Floral inducing extract from xanthium

Flower formation was initiated in Lemna by acetone extracts of flowering cocklebur (Xanthium). These extracts also initiated flower formation in Xanthium when they were supplemented with gibberellic acid. No flower formation was initiated in dluckweed (Lemna) or Xanthium by extracts from vegetative Xanthium. Extracts from vegetative plants supplemented ivith gibberellic acid did not initiate flowers in Xanthium or Lemna.     

板栗氮素营养与花性的表现

在板栗不同物候期间对其叶片,芽和枝皮中的蛋白态氮,非蛋白态氮和蛋白质氨基酸等进行测定,结果表明：能分化雌花的芽比只能分化雄花的芽含较多的非蛋白态氮和蛋白态氮,不同性别表现的新梢叶片非蛋白态氮含量及利用的时机不同,结果母枝上雌性表现区段枝皮比只有雄性表现区段枝皮中含较多的非蛋白态氮,氮素营养中以非蛋白态氮与雌性表现关系密切,花芽与叶芽中组成蛋白质的氨基酸种类没有差别,即花性表现与所测的１７种蛋白质氨     

Phyllotaxis in xanthium shoots altered by gibberellic Acid

Gibberellic acid treatment of vegetative Xanthium shoots induced a change in phyllotaxis and almost doubled the rate of leaf production. Phyllotaxis in control plants displayed a 2,3 contact parastichy pattern; that of the treated plants could be approximated with a 3,5 pattern. Thus, the Xanthium apex switched to a new mode of growth and a higher order of phyllotactic leaf arrangement not seen in untreated plants. It may be inferred from these experiments that gibberellic acid plays a role in determining the site of leaf initiation.     

Requirements for Floral Initiation of Los Angeles Xanthium

Cocklebur from the Los Angeles area was found to require more extensive short-day treatment for floral initiation than plants of the same species from the Chicago region. Data obtained by grafting the two regional types of cocklebur indicate that the leaves of the Los Angeles Xanthium produce a comparatively low amount of the flowering stimulus.     

兰花生长发育规律的探讨

本文对盆栽兰花拟球茎生长发育进行动态观察,对原球茎不同发育时期进行形态解剖观察,并对试管中开花的兰花表现不同的株型进行分析。分析認为:①盆栽兰花是由每株兰花各片叶的腋芽逐漸发育成株组成,长叶的个体不形成花蕾,开花的个体其叶片退化为苞叶及鞘。②兰花的生殖生长与营养生长有明显的拮抗现象。③实验结果表明兰花的花序是由腋芽转化为花芽,形成根发育成个体的特性。采用在原球茎增殖阶段用激素(6BA1毫克/升+NAA0.1毫克/升)誘导,能一年四季获得开花植株。开花率90%以上。④说明了试管苗盆栽后的生长发育不比分株繁殖法慢。     

玉露香梨抗逆性相关指标研究

为探讨减缓营养生长对降低玉露香梨僵芽发生的作用机制,该研究分析比较了河北魏县正常发育的玉露香梨短枝顶芽、山西太谷的正常发育的玉露香梨短枝顶芽和河北魏县玉露香梨僵芽在花芽形态分化期间活性氧代谢的变化规律.结果表明,魏县僵芽梨园新梢年生长长度和直径均极显著大于魏县正常梨园和太谷正常梨园,且枝条停长时间最晚;花芽形态分化期间,魏县正常梨园与太谷正常梨园玉露香梨芽内的SOD、CAT和POD活性以及MDA含量表现出先升高后降低的趋势,而魏县僵芽梨园芽内的SOD和POD活性呈下降趋势,CAT活性和MDA含量则呈先升后降趋势;魏县僵芽梨园芽内SOD、CAT和POD活性整体显著低于魏县正常梨园、太谷正常梨园,MDA含量显著高于正常梨园.可见,营养生长过旺可能导致玉露香梨僵芽的发生;同时,僵芽的发生与芽内SOD、CAT和POD活性密切相关.     

Gibberellin-Induced Inhibition of Bud Development in Some Species of Prunus

Development of both floral and vegetative buds was inhibited by application of gibberellin to branches of Prunus species. The development of the lateral meristem was blocked, in general, through inhibition of mitosis, while, concurrently, the growth of certain other plant organs was stimulated in some cases. That higher dosages were required to block vegetattive than floral bud growth suggests that gibberellin also exerts the more specific effect of inhibiting floral initiation.     

