Increase in the number of decorative florets in the inflorescence of Hydrangea through phytoplasma infection

Hydrangea (Hydrangea spp.) has two types of florets in an inflorescence. One has decoratively developed sepals and is termed as the decorative floret. The other has plain sepals and is termed as the non-decorative floret. Hydrangea is classified into two types according to its inflorescence: globular (hortensia) and lacecap. In hortensia, the surface of inflorescence is covered with decorative florets. In lacecap, decorative florets are situated around the periphery of the inflorescence. Japanese hydrangea phyllody (JHP) phytoplasma infection often leads to an increase in the number of decorative florets. JHP phytoplasma was inoculated into ten hortensia and five lacecap cultivars by grafting. The ratios of decorative florets to total florets were compared between the JHP phytoplasma-infected and non-infected plants. The infected plants showed lower decorative floret ratios in six hortensia cultivars and higher decorative floret rations in four lacecap cultivars. The composition of inflorescence was investigated using infected and non-infected plants of ‘Midoribanaajisai’ (hortensia cultivar) and ‘Libelle’ (lacecap cultivar). In ‘Libelle’, the lacecap type, an alteration in the lateral non-decorative floret to the decorative floret was observed and considered to be the main cause of increase in the decorative floret ratio.     

Correlation of phytoplasma concentration in Hydrangea macrophylla with green-flowering stability

The interaction between phytoplasma concentration and green-flowering stability was studied in hydrangea cultivars. Three green and 18 nongreen cultivars were subjected to polymerase chain reaction (PCR) analysis to determine Japanese hydrangea phyllody (JHP) phytoplasma infection. The results showed that JHP-phytoplasma was detected only in ‘Midori’ plants, which have green sepals. ‘Midori’ plants were propagated, and from 29 rooted cutting plants, they were grouped into three types on the basis of sepal color, that is, green (75.9%), blue-green (13.8%) and blue (10.3%) sepals. To clarify the variability in the sepal color of ‘Midori’ plants, JHP-phytoplasma concentration in the sepals and leaves of green-, blue-green- and blue-flowering plants was determined by PCR analysis. The semiquantitative PCR comparisons of 370 bp DNA fragments showed that the JHP-phytoplasma concentrations in green sepals were 16 times higher than that in blue-green sepals. JHP-phytoplasma could not be identified by PCR analysis in blue sepals and leaves. These results showed that JHP-phytoplasma concentration correlated with green sepal stability in ‘Midori’ plants. A histological observation of sepals showed that epidermal cells of blue and blue-green sepals had a dome shape. Otherwise, green sepals were leaflike with flat epidermal cells, and palisade parenchyma cells with numerous chloroplasts.     

Flower greening in phytoplasma-infected Hydrangea macrophylla grown under different shading conditions

To determine the effect of light intensity on flower greening, the Japanese hydrangea phyllody (JHP) phytoplasma-infected hydrangea cultivars ‘Midori’, ‘Libelle’, ‘Rosea’ and ‘Madame E. Mouillere’ plants were grown under different shade conditions. In the first-year experiment, the results indicate that the flowers of the JHP-phytoplasma-infected hydrangea become green under shaded conditions (70% and 49% sunlight intensities). On the other hand, under full sunlight intensity (100% sunlight intensity), the flowers of ‘Midori’, ‘Rosea’, and ‘Libelle’ plants were blue, pink or white. To calculate the percentage of flower greening, inflorescences of these plants were separated and divided into individual flowers, and classified into four types by green-area ratio, calculated using Adobe Photoshop. Under shading with one sheet of cheesecloth (70% sunlight intensity), the inflorescences of ‘Midori’, ‘Libelle’ and ‘Madame E. Mouillere’ plants were composed of more than 40% completely green flowers (0.8 ≦ green-area ratio), whereas those of ‘Rosea’ plant had 0% completely green flowers. Under shading with two sheets of cheesecloth (49% sunlight intensity), the inflorescences of ‘Midori’, ‘Libelle’ and ‘Madame E. Mouillere’ plants had more than 75% completely green flowers; ‘Rosea’ plants had 28%. In the second-year experiment, under full sunlight intensity, ‘Midori’ plants had four types of flower depending on their green-area ratio, namely, completely blue or pink, pink-green, greenish and completely green flowers. Under shading with two sheets of cheesecloth, ‘Midori’ plants had more than 90% completely green flowers. The JHP-phytoplasma could not be identified by PCR analysis in flowers with a green-area ratio = 0 (completely blue/pink/white flowers). On the other hand, in flowers with a green-area ratio > 0, the JHP-phytoplasma was detected by PCR analysis. Thus, we conclude that shading enhances flower greening in hydrangea by increasing the JHP-phytoplasma concentration in the flowers.     

