 ,为选择具有显著抗虫性的植株 (无性系 )提供依据。分子生物学检测结果 ,证明被选择植株 (无性系 )的基因已转入 ,且生长发育正常 ,占参试饲虫试验植株的 38 1 %

杨树新杂种的SSR分析及鉴定

以2个杨树杂交新品种(编号分别为:02-9-22,02-12-29)及其亲本和毛白杨无性系30号为材料,从36对SSR引物中筛选出在杂交新品种双亲之间多态性明显、重复性比较好的12对引物,用于杨树的遗传变异分析。共扩增出125个DNA片段,其中111个片段呈现多态性,占总扩增片段的88.8%,片段大小介于80～1 000bp之间。基因型间的平均遗传相似系数为0.445 9。聚类分析结果表明,杂交种与亲本的亲缘关系较近,与毛白杨30号的亲缘关系较远。选用3对引物构建5个杨树品种的指纹图谱,在该图谱中,每个品种都有自身独特的片段。

白杨派杂种无性系植株早期性状变异与选择研究

以30个白杨杂种无性系为材料,测定树高、胸径、树形、叶片、树皮特性等17个指标。方差分析与遗传参数计算结果表明,白杨杂种无性系各指标差异极显著(P<0.001),各指标表型变异系数变化范围为15.63%～57.50%,遗传变异系数变化范围为8.99%～52.57%,重复力高(0.7734～0.9848)。说明白杨杂种无性系各性状存在广泛变异,且这种变异受较强的遗传因素控制。表型相关结果表明,白杨杂种无性系树高、地径、胸径、单株材积和冠幅之间均达显著相关水平,遗传相关系数接近表型相关系数。主成分分析结果显示,白杨杂种无性系14个性状前3个主成分的累积贡献率为84.93%,其中第1主成分为生长量等性状,第2主成分为干形等性状,第3主成分为叶片性状。利用综合评定法对无性系进行评价,当入选率为10%时,无性系BL204、BL206和BL207入选,入选无性系树高、地径、胸径和单株材积的遗传增益分别为27.41%、31.73%、32.90%和102.37%。这些分析结果为下一步选育优良无性系提供了重要的信息和依据。

杨树体细胞融合研究

为克服有性杂交障碍 ,利用原生质体电融合技术开展杨树体细胞融合研究。本研究选择杨树不同种或无性系分离原生质体 ,并应用IOA和X 射线分别对融合双亲处理 ,使其失去分裂能力 ,筛选杂种细胞 ,并探索杨树原生质体融合的最适电场参数与培养条件 ,建立杨树体细胞电融合体系。首次得到了美洲黑杨 +胡杨、青杨 +胡杨、美洲黑杨 +青杨等体细胞杂种愈伤组织。其中美洲黑杨 +胡杨、青杨 +胡杨体细胞杂种愈伤组织可在附加 0 .4%氯化钠的培养基上生长 。

杨树新杂种无性系生长与材性的联合选择

以青海省西宁市湟水林场9年生10个杨树新杂种无性系为材料，对生长和材性等9个性状进行了方差分析和遗传参数估算。研究结果表明，树高、胸径、材积、Pilodyn值、南向外侧基本密度、整株木材基本密度、纤维长度、纤维宽度、纤维长宽比在无性系间存在极显著或显著差异。无性系8-25的材积最高，为0．213 m3；8-24的最低，为8-25的14．5％。各性状的重复力在0．711～0．977，其中树高重复力最高，为0．977，纤维长度的最低，为0．711，胸径和材积的均高于0．900。 Pilodyn测定结果与木材密度的相关分析结果表明无性系Pilodyn平均值、南向外侧木材基本密度平均值和整株木材基本密度平均值间存在极显著的相关关系，相关系数为-0．846～0．981。胸径与树高、材积、南向外侧木材基本密度单株间存在极显著和显著的相关关系，相关系数分别为0．852、0．962和0．462。通过对10个无性系生长和材性之间的相关分析，发现杨树新杂种无性系胸径、材积、纤维长与南向外侧整株木材密度显著相关；参试无性系与对照北京杨和青杨比较，杂种无性系都超过青杨对照，有两个超过了北京杨，整株木材密度与对照相近，差异不显著。利用多性状主成分分析，选出8-6、8-16、8-25综合性状表现优良的无性系，其中8-25生长最好，胸径分别是对照青杨、北京杨的1．14、1．61倍，单株材积分别是对照青杨、北京杨的1．80、5．76倍。

