Sample records for dichogamy

  1. 核桃雌雄异熟性研究进展%Research Advances on Dichogamy of Walnut

    赵书岗; 王红霞; 张志华


    Walnut (Juglans regia L.) is monoecious plant. Dichogamy, affects sexual reproduction such as flowering and pollination, and ultimately influences the yield and quality of nut. The research situation of dichogamy in walnut was briefly introduced; and the manifestation of dichogamy in walnut, phenology characteristics, floral differentiation, genetic characteristics and utilization in cultivation was summarized so as to reflect the rule of dichogamy in walnut and provide guidance for walnut cultivation.%核桃(Juglans regia L.)为雌雄异花同株植物,其雌雄异熟性直接影响着开花、授粉等有性繁殖过程,从而影响核桃坚果的产量和品质.概述了国内外核桃雌雄异熟性的研究现状,对核桃雌雄异熟性在自然界中的表现、物候期特点、花芽分化进程、遗传特性和生产利用价值等进行了综述,以期反映核桃雌雄异熟性的规律及对高产栽培的指导意义.

  2. Low-copy nuclear DNA, phylogeny and the evolution of dichogamy in the betel nut palms and their relatives (Arecinae; Arecaceae).

    Loo, Adrian H B; Dransfield, John; Chase, Mark W; Baker, William J


    For the betel nut palm genus Areca and the other seven genera in subtribe Arecinae (Areceae; Arecoideae; Arecaceae) we collected DNA sequences from two low-copy nuclear genes, phosphoribulokinase (PRK) and the second largest subunit of RNA polymerase II (RPB2). The data were used to evaluate monophyly of the subtribe and its component genera, explore the radiation of the group across its range, and examine evolution of protandry and protogyny, which is particularly diverse in Arecinae. The subtribe and some genera are not monophyletic. Three lineages of Arecinae are recovered: one widespread, but centered on the Sunda Shelf, another endemic to the islands east of Wallace's line and a third, comprising the Sri Lanka endemic Loxococcus, that is most closely related to genera from outside subtribe Arecinae. Strong support is obtained for broadening the circumscription of the genus Hydriastele to include Gronophyllum, Gulubia and Siphokentia. In clarifying phylogenetic relationships, we have demonstrated that a perceived bimodal distribution of the subtribe across Wallace's line does not in fact exist. Character optimizations indicate that the evolution of protogyny, an unusual condition in palms, is potentially correlated with a large radiation in the genus Pinanga and possibly also to dramatic diversification in pollen morphology and genome size. The evolution of dichogamy in the clade endemic to the east of Wallace's line is complex and reveals a pattern of numerous transformations between protandry and protogyny that is in marked contrast with other Arecinae. We suggest that this contrast is most likely a reflection of differing geological histories and pollinator spectra in each region.

  3. Evidence of Dichogamy in Santalum album L.


    Flowering, fruit set, embryological development, and pollination trials were investigated in Santalum album L.Each ovary may have three to four ovules. Microsporogenesis and megasporogenesis in the same flower were synchronized at the earlier stages of flower development. However, at anthesis, when pollen was mature, the magaspore had developed only to the stage of a one- to two-nucleus embryo sac. As the eight-nucleus embryo sac developed, some mamelon cells began to undergo programmed cell death, forming holes into which the eight-nucleus embryo sacs extended, becoming "N" or "S" shaped. The development from a two-nucleus embryo sac to a matured eight-nucleus embryo sac lasted up to 10 d. Fruit-set from open pollination was less than 2%. The endosperm develops prior to division of the zygotic embryo and one to three embryos and endosperms were formed in the same fruit. A mature seed usually germinates to produce one seedling;however, two and three seedlings from one seed were also observed, albeit at a Iow frequency. Pollination trials showed that no seed sets when inflorescences were covered with a bag; however, artificial pollination could improve fruit set. Our pollination trials and embryological studies proved that the flower of S. album is dichogamous and fruit set has high heterozygosity.


