Comparison of floral ontogeny in wild-type and double-flowered phenotypes of Syringa vulgaris L. (Oleaceae)

A comparative study of floral ontogeny in normal and double-flowered phenotype of Syringa vulgaris was conducted using the epi-illumination light microscopy. In the wild phenotype, floral differentiation starts with calyx inception and the formation of four sepals in orthogonal positions (two median and two lateral). The corolla emerges as a continuous ring-like structure leading to the appearance of four petal lobes alternating with the sepals. Androecium was formed by initiation of two stamen primordia in transverse plane and finally the bicarpellate gynoecium emerges in median position. In the case of the double-flowered lilac, there are supernumerary petals in an additional whorl. In double-flowered phenotype, a ring meristem is formed acropetally after the first petal whorl initiates. Stamens and carpels initiated similarly in double-flowered as well as in wild-type plants. However, position of stamens deviates from the typical transverse situation. It seems that the appearing of an extra petal whorl did not exhibit any adverse effect on the initiation of other whorls, in terms of organ identity. Therefore, it would be suggested that the double-flowered phenotype of Syringa represents a case of neoheterotopy, with formation of an extra petal whorl, rather than a case of homoheterotopy with transformation of an ancestral androecium whorl into petals.     

CPPU application on size and quality of hardy kiwifruit

For the purpose of determining the appropriate conditions of application to increase the size of a hardy kiwifruit, Actinidia arguta ‘Mitsuko’, N₁-(2-chloro-4-pyridyl)-N₃-phenylurea (CPPU) was applied at three different growth stages of the crop: at petal fall, 10 and 25 days after petal fall (DAPF), and three different concentrations: 1, 5 and 10 mg l⁻¹. A significant increase in fruit size was obtained by treatment at the concentrations of 5–10 mg l⁻¹ and at 10 DAPF. The fruit weight doubled. Although a significant reduction in the concentrations of total soluble solids (TSS), titratable acids (TA) and ascorbic acid (AsA) in the CPPU-treated fruits was recorded, the TSS/TA ratio and AsA content per fruit increased by the treatment. CPPU application at petal fall induced abnormally protruding fruit tip.     

Cultivar and anatomical analysis of corolla enlargement of petunia (Petunia hybrida Vilm.) by cytokinin application

We found that the corolla of petunia (Petunia hybrida Vilm.) could be conspicuously enlarged by the separate application of three cytokinins: forchlorfenuron (CPPU), N⁶-benzylaminopurine (BA), and zeatin. To obtain the same enlargement as that achieved by CPPU, approximately 30 and 900 times the concentration of BA and zeatin, respectively, were required. CPPU at 3.2 μmol/L increased the limb area of the corollas of 15 cultivars to between 1.3 and 2.4 times (1.8 times on average) the size of the control area. The increase was negatively correlated (R = 0.58) with the “genetic” limb area (i.e., that of the untreated plant). The enlargement of the corolla caused by cytokinin application was mainly attributed to an increase in cell number in most cultivars. This increase resulted from a high rate of cell proliferation and from prolongation of the cell proliferation phase during corolla development. This anatomical change caused by cytokinin application was similar to the anatomical difference among cultivars because genetic differences in limb area resulted mainly from differences in cell number.     

托桂花型菊花花发育的组织结构观察

采用石蜡切片技术对托桂型菊花和非托桂型菊花的花发育过程以及花瓣的组织机构进行观察。结果表明：菊花的花芽分化可分为花序分化和小花分化两个阶段,托桂和非托桂型菊花的花芽分化过程在小花花冠伸长期开始出现差异,桂瓣的发育过程中组织结构的变化更类似于舌状花;成熟的桂瓣和舌状花一样,其花瓣结构均由上下表皮细胞和内部多层叶肉细胞构成,而非托桂花型菊花管状花花瓣仅有上下表皮细胞。桂瓣内层细胞旺盛的分裂能力以及发达的维管束组织可能是菊花形成托桂花型的重要原因。     

A petal breakstrength meter for Arabidopsis abscission studies

Background  

Abscission is the regulated dropping of plant organs, such as leaves or flower petals. This process involves a break down of the cell wall between layers of cells in the abscission zone, causing the organ to become detached. The model plant Arabidopsis thaliana undergoes floral organ abscission. Various experimental methods have been used to study Arabidopsis floral organ abscission, including measuring the petal breakstrength, or the amount of force required to pull a petal from the receptacle. Petal breakstrength provides a quantitative insight into the physical integrity of the petal abscission zone.     

