Number Of Stamens Research Articles

<i>Magnolia lacandonica</i> (subsection <i>Talauma</i>, Magnoliaceae), a new rainforest species from Chiapas, Mexico

A new species of Magnolia from the rainforest of Chiapas, Mexico, is described and illustrated. Magnolia lacandonica belongs to section Talauma subsection Talauma and is similar to M. mexicana , but it differs from the latter in having larger number of carpels and stamens, the dorsal wall of carpels unhumped vs humped, an outer spathaceous bract topped with a reduced leaf blade vs lacking leaf blade and petals entirely white vs tinged with purple.

Nonstop glumes (nsg), a novel mutant affects spikelet development in rice

The spikelet is a unique structure of grass plants, and its development involved with complicated molecular regulation network. nsg (nonstop glumes) mutant affecting spikelet development was identified from EMS-treated Jinhui10 (Oryza sativa L. ssp. indica.). Mutant plants had normal glumes (inner rudimentary glume, empty glumes and lemma/palea) and pedicel at the early flowering stage, but had longer ones at later stage. An extra glume-like organ was found in 84 % of mutant individuals. The number of stamens decreased in most mutant individuals whereas three stigmas or two carpels were found in some mutant individuals. The mutant phenotype suggests that NSG is involved in the whole rice spikelet development. NSG was mapped to a 15 kb region on the chromosome 4. According to sequence analysis, a gene encoding a protein with C2H2 domain exhibited a 13 bp insertion, causing a frame shift in genomics DNA and cDNA in nsg. This gene was identified as the candidated gene of NSG. The mutation of NSG influenced the transcription level of some floral hometic genes. The expression of OsMADS4, OsMADS16, DL and OsMADS3 decreased distinctly, and OsMADS1 increased in nsg panicle, suggests that NSG affected spikelet development through influencing the expression of floral hometic genes.

<i>Magnolia quetzal</i> and <i>Magnolia mayae</i>, a new species and a new record, respectively, for the flora of Guatemala

Magnolia quetzal , a new species from Quiche, Guatemala is described and illustrated; it belongs to section Talauma , subsection Talauma ; it differs from M. morii in having much larger flowers, thinner leaf blades, usually longer petioles larger fruits and larger number of carpels and stamens. Magnolia mayae from Huehuetenango is here presented as the first record for the Flora of Guatemala.

New form of China aster (Callistephus chinensis (L.) Nees). Structure and biology of ray florets with open tubular corollas (type RO)

A radiomutant of China aster with a new type of head and new type of ray florets was described. All florets in the head were bisexual and tubular although dimorphic - they varied in size and colour. The place of ray florets in the head was taken by bisexual open tubular florets which were often crowned with irregular teeth. Disc florets were short and parchment-like. In both types of florets the following were compared: number and size of stamens, vitality of pollen and floret fertility. A number of teeth (lobes) in the corolIas of disc florets was also determined. Attention was also paid to the frequently observed anomalies and in particular to stamen displation. The problem is discussed of whether the obtained form resulted from mutation of disc florets with the simultaneous mutation of factors determining the so far unknown in China aster the head type without the whorl ofray florets or whether it was a mutation of ray flowers (corolla type and androecium formation). The author presents the opinion that the form resulted from the mutation ligulate of ray florets to the type of florets described above.

New form of China aster (Callistephus chinensis (L.) Nees). Structure and biology of ray florets with open tubular corollas (type RO)

A radiomutant of China aster with a new type of head and new type of ray florets was described. All florets in the head were bisexual and tubular although dimorphic - they varied in size and colour. The place of ray florets in the head was taken by bisexual open tubular florets which were often crowned with irregular teeth. Disc florets were short and parchment-like. In both types of florets the following were compared: number and size of stamens, vitality of pollen and floret fertility. A number of teeth (lobes) in the corolIas of disc florets was also determined. Attention was also paid to the frequently observed anomalies and in particular to stamen displation. The problem is discussed of whether the obtained form resulted from mutation of disc florets with the simultaneous mutation of factors determining the so far unknown in China aster the head type without the whorl ofray florets or whether it was a mutation of ray flowers (corolla type and androecium formation). The author presents the opinion that the form resulted from the mutation ligulate of ray florets to the type of florets described above.