    Wiguna Rahman


    Full Text Available Observasi tentang tipe dikogami, sistem penyerbukan, dan keterbatasan serbuk sari telah dilakukan pada populasi Aeschynanthus pulcher di Kebun Raya Cibodas. Pengamatan fenologi bunga dilakukan untuk menentukan tipe dikogami. Dalam rangka menentukan sistem perkawinan dan keterbatasan serbuk sari, lima perlakuan penyerbukan telah dilakukan yaitu penyerbukan bebas sebagai kontrol, penyerbukan silang, penyerbukan sendiri, autogami, dan agamospermi. Hasil pengamatan menunjukkan bahwa dikogami pada A. pulcher adalah protandri, tidak sempurna dan durasi tampilan serbuk sari dan stigma reseptif masing-masing yaitu 3-9 hari dan 6-12 hari. A. pulcher merupakan tumbuhan yang dapat membuahi sendiri, sedangkan proses autogami dan agamospermi tidak terjadi. Sindrom keterbatasan serbuk sari pada populasi A. pulcher yang diamati diindikasikan terjadi. Derajat keterbatasan serbuk sari pada A. pulcher mencapai 0.79-0.80. Tiga faktor yang dapat menyebabkan keterbatasan serbuk sari adalah (1 kompetisi antar jenis tumbuhan yang berbunga bersamaan, (2 perilaku berbunga dalam satu periode yang sama, dan (3 kompetisi antara polinator dan pencuri nektar.

  5. Phenology, dichogamy, and floral synchronization in a northern red oak (Quercus Rubra L.) seed orchard

    We developed a novel scoring system to assess spring phenology in a northern red oak clonal seed orchard. The system was used to score between 304 and 364 ramets for three reproductive seasons and place clones into early, middle, and late phenology groups. While the absolute number of clones in ea...

  6. Outcrossing in Florida and California commercial avocado (Persea americana Mill) orchards estimated using microsatellite markers and the development of a genetic linkage map

    Avocado has an unusual flowering mechanism, diurnally synchronous protogynous dichogamy, which promotes cross pollination. Comemrcial groves usually contain pollinizer rows adjacent to the more desirable commercial cultivars. Conflicting results on the effect of pollinizer rows on out-crossing rates...

  7. Out-crossing between 'Bacon' pollinizers and adjacent 'Hass' avocado and the identification of two new avocado lethal mutants

    Avocado (Persea americana Mill) has an unusual flowering mechanism, diurnally synchronous protogynous dichogamy, which promotes cross pollination among avocado genotypes. In commercial groves, which usually contain pollinizer rows adjacent to the more desirable commercial cultivars, the rate of out-...

  8. Microsatellite markers reveal low breeding system efficacy and pollen contamination can limit production of full-sib avocado progeny

    Phytophthora cinnamomi causes a severe root rot in avocado, Persea americana. Breeding tolerant rootstocks is thought to be the most promising method for phytophthora root rot disease control but breeding avocado is challenging. The avocado flowering syndrome (synchronous protogynous dichogamy), com...

  9. Strategies of delayed self-pollination in Kosteletzkya virginica

    RUAN Chengjiang; QIN Pei; HAN Ruiming


    @@ Though in the face of selection against self-pollina-tion, mixed pollination systems are maintained in many plants. The transition from outcrossing to self-fertilization is one of the most common evolutionary trends in angio-sperms[1]. Floral morphological characters and behavior influence plant pollination mode and reproductive success, such as herkogamy[2,3], dichogamy[2,3], floral movement, and corolla abscission[4-6]. If a plant population relies solely on animal vectors to move pollen among individu-als and if pollinators are absent or in low numbers at cer-tain times or years, individuals that can self-pollinate if not previously outcrossed will be at a selective advantage[7].

  10. Pollinator responses to floral colour change, nectar, and scent promote reproductive fitness in Quisqualis indica (Combretaceae).

