Male Flower Buds Research Articles

CCLS96.1, a member of a multicopy gene family, may encode a non-coding RNA preferentially transcribed in reproductive organs of Silene latifolia.

Dioecy in the model dioecious plant Silene latifolia is determined genetically by its heteromorphic sex chromosomes. A bacterial artificial chromosome (BAC) clone, #19B12, was isolated by screening a BAC library from S. latifolia using polymerase chain reaction (PCR) with a set of sequence tagged site (STS) primers, ScD05, which are specific to the Y chromosome. A portion of #19B12 was subcloned to construct plasmid #25-1, with an insert of 7.8 kb. This 7.8-kb fragment encodes ScD05 homolog and an anther-specific gene, CCLS96.1. Northern blot analysis of CCLS96.1 indicated a faint band of 1.8 kb in male and female flower buds. 5' and 3' rapid amplification of cDNA ends (RACE) indicated that transcripts of CCLS96.1 are very varied in size. Moreover, semi-quantitative reverse transcription-PCR (RT-PCR) showed that CCLS96.1 was also expressed in both male and female leaves. RACE produced at least ten species of transcripts, with 79-97% similarity among them. However, no significant ORFs could be predicted from their nucleotide sequences, since each has numerous stop codons throughout all three reading frames. Genomic Southern hybridization showed that the S. latifolia genome contains numerous CCLS96.1 homologs. These results suggest that the transcripts of CCLS96.1 play some role as multiple non-coding RNAs in S. latifolia.

Isolation and characterization of two homeodomain leucine zipper genes from the dioecious plant Silene latifolia.

Homeodomain leucine zipper (HD-Zip) genes encode transcription factors that are characterized by both a homeodomain and a leucine zipper motif. Two HD-Zip genes were isolated from cDNA of the male flower bud of the dioecious plant Silene latifolia. The two isolated genes, SlHDL1 and SlHDL2, encode proteins with the characteristics of HD-Zip transcription factors belonging to HD-Zip classes I and II, respectively. The expression patterns of SlHDL1 and SlHDL2 throughout the floral developmental stages were studied using real-time PCR and in situ hybridization. SlHDL1 is specifically expressed in the outermost layer of the anthers and gynoeciums with a patchy pattern in the inner layers, suggesting that the product of SlHDL1 plays a role in the early developmental stage of the epidermal tissues of these floral organs. Its expression pattern in the anthers and gynoeciums suggests an involvement in differentiation of the reproductive organs. On the other hand, real-time PCR revealed accumulation of SlHDL2 transcripts in the anther and pollen grains of the male flower. These results suggest that SlHDL1 and SlHDL2 regulate specific targets in restricted regions leading to floral organ differentiation in S. latifolia.

An approach for the conquest of the sugi pollinosis using plant growth regulation

The sugi (Cryptomeria japonica) pollinosis becomes representative allergic disease in early spring in Japan. However, effective treatment for the sugi pollinosis and countermeasure against pollen of C. japonica at its source have not been developed in a practical sense. In this paper, the research aiming to prevent dispersion of pollen of the C. japonica is introduced on application and practical application to the field from the laboratory using the growth regulation of the plant. We found that formation of male flower bud in C. japonica could be suppressed by TNE, since the 3 beta-hydroxylase is inhibited by the action of Trinexysapacethyl, TNE.

Reproductive Ecology of Two Species of theAnthonomus grandisSpecies Group (Coleoptera: Curculionidae) onHampea(Malvaceae: Gossypieae) Host Plants in Southern Mexico

Abstract The phenology, spatial distribution, and reproductive ecology of Anthonomus palmeri Jones & Burke and Anthonomus townsendi Jones & Burke (Anthonomus grandis species group; Coleoptera: Curculionidae) were studied over a period of 2 yr on three species of Hampea (Malvaceae: Gossypieae) in southern Mexico. These weevil species are closely related to the cotton pest Anthonomus grandis Boheman, and Hampea is the probable ancestral host of the group. The three species of Hampea studied, H. montebellensis Fryxell, H. longipes Miranda, and H. mexicana Fryxell, are small to medium sized, dioecious trees that occur in montane habitats above 500 m in elevation in the central portion of the state of Chiapas, Mexico. All three species had limited reproductive periods, with flowering beginning with the rains during June and ended during August for H. longipes and H. mexicana and mid-September for H. montebellensis. Only male flower buds were found infested with weevils. Infestation levels of male flower buds w...

Flower bud abortion influences clonal growth and sexual dimorphism in the understorey dioecious shrub Aucuba japonica (Cornaceae).

