Complexes of MADS-box proteins are sufficient to convert leaves into floral organs

Genetic studies, using floral homeotic mutants, have led to the ABC model of flower development. This model proposes that the combinatorial action of three sets of genes, the A, B and C function genes, specify the four floral organs (sepals, petals, stamens and carpels) in the concentric floral whorls. However, attempts to convert vegetative organs into floral organs by altering the expression of ABC genes have been unsuccessful. Here we show that the class B proteins of Arabidopsis, PISTILLATA (PI) and APETALA3 (AP3), interact with APETALA1 (AP1, a class A protein) and SEPALLATA3 (SEP3, previously AGL9), and with AGAMOUS (AG, a class C protein) through SEP3. We also show that vegetative leaves of triply transgenic plants, 35S::PI;35S::AP3;35S::AP1 or 35S::PI;35S::AP3;35S::SEP3, are transformed into petaloid organs and that those of 35S::PI;35S::AP3;35S::SEP3;35S::AG are transformed into staminoid organs. Our findings indicate that the formation of ternary and quaternary complexes of ABC proteins may be the molecular basis of the ABC model, and that the flower-specific expression of SEP3 restricts the action of the ABC genes to the flower.     

Evolution of genetic mechanisms controlling petal development.

Molecular genetic studies in Arabidopsis thaliana and other higher-eudicot flowering plants have led to the development of the 'ABC' model of the determination of organ identity in flowers, in which three classes of gene, A, B and C, are thought to work together to determine organ identity. According to this model, the B-class genes APETALA3 (AP3) and PISTILLATA (PI) act to specify petal and stamen identity. Here we test whether the roles of these genes are conserved throughout the angiosperms by analysing the expression of AP3 and PI orthologues in the lower eudicot subclass Ranunculidae. We show that, although expression of these orthologues in the stamens is conserved, the expression patterns in the petals differ from those found in the higher eudicots. The differences between these expression patterns suggest that the function of AP3 and PI homologues as B-class organ-identity genes is not rigidly conserved among all angiosperms. These observations have important implications for understanding the evolution of both angiosperm petals and the genetic mechanisms that control the identities of floral organs.     

Tobacco floral homeotic gene homologues: partial sequence and expression pattern

Using PCR approach, three cDNA sequences, NTSQUA4, NTSQUA12 and NTSQUA15, were amplified from first_strand cDNAs of wild tobacco flower buds and identified as homologues for floral homeotic genes. All the three clones contained domains that a floral homeotic gene generally had, i.e. I domain, K domain and C_terminal domain except MADS_ box since the PCR primers were designed beyond this region. In addition, the amino acid sequences of them showed 50%-60% identity (70%-80% similarity) with the known floral organ identity class A gene AP1 and SQUA, possibly indicating that they are class A_like genes. NTSQUA4 and NTSQUA412 shared 95% identity in their amino acid sequence, while NTSQUA415 exhibited only 47% identity as compared with NTSQUA4 and NTSQUA12. Within tobacco flower, NTSQUA4 was expressed in sepals, petals and carpels, but not in stamens, while NTSQUA15 was expressed in every whorl of the flower. The possible functions of these genes are discussed.     

Assessing the redundancy of MADS-box genes during carpel and ovule development

Carpels are essential for sexual plant reproduction because they house the ovules and subsequently develop into fruits that protect, nourish and ultimately disperse the seeds. The AGAMOUS (AG) gene is necessary for plant sexual reproduction because stamens and carpels are absent from ag mutant flowers. However, the fact that sepals are converted into carpelloid organs in certain mutant backgrounds even in the absence of AG activity indicates that an AG-independent carpel-development pathway exists. AG is a member of a monophyletic clade of MADS-box genes that includes SHATTERPROOF1 (SHP1), SHP2 and SEEDSTICK (STK), indicating that these four genes might share partly redundant activities. Here we show that the SHP genes are responsible for AG-independent carpel development. We also show that the STK gene is required for normal development of the funiculus, an umbilical-cord-like structure that connects the developing seed to the fruit, and for dispersal of the seeds when the fruit matures. We further show that all four members of the AG clade are required for specifying the identity of ovules, the landmark invention during the course of vascular plant evolution that enabled seed plants to become the most successful group of land plants.     