    Yan, Juan; Wang, Gang; Sui, Yi; Wang, Menglin; Zhang, Ling


    Floral colour change is visual signals for pollinators to avoid old flowers and increase pollination efficiency. Quisqualis indica flowers change colour from white to pink to red may be associated with a shift from moth to butterfly pollination. To test this hypothesis, we investigated Q. indica populations in Southwest China. Flowers secreted nectar continuously from the evening of anthesis until the following morning, then decreased gradually with floral colour change. The scent compounds in the three floral colour stages were similar; however, the scent composition was different, and the scent emission rate decreased from the white to red stage. Dichogamy in Q. indica prevents self-pollination and interference of male and female functions. Controlled pollinations demonstrated that this species is self-incompatible and needs pollinators for seed production. Different pollinators were attracted in each floral colour stage; mainly moths at night and bees and butterflies during the day. Observations of open-pollinated inflorescences showed that white flowers had a higher fruit set than pink or red flowers, indicating the high contribution of moths to reproductive success. We concluded that the nectar and scent secretion are related to floral colour change in Q. indica, in order to attract different pollinators and promote reproductive fitness.

  11. The evolution of floral biology in basal angiosperms.

    Endress, Peter K


    In basal angiosperms (including ANITA grade, magnoliids, Choranthaceae, Ceratophyllaceae) almost all bisexual flowers are dichogamous (with male and female functions more or less separated in time), and nearly 100 per cent of those are protogynous (with female function before male function). Movements of floral parts and differential early abscission of stamens in the male phase are variously associated with protogyny. Evolution of synchronous dichogamy based on the day/night rhythm and anthesis lasting 2 days is common. In a few clades in Magnoliales and Laurales heterodichogamy has also evolved. Beetles, flies and thrips are the major pollinators, with various degrees of specialization up to large beetles and special flies in some large-flowered Nymphaeaceae, Magnoliaceae, Annonaceae and Aristolochiaceae. Unusual structural specializations are involved in floral biological adaptations (calyptras, inner staminodes, synandria and food bodies, and secretory structures on tepals, stamens and staminodes). Numerous specializations that are common in monocots and eudicots are absent in basal angiosperms. Several families are poorly known in their floral biology.

  12. The evolution of floral biology in basal angiosperms

    Endress, Peter K.


    In basal angiosperms (including ANITA grade, magnoliids, Choranthaceae, Ceratophyllaceae) almost all bisexual flowers are dichogamous (with male and female functions more or less separated in time), and nearly 100 per cent of those are protogynous (with female function before male function). Movements of floral parts and differential early abscission of stamens in the male phase are variously associated with protogyny. Evolution of synchronous dichogamy based on the day/night rhythm and anthesis lasting 2 days is common. In a few clades in Magnoliales and Laurales heterodichogamy has also evolved. Beetles, flies and thrips are the major pollinators, with various degrees of specialization up to large beetles and special flies in some large-flowered Nymphaeaceae, Magnoliaceae, Annonaceae and Aristolochiaceae. Unusual structural specializations are involved in floral biological adaptations (calyptras, inner staminodes, synandria and food bodies, and secretory structures on tepals, stamens and staminodes). Numerous specializations that are common in monocots and eudicots are absent in basal angiosperms. Several families are poorly known in their floral biology. PMID:20047868

