Tricolpate Pollen Grains Research Articles

Platimeliphyllum reznikoviorum N. Maslova, sp. nov. (Angiospermae) and associated infructescence from the Paleogene of central Kazakhstan

A new species Platimeliphyllum reznikoviorum N. Maslova is described from the Paleogene of Nizhnii Ashut locality (central Kazakhstan) based on the leaf macromorphological and epidermal characteristics. A capitate infructescence sharing characters of Platanaceae and some Hamamelidaceae was found together with the leaves. Small reticulate tricolpate pollen grains were found adhered to the carpel surface. The fossil leaves and reproductive structure are supposed to belong to the same plant. Fossil leaves attributed to Platimeliphyllum are associated with reproductive structures of various genera belonging to different families. Therefore we use the morphological classification for dispersed angiosperm leaves proposed by Krassilov (1979) to define the taxonomic position of this genus.

Echeveria marianae (Crassulaceae), a new species from Jalisco, México

A new species, Echeveria marianae (Crassulaceae) is described from Sierra del Tigre, Valle de Juárez, State of Jalisco, Mexico. The species belongs to ser. Gibbiflorae due to of its acaulescent or short caulescent rosette habit, paniculiform inflorescence, conical-urceolate corolla, and tricolpate pollen grains. Within ser. Gibbiflorae it shares morphological affinities with E. novogaliciana and E. dactylifera from which it differs in the shape, color and margin of leaves, corolla size and color, stamen length, nectaries morphology, and its geographical distribution.

Accelerated evolution of early angiosperms: Evidence from ranunculalean phylogeny by integrating living and fossil data

AbstractThe new discovery of angiosperm remains in the Jehol Biota of northeastern China contributes to our understanding of the origin and early evolution of flowering plants. The earliest eudicot genus with reproductive organs, Leefructus, was recently documented from the Lower Cretaceous Yixian Formation at 125.8–123.0 Ma, and was reconsidered to be close to the extant family Ranunculaceae based on gross morphology. However, this hypothesis has not been tested using a cladistic approach. To determine the possible allies of Leefructus within extant eudicots, we constructed a 66 morphological data matrix. Molecular and morphological analyses of extant Ranunculales combined with the fossil suggest that it has an affinity with the Ranunculaceae. The earliest fossil record of the eudicots is 127–125 Ma based on tricolpate pollen grains. Thus, we suggest a hypothesis that the basal eudicots might have experienced an accelerated evolution and diversification during the latest Barremian and earliest Aptian, leading to the stem groups of at least six extant families or lineages, 10–15 Myr earlier than currently documented. Angiosperms have undergone multiple uneven pulses of radiation since their origin. Many key character innovations occurred in different stages that could have triggered those radiations in concert with various biotic and abiotic factors.

Relationship between pollen morphology and chromosome numbers in Brazilian species of Lippia L. (Verbenaceae)

The pollen morphology and exine structure of 17 species of Lippia L. were investigated in this work using light and scanning electron microscopy. Among the species studied, 14 showed tricolporate pollen grains, two had tri- and tetracolporate pollen grains and a single species exhibited, only tetracolporate pollen. The amb ranged from triangular to square, and the shape varied from oblate-spheroidal to prolate-spheroidal. Three different types of exine ornamentation were observed: psilate, scabrate and perforate. In addition to morphological data, we found positive association between the chromosome numbers and size of pollen grains, and also between the length and width of the colpi. The results indicate that the characteristics of pollen grains in Lippia may be used as an additional taxonomic character of the genus.

Variation of pollen morphology, and its implications in the phylogeny of Clematis (Ranunculaceae)

Clematis s.l. (including Archiclematis and Naravelia) is a genus of approximately 300 species with cosmopolitan distribution. The diversity of its pollen was surveyed in 162 taxa belonging to all infrageneric groups of Clematis s.l. Pollen morphology was investigated by use of scanning electron microscopy to identify useful characters, test taxonomic and systematic hypotheses, and elucidate pollen character evolution on the basis of the molecular phylogeny. Clematis pollen is small to medium (14.8–32.1 μm × 14.2–28.7 μm), oblate to prolate (P/E = 0.9–1.4) in shape. The apertures may be tricolpate and pantoporate sometimes with 4-zonocolpate and pantocolpate pollen grains as transitional forms. The tricolpate pollen grains are predominant and occur in all the sections of the genus, whereas pantoporate pollen grains can be found in sect. Tubulosae, sect. Viorna, sect. Viticella, and Naravelia only. Phylogenetic mapping of aperture types reveals that the pantoporate pollen type may be the apomorphy in the genus and evolved several times. The surface ornamentation in all taxa studied is similar and characterized by microechinae evenly distributed on the microperforate tectum. The size and density of spinules on the tectum vary greatly but successive in the whole genus. According to the character syndromes of the ornamentation, separating sect. Brachiata from sect. Meclatis is supported. Though pollen morphology may contribute to investigation of problematic taxa, the taxonomic value of pollen morphology is limited at the species level.