Rapid switching of plant gene expression induced by fungal elicitor

The pattern of messenger RNA synthesis in suspension-cultured bean cells (Phaseolus vulgaris L.) was analyzed by blot hybridization and in vitro translation of newly synthesized messenger RNA. The RNA was separated from preexisting RNA by organomercurial affinity chromatography after in vivo labeling with 4-thiouridine. The elicitor induced the synthesis of messenger RNA's encoding phenylalanine ammonia-lyase, chalcone synthase, and chalcone isomerase, three enzymes of phenylpropanoid metabolism involved in the synthesis of isoflavonoidderived phytoalexins. This is part of a rapid and extensive change in the pattern of messenger RNA synthesis directing production of a set of proteins associated with expression of disease resistance.     

棉花优质高产结铃模式的调节技术研究

进行了采用除早蕾新技术创造多结伏桃、早秋桃最佳结铃模式的研究。栽培的中熟品种的伏桃、早秋桃的结铃期约40天,采用人工除早蕾技术,与常规植棉技术相比较,能节约输向早期蕾铃的养分,根系伤流液量、叶片叶绿素含量和光合作用强度均增加,地下地上生理活性增强,每亩增产皮棉5～18%,但化学药剂除早蕾效果不稳定。     

洋葱花器官B类MADS-box基因AcPI的克隆及表达分析

【目的】克隆洋葱花器官B类PI/GLO家族MADS-box基因,分析其序列特征及时空表达模式,为探讨其在洋葱花发育过程中的分子遗传机制奠定基础。【方法】以洋葱花蕾总RNA为模板,根据同源克隆策略设计简并引物,利用RT-PCR结合RACE技术,获得AcPI的全长cDNA序列。用生物信息学方法对其基因序列特征进行分析;利用RT-PCR和Real-time PCR分析AcPI在花蕾整个生长过程中的时空表达模式。【结果】克隆获得洋葱AcPI基因（GenBank登录号：JX679083）的cDNA全长931 bp,包含615 bp的完整开放阅读框,编码205个氨基酸。蛋白分析表明,AcPI蛋白具有植物MADS-box蛋白典型的MADS和K结构域;与水仙的NTPI、风信子的HoMADS2有78%、75%的相似性,与金鱼草的GLO也有52%的相似性。系统进化树分析表明,AcPI属于B类MADS-box蛋白家族的PI亚家族。RT-PCR表达分析表明,AcPI只在生殖器官花蕾中表达,但主要在花的第一、二、三轮花器官中表达,而在营养组织根、茎和叶中不表达。Real-time PCR进一步分析表明,AcPI在花芽整个生长过程中,在心皮中微弱表达,但表达丰度呈递增趋势;而在外轮被片、内轮被片和雄蕊中强烈表达,其表达丰度除了在外轮被片中呈先增后减的趋势外,在内轮被片和雄蕊中都呈递增趋势。【结论】AcPI在洋葱第一轮花器官中的表达支持了van Tunen提出的修正的ABC模型;但AcPI在洋葱第四轮花器官中也有表达,这表明AcPI除了调控外轮被片、内轮被片和雄蕊发育外,还可能在心皮的形成发育过程中起着重要作用。     

华北紫丁香花芽生长过程中蛋白质和核酸含量变化研究

本研究采用戊糖比色法和Folin -酚法分别测定了丁香花芽中核酸 (DNA、RNA)、蛋白质含量 结果表明 ,在花芽生长旺盛时期 ,代谢旺盛 ,蛋白质、核酸含量增加 ,而在花芽生长初期和末期 ,消耗增多 ,蛋白质、核酸含量降低     

TRANSCRIPTION IN VIVO OF DNA FROM BACTERIOPHAGE SP8

The DNA of bacteriophage SP8, when denatured, yields two components differing in buoyant density in cesium chloride gradients and separable by chromatography on a column of methylated bovine serum albumin and kieselguhr. The denser of the two strands (H) contains more pyrimidines and fewer purines than the lighter (L) strand. Only the H strand forms hybrids with the RNA synthesized by the infected host. The L strand is capable of annealing with complementary RNA synthesized in vitro with it as primer in reactions catalyzed by RNA polymerase. During the vegetative development of phage, host-specific messenger RNA is also synthesized.     

Hormone-induced stabilization of soluble RNA in pea-stem tissue

When indoleacetic acid labeled with carbon-14 in the carboxyl group is fed to excised green pea-stem segments, growth is initiated, and there is a parallel progressive labeling of the RNA extracted by cold phenol. The bulk of the label is found in the 4S fraction. This fraction is more resistant to degradation by ribonuclease than a similar fractian obtained from tissue not treated with indoleacetic acid.     