  13. 蜀葵花蜜成分与虫媒传粉模式的研究%Nectar Compositions and Insect Pollination of Althaea rosea

    李群; 包琎龙; 王学英; 陈旭辉; 阮成江


    蜀葵(A lthaea rosea)是我国一种重要的传统花卉,其花具有雌雄异熟和雌雄异位两种特征,柱头能发生弯曲与自身花粉接触,存在潜在的延迟自交.为了检测蜀葵花蜜成分和观察访花昆虫的访花行为,在自然居群内观察蜀葵花期物候、访花昆虫种类及主要访花昆虫的访花行为,采用高效液相色谱法分析其花蜜的主要成分和含量.结果表明,蜀葵每株每天开放0~40朵花,平均具有23朵处于不同发育时期的花.蜀葵的花朵在开花前分泌花蜜,单花花期内花蜜分泌呈单峰曲线.花蜜含糖量为8.41%,共检测出14种氨基酸.访花昆虫13种,主要为意大利蜂(Apis mellifera),其访花频率与花开放时间和花蜜分泌的高峰时间一致.意大利蜂在同一植株上访花数超过1朵的访问比例约占66.04%.蜀葵内同株异花传粉导致的双亲近交不可避免,两性花中的雌雄异熟和雌雄异位的适应意义可能主要是避免雌雄干扰.%Hollyhock (Althaea rosea) is an important traditional flower of china. A combination of dichogamy and herkogamy in the flower, meanwhile, the stigmas can curve and contact its own pollen, indicating the potential of delayed selfing. In order to detect the composition of nectar and observe the behavior of visiting, the flowering phenology, the species and visiting behavior of flower-visiting insects on Althaea rosea were investigated in naturalized population. The nectar content was determined by high performance liquid chromatography and analyse the compositions. Each individual plant has an average of 23 flowers in different developmental stages ranging from 0 to 40. The nectar is secreted before flower opening and has a single-peak curve in anthesis. The content of sugar is 8.41% in nectars, and 14 amino acids are detected in them. There are 13 flowering-visiting species and Apis mellifera is the main pollinator, the visiting frequency of Apis mellifera is correlated with the

  14. Inflorescence dimorphism, heterodichogamy and thrips pollination in Platycarya strobilacea (Juglandaceae).

    Fukuhara, Tatsundo; Tokumaru, Shin-ichiro


    Unlike other taxa in Juglandaceae or in closely related families, which are anemophilous, Platycarya strobilacea has been suggested to be entomophilous. In Juglandaceae, Juglans and Carya show heterodichogamy, a reproductive strategy in which two morphs coexist in a population and undergo synchronous reciprocal sex changes. However, there has been no study focusing on heterodichogamy in the other six or seven genera, including Platycarya. Inflorescence architecture, sexual expression and pollination biology were examined in a P. strobilacea population in Japan. Flowering phenology was monitored daily for 24 trees in 2008 and 27 in 2009. Flower visitors and inhabitants were recorded or collected from different sexes and stages. The population of P. strobilacea showed heterodichogamous phenology with protogynous and duodichogamous-protandrous morphs. This dimorphism in dichogamy was associated with distinct inflorescence morphologies. Thrips pollination was suggested by the frequent presence of thrips with attached pollen grains, the scarcity of other insect visitors, the synchronicity of thrips number in male spikes with the maturation of female flowers, and morphological characters shared with previously reported thrips-pollinated plants. Male spikes went through two consecutive stages: bright yellow and strong-scented M1 stage, and brownish and little-scented M2 stage. The latter contained more thrips, synchronized better with the receptive stage of female flowers of the reciprocal morph and is probably the main period of pollen export. Platycarya strobilacea is heterodichogamous and thrips-pollinated, both of which are relatively rare conditions in angiosperms. In male spikes of P. strobilacea, there is probably a temporal decoupling of pollinator attraction and pollen export.

  15. Pollination and floral biology of Adonis vernalis L. (Ranunculaceae – a case study of threatened species

    Bożena Denisow


    Full Text Available Although the knowledge of pollination systems of rare and threatened species is one of the principles for development of optimal conservation and management strategies, the data about their pollination requirements are scarce or incomplete. Different problems are listed (xerothermic habitat disappearance, overgrowing of patches, plant biology i.e., slow plant growth, problems with seed germination among the possible causes of Adonis vernalis being threatened, but until now no consideration was given to the flowering biology and pollination. The observations of flowering biology of A. vernalis (Ranunculaceae, a clonal species, were conducted in an out-of-compact-range population, in the Lublin Upland, Poland (51°18'55" N, 22°38'21" E, in 2011–2013. The reproductive potential of A. vernalis is related to the population age structure, pollination syndrome, and breeding system. The flowers exhibit incomplete protogyny. The dichogamy function is supported by different (biological, morphological mechanisms. Stigma receptivity occurred about one day before anthers started shedding self-pollen, and pollen viability was increasing gradually during the flower life-span (66.3% in distal anthers vs. 77.3% in proximal. The decrease in pollen production and in pollen viability coincided with the lowest degree of seed set, irrespective of the pollination treatment. Pollen vectors are necessary for efficient pollination, as the proportion of pistils setting fruits after open pollination (41–82.1% was significantly higher compared to spontaneous self-pollination (only 5.5–12.3%. The pollination requirements together with pollen/ovule ratio (P/O = 501 indicate a facultative xenogamous breeding system in A. vernalis. Therefore, in the conditions of the global lack of pollinators, improper pollination may weaken the population by leading to a decrease in the proportion of recombinants, and in addition to other factors, may accelerate extinction of small A

