北京常见的毛白杨和加拿大杨的主要区别

人们通常爱说杨树、柳树。其实杨树和柳树都有很多种。北京最常见的杨属种类是加拿大杨(Populus canodensis)和毛白杨(P.tomentosa);做为行道树在市区随处可见。但人们往往把两个不同的树种混为一谈,其实二者是有很多区别的。从树干和芽的形态来看:毛白杨树皮较光滑,为灰绿或灰白色,且带眼状皮孔;芽短粗、卵圆形。而加拿大杨树干灰褐色,有纵裂条纹,树皮粗糙;芽细长、圆维形。二者开花时间、花和果实的形态都不同。毛白杨花期较早,大约在三月下旬。花的苞片深褐色,边缘密生白毛。雄花序苞片不落,苞片比雄蕊长,能盖住雄蕊;雄蕊花药褐色。雌花序上花密集;果实密生,长圆锥状,果柄很短。加拿大杨花期比毛白杨晚一周左右。苞片白     

芽变毛白杨生根相关基因片段的克隆与序列分析

目的:克隆芽变毛白杨生根相关基因片段.方法:采用诱导生根和抑制生根两种处理,分别提取芽变毛白杨(Mutant Populus tomentosa)皮部 RNA,进行逆转录和差异显示,筛选和克隆特异片段.结果:研究表明不同处理基因表达有一定差别.经Northem鉴定,诱导生根处理的扩增产物中有一条与生根相关的差异片段.将其克隆和测序,该片段编码序列长度 316bp.Cen Bank 中查询没有发现同源性较高的基因.结论:成功地获得了长度 316bp 的芽变毛白杨生根相关基因片段,可能为新基因的一部分.该基因片段的获取将为分离全长生根相关基因,查明该基因表达调控的机理提供基础.     

葡萄早熟芽变与其亲本果实发育特征比较分析

‘峰早’和‘洛浦早生’葡萄分别是‘巨峰’和‘京亚’的早熟芽变,本研究对比分析了早熟芽变与其亲本间在果实发育过程中与成熟有关的生理指标动态变化的差异。结果表明,与亲本相比,两个早熟芽变品种在果实横径、纵径、单粒重的增长速率,叶绿素、类黄酮和总酚含量变化趋势,以及β-半乳糖苷酶活性等方面的变化趋势差别不大。可溶性固形物和可溶性糖的变化趋势、类胡萝卜素的含量及脂氧合酶（LOX）活性的变化趋势在两对芽变与亲本间无明显一致的趋势,表现出的情形比较复杂。但两芽变品种花色素苷的增长速率在花后50 d均显著快于亲本,且在成熟时的绝对含量均大于对应时期亲本,这可能是早熟芽变品种果实先着色的原因之一。两芽变与亲本间果胶甲酯酶（PE）活性和多聚半乳糖醛酸酶（PG）活性变化模式相一致,且两芽变的PG酶活性增长速率均明显大于其亲本,这种变化幅度也与早熟芽变性状变化的幅度相关,所以PG酶活性增加加快了芽变品种的成熟软化,这可能是芽变比亲本早熟的原因之一。     

1月份生物各科实验准备

植物学补充实验芽的形态和叶芽的结构目的:用带有已复苏芽的枝条观察芽的类型,从芽的着生部位和外部形态上区分项芽、侧芽、叶芽、花芽和混合芽。材料用具:毛白杨和丁香枝条、高枝剪、枝剪、塑料桶、放大镜、显微镜、镊子、单面刀片、叶芽结构模型和挂图、叶芽纵切永久装片。     

毛白杨蔗糖合酶基因PtSS2克隆与表达分析

为了解毛白杨蔗糖合酶(sucrose synthase,SS)基因功能和表达模式,以毛白杨茎段来源的cDNA为模板,根据毛果杨PtrSS2CDS序列信息设计特异引物,采用RT-PCR技术分离克隆了PtSS2基因。测序分析表明,PtSS2基因序列全长为2 412bp,编码803个氨基酸,蛋白大小为92.14kD,理论等电点6.00,属于酸性蛋白;氨基酸序列同源性分析表明,PtSS2与毛果杨PtrSS2和PtrSS1一致性分别高达100%和98.63%;结构域分析表明,PtSS2含有2个高度保守的功能域,即蔗糖合酶(5~552)和糖基化转移酶(554~744)功能域。qRT-PCR检测表明,PtSS2在毛白杨根、茎、叶、营养芽、雄雌花芽等各个组织中均有表达,但在营养芽和花芽中表达量较高,根部相对较低,总体呈组成型表达模式;在干旱胁迫下,PtSS2表达水平提升。研究结果推测,蔗糖合酶基因PtSS2在毛白杨各组织器官发育过程及干旱胁迫响应过程中具有重要功能。     