试论棉花花芽分化发育的序列性

对4个不同类型品种及不同生态条件下棉花花芽分化发育序列性研究表明:在3500～4000株/亩密度条件下,一级果枝上近主茎的5～6个花芽具较强的生长优势;同位花芽分化期间隔在0.70～0.94之间,邻位花芽分化期间隔在2.03～2.16之间。各果枝近主茎第一花芽具最强生长优势。现蕾后,棉株基部第一、二果枝花芽生长分化变慢;开花后,花芽增长量出现负值。现蕾节以上各分化果枝的花芽分化数有较稳定的序列性,自下而上其分布规律为4,4,3,3,2,2,1,1。     

A microRNA as a translational repressor of APETALA2 in Arabidopsis flower development

Plant microRNAs (miRNAs) show a high degree of sequence complementarity to, and are believed to guide the cleavage of, their target messenger RNAs. Here, I show that miRNA172, which can base-pair with the messenger RNA of a floral homeotic gene, APETALA2, regulates APETALA2 expression primarily through translational inhibition. Elevated miRNA172 accumulation results in floral organ identity defects similar to those in loss-of-function apetala2 mutants. Elevated levels of mutant APETALA2 RNA with disrupted miRNA172 base pairing, but not wild-type APETALA2 RNA, result in elevated levels of APETALA2 protein and severe floral patterning defects. Therefore, miRNA172 likely acts in cell-fate specification as a translational repressor of APETALA2 in Arabidopsis flower development.     

绿竹花发育相关基因BoAP3的克隆与分析

MADS—box基因家族在决定花分生组织特性和花器官发育过程中起着重要的作用。以绿竹Bambusaoldhamii开花试管苗花芽为植物材料,采用cDNA末端快速扩增技术（rapid amplification of cDNAends,RACE）技术,获得了1条MADS—box基因家族的基因,命名为BoAP3。序列分析结果表明：BoAP3开放阅读框（open reading frame,ORF）长度为654bp,编码218个氨基酸,具有典型的植物MADS—box蛋白结构,其编码肽链包含了MADS区、K区、I区和C区。B胡丹与小麦Triticum aestivum,水稻Oryzasatva等AP3-like同源基因所编码的氨基酸同源性达到80％以上。定量聚合酶链式反应（PCR）结果表明：BoAP3基因在开花试管苗的花芽中表达量是不开花试管苗营养芽表达量的8．1倍,表明该基因可能参与了花器官的发育。     

LEAFY(LFY)基因在花发育网络调控中的研究进展

成花是高等植物生命过程中最重要的阶段,在相当的程度上决定着繁育的成功和失败。综述了花分生组织特性基因LEAFY(LFY)基因,及其花发育(成花诱导途径)网络调控的相关研究进展。LFY基因在植物的营养性生长和生殖生长组织中均表达,从花序分生组织到花器官形成的过程中,LFY都起到重要的作用。     

毛白杨PtPCP—like基因的克隆及其遗传转化初报

利用滤纸吸附噬菌体 PCR法,从毛白杨花芽cDNA文库中分离克隆了PtPCP-like基因cDNA全长序列,测序表明克隆得到的该序列全长595 bp,包含一个完整的开放阅读框,编码91个氨基酸;经BLAST分析发现,该基因包含与拟南芥花粉外被蛋白基因相似的序列,命名为PtPCP-like。采用RT PCR技术检测PtPCP-like基因在各个组织部位的表达模式,结果显示在毛白杨的根和雄花芽中表达丰度最高,而在雌花芽部位表达丰度最低。并且构建35S∶∶PtPCP-like植物表达载体,采用农杆菌介导法将PtPCP-like基因导入烟草中,获得了一批阳性转化植株。采用qRT-PCR技术检测PtPCP-like基因在各个转基因烟草中的表达模式,结果显示在转基因烟草中各个株系均比野生型表达量高,且不同株系间相对表达量差异显著。      

不同时期苹果花芽和叶芽中内源赤霉素脱落酸和细胞分裂素活性的变化

本文为了探讨苹果花芽分化与内源激素的活性变化关系,改变了以往测定短枝混合样本（含花芽和叶芽）的传统作法,而采用花芽和叶芽分开测定的研究方法,取得了较好的效果。结果表明,所测内源GA#-3、CTK和ABA等激素在花芽分化过程中均存在。三者在叶芽和花芽中祗是数量和比例方面有差别。初步明确,花芽叶中CTK/GA#-3比值明显高于叶芽叶,前者为4.02,后者为1.69。显然,CTK/GA#-3比值与苹果花芽分化有密切关系。文中对这二种激素的比值在成花过程中的作用进行了讨论。     

银杏雌雄株内源激素和核酸的变化

测定了银杏朱和雄株实生树内源激素及核酸含量在生长季节的变化。结果表明,在３月上旬芽膨大时芽尖中赤霉素含量已达高峰,随后急剧下降,到９月中下旬降到最低点。６月上旬芽尖中玉米素含量升到最高值,生长素则降到最低点,而脱落酸减少到检测水平以下。