Krassilovianthus gen. nov., a new staminate inflorescence with similarities to Platanaceae and Hamamelidaceae from the Cenomanian–Turonian of western Kazakhstan

Staminate inflorescences from Cenomanian-Turonian deposits of the Sarbay locality of western Kazakhstan are described as Krassilovianthus gen. nov. The new genus is characterized by the unique structure of the flower, which is unknown in similar platanoid heads. Flowers of Krassilovianthus gen. nov. possess a perianth that is considerably longer than its two stamens. The stamens are bisporangiate and dithecate, with small tricolporate pollen grains. Platanoid reproductive organs and leaves found at the Sarbay locality are considered.

Alatococcus, a new genus of Sapindaceae from Espirito Santo, Brazil

The new genus Alatococcus (Sapindaceae) is described from Espirito Santo, Brazil. Alatococcus seems to be closely related to Scyphonychium of northeastern Brazil, as they both share similar vegetative morphology, flowers with zygomorphic calyx, fruits with indehiscent mericarps, and isopolar, tricolporate pollen grains. They however differ by the shape of the nectary disc, petal appendages, mericarps, and pollen shape and ornamentation. The new species Alatococcus siqueirae is described and illustrated.

Microsporogenesis, microgametogenesis, and pollen morphology of Ambrosia artemisiifolia L. in China

Ambrosia artemisiifolia L. from Ambrosia of the Heliantheae of the Asteraceae family is a recognized harmful weed worldwide and one of the major invasive foreign plants in China. In this study, we investigated its reproductive features, focusing on its microsporogenesis, microgametogenesis, and pollen morphology. The results show that (1) Ambrosia artemisiifolia L. is a dicotyledonous plant and has spherical, tricolpate pollen grains with spiny outer wall; (2) its anther wall comprises four layers, namely epidermis, endothecium, middle layers, and amoeboid tapetum; (3) cytokinesis of microspore mother cells is successive; (4) most of tetrads are tetrahedral; and (5) mature pollen grains are three-celled. In conclusion, although Ambrosia artemisiifolia L. is a dicotyledonous plant with tricolpate pollen, its microsporogenesis is successive, which is different from typical dicots.

Reproductive mechanisms and pollen characterization in some accessions of an underutilized legume: (Sphenostylis stenocarpa Hochst Ex. A. Rich) harms

Studies on flowering, pollen, pod and seed characters, germination rate and seed set percentage were carried out on twenty five accessions of African Yam Bean (AYB). Self compatibility tests confirmed all the accessions as obligate selfers, while the reciprocal crosses were not successful. Germination rate, percentage seed set and pollen fertility were observed to be high in the accessions. Correlation analysis among the reproductive traits revealed that pod length, pod width, number of locules per pod and number of seeds per pod contributed significantly to the percentage seed set in all the accessions. Pollen fertility and seed viability were also observed to be high in all the accessions except in TSs23 where low pollen fertility, low seed viability and low percentage seed set were recorded. All the accessions produced tricolporate pollen grains. Pollen size ranged from 66.15 μm in TSs40 to 82.75 μm in TSs119, pollen fertility ranged from 53.39% in TSs23 to 95.30% in TSs119, seed set ranged from 83.32% in TSs90, 89.21% in TSs23 and 95.72% in TSs3. The germination rate ranged from 59.68% in TSs23 to 99.03% in TSs22. The percentage moisture content ranged between 4.38% in TSs22 and 11.43% in TSs119. Key words: Pollen characters, seed set, germination rate, self compatibility.