Mutation of the cytosolic ribosomal protein-encoding RPS10Bgene affects shoot meristematic function in Arabidopsis

BackgroundPlant cytosolic ribosomal proteins are encoded by small gene families. Mutants affecting these genes are often viable, but show growth and developmental defects, suggesting incomplete functional redundancy within the families. Dormancy to growth transitions, such as the activation of axillary buds in the shoot, are characterised by co-ordinated upregulation of ribosomal protein genes.ResultsA recessive mutation in RPS10B, one of three Arabidopsis genes encoding the eukaryote-specific cytoplasmic ribosomal protein S10e, was found to suppress the excessive shoot branching mutant max2-1. rps10b-1 mildly affects the formation and separation of shoot lateral organs, including the shoot axillary meristems. Axillary meristem defects are enhanced when rps10b-1 is combined with mutations in REVOLUTA, AUXIN-RESISTANT1, PINOID or another suppressor of max2-1, FAR-RED ELONGATED HYPOCOTYL3. In some of these double mutants, the maintenance of the primary shoot meristem is also affected. In contrast, mutation of ALTERED MERISTEM PROGRAMME1 suppresses the rps10b-1axillary shoot defect. Defects in both axillary shoot formation and organ separation were enhanced by combining rps10b-1 with cuc3, a mutation affecting one of three Arabidopsis NAC transcription factor genes with partially redundant roles in these processes. To assess the effect of rps10b-1 on bud activation independently from bud formation, axillary bud outgrowth on excised cauline nodes was analysed. The outgrowth rate of untreated buds was reduced only slightly by rps10b-1 in both wild-type and max2-1 backgrounds. However, rps10b-1 strongly suppressed the auxin resistant outgrowth of max2-1 buds. A developmental phenotype of rps10b-1, reduced stamen number, was complemented by the cDNA of another family member, RPS10C, under the RPS10B promoter.ConclusionsRPS10B promotes shoot branching mainly by promoting axillary shoot development. It contributes to organ boundary formation and leaf polarity, and sustains max2-1 bud outgrowth in the presence of auxin. These processes require the auxin response machinery and precise spatial distribution of auxin. The correct dosage of protein(s) involved in auxin-mediated patterning may be RPS10B-dependent. Inability of other RPS10 gene family members to maintain fully S10e levels might cause the rps10b-1 phenotype, as we found no evidence for unique functional specialisation of either RPS10B promoter or RPS10B protein.

Total Control – Pollen Presentation and Floral Longevity in Loasaceae (Blazing Star Family) Are Modulated by Light, Temperature and Pollinator Visitation Rates

Stamen movements can be understood as a mechanism influencing pollen presentation and increasing outbreeding success of hermaphroditic flowers via optimized male function. In this study we experimentally analyzed the factors regulating autonomous and thigmonastic (triggered by flower visitors) stamen movements in eight species of Loasaceae. Both types of stamen movements are positively influenced by light and temperature and come to a virtual standstill in the dark and at low temperatures (12°C). Pollen presentation is thus discontinued during periods where pollinators are not active. Overall stamen presentation increases with increasing flower age. Contrary to expectation, no geometrical correlation between the floral scale stimulated and the stamen fascicle reacting exists, indicating that the stimulus is transmitted over the receptacle and stamen maturation dictates which and how many stamens react. Thigmonastic stamen presentation is dramatically accelerated compared to autonomous movement (3–37 times), indicating that the rate of stamen maturation can be adjusted to different visitation schedules. Flowers can react relatively uniformly down to stimulation intervals of 10–15 min., consistently presenting comparable numbers of stamens in the flower c. 5 min. after the stimulus and can thus keep the amount of pollen presented relatively constant even under very high visitation frequencies of 4–6 visits/h. Thigmonastic pollen presentation dramatically reduces the overall duration of the staminate phase (to 1/3rd in Nasa macrothyrsa). Similarly, the carpellate phase is dramatically reduced after pollination, down to 1 d from 4 d. Overall flower longevity is reduced by more than 2/3rds under high visitation rates (<3 d versus 10 d under visitor exclusion) and depleted and pollinated flowers are rapidly removed from the pool. Complex floral behaviour in Loasaceae thus permits a near-total control over pollen dispensation schedules and floral longevity of the individual flower by an extraordinary fine-tuning to both biotic and abiotic factors.