早红考密斯及其芽变果实中花青素含量与相关酶活性变化的研究

以西洋梨早红考密斯及其绿色芽变果实为材料,研究了果实发育期间果皮色泽、花青苷含量及其相关酶活性变化.结果显示:(1)早红考密斯果皮色泽从成熟前的暗红色逐渐变为成熟时的浅红色,并在色泽分布不均匀的地方显出黄色底色,色泽指数(a*)值从花后45 d的16.4降低到成熟时的7.4,降低54.9%;花青苷含量从成熟前的258.4μg?g-1降到成熟时的118.3μg?g-1;早红考密斯果皮色泽和果皮花青苷含量具有密切的相关性.(2)早红考密斯的绿色芽变在果实发育的前期检测不到花青苷,发育后期果实向阳部出现浅红晕,但花青苷含量极低,与亲本差异极显著.(3)果实发育期间,两品种间苯丙氨酸解氨酶(PAL)变化趋势相似,总体呈下降趋势,且早红考密斯的活性总体低于其绿色芽变;两品种查耳酮异构酶(CHI)活性总体变化趋势基本一致,均呈现缓慢上升的趋势,在前期绿色芽变的CHI活性高于其亲本,后期低于亲本;类黄酮3-O-葡(萄)糖基转移酶(UFGT)活性在两品种间的差异较大,在整个果实发育期间早红考密斯的UFGT活性远高于其绿色芽变.研究表明,早红考密斯果皮色泽变化主要由花青苷的含量不同引起;PAL和CHI不是绿色芽变的直接原因;UFGT与花青苷合成密切相关,绿色芽变果皮中UFGT活性显著降低.     

健杨＋毛白杨嵌合体的研究

健杨十毛白杨嵌合体是健杨嫁接毛白杨时产生的一个表皮基本是毛白杨,内层基本是健杨的嵌合体。但是,叶片上表皮细胞较大,偶尔也有气孔,又与毛白杨不同;花粉粒赤道面观,其网眼较大,网脊较平滑,以及木材纤维细胞壁厚、又与健杨有区别。这说明并非是单纯的机械嵌合、两种体细胞之间可能还有部份遗传物质的交换。生长速度较健杨稍慢,但材质却较健杨为优,适应性强,在土壤干旱的地方可试栽推广。为了论述方便,文内将此嵌合体简称为毛健杨。     

毛白杨优良无性系‘LM50’花药培养植株再生体系建立*

毛白杨‘LM50’具有速生、抗逆、不飞絮等优良特性,是木本植物进行遗传转化的理想材料。长期无性繁殖会导致优良性状衰退,在进行组织培养时,往往出现外植体不定芽分化和生根困难等问题。通过花药培养可以在较短时间内使毛白杨复幼,从而消除因外植体老化带来的负面影响,为转化研究提供理想的材料。与此同时,期望通过花药诱导创制单倍体植株,为基因组学研究和倍性育种提供材料。以山东冠县毛白杨基因库的‘LM50’为试验材料,对其花药发育时期与花芽形态的关系进行鉴定,选择单核靠边期的花药进行试验,探究了生长素和细胞分裂素在花药愈伤组织形成、不定芽分化及不定芽生根中的作用,建立了毛白杨花药离体再生体系,采用流式细胞仪和染色体压片计数法对诱导获得的再生植株进行了倍性鉴定。进一步利用花药培养再生植株的叶片建立了分化率高、生根率高的植物再生体系。小孢子发育时期与花芽外部形态特征对比表明,花芽长度为(1.98 ± 0.06) cm,1/4花序露出芽鳞的花芽,此时小孢子大部分处于单核靠边期;选择处于此时期的花药诱导形成愈伤组织,愈伤组织诱导率最高的培养基为H + 1.00 mg/L NAA + 1.00 mg/L BA,诱导率约为28.89%;愈伤组织进一步分化为不定芽,最佳分化培养基为MS + 0.05 mg/L NAA + 0.50 mg/L BA,分化率约为22.23%;不定芽接种至生根培养基,最佳生根培养基为1/2 MS + 0.30 mg/L IBA,生根率约为93.30%;利用流式细胞仪和染色体压片法对花药培养的27株再生植株进行倍性鉴定,鉴定植物均为二倍体;再生植株叶片分化成芽的最佳培养基为MS + 0.10 mg/L TDZ + 0.10 mg/L NAA + 0.50 mg/L BA,分化率高达92.23%。该叶片分化产生的不定芽的生根培养基与愈伤组织诱导不定芽生根的培养基相同,生根率一致。研究获得了毛白杨‘LM50’花药诱导再生植株,并建立了再生植株的叶片培养体系,可用于该优良无性系的快速繁育和毛白杨的遗传转化研究,为毛白杨的分子设计育种奠定了基础。     