Oncaglossum, a New Genus of the Boraginaceae, Tribe Cynoglosseae, from Mexico

A new monotypic genus, Oncaglossum Sutorý, endemic to central Mexico, is described based on Cynoglossum pringlei Greenm. from the state of Mexico and belongs within the tribe Cynoglosseae of the Boraginaceae. The new genus is related to Cynoglossum L. subg. Eleutherostylum (Brand) Riedl and can be distinguished from the North American species currently classified in Cynoglossum by its calyx with imbricate, colored, and broadly ovate sepals, the corolla lobes reduced to narrow strips, anthers on short filaments inserted on the corolla margin, the stigma in the form of a lenticular disc, and tricolporate pollen grains with an additional aperture in their polar region.

An uncorrelated relaxed-clock analysis suggests an earlier origin for flowering plants

We present molecular dating analyses for land plants that incorporate 33 fossil calibrations, permit rates of molecular evolution to be uncorrelated across the tree, and take into account uncertainties in phylogenetic relationships and the fossil record. We attached a prior probability to each fossil-based minimum age, and explored the effects of relying on the first appearance of tricolpate pollen grains as a lower bound for the age of eudicots. Many of our divergence-time estimates for major clades coincide well with both the known fossil record and with previous estimates. However, our estimates for the origin of crown-clade angiosperms, which center on the Late Triassic, are considerably older than the unequivocal fossil record of flowering plants or than the molecular dates presented in recent studies. Nevertheless, we argue that our older estimates should be taken into account in studying the causes and consequences of the angiosperm radiation in relation to other major events, including the diversification of holometabolous insects. Although the methods used here do help to correct for lineage-specific heterogeneity in rates of molecular evolution (associated, for example, with evolutionary shifts in life history), we remain concerned that some such effects (e.g., the early radiation of herbaceous clades within angiosperms) may still be biasing our inferences.

Enigmatic morphology ofDjinga felicis(Podostemaceae - Podostemoideae), a badly known endemic from northwestern Cameroon

Djinga is a monotypic genus restricted to the Cameroon Ridge (‘Dorsale Camerounaise’) of NW Cameroon. Besides the type locality Mount Djinga (Adamawa Province, near Tignere), it also grows in waterfalls near Mount Oku (NW Province). This paper describes the structure and development of Djinga felicis using scanning electron microscopy and microtome sections. Cusset's protologue is enriched considerably. Roots are green, dorsiventrally flattened and adherent to submerged rocks. They are broad ribbons or crusts (up to 1 cm broad) which branch exogenously. Root-borne shoots (up to 17 cm) have filamentous leaves with sheaths and (occasionally) attached stipules. Flowers are borne as part of reproductive short shoots which arise exogenously along the stems and endogenously along the roots. Djinga shows non-axillary stem branching. Reproductive shoots along the main stem usually stay short. They arise from the abaxial side of double-sheathed leaves, a key innovation of Podostemoideae. These short shoots shift into pocket-like stem positions clearly below their associated leaves. Each flower bud inside a spathella is erect, but with an inclined ovary. The flowers are unistaminate with a broad connective. Unlike many other Podostemoideae, the tricolpate pollen grains are arranged in both dyads and monads. The ovary is globular and unilocular. The mature 8-ribbed capsule dehisces by two slightly unequal valves, releasing 40–50 seeds. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160, 64–81.

Diversidade Palinológica das Convolvulaceae do Parque Nacional do Catimbau, Buíque, PE, Brasil

Foram registradas quatorze espécies de Convolvulaceae no Parque Nacional do Catimbau. Com base na morfologia polínica, os táxons foram subdivididos em dois grupos: Psiloconiae - Evolvulus elegans Moric, E. frankenioides Moric, E. glomeratus Choisy, E. linarioides Meisn, Jacquemontia densiflora Hallier, J. montana Meisn, Jacquemontia sp. e Merremia cissoides Hallier, e Echinoconieae - Ipomoea bahiensis Willd., I. brasiliana (Choisy) Meissn, I. pintoi O'Donnel, I. rosea Choisy, I. subincana Meisn e Turbina cordata (Choisy) Austin & Staples. As espécies de Evolvulus são diferenciadas por diâmetro dos grãos de pólen e espessura da exina. Jacquemontia mostrou dois tipos polínicos - pantocolpado e tricolpado. Em Merremia cissoides, os grãos de pólen são tricolpados e as columelas são ramificadas. Ipomoea e Turbina têm grãos de pólen espinhosos. Entretanto, apenas em Ipomoea os espinhos apresentam base bulbar. Palinologicamente, Convolvulaceae no Parque Nacional do Catimbau é bastante diversificada e com grupos facilmente reconhecidos.