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Magnolia zoquepopolucae &lt;/em&gt;&lt;/strong&gt;&lt;strong&gt;(subsection &lt;em&gt;Talauma&lt;/em&gt;, Magnoliaceae), a new species from Sierra de Santa Marta, Veracruz, Mexico&lt;/strong&gt;&lt;/p&gt;

A new rainforest species of Magnolia from Sierra Santa Marta, Soteapan, Los Tuxtlas, Veracruz, Mexico, is described and illustrated. Magnolia zoquepopolucae belongs to section Talauma, subsection Talauma. It differs from M. mexicana in having fruits spheroidal versus ovoid to ellipsoidal, the dorsal wall of carpels non humped versus humped, a larger number of carpels and stamens, longer petioles, petals and sepals, and more gradually attenuated petals. The flowers of this species are used to prepare a chocolate-like and masa (maize)-based hot drink by the Zoque Popoluca culture, which is valued for medicinal purposes.

Crateva formosensis (Jacobs) B. S. Sun, (Capparaceae Juss.) - A new record for flora of Vietnam

We have found that Crateva formosensis (Jacobs) B. S. Sun has also distributed in Vietnam, with specimens collected in Tra Linh district, Cao Bang province. The specimens are preserved in HN Herbarium, Institute of Ecology and Biological Resources. This species is closely related to Crateva trifoliata (Roxb.) B. S. Sun but differs in characters: size and apex of leaflet blade and number of stamens, hence, Crateva formosensis (Jacobs) B. S. Sun is a new record for the flora of Vietnam. The main characters of Crateva formosensis: shrub or tree, 2-21m tall, with flowers before having leaves or when having young leaves. Twigs with flowers: leaflet blades ovate to obovate, 10-11.5 ´ 4-5 cm, dried leaves green-grey color to green-brown; twigs without flowers: leaflet blade 13-15 ´ 6 cm, apex acuminate to long acuminate. Inflorescences 10-15 flowered, pedicel 2.5-4 cm. Sepals 4, oblong. Petals yellow, claw 4 mm, blade elliptic. Stamens 10-15. Gynophore 2.4-3.2 cm. Ovary ovate. Fruits circular to oval, red to red-brown, smooth. Seeds small, brown. Loc. class.: Formosa. Holotypus: E. H. Wilson 11114 (K). Ecology and Biology: Flowering June - July, fruting August - January. In valley, near stream, dense forest and coastal region to 400 m alt.. Distribution: Cao Bang (Tra Linh). Also in China, Japan. Studied specimens: Cao Bang (Tra Linh), W17463, VN 478 (HN).

Temperature-Dependent Fluctuation Of Stamen Number InCardamine hirsuta(Brassicaceae)

Floral organ number is often fixed within families, and the basic floral ground plan of Brassicaceae is well conserved. Cardamine hirsuta L. (Brassicaceae) shows variation in lateral stamen number, that is, zero to two lateral stamens. The aim of this study was to examine whether temperature conditions alter stamen number. Temporal changes in the frequency of flowers with zero, one, and two lateral stamens were assessed during the flowering periods of a natural population and a garden-transplanted population in Japan. We conducted an experiment to evaluate how temperature regimes during flowering (15°/15°C and 15°/5°C) alter the number of stamens. The proportion of flowers with zero lateral stamens increased in both the natural and the garden-transplanted population as the flowering season progressed. In the growth experiment, lateral stamen numbers fluctuated even within individual inflorescences, but the frequency of flowers with zero lateral stamens was higher in the high-temperature condition than in the low-temperature condition. Temperature-dependent phenotypic plasticity is likely to be the cause of the field-observed variation in lateral stamen number for C. hirsuta. Developmentally unstable but partly temperature-dependent production of the lateral stamen may be an indication of some epigenetic regulations as an underlying mechanism.