  16. Wind-Dragged Corolla Enhances Self-Pollination: A New Mechanism of Delayed Self-Pollination

    Qu, Rongming; Li, Xiaojie; Luo, Yibo; Dong, Ming; Xu, Huanli; Chen, Xuan; Dafni, Amots


    Background and Aims Delayed self-pollination is a mechanism that allows animal-pollinated plants to outcross while ensuring seed production in the absence of pollinators. This study aims to explore a new mechanism of delayed self-pollination facilitated by wind-driven corolla abscission in Incarvillea sinensis var. sinensis. Methods Floral morphology and development, and the process of delayed self-pollination were surveyed. Experiments dealing with pollinator and wind exclusion, pollination manipulations, and pollinator observations were conducted in the field. Key Results Delayed self-pollination occurs when the abscising corolla driven by wind drags the adherent epipetalous stamens, thus leading to contact of anthers with stigma in late anthesis. There is no dichogamy and self-incompatibility in this species. The significantly higher proportion of abscised corolla under natural conditions as compared with that in wind-excluding tents indicates the importance of wind in corolla abscission. When pollinators were excluded, corolla abscission significantly increased the number of pollen grains deposited on the stigma and, as a result, the fruit and seed set. Only half of the flowers in plots were visited by pollinators, and the fruit set of emasculated flowers was significantly lower than that of untreated flowers in open pollination. This species has a sensitive stigma, and its two open stigmatic lobes closed soon after being touched by a pollinator, but always reopened if no or only little pollen was deposited. Conclusions This delayed self-pollination, which involved the movement of floral parts, the active participation of the wind and sensitive stigma, is quite different from that reported previously. This mechanism provides reproductive assurance for this species. The sensitive stigma contributes to ensuring seed production and reducing the interference of selfing with outcrossing. The pollination pattern, which combines actions by bees with indirect

  17. Timing of pollen release and stigma receptivity period of Piper vicosanum: New insights into sexual reproduction of the genus.

    Valentin-Silva, Adriano; Coelho, Victor Peçanha de Miranda; Ventrella, Marília Contin; Vieira, Milene Faria


    Dichogamy is a common characteristic among angiosperms, including Piper species. In this genus, the tiny flowers are morphologically similar and have an asynchronous stamen development. However, there is no information on the duration of stigma receptivity and whether it overlaps with pollen release. To better understand mechanisms of floral function in Piper vicosanum, we provide a detailed characterization of the timing of pollen release from the four stamens and the period of stigma receptivity and exposure mode of the receptive areas. We investigated plants of a natural population in a semideciduous seasonal forest (Viçosa, Minas Gerais State, southeastern Brazil), based on chemical tests, light microscopy, and scanning electron microscopy analyses. Incomplete protogyny-a mechanism that favors outcrossing-was recorded. The period of stigma receptivity was long (14 d), and the sequential exposure and senescence of stigmatic papillae occurred gradually and in a basipetal direction. Pollen release began 2-6 d after the beginning of the pistillate phase, with an average pollen viability of 87.7%, during the bisexual flower phase. Pollen was released for up to 6 d and occurred in one stamen at a time. The fruit set observed in tests of self-pollination indicated self-compatibility. The gradual and sequential exposure of stigmatic papillae in P. vicosanum flowers is described here as the mechanism for the long duration of receptivity. Anther development and pollen release were also sequential. These findings are yet unreported reproductive characteristics of the genus and offer new perspectives for future studies on the floral biology of other Piper species. © 2015 Botanical Society of America, Inc.