Sexual differences were investigated to determine the significance of flower bud abortion in the dioecious shrub Aucuba japonica Thunb. The mean number of flowers per inflorescence and the mean number of flowering inflorescences (as opposed to aborted inflorescences) per individual were greater in males than in females in 1997 and 1998. Reproductive investment by males was 0.4-times (1997) and 1.4-times (1998) that by females. In addition, females aborted 30.9% (1997) and 42.7% (1998) of their total flower buds without blooming, whereas no male flower buds aborted. One of the architectural traits of this shrub is that in the year that a flower bud is produced at the shoot apex, the shoot will branch into two or more shoots. Thus, there was less sexual difference in the number of current shoots per individual than there was in the number of flowering inflorescences. The relationship between annual growth and reproduction, and the probability of reproduction in the following year, suggested that the higher investment in female reproduction was manifested as a cost for reproductive frequency rather than as a cost for annual growth. The spatial distribution of both males and females was clumped, which may be the result of clonal growth. In addition, overall sex ratios were not skewed and the number of sprouts did not differ significantly between sexes. These results suggested that flower bud abortion by females might reduce sexual dimorphism in terms of clonal growth.

Regeneration of banana (Musa spp. AAB cv. Dwarf Brazilian) via secondary somatic embryogenesis

A method has been developed for the regeneration of the banana cultivar Dwarf Brazilian (Musa spp. AAB group). Primary somatic embryos were produced when explants of immature male flower buds were cultured on Murashige and Skoog (MS) medium plus 1 mg/l biotin, 100 mg/l malt extract, 100 mg/l glutamine, 4 mg/l 2,4-dichlorophenoxyacetic acid, 1 mg/l indole-3-acetic acid (IAA), 1 mg/l α-naphthaleneacetic acid, 30 g/l sucrose and 2.6 g/l Phytagel, pH 5.8 (M1 medium) and then transferred to M1 medium plus 200 mg/l casein hydrolysate and 2 mg/l proline. Subsequent transfer to MS supplemented with 10% coconut water produced rapidly proliferating embryogenic callus that developed into secondary somatic embryos (SE2); these were subcultured on half-strength MS supplemented with 5 mg/l 6-benzylaminopurine (BA). Differentiated embryos were transferred to MS medium supplemented with 5 mg/l BA for development, and mature SE2 were isolated and cultured on hormone-free MS for germination and development into plantlets. Approximately 90% of the SE2 germinated and developed into plantlets, and these were subcultured onto MS medium plus 0.1% activated charcoal, 1 mg/l BA and 1 mg/l IAA where complete plantlets developed. Morphologically normal banana plants developed from all of the regenerated plantlets, the first of which were produced within 6 months of culture initiation.

Ontogeny of floral organs and morphology of floral apex in Phellodendron amurense (Rutaceae)

The ontogeny of floral organs and the morphology of floral apex in the dioecious Phellodendron amurense Rupr. were investigated by light microscopy (LM), scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM). Investigations indicated that P. amurense is hermaphroditic in its organisation and a common set of floral organs (sepals, petals, stamens and carpels) arise in all flowers during the early stages of development. Later, selective abortion of gynoecium and androecium occurs resulting in dimorphic unisexual flowers. The carpels in male flower buds become different from those in female flower buds soon after their initiation. The stamens of female flowers are not differentiated into anthers and filaments before abortion. The poorly differentiated carpel of male flowers never develops normal structures. Floral morphological evidence supports that Zanthoxylum, Tetradium and Phellodendron are related to one another in a linear sequence. LSCM revealed some interesting features on the apical meristem surface such as zonal differentiation, a triangular or sectorial cell, radiating cell files and linear rows of anticlinal cell walls fluorescing relatively brightly. The concept of carpel-enhancing meristem in the floral apex is tentatively proposed to account for the different fates of carpel development in male and female flowers in P. amurense.

Inhibition of Flower Bud Formation in Betula platyphylla and Betula pendula by Gibberellin (GA3) Application

Birch (Betula) trees produce a large amount of pollen, which is a cause of serious pollinosis. To control the pollen scattering, we examined the inhibitory effect of gibberellin (GA3) on flower bud formation of birch. Field-grown trees ofBetula pendula, nine years of age, were treated with a foliar spray of GA3 (1, 10, and 100 mg L−1), Betula platyphylla trees, 17–23 years of age, were treated with a stem injection of GA3 (5, 50, and 500 mg per plant) in June or July, 1998. Male flower buds were not observed at the top of new shoots in June, but were observed in July. The number of inflorescence that emerged from randomly sampled branches was counted the next spring. The foliar spray of GA3 in June at the dose of 10 or 100 mg L −1 decreased the number of inflorescence. Stem injection in June at a dose higher than 50 mg per plant completely inhibited flower bud formation, although it increased bud mortality in some trees. The most effective dose of GA3 for stem injection to inhibit flower bud formation was between 0.04 and 0.44 mg per cm2 of stem cross-section area at breast height. These results indicate that GA3 applied during the period of floral differentiation markedly inhibits flower bud formation in birch.