不同发育时期的荔枝花芽冷敏感性比较

【目的】为了探明不同发育时期的荔枝(Litchi chinensis Sonn.)花芽的冷敏感性差异,【方法】以发生在2008年1月下旬至2月下旬的极端低温作为低温处理的条件,研究了低温对‘妃子笑’与‘糯米糍’2个品种的"白点"(一级侧花序原基)和初生花序(花序轴伸长的一级侧花序,长1~2 cm)2种不同发育时期的花芽相对电导率、过氧化氢(H2O2)含量、花芽表面茸毛以及细胞超微结构的影响。【结果】结果表明,低温使花芽的H2O2含量升高,相对电导率增大,无论是低温期间还是温度回升后,‘妃子笑’"白点"的相对电导率低而且变化幅度小。受冷害的初生花序的茸毛较杂乱,表面有裂痕和碎片,但‘糯米糍’的裂痕和碎片相对较多。受冷害的"白点"茸毛排列较初生花序有序,表面也有裂痕,但‘糯米糍’的"白点"表面裂痕较多。而未受冷害的花芽茸毛致密而有条理,没有裂痕。2个品种受害细胞的细胞壁变得模糊,液泡膜出现破损,细胞质渗漏到液泡中,而没有受害的初生花序或"白点"上的细胞壁、液泡膜清晰。【结论】研究结果显示花序比"白点"对低温更敏感。     

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.     

Inheritance of floral colour and type in four new inbred lines of ornamental sunflower (Helianthus annuus L.)

Sunflower (Helianthus annuus L.) is grown commercially and as an ornamental plant. Floral colour and inflorescence type are important traits in the breeding of ornamental sunflower. Sunflowers consist of ray florets, which are arranged around the perimeter with disc florets in the centre. The colour of the ray florets can vary from various shades of red to lemon-yellow. The inheritance of ray floret colour was studied through diallel crossing of inbred lines with red, yellow, or lemon-yellow coloured florets. In the F₁ generations, the red colour was partially dominant over yellow and lemon-yellow ray florets, forming a ‘Gaillardia‘ pattern, while yellow was dominant over lemon-yellow. The segregation ratios in the F₂ generations were 9:7 (red × yellow) and 3:1 (red × lemon-yellow and yellow × lemon-yellow), indicating control by one or two genes, respectively. The colour of the disc florets depended on the presence or absence of anthocyanin pigmentation. Disc florets that lacked anthocyanin pigmentation were usually different shades of yellow. Anthocyanin pigmentation was dominant over yellow and lemon-yellow, showing monohybrid inheritance with a segregation ratio of 3:1 in the F₂ generation. Chrysanthemum-type inflorescences had elongated disc florets. In crosses between chrysanthemum-type and normal-type inflorescences, the segregation ratio in the F₂ populations corresponded to the theoretical ratio of 3:1 for chrysanthemum-type:normal-type inflorescences. We conclude that the genes controlling floral colour and inflorescence type are inherited independently and have different effects. The interaction of these genes revealed new combinations of floral colour and type, which can increase variability in ornamental sunflowers.     

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.     

洋葱花发育B类MADS-box基因AcDEF的克隆与表达分析

 以紫皮洋葱常规品种‘RUPI’为试材,通过RACE方法克隆了AP3/DEF同源基因AcDEF,并用半定量RT-PCR和实时荧光定量PCR研究AcDEF在洋葱各类器官中的表达模式。GenBank登录号为JX661502的AcDEF基因长1 014 bp,开放阅读框长度为675 bp,编码224个氨基酸。系统发育分析表明,AcDEF基因属于单子叶B功能基因家族的AP3/DEF亚家族。表达模式分析显示,AcDEF在花器官中特异表达,其中在花瓣、雄蕊内高丰度表达,在花葶和膜状总苞中微量表达,在心皮中表达水平极低,在无性营养器官如根、假茎、叶片和鳞茎中无表达。在开花过程中,各花器官中AcDEF转录物的积累呈动态变化;在花瓣和雄蕊发育过程中AcDEF均高丰度表达,但在完全开放花的花瓣和雄蕊中表达量略有降低;在花葶、膜状总苞和心皮中表达量递减,在完全开放花的膜状总苞和心皮中AcDEFAcDEF基因的序列结构和表达模式具有单子叶物种AP3/DEF基因的特征,属于paleoAP3进化系。的表达量很低。     