重瓣百合LiSEP3基因克隆与表达分析

【目的】克隆百合LiSEP3基因并确定其在百合不同地上器官及不同花瓣中的表达差异,探讨SEP3基因在重瓣花中的表达模式。【方法】利用RACE方法从重瓣百合品种‘比罗尼卡’中克隆得到LiSEP3基因核苷酸序列,利用SMART软件对其蛋白结构进行分析,以MEGA 5.0软件进行系统进化树分析,用基因枪轰击法进行亚细胞定位分析,采用荧光定量PCR进行不同地上器官及不同花瓣中LiSEP3基因表达差异分析。 【结果】LiSEP3基因属于MADS-box家族E类基因,其开放阅读框为729 bp,共编码242个氨基酸; LiSEP3基因编码的蛋白具有典型的MADS结构域、K-box区及2个SEP基序; LiSEP3与同为单子叶植物的六出花的SEP3亲缘关系最近; LiSEP3蛋白定位于细胞核中; LiSEP3基因在花中的相对表达量最高,在茎、叶中几无表达; 在1～7轮花瓣中均能检测到LiSEP3表达,且位于最内侧的第7轮花瓣中相对表达量最高。 【结论】LiSEP3基因属于MADS-box家族E类基因,主要在花中表达,其中在最内侧花瓣中表达量最高,其表达模式与双子叶植物花中SEP3基因表达模式存在不同。     

Functional characterization and mapping of two MADS box genes from peach (Prunus persica)

Previously an AGAMOUS gene homologue PpMADS4 and a FRUITFULL gene homologue PpMADS6 were isolated from peach (Prunus persica), and both genes were shown to express in the developing floral and fruits. To gain insight into their function, the two genes were constitutively expressed in Arabidopsis thaliana and their effects on plant growth and floral organ development were studied in this work. The transgenic plants all displayed early flowering and conversion of inflorescence to floral meristem. However, the two genes had different effects on the floral organ structures in A. thaliana. The transgenic plants overexpressing PpMADS4 displayed homeotic conversion of floral organs, and par- ticularly the perianth abscission was inhibited. The plants overexpressing PpMADS6 showed early flowering, produced higher number of carpels, petals, and stamens than nontransgenic plants, and pod shatter was prevented; significantly, the transgenic plants yielded more than one siliques from a single flower. A SSR molecular marker was developed for PpMADS4, and it was then assigned into the G5 linkage group of Prunus sp. Both PpMADS4 and PpMADS6 genes were located at the same region in the G5 linkage group. Our results showed the potential application of these two MADS box genes for crop and fruit tree improvement.     

河南《鸡公山木本植物图鉴》增补(Ⅱ)——河南玉兰属两新种

描述了河南玉兰属Yulania Spach两新种:两型玉兰Y.dimorpha T.B.Zhao et Z.X.Chen,sp.nov.和信阳玉兰Y.xinyangensis T.B.Zhao,Z.X.Chen et H.T.Dai,sp.nov..两型玉兰形态特征是:叶2种类型,玉蕾2种类型.花2种类型:①单花花被片9枚,有萼、瓣之分,瓣状花被片先端具喙,边部明显波状起伏;②单花花被片9枚,花瓣状,先端无喙,边缘微波状起伏.信阳玉兰的形态特征是:叶宽倒卵圆状三角形,先端最宽,通常微凹,或具短尖头,有时2裂,或具3个短三角状尖头.玉蕾顶生,小,卵球状,或短柱状.花喇叭型,单花花被片6～9枚,匙形.     

紫花地丁开放花和闭锁花繁殖特征的研究

对北京地区一扰动生境中紫花地丁(Viola yedoensis)开放花和闭锁花的产量、结实率和种子质量等繁殖特征进行了比较.开放花在3月初开始开放,雄蕊5枚,具有吸引传粉者开放的花冠等特征.闭锁花4月初开始形成,雄蕊2枚,且与柱头紧密接触,适应闭花受精.在扰动生境中,紫花地丁个体往往形成更多的闭锁花,而且闭锁花的结实率显著高于开放花的结实率.所以,大部分种子都是通过闭锁花闭花受精形成的.但是,开放花产生的种子更大,因而可能具有更高的幼苗存活率.即使在不利生境中,闭锁花也能保障植物繁殖和一定的种子产生.而开放花则产生更多的异交种子以适应新的生境.     