Physiological and biochemical studies during flower development in two rose species

The present investigation was aimed to study the changes in various physio-chemical attributes in petals of two different rose species, Rosa damascena Mill and Rosa bourboniana Desport differing in flowering behaviour from small bud (stage 1) till full bloom (stage 8). In both rose species fresh weight, dry weight and moisture content were maximum during full bloom. Electrical conductivity of the petal diffusates reached maximum at full bloom with significantly higher values in R. damascena. In both the species, starch content declined as the flower reached its full bloom stage with maximum reducing sugar content during this period. With progressive increase in petal growth, total protein and RNA declined. The results showed that in both the species peroxidase (POX) and catalase (CAT) activity were lower during full bloom with high activity of invertase and lipoxygenase (LOX) at this period. The present study indicates that lipid peroxidation induced membrane permeability could partly be the result of higher lipoxygenase activity during full bloom. The possible significance of these findings is discussed in relation to flower development in the two diverse rose species.     

Current status of commercial Calibrachoa cultivars as assessed by morphology and other traits

To study the morphological diversity of the popular ornamental crop Calibrachoa, traded since the 1990s, floral and vegetative characters of 91 commercial cultivars were compared to those of natural species. Floral colours were classified according to the ISCC-NBS system and the CIE LAB system. The numerical data obtained by measuring 19 floral and vegetative characters was tested with principal component (PC) analysis. Floral colour classes of commercial cultivars were divided into 37 groups according the ISCC-NBS system, whereas those of natural species were divided into 9 groups. These tendencies were readily observable in the scatter diagrams of the a* vs. b* values and the C* vs. L* values. As the result of PC analysis, six PCs were obtained. For PC4, which negatively correlated with the degree of nocturnal corolla limb closure, the majority of natural species showed negative scores whereas the majority of cultivars had positive PC4 scores. In terms of PC2 (flower size), PC3 (growth form), PC5 (floral shape) and PC6 (leaf shape), natural species were dispersed in a range wider than the cultivars. These results suggest that Calibrachoa cultivars possess more highly variable floral colour than natural species, and breeding programmes to diversify the floral colour seem to have progressed rapidly. The tendency of natural species to close the corolla limb toward evening has been removed almost completely from the cultivars. The floral size, growth form, floral shape and leaf shape of the cultivars were rather uniform compared to those of natural species.     

凤仙花花逆转突变体的组织学研究

从经过卫星搭载的凤仙花种子后代中获得了可遗传的仅顶花叶化的花逆转突变体。该突变体保持了花的基本结构,但是不同程度地出现了花瓣增厚、变绿、出现锯齿等现象,雄蕊也片状化、早衰或完全消失。组织学观察发现,在叶化花瓣中出现了叶绿体和栅栏组织。统计分析结果表明,叶化花瓣与正常花瓣相比组织结构上确实发生了显著变化。     

牡丹和芍药雄蕊筒状花瓣的形态解剖特征及形成

 对牡丹(Paeonia suffruticosa)、紫斑牡丹(P．rockii)、大花黄牡丹（P.ludlowii）、四川牡丹(P.decomposita)、杨山牡丹(P.ostii)、卵叶牡丹(P.qiui)、滇牡丹(P.delavayi)和芍药（P．lactiflora）等8个分类群中雄蕊瓣化瓣的形态特征进行了观察，并对仅出现在牡丹、紫斑牡丹和芍药花中的雄蕊筒状花瓣进行了统计分析和形态解剖学研究。结果表明：（1）在牡丹和紫斑牡丹中雄蕊筒状花瓣出现的频率低，且形态单一；而在芍药中其出现频率较高，且形态多样。（2）在解剖结构方面，雄蕊筒状花瓣从基部到顶部存在一系列的转化，与牡丹和紫斑牡丹相比，芍药中筒状花瓣的解剖结构更具多样性。（3）维管束边缘分生组织的不断分化和维管束数量的不断增多，在雄蕊原基转向雄蕊筒状花瓣的发育中起到关键作用。（4）雄蕊筒状花瓣的发育过程可分为原基分化、转化发育、筒状花瓣形成和筒状花瓣成熟4个阶段。      