牡丹泛素延伸蛋白基因ubiquitin克隆及其作为内参基因的研究

以牡丹品种‘洛阳红’（Paeonia suffruticosa‘Luoyanghong’）为试验材料,采用RT-PCR方法获得一个牡丹泛素延伸蛋白基因Psubiquitin（PsUBI）,其cDNA开放阅读框（ORF）长度为447 bp,编码148个氨基酸,GenBank登录号为KP742952。序列比对发现,该基因与其他23种植物泛素延伸蛋白核苷酸序列的相似性均在81%以上,氨基酸序列的相似性达96%。进化分析表明,牡丹泛素延伸蛋白与棉花泛素延伸蛋白的亲缘关系最近。实时荧光定量PCR结果显示,在牡丹不同组织器官中,相对于其他5个常用看家基因（GAPDH、GAPDH1、tubulin、tubulin2、18S rRNA）,ubiquitin的PCR扩增曲线的CT值最为恒定,尤其是在不同花器官中的CT值完全一致。进一步分析发现该基因在牡丹的根、茎、叶片、花、雄蕊和心皮组织中均恒定表达,特别是花器官中的表达量几乎完全一致。以ubiquitin作为内参基因探讨控制花器官发育的基因PsAG的表达情况,结果显示PsAG的表达模式与其作用位点相吻合,ubiquitin更适宜作为牡丹花器官研究的内参基因。     

Pathogenesis-related (PR)-proteins: Chitinase and β-1,3-glucanase in defense mechanism against malformation in mango (Mangifera indica L.)

Mango, the king of fruits in India is cultivated commercially in many tropical and subtropical regions of the world. Undoubtedly, mango malformation is a serious disease affecting mango production in India and many other countries around the world. It is now shown that the malady is inflicted by Fusarium, a fungus, and also that the plants have the capacity to suppress or reduce pathogen attack by inducing the synthesis of antimicrobial metabolites such as chitinase and/or the synthesis of lignin, both of which may enhance plant defense system. The present study was aimed at investigating the variability and relationship between activities of chitinase, β-1,3-glucanase and content of lignin in the leaves using 12 mango cultivars with the different degree of resistance to floral malformation. Results revealed that the activity of chitinase and β-1,3-glucanase in the leaves were significantly high in mango cultivars resistant to malformation (r = −0.90 and r = −0.91, respectively) during the flowering period, whereas lignin content did not show a significant correlation with malformation. The highest activity of chitinase (1.977–2.011 units) and β-1,3-glucanase (80.54–82.06 units) was recorded in resistant mango cultivars Bhadauran and Elaichi. In contrast, these activities were less than 1.010 and 25.21 respectively in highly susceptible mango cultivars such as Amrapali, Eldon and Neelum. Lignin content was highest in resistant cultivar Bhadauran, but it did not show significant relation to the malformation intensity of the cultivars. Thus, leaf chitinase and β-1,3-glucanase may be contributing towards resistance to malformation in mango and that the relative activities of these enzymes can be used as a criterion to predict and screen the mango germplasm and cultivars for resistance to floral malformation.     

Inflorescence development of flowering and blasted gladiolus plants in relation to development of other plant parts

Flower differentiation in Gladiolus × grandiflorus takes place immediately after initation of all the leaves. The prefloral stage was observed in shoots 3–4 mm long and the shoot apex was floral when the first foliage leaf was half extended.Initiation of individual florets continued up to the 7-leaf stage. Flower development is acropetal and continued up to anthesis of each individual floret.Flower blasting generally starts at the tip of the inflorescence and advances towards the base of the flower stalk. Blasting starts as a stoppage in the growth of the inflorescence, the flower stalk and the leaves on the stalk. Later these organs shrivel. Daughter corms fill early as a consequence of blasting.     