Isolation of early genes expressed in reproductive organs of the dioecious white campion (Silene latifolia) by subtraction cloning using an asexual mutant.

The dioecious white campion (Silene latifolia) has been chosen as a working model for sexual development. In this species, sexual dimorphism is achieved through two distinct developmental blocks: inhibition of carpel development in male flowers, and early arrest of anther differentiation in female flowers. The combined advantages of the dioecious system and the availability of a sexual mutant lacking both male and female reproductive organs have been exploited in a molecular subtraction approach using male and asexual flower buds. This resulted in the cloning of 22 cDNA clones expressed in stamens at distinct stages of development. Fourteen of these clones corresponded to genes whose expression was detected in pre-meiotic stamens, a stage of development for which very little information is presently available. Furthermore, the absence of similarities with database sequences for ten clones suggests that they represent novel genes. Functional analysis of each clone will enable their positioning within the reproductive organ developmental pathway(s). In parallel, these clones are being exploited as developmental markers of early differentiation within the flower.

In vitro plant regeneration from embryogenic cultures of a diploid and a triploid, Cavendish banana

Plant regeneration by somatic embryogenesis was attempted with diploid (Musa acuminata ssp. malaccensis) and triploid ('Grand Nain') bananas. Explants inoculated in vitro were, respectively, immature zygotic embryos and male flower bud primordia. An histological study showed that the embryogenic process involves a sequence of similar events for both species. A yellow-green compact callus was initiated, which consisted of an actively dividing meristematic zone surrounded by several layers of starchy cells. A white and friable callus, characterized by the presence of proembryonic cells, bicellular proembryos and proembryonal masses in its periphery gradually appeared, which finally gave rise to somatic embryos from which plants were recovered. Induction media contained 2,4-D (and also NAA and IAA for the triploid); zeatin and kinetin were necessary for embryo maturation and 6-BA and IAA were used for germination.

A Research on the Stages of Flower Development in Hazelnut II. The Relationships Between the Time of Flower Development Stages and the Development of Flower Organs

This research is done on the hazelnut cultivars, which are Tombul, Palaz, Sivri, Çakildak, Kalinkara, Yerlifindik and Hanimfindigi, in Samsun between the years 1991 and 1993. On the test cultivars, male and female flower development stages are observed and the seizes of male and female flower organs are measured. As a result of this research, that male flower bud initiation occurs in may and june, and female flower bud initiation occurs in july and august according to the cultivar and year is observed. The organ primordia and growth of catkins on the male and female flower have not occured since october till the beginning of the anthesis.

Embryogenic cell suspensions from the male flower of Musa AAA cv. Grand nain

There are very few reports on the establishment of long‐term embryogenic cell cultures of banana, especially of triploid cultivars of commercial interest. Embryogenic cell suspensions were prepared using the cultivar Grand nain, the most widely grown dessert banana in the world. After culture for 5 or 6 months of immature male flowerbuds adjacent to the floral apex, yellow, compact calluses and white, friable embryogenic tissues were induced. Suspension cultures were initiated from embryogenic tissues placed in liquid medium. The packed cell volume (PCV) of the suspensions increased 2‐ to 5‐ fold with each monthly culture cycle. Plating of the embryogenic suspensions resulted in approximately 370×103 embryos per ml of PCV. Depending on the size of embryos, 3 to 20% germination was observed. A histological survey of cell suspensions and embryo development was carried out. Cellular aggregates with cells displaying typical embryogenic features were formed. Most of the somatic embryos were probably of unicellular origin.