An unusual appearance of a common pollen type indicates the scene of the crime

Forensic palynology is a useful source of evidence in cases of violence committed in the open. A young girl was grabbed off the street, threatened and brutally raped. During the investigation the exact place of the rape became an issue. Growing around the scene identified by the victim were shrubs identified as Coprosma, a common New Zealand plant and one that produces abundant, easily wind-dispersed pollen. Abundant Coprosma pollen was found at the scene. The pollen were unusual in that the site was very damp, encouraging fungal growth, and fungal hyphae had penetrated the pores of many of the tricolporate pollen grains. Some grains had fungal spores inside. Coprosma pollen identical in preservational characteristics and morphology to those from the scene and containing fungal hyphae and spores were found in considerable numbers on the victim's clothes. This and rare Coprosma pollen grains and fungal remains recovered from vaginal swabs provided evidence that she had been at the scene where she claimed to have been raped. The diversity of pollen types recovered from the clothing in this case provides further evidence of the usefulness of clothing in picking up and retaining pollen from crime scenes and that obvious staining on clothes is not a pre-requisite for good pollen recovery. It also demonstrates the importance of collecting samples from different parts of the same garment in order to get a full picture of events since different parts of a garment can come into contact with different plants or different parts of the ground in a scuffle. It is also demonstrated that significant evidential material can be collected from the body, in this case from vaginal swabs from the victim. Forensic palynology should be considered in every case of violent assault, especially, but not exclusively, when having occurred in an open area subject to extensive pollen settlement.

Inflorescence with tricolpate pollen grains from the Cenomanian of Tschulymo-Yenisey Basin, West Siberia

A new taxon Freyantha sibirica gen. et sp. nov. is erected for a delicate racemose inflorescence from the Cenomanian of the Tchulymo-Yenisey Basin, West Siberia. The inflorescence bears male flowers of partly connate stamens that produced tricolpate reticulate pollen grains. The flowers are subtended by calyptrate bracts. The taxonomically significant features of the general inflorescence morphology, prophylls, floral bracts, stamens and pollen grains are shared with different angiosperm groups, such as the Menispermaceae and Sargentodoxaceae. Prominent glands on the floral bracts indicate pollination by nectar-sucking insects.

Palinologia de espécies da tribo Eupatorieae (Compositae Giseke) ocorrentes na Restinga de Carapebus, Carapebus, Rio de Janeiro

Foram estudados os graos de polen de sete taxons pertencentes a tribo Eupatorieae, ocorrentes na Restinga de Carapebus, Carapebus, Estado do Rio de Janeiro. Sao eles: Barrosoa atlantica King & Robins., B. betonicaeformis (DC.) King & Robins., Mikania belemii King & Robins., M. cordifolia Willd., M. glomerata Spreng., M. micrantha H.B.K., M. trinervis Hook & Arn. e Trichogoniopsis podocarpa (DC.) King & Robins. A tribo apresentou em comum, graos de polen pequenos a medios, oblato-esferoidais a prolato-esferoidais, tricolporados, sexina espinhosa e cavada. Os taxons puderam ser separados quando foram consideradas a forma polinica, as dimensoes do espinho e a distância entre eles. Assim, foi possivel formar dois conjuntos de especies identificados pela forma polinica: o primeiro, com forma oblato-esferoidal, composto por Barrosoa atlantica, Mikania micrantha e M. trinervis e o segundo, com forma prolato-esferoidal, composto por Barrosoa betonicaeformis, Mikania belemii, M. cordifolia, M. glomerata e Trichogoniopsis podocarpa. Os resultados obtidos, em comparacao a literatura corrente, permitem concluir que a tribo Eupatorieae e, palinologicamente, homogenea, porem algumas especies podem ser separadas pelo grao de polen, exceto M. glomerata de T. podocarpa e M. belemii de M. cordifolia.