Does the clash between instinct and science exist in naming nature?

Does the clash between instinct and science exist in naming nature?

Molecular phylogenetics of Hydatellaceae (Nymphaeales): Sexual‐system homoplasy and a new sectional classification

Species relationships are unknown in Hydatellaceae, a small family of dwarf aquatics related to water lilies that arose near the base of angiosperm phylogeny. Here we use molecular evidence to infer a species tree for the family and apply this to reconstructing major transitions in morphology and sexual system in this early branch of angiosperms. We assembled plastid (atpB, matK, ndhF, rbcL) and nuclear (ribosomal ITS) data for 50 samples (including outgroups) and estimated a species tree for Hydatellaceae using a Bayesian multispecies coalescent approach. We reconstructed the evolution of several morphological characters, then tested for associations between sexual system and reproductive morphology using phylogenetic ANOVA. Dioecious species of Hydatellaceae have significantly greater stamen number and anther length than do cosexual species, suggesting changes in male function. The perennial habit that defines one subclade likely represents a reversion from annuality. Species relationships do not fall along traditional morphological divisions, but new sections proposed here are supported by fruit and seed synapomorphies. The earliest split in the family is reflected in geography and climate (i.e., tropical vs. subtropical/temperate clades). We found limited evidence of incongruence between plastid and nuclear trees, with one exception involving gene-tree nonmonophyly for two close relatives (Trithuria submersa, T. bibracteata). While the direction of sexual-system evolution is ambiguous, transitions are significantly associated with changes in involucral phyllome length and proxies of pollen production. We propose a new sectional circumscription based on fruit, seed, and DNA evidence.

Homologies of the flower and inflorescence in the early‐divergent grass Anomochloa (Poaceae)

The grass subfamily Anomochlooideae is phylogenetically significant as the sister group to all other grasses. Thus, comparison of their structure with that of other grasses could provide clues to the evolutionary origin of these characters. We describe the structure, embryology, and development of the flower and partial inflorescence of the monotypic Brazilian grass Anomochloa marantoidea. We compare these features with those of other early-divergent grasses such as Pharus and Streptochaeta and closely related Poales such as Ecdeiocolea. Anomochloa possesses several features that are characteristic of Poaceae, notably a scutellum, a solid style, reduced stamen number, and an ovary with a single ovule that develops into a single indehiscent fruit. Interpretation of floral patterning in Anomochloa is problematic because the ramification pattern of the florets places the bracts and axes in unusual positions relative to the primary inflorescence axis. Our study indicates that there is a single abaxial carpel in Anomochloa, probably due to a cryptic type of pseudomonomery in Anomochloa that resembles the pseudomonomery of other grasses. On the other hand, the Anomochloa flower differs from the "typical" grass flower in lacking lodicules and possessing four stamens, in contrast with the tristaminate condition that characterizes many other grasses. Using the median part of the innermost bract as a locator, we tentatively homologize the inner bract of the Anomochloa partial inflorescence with the palea of other grasses. In this interpretation, the pattern of monosymmetry due to stamen suppression differs from that of Ecdeiocolea.

Taxonomic Revision of the Neotropical Genus &lt;I&gt;Lacunaria&lt;/I&gt; (Quiinaceae / Ochnaceae s. l.)

Abstract A taxonomic revision of the Neotropical dioecious genus Lacunaria (Quiinaceae / Ochnaceae s. l.) is presented including keys to the species and subspecies, descriptions, illustrations, nomenclature, typification, and geographical distribution of each species. Seven species are recognized within the genus, one subspecies, L. jenmanii subsp. subsessilis, is described newly, and the status of Lacunaria decastyla has been changed, transferring it to Lacunaria crenata subsp. decastyla. Leaf pubescence, number of secondary veins, and petal, stamen, and carpel number, although all quite variable, are the most important characters to distinguish the species.