  18. Annual Variation in Flowering Phenology, Pollination, Mating System, and Pollen Yield in Two Natural Populations of Schima wallichii (DC. Korth

    Vinod Prasad Khanduri


    Full Text Available Background. Schima wallichii is a highly valuable tree of tropical forest in north-east Himalaya region that grows naturally in a wide range of altitudes between 750 and 2400 m asl with varying environments. Flowering phenology of tropical tree species at population level is generally ignored and therefore a detailed knowledge of flowering and fruiting patterns of important multipurpose tree species is critical to the successful management of forest genetic resources. Materials and Methods. The study was conducted at two different altitudes (i.e., 750 m and 900 m asl in the tropical semideciduous forest of north-east Himalaya. The floral phenology including flowering synchrony in the populations, anthesis, anther dehiscence, stigma receptivity, pollinators visitation frequency, and mating system including index of self-incompatibility were worked out in Schima wallichii according to the ear-marked standard methods given by various scientists for each parameter. Results. The flowering period in Schima wallichii varied from 33 to 42 days with mean synchrony of 0.54 to 0.68 between the populations. The stigma was receptive up to 2.5 days only and showed slightly protandrous type of dichogamy. Average pollen production ranged between 6.90 × 107 pollen per tree in 2007 and 15.49 × 108 pollen per tree in 2011. A three-year masting cycle was noticed in this species. The frequency of visitation of honey bees was fairly high (5.2 ± 1.12 visits/flower/hour as compared to other pollinators. The hand pollination revealed maximum fruit (74.2 ± 5.72% and seed (70.8 ± 7.46% settings. Conclusions. The variation in flowering phenology and pollen yield individually and annually along with temporal separation in anther dehiscence and pollinator’s visitation cause pollen limited reproduction, which ultimately influences the reproductive success in Schima wallichii.

  19. A first linkage map of pecan cultivars based on RAPD and AFLP markers.

    Beedanagari, Sudheer R; Dove, Sue K; Wood, Bruce W; Conner, Patrick J


    We report here the first genetic linkage maps of pecan [Carya illinoinensis (Wangenh.) K. Koch], using random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers. Independent maps were constructed for the cultivars 'Pawnee' and 'Elliot' using the double pseudo-testcross mapping strategy and 120 F1 seedlings from a full-sib family. A total of 477 markers, including 217 RAPD, 258 AFLP, and two morphological markers were used in linkage analysis. The 'Pawnee' linkage map has 218 markers, comprising 176 testcross and 42 intercross markers placed in 16 major and 13 minor (doublets and triplets) linkage groups. The 'Pawnee' linkage map covered 2,227 cM with an average map distance of 12.7 cM between adjacent markers. The 'Elliot' linkage map has 174 markers comprising 150 testcross and 22 intercross markers placed in 17 major and nine minor linkage groups. The 'Elliot' map covered 1,698 cM with an average map distance of 11.2 cM between adjacent markers. Segregation ratios for dichogamy type and stigma color were not significantly different from 1:1, suggesting that both traits are controlled by single loci with protogyny and green stigmas dominant to protandry and red stigmas. These loci were tightly linked (1.9 cM) and were placed in 'Elliot' linkage group 16. These linkage maps are an important first step towards the detection of genes controlling horticulturally important traits such as nut size, nut maturity date, kernel quality, and disease resistance.