水分胁迫下白杨双交杂种无性系苗木生长研究

以白杨双交杂种无性系为材料 ,在水分胁迫条件下 ,对无性系幼苗的生长进行了研究。结果表明 ,水分胁迫对叶片、苗高和生物量生长均产生显著影响。轻度水分胁迫即可使苗木叶面积生长受到抑制 ,随着水分胁迫的加剧 ,叶片速生期有提前的趋势 ,速生期持续时间有延长趋势 ,但受胁迫的苗木绝对生长速率较低 ,没有明显的生长高峰期出现 ,造成单叶面积随水分胁迫的发展而显著减小。水分胁迫对叶面积的影响大于对苗高生长的影响 ,在供水量为 6 0 %时 ,苗高生长才受到明显抑制。根、茎、叶干物质积累以供水量 80 %最为适宜 ,供水量进一步下降 ,各部分干物质积累逐渐受到抑制 ,茎和叶生物量受抑制最明显 ,根生物量受影响相对较小 ,因此随着水分胁迫的发展 ,茎 根比值表现为明显的下降趋势。不同无性系在各生长指标上和各指标随水分胁迫下降幅度上均存在着显著差异。大部分指标间表现为正相关关系 。

利用SSR对杨属部分种及杂种的分析鉴定

利用SSR标记对17个杨树优良品种进行遗传多样性分析。从25对杨树引物中筛选出12对优良引物并进行PCR扩增,共扩增出138个位点,其中多态性位点133个,所占比率为96.38。基因型间的平均遗传距离为0.243。聚类分析结果表明,各杨树品种间存在一定的遗传差异,同时也较准确的进行了各优良品种的分子鉴别。

10个杨树杂种组合木材密度与纤维遗传变异研究

对保定5年生杨树无性系测定林和7年生育种资源保存林10个杂交无性系木材密度,纤维长、宽度分析结果表明:①不同杂种组合、个体间的木材密度、纤维长度均有很大变异。木材密度与速生特性之间呈微弱的负相关;纤维长度与生长性状相关不显著。②木材密度和纤维长度可以独立选择,从而选出密度较高,纤维较长和速生优质的杨树杂交新个体。③幼龄与中、成龄的木材密度相关显著,从而说明了在杨树材性育种中早期选择的可行性。研究证明,对华北地区来说,69杨为母本,欧亚黑杨及其种内杂种为父本是选育速生优质杨树新品种的优良组合。

不同地点白杨杂种无性系生长和适应性表现分析和评价

以不同地点30个白杨杂种无性系为材料，对其2—4年生树高、胸径和材积进行调查分析。结果表明：白杨杂种无性系树高、胸径和材积在无性系间、地点间、无性系和地点的交互作用间差异均达极显著水平；树高、胸径和材积的表型变异系数、遗传变异系数及重复力均随着树龄的增加而增大，且遗传变异系数占表型变异系数的比例随着树龄的增大而增加；随着树龄的增长，白杨杂种无性系变异增大，但这种变异主要由遗传因素控制。相关性分析结果表明，所有性状相关性均达到极显著正相关水平（0．4042～0．9887），表明植株在生长过程中各指标相互联系密切。稳定性分析结果表明，无性系BL28、BL103和BL49是较稳定无性系，而BL106、BL107等无性系稳定性较差，对不同地点有特殊的适应性。利用综合评价法，以20％的人选率对无性系进行选择，不同地点无性系BL104、BL106和BL107均可以入选，表明这3个无性系不仅对不同地点有特殊的适应性，而且在不同地点均表现优良，本研究对后续新品种选育很有价值。

84K杨的生长特性及杂交可配性

经过多年育苗、造林试验及相关研究,得出了84K杨的生长特性主要表现为:生长迅速,1年生苗通直高大,平均高3.5m左右,最高达5.0m;苗木速生期出现在6、7月份,苗高、地径生长量分别占全年总量的64.5%和46.4%。对比试验林中材积生长量比毛白杨高79.8%,比毛白杨3个优良无性系大11.3%;抗病性强,3年生对比林中84K杨对主要病害黑斑病、叶枯病和锈病的感病指数分别为1.60%、1.18%和0.28%;对干部溃疡病,生长旺盛的植株几乎不感染;抗寒、抗旱性强,84K杨的抗寒、抗旱性比新疆杨、M101杨、毛白杨30号都强;根系发达,根蘖能力强,育苗成活率高;84K杨作亲本的杂交组合杂交可配性好,杂种优势强,是很好的杂交亲本。

转双抗虫基因741杨的抗虫效应及其规律研究

通过室内饲虫试验 ,应用昆虫的总死亡率、各龄期死亡率、各龄历期及发育速率、昆虫体重增长速率等指标 ,测定了转双抗虫基因 74 1杨的抗虫性。研究结果表明 ,转基因抗虫杨不同株系对昆虫的致死效应有显著差异 ;不同昆虫种类和同一昆虫幼虫的不同龄级对转基因杨株系的敏感性有明显差异 ,4种测试昆虫的敏感性强弱依次为 :杨小舟蛾 >美国白蛾 >杨扇舟蛾 >舞毒蛾 ,随着昆虫幼虫龄级的增加 ,昆虫对转基因杨株系的敏感性逐渐降低 ;高抗虫株系主要表现为对低龄幼虫的强致死作用 ,中等抗虫株系表现为对各龄幼虫稍低的但是持续的致死效应 ;各转基因杨株系对测试昆虫的生长和发育都有明显抑制作用 ,可导致昆虫的发育历期延长、发育速率和体重增长速率降低。