Molecular characterization of the PpMADS1 gene from peach

PpMADS1, a member of the euAP1 clade of the class A genes, was previously cloned from peach. In this study, PpMADS1 was constitutively expressed in Arabidopsis thaliana to study its function in plant development. The transgenic A. thaliana plants containing 35S::PpMADS1 showed severe phenotype variation including early flowering, conversion of inflorescence branches to solitary flowers, formation of terminal flowers, production of higher number of carpels, petals, and stamens than non-transgenic plants, and prevention of pod shatter. Significantly, the transgenic plants produced more than one silique from a single flower. The results obtained by using cDNA microarray and real-time PCR analyses in the transgenic Arabidopsis indicated that PpMADS1 might play dual roles in regulating the floral meristem development by activating or repressing different sets of genes that would determine the different fate of a floral meristem. In addition, the PpMADS1 gene promoter was further cloned, and deletion analyses were conducted by using fused GUS as a reporter gene in transgenic A. thaliana. Histochemical staining of different organs from transgenic plants revealed the region between −197 and −454 bp was specific for GUS expression in flower primordium, and the region between −454 and −678 bp was specific for GUS expression in sepals and petals. In contrast, a negative regulatory element present between −678 and −978 bp could suppress GUS expression in filament.

Blooming biology and pollen abundance of Anemone japonica Houtt.= Anemone x hybrida hort

The studies were carried out between 2002 and 2003 and in 2005 in the Botanical Garden in Lublin. The blooming and the pollen flow of &lt;i&gt;Anemone japonica&lt;/i&gt; Houtt. (=&lt;i&gt;A. x hybrida&lt;/i&gt; hort) were observed. The blooming of the perennial took place in the middle and end of summer. The number of flowers per inflorescence and the mass of pollen produced in anthers significantly depended on insolation conditions and were greater on sunny plots. &lt;i&gt;Anemone japonica&lt;/i&gt; is characterized by the variability of many features which directly influence the amount of delivered pollen. The number of stamens varied from 175 to 507 per flower, the mass of pollen from 1.1mg to 4.9 mg per 100 anthers, the number of flowers from 25 to 118 per one inflorescence and from 355⋅m&lt;sup&gt;-2&lt;/sup&gt; to 2202⋅m&lt;sup&gt;-2&lt;/sup&gt;. Therefore the pollen efficiency varied widely from 1.3g⋅m&lt;sup&gt;-2&lt;/sup&gt; to 27.7g⋅m&lt;sup&gt;-2&lt;/sup&gt; and reached 15.3 g ⋅ m&lt;sup&gt;-2&lt;/sup&gt; on average.

Evaluation of cloudberry (Rubus chamaemorus L.) clones for selection of high-quality varieties

Two female and two male cultivars of cloudberry (Rubus chamaemorus L.) have previously been released as a result of clone evaluation at the Norwegian Institute for Agricultural and Environmental Research. Selection criteria have been number of pistils or stamens per flower, number of flowers and number of shoots per m2. Recently two groups of clones have been evaluated with the aim of finding new cultivars for release. The clones were collected at different locations in Norway, as well as in England and at Svalbard. Results from harvesting in 2005 to 2008 show large genetic variation in all evaluated traits and indicate good production potential for some of the tested clones. Previously released ‘Fjellgull’ and ‘Fjordgull’ are confirmed as stable and high producing. Of the clones evaluated for the first time, especially clone 102 and clone 306 are possible contenders for release. In addition to prior selection criteria based on berry yield, berry contents also have been analysed. The results indicate that clones with a northern origin have higher levels of total phenols, total anthocyanins and carotenoids than clones of a southern origin.