  20. Evolutionary steps in the reproductive biology of Annonaceae

    Gerhard Gottsberger


    Full Text Available Flowers of Annonaceae are characterized by fleshy petals, many stamens with hard connective shields and numerous carpels with sessile stigmas often covered by sticky secretions. The petals of many representatives during anthesis form a closed pollination chamber. Protogynous dichogamy with strong scent emissions especially during the pistillate stage is a character of nearly all species. Scent emissions can be enhanced by thermogenesis. The prevailing reproductive system in the family seems to be self-compatibility. The basal genus Anaxagorea besides exhibiting several ancestral morphological characters has also many characters which reappear in other genera. Strong fruit-like scents consisting of fruit-esters and alcohols mainly attract small fruit-beetles (genus Colopterus, Nitidulidae as pollinators, as well as several other beetles (Curculionidae, Chrysomelidae and fruit-flies (Drosophilidae, which themselves gnaw on the thick petals or their larvae are petal or ovule predators. The flowers and the thick petals are thus a floral brood substrate for the visitors and the thick petals of Anaxagorea have to be interpreted as an antipredator structure. Another function of the closed thick petals is the production of heat by accumulated starch, which enhances scent emission and provides a warm shelter for the attracted beetles. Insight into floral characters and floral ecology of Anaxagorea, the sister group of the rest of the Annonaceae, is particularly important for understanding functional evolution and diversification of the family as a whole. As beetle pollination (cantharophily is plesiomorphic in Anaxagorea and in Annonaceae, characters associated with beetle pollination appear imprinted in members of the whole family. Pollination by beetles (cantharophily is the predominant mode of the majority of species worldwide. Examples are given of diurnal representatives (e.g., Guatteria, Duguetia, Annona which function on the basis of fruit

  1. 大花百子莲的花粉活力与柱头可授性1)%Pollen Viability and Stigma Receptivity of Agapanthus praecox ssp.orientalis ‘Big Blue


    We investigated the pollen viability and stigma receptivity of A.praecox ssp.orientalis‘Big Blue’ in Shanghai, Chi-na, and analyzed the influence of pollen viability and stigma receptivity to reproduction.The best composition of medium is 10%sucrose+0.1%H3 BO3+0.2 g・ L-1 Ca(NO3 ) 2 .Pollen viability gradually reduces with the flowering process.Pollen viability is 80%at initial time of florescence and the value is 3%at the end of florescence.Survival time of pollen is seven days in 4℃.The value is five days in 25℃and two days in 35℃.Pollen has the germination ability at the first day of flowering and stigma has receptivity ability at the next day of flowering.Therefore, A.praecox ssp.orientalis‘Big Blue’ is dichogamy.%  以引种植物大花百子莲为对象,对其在引种地的花粉活力、柱头可授性进行了研究,探讨了两者与授粉成功的关系。结果表明:大花百子莲花粉萌发的最佳培养基为10%蔗糖+0.1% H3 BO3+0.2 g・ L-1 Ca(NO3)2;随着开花进程的不断深入,花粉活力不断下降,始花期的花粉活力接近80%,末花期花粉活力只有3%左右;花粉在4℃条件下存活时间约为7 d,25℃条件下存活时间为5 d,而在35℃条件下存活时间只有2 d;大花百子莲花粉在开花当天已具有萌发能力,而柱头在开花第2天具有可授性,因此大花百子莲存在雌雄异熟现象。

  2. 新疆高葶韭雄蕊开花动态特征与花粉育性研究%Stamen dynamics and pollen fertility of Allium obliquum in Xinjiang Province,China

    林辰壹; 韩文娟; 祁晨霞; 叶强


    Allium obliquum only distributes in the Xinjiang Province,China.The marked plants were used to observe stamen morphological characteristics to analyze the floral dynamics of stamen and test pollen fertility of A.obliquum by 6 methods.This study showed that five morphological phases were found during flowering period.The inner filaments earlier expanded than the outer ones,and the inner anthers firstly expanded from perianth.It was about 4-5 d for all 6 anthers from open to fall.The individual anther released pollen about 1.5-2.0 h from the beginning dispersion to the end.Pollen viability kept about 0-10 h above 50% after anther dehiscence.The triphenyl tetrazolium chloride,diphenyl tetrazolium bromide,benzidine,and the in vitro germination test were used to test pollen fertility and the acetocarmine and iodine potassium iodide test was not suitable for A.obliquum pollen testing.A.obliquum was dichogamy and protandry with fertility,short longevity pollen,which would provide basic theory and method for pollen development,pollination biology and artificial sexual reproduction by and six methods were used to test pollen fertility.%为进一步研究国内仅分布于新疆的高葶韭(Allium obliquum)花粉发育、传粉生物学以及为高葶韭人工有性繁殖提供理论依据和试验方法,定株观察了花期高葶韭雄蕊的开花进程以及形态变化特征,并采用6种方法测定了高葶韭花粉育性。结果显示,高葶韭单花开放经过5个形态变化至花药脱落和花被片完全闭合。高葶韭内轮花丝先于外轮花丝伸长,内轮花药先伸出花被片,随后外轮花药陆续伸出花被片。雄蕊开放至6枚花药全部脱落4~5d。单枚花药从散粉到完全散粉一般需要1.5~2.0h。散粉后高葶韭花粉活力(萌发率)0~10h内超过50%。0.5%氯化三苯基四氮唑、四甲基偶氮唑、联苯胺和离体萌发法可以用来检验高葶韭花粉活力和花粉萌发率,而醋酸洋红和碘-