3种杂交杨在不同盐碱地上的生长和生理适应性研究

杂交杨树是松嫩平原盐碱地重要的园林和造林树种,野外长期监测是评价和优选优良品种的关键。本研究在自然条件下(5～12月),以大庆不同盐碱地上生长的青山杨(Populus pseudo-cathayana×P.deltodides cv.Shan Hai Guan)、小黑14(Populus×xiao hei T.S.Hwang et Liang‘14’)及中黑防(Populus deltoids×P.cathayana)的4年生扦插苗为研究对象,通过对3种杂交杨生长量、根系活力、根呼吸量和叶绿素含量的对比和分析,探讨其在盐碱地生长的适应性及耐盐能力的差异。结果表明,随盐碱胁迫加强(土壤电导率609.33～910.48μs.cm-1,pH值(8.92～8.98),各杂交杨的生长量受到明显抑制,其中中黑防和小黑14株高均下降达到40%,而青山杨的株高只下降了20%,是前者的一半。随盐碱胁迫加强,根系活力和呼吸作用增强,青山杨、中黑防和小黑14的根系活力分别提高了10.75%、15.90%和33.17%,而根系呼吸青山杨仅上升3.59%,中黑防和小黑14则上升了24%以上。但是盐碱胁迫对于叶绿素含量影响较小,年平均值稍有降低,叶绿素a/b的比值则增大,不同品种间差异较小。综合对3种杂交杨的各项指标的研究,青山杨的耐盐碱能力更强,生长量显著高于目前在盐碱地区较为普遍应用的小黑14和中黑防,比较而言,青山杨是盐碱地区造林与绿化树种的优良杂交杨品种。

转基因741杨抗虫性研究

采用群体和单体饲养的方法,用转双抗虫基因741杨叶片饲养舞毒蛾和美国白蛾幼虫,测定其死亡率、各龄期的发育速率、体重增加速率和取食效率。结果表明:4个转双抗虫基因的741杨株系对舞毒蛾和美国白蛾均有明显抗虫效果,主要表现为对低龄幼虫的毒杀作用和对高龄幼虫生长发育的抑制作用。用转抗虫基因杨树叶片饲养的昆虫幼虫死亡率均高于对照,最高可达100%,而且,可导致存活幼虫的不正常的发育,使其发育历期明显延迟,发育速率、体重增加速率和取食增长率均显著降低。

4种杂交杨对土壤水分变化的生态学响应

以田间持水量的100%(T1,对照)、70%(T2)、50%(T3)和30%(T4)为4个水分处理梯度,比较研究了4种不同品系的杂交杨(Populus)——15-29(P.trichocarpa×P.deltoids)、DN-2(P.deltoids×P.nigra)、DN-14274(P.deltoids×P.nigra)和R-270(P.deltoids×P.nigra)在不同水分处理和不同处理阶段对水分亏缺的反应。结果表明,4种杂交杨品系对水分亏缺较敏感,都通过关闭气孔、降低叶面积以有效地调节水分的散失,降低光合速率、蒸腾、水势,增加水分利用效率,改变生物量的分配等一系列生理适应机制以及形态策略,来应对不同程度的水分亏缺,只是不同品系的适应程度不同。在生物量分配上,R-270主要降低叶干重,而其它3个品系的叶、茎和根干重全部降低;随着水分亏缺的加重,15-29和R-270的根冠比增加,根部获得更多的同化物分配,从而有利于水分的吸收,增加其抗旱性。DN-2的碳同位素组成δ13与水分利用效率呈显著正相关(r=0.631,p<0.01)。而R-270的δ13与水分利用效率呈负相关,但不显著,只有在处理T4下呈显著负相关(r=-0.732,p<0.01),表明土壤水分影响了碳同位素的分馏,不同品系相反的结果表明同位素分馏的遗传变异。与T3和T4相比,T1和T2处理的苗木具有较高的生物量、叶面积、光合速率、蒸腾、水势以及气孔导度,说明4个杂交杨品系在充足或适当的灌溉条件下具有较高的生产力。在T3和T4处理下,4个品系表现出不同的生存策略,但生产力均较低,因此在干旱胁迫下很难形成高生产力。与DN-2和DN-14274相比,15-29和R-270对水分胁迫表现出更强的适应性反应,具有较强的抗旱性,可用作防护林品种。