托桂型菊花花器性状杂种优势与混合遗传分析

以托桂型菊花品种‘QX-053’为母本,非托桂型菊花品种‘南农惊艳’为父本配制组合,调查F1代10个花器性状在2012和2013年的表型,运用单个分离世代的主基因 + 多基因混合遗传模型进行花器性状遗传分析。结果表明：10个花器性状均存在一定的杂种优势,除花径、舌状花数、舌状花长和管状花宽外,心花直径、舌状花宽、管状花数、管状花长、最深齿裂长和花柱长等6个性状的中亲优势值均达极显著水平。10个花器性状中,花径、心花直径、舌状花长、舌状花宽、管状花数、管状花长和花柱长均符合A-0模型,即无主基因控制,可能受环境影响比较大的多基因控制;而舌状花数、管状花宽、最深齿裂长符合B-1模型,即表现为加性-显性-上位性的两对主基因控制,主基因遗传率分别为93.85%、42.86%和52.00%。     

Floral analysis cannot be considered as an alternative to the foliar diagnosis in the olive

Correlations between macro and micronutrient concentration of olive leaves and those obtained in floral buds at five development stages, were studied in order to evaluate the utility of floral analysis for the diagnosis of the nutritional status of olive orchards. Olive leaves from ‘Arbequina’, ‘Frantoio’, ‘Hojiblanca’, ‘Bella de España’ and ‘Picual’ cultivars were taken during July of 2002 and 2003. Samples of floral buds were collected at five development stages: closed bud (E), petal fall (G), G + 15 days, G + 30 days and pit hardening (H). Results showed a lack of signification of the correlation coefficients between leaf and floral analysis for N, P, K, Ca, Mg, B, Zn, Mn, Fe, Cu and Na in both years of the experiment. The few significant correlations obtained were not repeated in both years. Therefore, the results indicate that floral bud mineral analyses cannot substitute the foliar diagnosis to establish the nutritional status of the olive orchards.     

Effect of arbuscular mycorrhizal fungi inoculation on aster yellows phytoplasma-infected tobacco plants

The objective of the research was to asses if arbuscular mycorrhizal fungi (AM) can modify the effect of two aster yellows phytoplasma strains infection in tobacco plants. Tobacco plants experimentally inoculated with aster yellows phytoplasma strains did not develop visible disease symptoms. However, PCR examination indicated that the inoculated plants were phytoplasma infected. Mycorrhiza inoculation had a positive effect on the shoot height of healthy plants, but did not influence shoot growth and weight of phytoplasma-infected plants. The roots of all mycorrhiza-inoculated plants were slightly reduced but significant differences were found in the total root length of plants infected with the phytoplasma strain AY1. AM inoculation had a positive effect on photosynthetic activity of tobacco plants infected with the phytoplasma strain AYSim, but net photosynthesis of tobacco infected with the phytoplasma strain AY1 was decreased. Transpiration rate and calcium content of AM and phytoplasma-infected plants were not affected. The mechanisms underlying these interactions are discussed and a direct action of the AM fungus is hypothesized.     

大白菜花芽形态分化的研究

 通过对3个不同熟性大白菜的观察,将其花芽形态分化过程分为营养生长期、生长锥伸展期和花原基分化期3个时期,并将花原基分化期细分为萼片分化期、雄蕊和雌蕊分化期和花瓣分化期。所观察材料的侧枝分化顺序都是由顶部向基部依次进行。熟性不同的材料问花芽发育速度为极早熟>早熟>晚熟。     

Identification of Petunia hybrida cultivars that diurnally emit floral fragrances

In order to identify genetic resources for breeding fragrant petunias for use as bedding plants, volatile compounds released by day from the flowers of 40 commercial Petunia hybrida cultivars were analyzed using a solid-phase micro-extraction technique coupled with GC–MS. The three cultivars with solid deep-blue flowers that accumulate malvidin in corollas with high tissue pH were found to emit abundant iso-eugenol as the principal floral fragrance. Several other cultivars that emitted considerable amounts of methylbenzoate and/or benzylbenzoate from the flower were also identified. Association between the floral fragrance and the other floral traits such as floral anthocyanin composition and corolla-tissue pH was discussed.     