油菜素内酯合成酶(Steroid 5α-Reductase)基因的超量表达对毛白杨生长的影响

将棉花Steroid 5α—reductase基因（DET2）超量表达载体导入毛白杨中,观察其对毛白杨生长和芽休眠的影响。结果表明,超量表达DET2基因的毛白杨茎高度、直径生长和不定根的生长增强,芽的休眠破除提前。     

毛白杨二氢黄酮醇-4-还原酶基因PtDFR的克隆和特性分析

二氢黄酮醇-4-还原酶(dihydroflavonol-4-reductase,DFR)是调控花青素合成的关键酶。DFR对底物的选择是决定植物中花色苷种类的重要因素,并在很大程度上决定花青素的比例,最终使植物呈现不同的颜色。此外,DFR基因家族中的不同成员对底物具有不同的催化效率,影响了植物中花青素的种类和含量,从而使植物组织或器官呈现不同的颜色。该文在分析已有毛白杨转录组数据的基础上,以毛白杨二氢黄酮醇-4-还原酶基因为研究对象,设计了一对PCR引物,以毛白杨基因组DNA为模板,通过PCR扩增获得了毛白杨DFR基因家族的1个成员,命名为PtDFR。测序结果表明,该基因序列全长为1 591 bp,包含6个外显子和5个内含子,CDS长度为954 bp,编码317个氨基酸,具有1个NADP(H)保守结构域。氨基酸序列相似性分析和进化分析表明,毛白杨与银白杨、毛果杨DFR的氨基酸相似性分别高达95.65%和94.21%,而与柑橘、枣、葡萄等7个物种DFR的氨基酸相似性达到82.14%～89.29%。转录组数据分析显示,PtDFR在不同组织器官中的表达量存在明显差异,萌动营养芽表达量最高,休眠营养芽最低,且不同时期雌雄花芽表达趋势相似,该研究结果将为深入探究PtDFR的功能奠定基础。     

三倍体毛白杨叶片营养DRIS诊断

采用L1645正交设计法对造林后的三倍体毛白杨进行了施肥试验,运用DRIS诊断法对其叶片营养元素进行了研究.结果表明,以造林第3年7～10月份三倍体毛白杨叶片N、P、K元素浓度测定值为依据,成功制定了DRIS图解法及指数法的营养诊断标准,经检验取得了较高的诊断正确率.三倍体毛白杨叶片N、P、K三元素浓度最佳比值范围为N/P=19.116±1.270;N/K=3.054±0.289;K/P=6.356±0.651.DRIS诊断标准分别经各月份林木叶片养分元素浓度回代检验,林木N、P、K需肥次序与实际施肥量基本一致,其中以9月份林木各处理为例,诊断正确率达到了80%以上.3年生三倍体毛白杨林木对N、P、K需求次序为N>K>P,与DRIS诊断结果一致.运用DRIS法诊断得到的三倍体毛白杨叶片养分浓度最佳比值范围将为三倍体毛白杨的合理施肥,大面积推广提供科学依据.     

Development of 15 novel microsatellite markers from cellulose synthase genes in Populus tomentosa (Salicaceae)

? Premise of the study: Microsatellite markers from cellulose synthase genes were developed for the Chinese white poplar, Populus tomentosa, to investigate the genetic diversity of wild germplasm resources and to further identify favorable alleles significantly associated with wood cellulose content. ? Methods and Results: Fifteen microsatellite markers were developed in P. tomentosa by deep sequencing of cellulose synthase genes. Polymorphisms were evaluated in 460 individuals from three climatic regions of P. tomentosa, and all 15 markers revealed polymorphic variation. The number of alleles per locus ranged from two to nine with an average of 4.3; the observed and expected heterozygosity per locus varied from 0.029 to 0.962 and from 0.051 to 0.713, respectively. ? Conclusions: These polymorphic markers will potentially be useful for genetic mapping and in molecular breeding for improvement of wood fiber traits in Populus.     