牡丹和芍药雄蕊筒状花瓣的形态解剖特征及形成

对牡丹(Paeonia suffruticosa)、紫斑牡丹(P.rockii)、大花黄牡丹(P.ludlowii)、四川牡丹(P.decomposita)、杨山牡丹(P.ostii)、卵叶牡丹(P.qiui)、滇牡丹(P.delavayi)和芍药(P.lacti- flora)等8个分类群中雄蕊瓣化瓣的形态特征进行了观察,并对仅出现在牡丹、紫斑牡丹和芍药花中的雄蕊筒状花瓣进行了统计分析和形态解剖学研究。结果表明:(1)在牡丹和紫斑牡丹中雄蕊筒状花瓣出现的频率低,且形态单一;而在芍药中其出现频率较高,且形态多样。(2)在解剖结构方面,雄蕊筒状花瓣从基部到顶部存在一系列的转化,与牡丹和紫斑牡丹相比,芍药中筒状花瓣的解剖结构更具多样性。(3)维管束边缘分生组织的不断分化和维管束数量的不断增多,在雄蕊原基转向雄蕊简状花瓣的发育中起到关键作用。(4)雄蕊筒状花瓣的发育过程可分为原基分化、转化发育、筒状花瓣形成和筒状花瓣成熟4个阶段。     

Chemically induced floral morphological mutations in two cultivars of Ipomoea purpurea (L.) Roth

Two cultivars of Ipomoea purpurea (Morning Glory) differing in flower colour and corolla morphology were investigated for artificial mutagenesis. The violet blue (VB) cultivar bears flowers with a typical gamopetalous corolla. The red purple (RP) cultivar has flowers with an incised corolla at one or more places at the petal union, i.e. incompletely gamopetalous and has petaloid appendages borne on the outer side. It has been described as petalomaniatic. The petaloid appendages were part and parcel of the petal itself. The mutagens used were ethyl methanesulfonate (EMS), N-methyl-N′-nitro-N-nitrosoguanidine (NMG) and sodium azide (SA). Mutants affecting the petal union and petalomaniatic tendency were discussed. It was possible to induce an incompletely gamopetalous petalomaniatic mutant in cultivar VB as well as the typical gamopetalous corolla morphotype in cultivar RP. Preliminary hybridization studies were made using cv. RP and its white colour mutant as one of the parents and crossed with cv. VB. Hybridization studies revealed that independent loci exist for the incomplete gamopetalous nature of the corolla and its petalomaniatic tendency. The mutants obtained were corolla whorl specific and were described as meristic mutations in I. purpurea.     

重瓣花研究进展与展望

该研究指出了近年来我国有关重瓣花多层面研究中的关键方向,归纳了不同起源方式及种类的重瓣花的研究成果,重点总结了近年来有关重瓣型植物形态分化、繁殖技术、分子研究及应用的研究,并在此基础上对重瓣植物花器官发育理论研究的价值、前景和存在的问题等进行了探讨与展望,以期为今后重瓣植物的选育提供参考依据和技术手段。     

蝴蝶兰Ph SVP的克隆及其在花发育过程中的表达分析

从蝴蝶兰杂交品种‘大辣椒’中克隆到SVP同源MADS-box基因PhSVP,使用RACE方法获得PhSVP全长,其开放阅读框为687 bp,编码228个氨基酸。蛋白序列多重比对表明PhSVP蛋白包含一个高度保守的MEF2-like MADS结构域和一个中度保守的K-box结构域,且与兰科的SVP/AGL24同源蛋白相似度高,进化树分析也表明PhSVP蛋白与其他兰科植物的SVP/AGL24同源蛋白亲缘关系最近。PhSVP的空间表达模式表明其在营养器官表达量高,在萼片、侧瓣和唇瓣等生殖器官表达量低。进一步对PhSVP在成花转换和花发育过程中花序顶端的表达进行分析,表明PhSVP的转录水平在营养分生组织向花序分生组织过渡的过程中无显著变化,仅在花序分生组织阶段有少量上升,但在花发育早期花分生组织阶段中的表达水平显著升高,而在花发育后期的萼片原基、花瓣原基和合蕊柱原基阶段持续下降。此外还发现A类基因PhAP1在花发育过程中的花序顶端的表达模式与PhSVP相似,而B类基因PhPI和C类基因PhAG在花瓣原基和合蕊柱原基阶段的表达量最高。检测了PhSVP在抽葶期、花蕾期和盛花期的根、叶和花葶中的转...     

Comparative anatomy of bisexual and female florets,embryology in Calendula officinalis (Asteraceae), a naturalized horticultural plant

Calendula officinalis is a perennial gynomonoecious herb, often used for medicinal purpose and as ornamentation. The corolla consists of only one petal for ligulate florets, whereas it consists of four to seven petals for disk florets with four to seven stamens accordingly. The bisexual florets are functionally male and their ovaries are either solid or unilocular with no ovule. In contrast, the ovaries of female florets are always unilocular with an anatropous ovule. For bisexual florets, simultaneous cytokinesis in the microsporocyte meiosis leads to tetrahedral, also decussate tetrads. The mature pollen grain is of the three-cell type. The tapetum is mainly of amoeboid type, yet 6.5% antheral tapetum disintegrates in situ, as called glandular tapetum. The young anther wall is composed of epidermis, endothecium, middle layer and tapetum, but the middle layer degenerates at the microspore tetrad stage. The mature anther wall comprises only endothecium, which develops fibrous thickenings. The ovules are unitegmic, tenuinucellatae and the development of the embryo sac follows the monosporic, polygonum type. Before the differentiation of the micropylar cells into egg cell and two synergids, the two polar nuclei fuse into a secondary nucleus and the antipodal cells start degenerating. Two days after blooming, the secondary nucleus has been fertilized by a single sperm nucleus, generating the triploid primary endosperm nucleus.     