小苍兰ACC合成酶基因FhACS1在花中的时空表达特征

 研究了小苍兰‘上农金皇后’ACC合成酶基因FhACS1在花中的时空表达特征。结果表明,FhACS1基因在花朵不同器官、花朵的不同发育阶段以及瓶插期间在花朵不同器官中的表达量均存在明显的差异。FhACS1基因在花朵不同器官的表达量由高到低为：雄蕊 > 花瓣 > 雌蕊。不同发育阶段中FhACS1基因的表达特征表现为：花朵完全开放（0级）时表达量最高,大部分开放（1级）时次之,完全衰老花朵（–2级）中的表达量最低。将小苍兰鲜切花用蒸馏水瓶插,取花序上自基部起第3朵和第6朵小花为材料,研究了FhACS1基因随瓶插时间的表达谱,结果表明FhACS1基因在第6朵小花中的整体表达量显著高于第3朵。第3朵小花中FhACS1基因在花瓣、雄蕊、雌蕊中的表达均表现为先上升后下降,但最大表达量的出现时间存在差异;FhACS1基因在整朵花中的表达量变化与在花瓣中一致。第6朵小花花瓣中FhACS1基因的表达量持续上升,在雄蕊、雌蕊中的表达量则先上升后下降,达到最大表达量的时间分别为第3天和第6天;在整朵花中的表达变化也与在花瓣中的变化趋势一致。     

Light quality of continuous illuminating at night to induce floral initiation of Fragaria chiloensis L. CHI-24-1

A wild strawberry strain, Fragaria chiloensis CHI-24-1, produced inflorescences from both parent and asexually propagated daughter plants linked with runners when grown at 23 °C/20 °C (day/night) under a 24 h day-length (DL) of daylight plus nightly lighting by an incandescent lamp, but not under 8 or 16 h DLs. In the present study, the effect of light quality for continuous illuminating at night on floral initiation of CHI-24-1 plants grown under a 24 h DL was examined. The CHI-24-1 plants were grown under a 24 h DL consisting of natural daylight and continuous lighting at night by an incandescent, a blue fluorescent, a red fluorescent or a far-red fluorescent lamp for 40 days in summer and autumn. Also, the CHI-24-1 plants were grown for 40 days in a growth chamber at 25 °C/20 °C (day/night) with natural daylight and continuous lighting at night by red- and four types of far-red light-emitting-diodes (LEDs with peak wavelengths of 660, 700, 735, 780 and 830 nm). In both experiments, floral initiation of the parent and daughter plants was observed under a stereomicroscope. Although more than 50% of the parent and daughter plants initiated flower buds under the incandescent and far-red fluorescent lamps, about 15% and 0% of those initiated flower buds under blue and red fluorescent lamps, respectively. Floral initiation of the parent and daughter plants occurred under the far-red LED light source whose peak wavelength was 735 nm, but not under the red or the other far-red LEDs. From these results, it can be concluded that the effective light wavelength range of nightly continuous illuminating for floral induction in the CHI-24-1 plants is 735 nm in the far-red light region. Hence, the induction of floral initiation by nightly continuous far-red light (735 nm) appeared to be a response mediated by phytochrome.     

Gibberellin-mediated suppression of floral initiation in the long-day plant Rhododendron cv. Hatsugiri

In a number of woody perennial species a decrease in gibberellins concentrations in the apical meristems is required for floral initiation to occur. In Rhododendron, applied gibberellins inhibit flowering and gibberellin biosynthesis inhibitors promote flowering. However, unlike previous reports on other Rhododendron cultivars, Rhododendron cv. Hatsugiri is a faculatitive LDP. It was therefore unknown how gibberellins regulate flowering in this cultivar and if non-inductive short daylengths stimulate the productions of endogenous gibberellins to suppress flowering. By inhibiting floral initiation while not stimulating vegetative growth we found applications of GA₅ to best match the natural response of Rhododendron cv. Hatsugiri under short-day regimes. GA₅-mediated effects on flowering have previously been reported to be due to conversion to GA₆, however, GA₅ was found to be present in tissue samples at up to 0.57 ng g⁻¹ FW, while GA₆ was never found. In addition, foliar applications of [¹⁴C] GA₅ were not found to have metabolised to GA₆. In line with the hypothesis that gibberellins inhibit floral initiation in short days in Rhododendron cv. Hatsugiri, the concentration of GA₂₀, a precursor to many bioactive gibberellins, was higher in leaf tissues from plants in short days, compared to those in permissive long days when analysed using GC–MS.