三倍体毛白杨速生林土壤养分因子及pH值动态变化

通过连续4a测定2年生三倍体毛白杨(B304)及其对照二倍体(1319)林地内0-20cm、20-40cm和40-60cm土层中土壤理化指标(包括pH值、有机质、全N、碱解N、全P、有效P、全K和速效K含量),以明确三倍体毛白杨种植对土壤养分及其理化性质的影响。试验结果表明,(1)在4a生长期内林地土壤的pH值呈现碱性增强变化;B304的平均pH值由8.13升至8.43,1319由8.12升至8.78,虽然二者没有显著差异,但三倍体对林地的pH值影响相对较小,更利于土壤酸碱平衡及土壤缓冲力的稳定性;(2)土壤中有机质及碱解N含量呈现先降低后升高的变化特点,品种间差异不显著;(3)在2006年,毛白杨林地土壤中有效P和速效K含量显著下降,降幅均为0-20cm20-40cm40-60cm;(4)年份、土层及年份和土层的交互作用对毛白杨土壤pH值及所测定的全部养分因子影响均达显著水平(P0.05);而品种、年份、土层三者的交互效应对土壤pH值、有机质、全N、全P和速效K的含量影响也达到了显著性水平。体现了三倍体毛白杨速生林种植对当地不同土层理化性质和养分因子影响的时间效应,生产中应采取积极措施改善或减缓土壤环境恶化,促进林木更好生长。     

Study on Origin of Populus tomentosa Carr.

This study analyzed five varieties of P. tomentosa and their putative parents, P. alba, P. davidiana, P. adenopoda and P. tremula by RAPD and artificial cross. Of 78 bands revealed by 13 arbitrary primers selected, 58 (74.36%) bands were polymorphic among P. tomentosa and four putative parents. The RAPD statistical results showed the relationship between P. tomentosa and P. alba or P. adenopoda was closer than that between P. tomentosa and P. davidiana or P. tremula . There were higher similarity and lower genetic distance between P. tomentosa and P. alba or P. adenopoda than that between P. tomentosa and the other two putative parents. The results from UPGMA, Fitch margoliash phylogenetic dendrogram were similar. In addition, artificial hybrids including reciprocal cross between P. alba and P. adenopoda were used to compare with five varieties of P. tomentosa . And those hybrids between P. alba as female and P. adenopoda as male were closer to P. tomentosa than those from reciprocal cross. The results demonstrated that P. tomentosa was a natural hybrid between P. alba as female parent and P. adenopoda as male parent.     

外源突变基因AP1M2转化毛白杨的研究

为探究毛白杨开花调控分子机制并获得不飞絮毛白杨株系,利用农杆菌介导法将显性负突变结构基因爿Pm挖转入毛白杨中,经PCR检测,共获得阳性转化植株7株。通过RT_qPCR检测转基因植株中外源基因AP1M2表达量,发现各株系间的表达水平差异显著,最高为内参的5．41倍,最低为1．89倍。对转基因毛白杨中内源刚尸,和其他开花关键基因的表达量进行检测,发现内源AP1的表达受到抑制,表达量明显下调;其他开花关键基LFY、AP3、PI、SEP3和FTI等的表达量也有不同程度的降低,而FT2表达量并没有明显变化。这些研究结果表明转4尸m扭毛白杨中API、LFY、AP3、PI、SEP3和FT2的表达受到明显抑制．对毛白杨花发育将有一定影响。     

毛白杨COMT基因cDNA的克隆、序列与特异性表达分析

The cDNA fragment encoding caffeic acid 3-O-methyltransferase(COMT) in Chinese white poplar (Populus tomentosa Carr.) was isolated and cloned by RT-PCR technique. The size of the cDNA fragment is 1 080 bp, which almost covers the whole cDNA-encoding region. Authors’ cDNA fragment in P. tomentosa shares 98.7% homology with the reported corresponding cDNA in the P. tremuloids at nucleotide level, 99.4% homology at amino acid level, respectively. The analysis of Northern dot hybridization showed that COMT is expressed specifically in the developing secondary xylem of stem during the season of xylem differentiation, which means the linkage between the gene expression for a monolignol biosynthetic enzyme and seasonal regulation of xylem development in woody plant.     