  3. Pollination biology and breeding system of Craigia yunnanensis in fragmented habitat%片断化生境中滇桐传粉生物学和繁育系统

    高则睿; 张长芹; 韩智强; 李忠; 魏杰; 施红林


    通过野外观察和人工授粉试验方法,对云南省文山州西畴县法斗分布区片断化生境中濒危植物滇桐(Craigia yunnanensis)的传粉生物学特征和繁育系统进行研究.结果表明:滇桐每个聚伞花序有2~9朵两性花,单花花期为3~4d,单花雌雄蕊在时空上有一定的隔离;杂交指数(OCI) >4,花粉-胚珠比(P/O)为1381±53;有效传粉昆虫为大头丽蝇(Chrysomyia megacephala);同株异花授粉结实率低;滇桐的繁育系统属于异交为主,部分自交亲和,传粉过程需要传粉者;自然状态下滇桐的座果率(56.67%±3.85%)和结籽率(6.26%±0.75%)均较低,而异株异花授粉均可显著提高座果率及结籽率(P<0.01),这与当前片断化生境中传粉昆虫少、效率低下等有关,表明生境片断化正在影响滇桐植株的早期生殖成功.%By the methods of field observation and artificial pollination, this paper studied the characteristics of pollination biology and breeding system of endangered species Craigia yunnanensis in the fragmented habitats of Fadou distribution area, Xichou County of Yunnan Province, Southwest China. Each cyme of the C. yunnanensis had 2-9 hermaphroditic flowers, and the lifespan of a single hermaphroditic flower was approximately 3-4 days. There existed certain temporal isolation ( dichogamy) and spatial isolation ( herkogamy) between the pistils and stamens of each hermaphroditic flower. The outcrossing index ( OCI) was >4, and the ratio of pollen to ovule (P/O) was 1381+53. The most frequent and effective pollinator was Chrysomyia megacephala. The fruiting rate of geitonogamous pollination was rather low, and thus, the breeding system of C. yunnanensis was mainly belonged to outcrossing, with partial self-compatibility, and the pollinator insects were essential. Both the fruit-setting ratio and the seed-bearing ratio under natural conditions were low as 56. 67% ±3. 85% and 6. 26% ±0. 75% , respectively, whereas

  4. Fenologia reprodutiva e sistema de polinização de Ziziphus joazeiro Mart. (Rhamnaceae: atuação de Apis mellifera e de visitantes florais autóctones como polinizadores Reproductive phenology and pollination system of Ziziphus joazeiro Mart. (Rhamnaceae: the role of Apis mellifera and autochthonous floral visitors as pollinators

    Tarcila de Lima Nadia


    Cariri Paraibano, northeastern Brazil. Flowering and fruiting periods occurred at the end of the dry season and beginning of the rainy season, with peaks in December (flowering and February (fruiting. The green, dish-shaped flowers last about 12 hours and have a large yellow nectary surrounding the gynoecium. Protandry occurs associated with heterodichogamy, another type of dichogamy. Ziziphus joazeiro produces little nectar (1 µl but with a high sugar concentration (75%. Floral visitors were wasps, bees and flies. Apis mellifera had the highest frequency of visits (77.5%, followed by wasps (20.4%, both acting as effective pollinators. Flies and other bee species had a lower percentage of visits (2.1% and acted as nectar robbers. The high rate of initial fruit development per inflorescence suggests high pollinator efficiency, since the dichogamic mechanism prevents the occurrence of spontaneous self-pollination and geitonogamy.