Responses by the capercaillie Tetrao urogallus, and the willow grouse Lagopus lagopus, to the green matter available in early spring

Food matter eaten in the first snowless spots early in the spring by capercaillie Tetrao urogallus and willow grouse Lagopus lagopus was studied in Finnish Forest Lapland. When the snow disappears, both species change to feeding mainly on the plants available in the snowless spots, although male capercaillie does not exploit this nutritious diet to the same extent as female capercaillie and willow grouse. Selection in favour of nitrogen and phosphorus‐rich food items, i.e. Betula pubescens, male catkins Eriophorum vaginatum, flower buds, and Equisetum spp., stems and tips, seems to be characteristic especially of the female capercaillie, whose winter diet is poor in these elements. Female capercaillie also feeds on more plant species or different parts of plants at one time than willow grouse, while no differences were recorded between male and female willow grouse in the composition of their spring food. The crowberry Empetrum hermaphroditum, almost regularly produces a bountiful berry crop in northern Finland, and since it overwinters well, it represents an easy source of energy and water available almost every spring. The quality and/or the quantity of the green food matter available early in the spring may fluctuate considerably and be of importance for short‐term fluctuations in the populations of these tetraonid species.

Modification of flower sex and acid phosphatase activity by phthalimides in female plants of Morus nigra L.

Phthalimide treatments at 125, 250 and 500 mg 1−1 to female plants of dioecious Morus nigra L. induced intersex and male flowers. Qualitative and quantitative analyses of acid phosphatase in male and female flower buds showed that the male flower had significantly higher levels of the enzyme activity than the female flower buds. The level of acid phosphatase activity significantly increased in intersex and male flowers induced on female plants after phthalimide treatments.

Rapport des sexes, effort et succès de reproduction chez Rubus chamaemorus, plante herbacée vivace dioïque de distribution subarctique

Studies published on the reproductive success of dioecious species concentrate on the role of sex ratios and pollinator behaviour. In the case of Rubus chamaemorus L., a circumboreal dioecious species, we hypothesized that flower survival and biomass allocation to reproductive tissues, which are climate dependent, also influence fruit production. Only 0.05% of total biomass is allocated to reproduction, whereas 94% goes to underground organs responsible for vegetative propagation. Many male (28 – 51%) and female flower buds (35 – 54%) and young fruits (24–51%) die prematurely mainly because of the climate; fruit production then becomes independent from initial female flower density. The scarcity of female flowers at most sites (except near open water) limits fruit production. The limited sexual reproduction would allow cloudberry to maintain somatic resources, thereby increasing the longevity of individuals and their chance of encountering the climatic conditions required for reproductive success. Such a strategy is adaptive in a variable climate like that of the subarctic. Furthermore, the reduced importance of sexual reproduction would diminish the need to optimize sex ratios. Other selective pressures (e.g., competition) would then favour male clones in most sites, in spite of the unproductive pollen excess.

Primary productivity and nitrogen, carbon, and biomass distribution in a dense Myrica gale stand

Aboveground vascular vegetation was harvested in twenty 0.25-m2 plots at the end of the growing season in a weakly minerotrophic, central Massachusetts peatland. The materials were separated by species and component and the Myrica gale fractions analyzed for N and C content. Myrica gale strongly dominated the site, contributing 66% of the total aboveground biomass and 74% of the main canopy leaf area. Its shoots had a mean density of 69 stems m−2 and mean height of 63 cm and reached a maximum age of 7 years. Myrica gale aboveground biomass was 604 g m−2 with stems contributing 75%, leaves 24%, and reproductive organs 2%. Similar patterns of biomass distribution have been reported in other peatland low shrubs. Above-ground net production was 392 g m−2 year−1 and total net production estimated to be 549 g m−2 year−1. Nitrogen contents were higher than in other peatland shrubs and ranged from 0.94% in stems ≥ 3 years old to about 2.4% in leaves, nodules, and male flower buds. Carbon contents ranged from 50% in stems s ≥ 3 years old to 56% in male flower buds. The N content of total annual net production was estimated to be 8.6 g m−2 and the C content 281 g m−2. Nitrogen fixation provided 43% of the estimated annual N requirement.

The occurrence and structure of apparently bisexual flowers in the date palm, Phoenix dactylifera L. (Arecaceae)

Individuals ofPhoenix dactylifera L. have expanded pistillodes or pseudocarpels in staminate flowers. These pseudocarpels are located in the centre of the male flowers and are surrounded by stamens. The gynoecium has the characteristic three carpellate arrangement commonly found in female date palm flowers. Pseudocarpels from male flower buds can expand into parthenocarpic fruit. Histology of the expanded pistillodes or pseudotarpels is similar to that of normal carpels from pistillate plants. These pseudocarpels lack ovules. Nutrient medium containing 10 mg 1-1 of 2,4-dichlorophenoxyacetic acid or p-chlorophenylacetic acid and 0.3% activated neutralized charcoal enhanced the development and outgrowth of the pseudocarpels of cultured male flowers.