用RAPD探讨毛白杨起源

利用RAPD分子标记对山杨、欧洲山杨、银白杨、响叶杨及毛白杨的5个不同类型,即抱头毛白杨、截叶毛白杨、易县毛白杨、陕西毛白杨和南京栽培的毛白杨进行了分析,并进行了银白杨×响叶杨正反交实验,研究杂种后代与毛白杨的关系。RAPD分析说明,毛白杨的亲缘关系与银白杨和响叶杨较近,而与山杨和欧洲山杨的亲缘关系则较远。毛白杨在聚类图上首先是与银白杨和响叶杨聚为一类,再与山杨和欧洲山杨聚在一起。通过比较毛白杨与银白杨和响叶杨的正反交子代,发现毛白杨更接近银白杨×响叶杨的子代,而与反交子代有所区别。由此可见,毛白杨为天然杂种是没有疑义的,而且很可能是银白杨×响叶杨的杂种。本研究筛选出的13个引物,产生了78条谱带,覆盖了基因组的一定区域,其可靠性是较高的。     

Increase of Cd accumulation in five poplar (Populus L.) with different supply levels of Cd

The present investigation reports the results of the Cd accumulated by five Populus at six Cd supply levels (0, 0.5, 2, 6, 25, 60 mg/kg) in soils. For all tested Populus species, Cd accumulated by the leaves, stems, and roots linearly increased with increasing Cd supply levels, the higher concentration Cd treatments significantly promoted the Cd accumulation. P. hopeiensis, and P. tomentosa always performed the stronger ability of Cd accumulation than other three Populus species under different Cd supply treatments, and P. nira var. thevestina and P. leucoides had the poorer accumulation ability. Cd in soil was more intensively absorbed in the leaves and stems for all 5 Populus species, was not retained in roots and was transferred to aboveground plant tissues.     

Differential accumulation of water stress-related proteins, sucrose synthase and soluble sugars in Populus species that differ in their water stress response

Proteins inducible by dehydration and abscisic acid (ABA), have been identified in a number of species and have been suggested to play a role in desiccation tolerance. Recently, we identified a novel boiling-stable protein (BspA) which accumulated in shoots of aspen ( Populus tremula L.) cultured in vitro, in response to gradual water stress and ABA application (Pelah et al. 1995. Tree Physiol. 15: 673–678.). Accumulation of BspA, and of the water stress-related protein dehydrin dsp- 16 and sucrose synthase from the resurrection plant. Craterostigma plantagineum , was examined in two greenhouse-grown Populus species to investigate the relationship between the presence of the proteins and water stress tolerance. Detached leaves of Populus tomentosa lost more water than Populus popularis , resulting in a significant decrease in leaf water potential. Using electrolyte leakage analysis, it was found that detached leaves of Populus popularis are more tolerant to water stress than those of Populus tomentosa . Using western blots with the corresponding antibodies, we have found in Populus popularis accumulation of BspA and sucrose synthase due to water stress, and the constitutive presence of a dehydrin-like protein. In contrast, a low expression of BspA was found in Populus tomentosa , but not of sucrose synthase and dehydrin-like proteins. Desiccation tolerance in many tissues can be partly attributed to soluble sugars. Analysis of the amount of soluble sugars did not reveal clear-cut differences between the two species, except for significant sucrose accumulation and glucose reduction in water-stressed Populus tomentosa and increase in glucose in water-stressed Populus popularis . The data obtained points to a positive correlation between increased water stress tolerance of one poplar species as compared with another and accumulation of water stress-related proteins and sucrose synthase.     

北京市顺义区公路绿化植物群落的光环境特性

公路绿化是国土绿化的重要组成部分,对于促进社会经济和自然生态系统的和谐发展具有重要的作用.以北京市顺平路(S305)顺义段两侧绿化的毛白杨(Populus tomentosa)和垂柳(Salix babylonica)群落为研究对象,应用WinSCANOPY For Canopy Analysis冠层分析仪及软件采集、分析照片,研究比较了不同径阶的两种群落光环境特性和冠层结构指标:光合光量子通量密度(photosynthetic photon quanta flux density,PPFD)、总空隙度(gap fraction)、叶面积指数(leaf area index,LAI)、平均叶倾角(mean leaf angle,MLA)等,得出以下结论:不同径阶两种群落的冠层总辐射水平基本相同,林下直射和总辐射随胸径增加而降低,而林下散射没有明显变化规律;毛白杨群落总空隙度随胸径增加先降低后增加.垂柳群落总孔隙度随胸径增加而降低,并且平均值低于毛白杨群落;两种群落叶面积指数都随胸径增加而增加,但是垂柳群落叶面积指数稍大于毛白杨群落;两种群落平均叶倾角随胸径增加而降低,平均值约为32°;从消光系数分析,可以看出毛白杨群落冠层截获光辐射能力较强,林下光环境较差;对比林下散射变化情况与平均叶倾角变化情况,还可看出林下散射在一定程度上受冠层平均叶倾角的影响显著.因此,两种群落相比,毛白杨群落的总光辐射变化更明显,并且比垂柳群落差.如果只考虑光环境,垂柳群落更有利于建立绿化复层群落结构,这为公路绿化建立复层的、多样性的和稳定性的群落结构提供了基础分析和参考.