Distribution and taxonomic implications of some phenolics in the family Lamiaceae determined by ESR spectroscopy

The dihydric phenolics from the leaves of 365 specimens representing 355 species and varieties of 110 genera of Lamiaceae (Labiatae) have been examined as semiquinones by ESR spectroscopy. Of these 89 genera comprising 194 species belong to the Lamiaceae, whereas 21 genera comprising 161 species have been transferred from the Verbenaceae in the most recent classification. Two chemical characters give strong support to the subfamily division of the Lamiaceae as recognised by Erdtman (1945). (Svensk Bot. Tidskr. 29, 279–285) and others. Rosmarinic acid was observed in 110 species out of 127 studied and confined to the subfamily Nepetoideae sensu Erdtman. These species produce tricolpate pollen grains. 3,4- Dihydroxyphenylethanoid glycosides were observed in 111 species all confined to Lamioideae sensu Erdtman with hexacolpate pollen grains. The acid and the phenylethanoid glycosides were found to be mutually exclusive, apart from one species, Teucrium scorodonia. A compound tentatively assigned as a β-hydroxy-(3,4-dihydroxyphenyl) ethanoid glycoside, was observed in 49 species, solely confined to subfamily Lamioideae. Furthermore, rosmarinic acid was observed in Aegiphila mollis and in Hymenopyramis brachiata, both belonging to Lamioideae. No phenylethanoid glycosides were observed from any of 5 Hymenopyramis or from any of 30 species of Vitex. The latter result questions the transfer of the genus to Lamiaceae, but strengthens its isolated position. Chlorogenic acid was observed in 34 species and protochatechuic acid in 16 species. Hydroquinone is scattered in the family (4 species) and thymohydroquinone was observed in 7 species all belong to the Nepetoideae.

Embryology of Phryma leptostachya L. (Verbenaceae) with considerations of its systematic status and affinities

AbstractSome embryological aspects – structure and development of the microsporangium, microporogenesis and male gametophytes; embryogeny and some features of seed‐coat of Phryma leptostacha L. have been studied. The microsporangial wall develops confirming to the Dicot type of Davis (1966). The anther tapetum is secretory and displays dual origin. Endothecial cells exhibit fibrous thickenings. The tricolpate pollen grains are shed at 3‐celled stage. The embryogeny follows the Hyoscamus variation of the Solanad type (Johansen 1950) or the Period‐I, Series C, Megarchetype IV of Soueges (1948). The mature embryo is dicotyledonous. Only a papery layer of endosperm encompasses the embryo. In the light of the present study with the other relevant informations from diverse sources the taxonomic status of the taxon Phryma leptostachya L. is examined. It is suggested, that this genus is undoubtedly related to some verbenaceous taxa and so merits to be retained in a separate tribe (Phrymeae) of its own nearer but not within the sub‐family Verbenioideae, a view expressed by Thorne (1976, 1983, 1992) and Takhtajan (1980, 1987).

Structure of the apertural sporoderm of pollen grains inEuphorbia andChamaesyce (Euphorbiaceae)

The tricolporate pollen grains of 38 Mediterranean and Macaronesian species ofEuphorbia L. andChamaesyce S. F. Gray have a special apertural sporoderm not found in the other taxa of theEuphorbiaceae. At the apertural margo the ectexine is thinner because of shorter columellae and the thin, fragmented or even absent foot-layer. Ectexinous granules, mixed with endexinous material, are present near the ora. The endexine is homogeneous and thickened under the colpi (at the end and at the proximity of the end of colpus). Around the ora, the endexine is granulate and lamellar with irregular cavities. The apertural intine presents a characteristic structure with thickenings running along both sides of the colpi. The arrangement and structure of these intinous thickenings depend on the distance from the ora. This special morphology of the intine is present in all taxa studied here. The genusEuphorbia is considered to be the most evolved taxon of this family. The characteristic apertural sporoderm may be an adaptative modification to different physiological conditions, so it may present an apertural mechanism which is more adapted to harmomegathic changes and thus facilitate the germination and the formation of the pollen tube.

Morphological Difference on Leaf Surface and Pollen Grains in Genus Artemisia

The leaf surface of 12 Artemisia species was examined under scanning electron microscope in order to verify the posslbility of identifying the species and the affinities among them through morphological features. Roundish glandular trichomes were found on the leaf surface of A. princeps, A. montana, A. monophylla, A, keiskeana, A, absilethium, A. Genipi-Big T-shaped trichomes were observed on the vein of A. princeps 'Okinawa' line. All the species had characterlstic small T-shaped trlchomes. The examination of the pollen morphology was done for 9 Artemisia species. All the species had tricolporate pollen grains with reduced exine ornamentation belonging either to the small or medium size class. The results of the investigation suggest the possibility of using new morphological parameters for botanical classification.