ARTP辐照对两色金鸡菊种子诱变的生物学效应

ARTP(常压室温等离子体)作为一种新型安全高效的生物诱变育种手段,已成功应用于微生物的育种研究,在植物上的应用刚刚起步.本研究首次采用ARTP处理两色金鸡菊(Coreopsis tinctoria Nutt.)种子,研究其对种子萌发、幼苗生长、花形和品质的影响,以期获得观赏价值大、品质好的诱变品系.结果表明:(1)与对照相比,不同时间(7.50～37.50min)的ARTP辐照提高了两色金鸡菊种子的发芽势和发芽率,辐照22.50min时其发芽势(80.00%)和发芽率(86.70%)达最大;不同时间的ARTP辐照也不同程度地增加了其幼苗的最大冠幅、叶片数量、叶柄长度、叶面积,以22.50min的辐照效果最好.(2)ARTP辐照种子22.50min后,其大部分植株最大花径明显增加、舌状花红褐色区域明显增大,13.33%的植株舌状花瓣数增多(Tm)、6.67%的植株雄蕊瓣化(Ts)、6.67%的植株舌状花管状化(似喇叭状)(Tt);部分植株花朵总黄酮、绿原酸和木犀草苷成分增加,其中Tt植株不仅花形发生变化且活性成分也有所提高.ARTP诱变有望成为两色金鸡菊育种的新途径.     

Functional characterization and mapping of two MADS box genes from peach （Prunus persica）

Previously an AGAMOUS gene homologue PpMADS4 and a FRUITFULL gene homologue PpMADS6 were isolated from peach （Prunus persica）, and both genes were shown to express in the developing floral and fruits. To gain insight into their function, the two genes were constitutively expressed in Arabidopsis thaliana and their effects on plant growth and floral organ development were studied in this work. The transgenic plants all displayed early flowering and conversion of inflorescence to floral meristem. However, the two genes had different effects on the floral organ structures in A. thaliana. The transgenic plants overexpressing PpMADS4 displayed homeotic conversion of floral organs, and particularly the perianth abscission was inhibited. The plants overexpressing PpMADS6 showed early flowering, produced higher number of carpels, petals, and stamens than nontransgenic plants, and pod shatter was prevented; significantly, the transgenic plants yielded more than one siliques from a single flower. A SSR molecular marker was developed for PpMADS4, and it was then assigned into the G5 linkage group of Prunus sp. Both PpMADS4 and PpMADS6 genes were located at the same region in the G5 linkage group. Our results showed the potential application of these two MADS box genes for crop and fruit tree improvement.     

凤丹牡丹花瓣化学成分研究

对凤丹牡丹花瓣化学成分进行深入研究,运用高效液相色谱方法进行分离纯化,运用1H NMR、13C NMR和MS波谱学数据鉴定其结构。结果得到2个没食子酸鞣质类化合物,分别为1-O-galloyl-β-D-glucose(1)和1,2,3,4,6-Trigalloyl-β-D-glucose(2),以及一个黄酮类化合物kaempferol-3,7-di-O-β-D-glucopyranoside(3)。化合物1~3均首次从凤丹牡丹花中分离得到,化合物1~2也是首次从凤丹牡丹花中分离得到鞣质类化合物。     

建兰花色形成的成分检测

【目的】花色是建兰重要的观赏性状之一。对建兰花色形成的色素类成分进行检测分析,为探索建兰花色形成的物质结构组成及新花色品种培育提供依据。【方法】以建兰复色花瓣为材料,用色差计测定花色表型并进行色度比色,检测两种颜色花瓣的总蛋白含量和pH; 通过高效液相色谱-质谱联用,检测两色组织的主要色素成分和结构组成。【结果】黄绿色花瓣组织亮度值(L*, 70.1±1.7)是红色系花瓣组织的近2倍; 红色花瓣红度值(a*, 51.2±1.9)为黄绿色组织4倍多,而黄绿色花瓣黄度值(b*, 35.2±1.5)为红色组织近3倍,两种颜色组织色度差异较显著; 红色系花瓣组织可溶性蛋白含量[(3.44±0.11)mg/g]是黄绿色花瓣组织2倍多; 从两种颜色组织材料中共检测出12种黄酮醇苷和8种花青素苷。【结论】异鼠李素糖苷为建兰黄绿色花瓣组织特有,天竺葵素-二糖苷、飞燕草葡萄糖苷、山奈酚鼠李糖苷、矢车菊素芸香糖苷、山奈酚芸香糖苷和山奈酚芸香糖苷半乳糖苷为红色花瓣组织特有。     