The evolutionary history of Mimosa (Leguminosae): Toward a phylogeny of the sensitive plants

Large genera provide remarkable opportunities to investigate patterns of morphological evolution and historical biogeography in plants. A molecular phylogeny of the species-rich and morphologically and ecologically diverse genus Mimosa was generated to evaluate its infrageneric classification, reconstruct the evolution of a set of morphological characters, and establish the relationships of Old World species to the rest of the genus. We used trnD-trnT plastid sequences for 259 species of Mimosa (ca. 50% of the total) to reconstruct the phylogeny of the genus. Six morphological characters (petiolar nectary, inflorescence type, number of stamens, number of petals, pollen type, and seismonasty) were optimized onto the molecular tree. Mimosa was recovered as a monophyletic clade nested within the Piptadenia group and includes the former members of Schrankia, corroborating transfer of that genus to Mimosa. Although we found good support for several infrageneric groups, only one section (Mimadenia) was recovered as monophyletic. All but one of the morphological characters analyzed showed high levels of homoplasy. High levels of geographic structure were found, with species from the same area tending to group together in the phylogeny. Old World species of Mimosa form a monophyletic clade deeply nested within New World groups, indicating recent (6-10 Ma) long-distance dispersal. Although based on a single plastid region, our results establish a preliminary phylogenetic framework for Mimosa that can be used to infer patterns of morphological evolution and relationships and which provides pointers toward a revised infrageneric classification.

Floral development of Urospatha: merosity and phylogeny in the Lasioideae (Araceae)

In this paper we study merosity in the genus Urospatha within the framework of a resolved phylogeny of the Araceae. We analyse how a transition from dimerous or tetramerous merosity to pentamerous or hexamerous merosity can occur developmentally in the Lasioideae. In Urospatha, initiation of floral primordia along the inflorescence is acropetal, while development of flowers is basipetal. This indicates the presence of two distinct phases in the development of the Urospatha inflorescence. The first phase corresponds to initiation of flowers and establishment of the phyllotactic pattern, and the second phase to differentiation of floral organs. Urospatha is characterized by the presence of trimerous, tetramerous, pentamerous and rarely hexamerous flowers. In all types of flowers, the stamens are closely associated and opposite to the tepals. Pentamerous flowers are formed by addition of a sector comprising a stamen and tepal. Likewise, in the case of hexamerous flowers, two sectors are added. In the Lasioideae, the increase in the number of tepals and stamens is linked with two developmental processes that have appeared independently in the subfamily: (1) addition of one or two stamen–petal sectors (Anaphyllopsis and Urospatha), and (2) independent increase in the number of tepals and stamens on whorls, more or less organized and inserted in alternate position (Dracontium). Tetramerous whorls as they occur in basal Lasioideae would be homologous to two dimerous whorls from an evolutionary point of view.

Staminodial Nectary Structure in Two Pulsatilla (L.) Species

In plants belonging to the Ranunculaceae the floral nectaries may differ in origin, location in the flower, shape and structure. In many cases they are defined as modified tepals or modified stamens. The nectary organs in this family are frequently termed honey leaves, and staminodial origin is attributed to them. Gynopleural and receptacular nectaries are rarely found in Ranunculaceae. To date there are no reports on the structure of the nectary organs in plants of the genus Pulsatilla. We used light and scanning electron microscopy to study the location and structure of the nectaries in Pulsatilla slavica and P. vulgaris flowers. The staminodial nectaries were found to be nectar-secreting organs. The number of stamens per flower (102-398) increases with plant age. The share of staminodes is 12–15%. The staminodes are composed of a filament and a modified head. They are green due to the presence of chloroplasts in the epidermal and parenchymal cells. The parenchymal cells are in a loose arrangement. Stomata (3–20), through which nectar exudation occurred, were found only in the abaxial epidermis of the staminode head. The stomata are evenly distributed and have well-developed outer cuticular ledges. Some of them are immature during nectar secretion, with their pores covered by a layer of cuticle. During the activity of the nectariferous organs in the flowers, primary (on the staminode surface) and secondary nectar (at the base of tepals) are presented. The staminodes of the two Pulsatilla species show similar structural features and have similar shares in the androecium.