The rest period of pecan in Egypt

Pecan trees cv. ‘Moneymaker’ and seedling trees growing in Northern Egypt were sprayed with dinitrocresol mineral oil emulsion, to test its effect on male and female flower bud growth, flowering and fruiting. The treatments had a stimulating effect on growth of male and female flower buds. The treated trees flowered from 1 to 3 weeks earlier than the control. Fruit drop was greatly reduced and, consequently, fruit yield was remarkably increased.

Hormonal Regulation of Pedicel Abscission in Begonia Flower Buds

AbstractIn order to analyse the hormonal regulation of flower bud shedding in Begonia, levels of indoleacetic acid (IAA), abscisic acid (ABA) and ethylene were determined in buds and pedicels. The translocation and metabolism of 14C‐labeled IAA in pedicel segments were also studied.In a monoecious Begonia fuchsioides hybrid, abscising male flower buds contain about 1% of the IAA present in non‐abscising female flowers. In a male Begonia davisii hybrid, the seasonal variation in bud drop coincides with changes in the IAA content of the buds, while also the release of IAA from the bud to the pedicel is hampered.Abscission zones of these pedicels always contain abscission promoting ethylene concentrations. The tissue is prevented from responding with abscission by IAA from the flower buds. The buds also contain ABA but without influencing abscission considerably.Pretreatment with ethylene or ABA does not affect IAA transport in pedicel segments. The rate of this transport is 4–6 mm × h–1:; the capacity increases with the transverse area. In young segments, IAA is decarboxylated and also otherwise metabolized.

Preferential Use of Aspen by Ruffed Grouse in Northern Minnesota

A study of winter use of the staminate flower buds of quaking and bigtooth aspen (Populus tremuloides and P. grandidentata) by ruffed grouse (Bonasa umbellus) on an area in a northern Minnesota boreal forest shows a significant (P < 0.05) preference for the male flower buds of qualQing over bigtooth aspen for 4 out of the 8 years of the study. Preferences for quaking aspen over paper birch (Betula papyrifera) were highly significant (P < 0.01). Aspen utilization varied according to soil type; ratios of occurrence:use indicated that trees on peat soil were used most heavily. Based on their representation in the forest, trees in the 16to 25-year-age-class were used significantly less (P < 0.01 ) for feeding than was expected. Close agreement existed between observed mean feeding periods of 15.S minutes determined by radiotelemetry and our calculated value of 16.2 minutes based on crop volume, bud size, and observed feeding rates. During the winters of 196647 and l9S8 69, when snow accumulation was average or above, frequency of arboreal feeding observations ranged from none (March 1967) to 0.09 bird per mile (November-December 1968). During winters characterized by soft powdery snow, or below normal accumulations of snow, or poor production of hazel (Corylus cornuta) catkins, or a combination of these snow conditions and poor production of hazel catkins, arboreal feeding was more prevalent, with frequency values of 0.25 bird per mile (March 1968) to 0.30 bird per mile (January-February 1968). Aspen provides not only an abundant, reliable, and highly nutritious winter food resource for ruffed grouse, but it can be readily managed as an important wood fiber resource. cies of aspen, quaking and bigtooth, which are abundant in this area. The objective of the present paper is to examine the nature of winter feeding habits of ruffed grouse and to document preferential use of certain quaking aspen over offier available hardwoods. The exploitation of these preferences in derreloping a ruffed grouse management program has been described by Gullion (1972). Drs. A. C. Hodson, Head, and W. H. Marshall, Professor, respectively, Department of Entomology, Fisheries, and Wildlife, University of Minnesota, gave strong support to this program and Dr. B. A. Brown, Superintendent of the Cloquet Forestry Center, College of Forestry, University of Minnesota provided accommodations for this project. Botanical nomenclature is based on Gleason and Cronquist ( 1963 ) . In a recent paper, the significance of some studies of food habits of game birds was questioned, and observations concerning the feeding behavior of ruffed grouse in the vicinity of Cloquet, Minnesota, were cited as an example of selective or preferential feeding in certain tees by these biids (Gullion 1966a). The example cited is the use of staminate flower buds of the two spe1 Paper 7980 Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul. This paper reports progress on the Forest Wildlife Relations project of the Minnesota Agricultural Experiment Station, the Department of Entomology, Fisheries, and Wildlife, in cooperation with the College of Forestry, University of Minnesota, and the Minnesota Department of Natural Resources, Division of Game and Fish. Earlier phases of the study were supported by Federal Aid to Wildlife Restoration funds as Minnesota Project W-35-R; the radiotelemetry work cited was made possible by National Science Foundation Grants GS-8644, O17858, and GO1345.