1-MCP复合保鲜液对非洲菊切花保鲜的影响

以非洲菊(Gerbera jamesonii)切花为材料,采用四因素[1-甲基环丙烯(1-MCP)、柠檬酸(CA)、蔗糖、 8-羟基喹啉(8-HQ)]三水平的正交试验设计,通过比较各项形态指标和生理指标的变化情况,探讨了各配方的保鲜效果.结果表明, 100 mg/L CA+12 mg/L 1-MCP+6%蔗糖+300 mg/L 8-HQ和200 mg/L CA+10 mg/L 1-MCP+6%蔗糖+200 mg/L 8-HQ保鲜液处理,能增加鲜质量、增大花径、增加花瓣蛋白质质量比;降低花瓣丙二醛含量,延缓花瓣细胞膜透性的增加,且均比CK组延长了其3d瓶插寿命;提高了切花的观赏品质.     

Flower Opening Simulation Based on Key Lines Using WebGL

A flower opening simulation based on key lines model is proposed. First, this model generates several petals with b-spline surfaces based on key lines. Second, a flower bud is constructed according to layers of the bud and petal numbers in each layer. Then, flower opening process is simulated with Logistic function. At last, flowers opening simulations of seven types are carried out with Web GL. The results show that, using this model, the average rendering time of these 7 flowers is 195.84 s, the minimum rendering time is only 12.23 s in gardenia flower opening simulation. Compared with Takashi's method, this model is more efficient in flower opening simulation process.     

白肋烟雄性不育性的细胞形态学研究

作者以白肋烟雄性不育系及其保持系为材料,从细胞形态学角度对雄性不育性作了较系统的研究,得出如下结果和结论：1．白肋烟雄性不良系雄性器官显著异常,表现为：（1）雄蕊原基根本不发生或发生后随着花器的发育完全退化消失,结果表现为完全无雄蕊,（2）有雄蕊原基发生,能形成雄蕊类似物,但都表现出显著畸变退化,形式多样,呈细丝状,短棒状,瓣状,类柱头状等,数目少于5个,并且极短于柱头,2．确定了不育系败育的时期和方式：不能形成正常的小孢子发生组织,根本无减数分裂过程发生,败育时期在小孢子母细胞形成期前后,为完全的结构性雄性不育类型;3．雄蕊的维管束显著异常,表现为雄蕊中完全不存在维管束结构,或者即使有维管束,但结构分化极为不良,雄蕊中严重缺乏淀粉粒等物质,是雄蕊退化和小孢子发生出现障碍的直接原因。     

香花糙果茶--广东糙果茶一新种

描述了山茶属Camellia Sect.Furfuracea Chang一新种.新种以其芳香的花10～13较多的苞被,苞被内面被向顶的毛,较外面的花瓣内面亦被向顶的毛而与其余已发表的种不同.     

莼菜花的形态解剖

莼菜的花单朵着生于长柄上,花柄内有3-4束维管束.花下位,萼片3枚,花瓣3枚,结构相似,上下表皮均具一层细胞,薄壁基本组织层次较厚密,其间分布有维管束.雄蕊多数,花丝不成瓣状而呈长丝状,花药内向,每一雄蕊具1条维管束.雌蕊群由6-12枚分离心皮组成,排成2-3轮.每一心皮具1长柱头.在心皮整个发育期间,其腹面仍留有裂缝,倒生胚珠2枚,有时为1枚,着生于心皮背面的中央.根据形态和解剖的观察,我们认为莼菜属及Cabomba 亲缘密切,可独立为莼菜科.它较广义的睡莲科中具合生心皮的各属为原始.另方面莼菜属具下垂倒生,两层珠被、厚珠心的胚珠,维管束中有原生木质部空腔.这些事实表明,莼菜属与睡莲科的其它属亦有联系.故把它们(除莲属)归入睡莲目是恰当的.     

拟南芥雄性不育突变体ms1521的基因定位

ms1521是经EMS诱变筛选得到的一拟南芥雄性不育突变体,通过背景纯化与遗传分析,发现ms1521突变体是受隐性单基因控制,形态学观察表明：突变体的花缺失部分花瓣,雄蕊比较短,花药肥大,部分雄蕊的花药成丝状,利用图位克隆的方法对不育基因MS1521进行了定位,结果表明：MS1521位于第一条染色体分子标记F17F8Alu1和T19E23之间161kb的区间内,数据库预测,其中有11个与花发育有关的基因,试验将有助于对目的基因的克隆,控制花器官研究和雄性不育分子机制的研究。