Production of intraspecific hybrids between wild-type and petaloid-sepal cultivars in Habenaria radiata

Orchids are commercially important plants with flowers that are unique and very specialized in shape and color. The flowers consist mostly of sepals, lateral petals, lip (labellum) and column, and are zygomorphic and resupinate. Whereas most orchid species have petaloid tepals in the first and second whorls, Habenaria radiata has a flower with greenish sepals and white lateral petals and lip. ‘Hishou’, one of the cultivars of H. radiata, is a floral homeotic mutant and has a petaloid median sepal and lip-like lateral sepals in the first whorl. Additionally, this cultivar often has non-resupinate flowers whereas wild-type H. radiata flowers are resupinate. In the present study, we investigated the genetic inheritance of these characters in the ‘Hishou’ cultivar by crossing it with wild-type plants. Some intraspecific hybrids, which were confirmed by PCR-RFLP analysis, had flowers with a petaloid median sepal and lip-like lateral sepals in the first whorl, indicating that these were dominant characters. Since the remainder of the intraspecific hybrids had wild-type flowers, these characters must be heterozygous in ‘Hishou’ plants. Although ‘Hishou’ plants had non-resupinate flowers, intraspecific hybrid flowers were resupinate, even though they had the petaloid median sepal and lip-like lateral sepals. This result indicates that non-resupination must be a recessive character. Since sepal-petalization and triple lip characters of ‘Hishou’ inherited dominantly, these characters can be utilized for the breeding of Habenaria species by intra- and interspecific crosses.     

Selection of ABC genes for candidate genes of morphological changes in hydrangea floral organs induced by phytoplasma infection

The mechanism underlying the green colouration of floral organs in phytoplasma-infected hydrangeas was studied. Elucidation of morphological changes of floral organs induced by phytoplasma infection and a comparison of the expression level of genes related to floral organ morphogenesis between phytoplasma-infected and non-infected hydrangea plants was conducted. Sixteen hydrangea (Hydrangea spp.) cultivars were used to study structural changes in floral organs induced by Japanese Hydrangea Phyllody (JHP) phytoplasma infection. The homeotic conversion of sepals to leaves was observed in different number of florets between cultivars, and was observed in 75.8–100% of the decorative florets and 2.7–67.3% of the non-decorative florets of JHP phytoplasma-infected inflorescences. The homeotic conversion of carpels to leaves was observed in 1.2–17.9% of the decorative florets and 0.1–18.9% of the non-decorative florets of infected inflorescences. The expression levels of hydrangea orthologues of class A, B and C genes were suppressed in the infected inflorescences during the developmental stage in which no morphological differences in the internal structure of floral organs have been observed. The contribution of this suppression to homeotic conversion of sepals and carpels to leaves was suggested.     

蓝猪耳花器官的发生与发育

玄参科植物蓝猪耳（Torenia fournieri）的萼片、花冠、雄蕊和雌蕊原基都具两侧对称性,且为合萼、合瓣花,雄蕊着生在花冠上,子房两心皮两室。花器官分化顺序为萼片、雄蕊原基、花瓣原基、雌蕊原基。5枚萼片原基发生顺序不一致,其式样为近轴面1原基－远轴面2原基－2侧生原基,萼片原基的发育是同步的;雄蕊原基先于花瓣原基发生,但其发育比花瓣原基缓慢,4枚雄蕊原基几乎同时发生;5枚花瓣原基同时发生,且远轴面的两枚花瓣原基后来有愈合迹象。与同科Agalinis densiflora花发育比较,两种植物花器官原基发生的时间和先后顺序有较大的差异。与同科地黄属（Rehmannia）、苦苣台科（Gesneriaceae）异叶苣苔属（Whytockia）、尖舌苣苔属（Rhynchoglossum）和台闽苣苔属（Titanotrichum）的花器官发生和发育比较,发现玄参科和苦苣苔科的花器官发生和发育关系比较复杂,5属并不能笼统划分为两种不同的式样,认为以子房室数和胎座类型划分玄参科和苦苣苔科的可靠性仍需进一步探讨。