Germination and sporophytic development of Regnellidium diphyllum Lindman (Marsileaceae in the presence of hexavalent chromium Germinação e desenvolvimento esporofítico de Regnellidium diphyllum Lindman (Marsileaceae na presença de cromo hexavalente
Full Text Available Regnellidium diphyllum Lindman is a heterosporous fern, growing in aquatic environments and surrounding wetlands, which is assumed to be threatened by increasing water pollution and disappearance of its natural habitats. Among contaminants, hexavalent chromium - Cr(VI - is known to be present in effluents from some leather tanning factories. Megaspore germination tests were performed using Meyer's solution, at concentrations 0 (control, 0.1, 0.5, 1, 5, 10, 15, 20, 30, 50, and 80 mg.L-1, from a standard solution of Titrisol® 1000 mg.L-1. The primary development of apomictic sporophytes was studied using solutions containing 0.025 to 4.8 mg.L-1 of Cr(VI. The experiments were conducted in a growth chamber at 24 ± 1 ºC and for a 12-hour photoperiod under fluorescent lights, providing a nominal irradiance of 77 µmol.m-2/s. Significant differences in megaspore germination, with subsequent sporophytic development, were verified from 0.5 mg.L-1 Cr(VI concentration onwards. Growth of primary root and primary and secondary leaves was significantly reduced at 3.2 mg.L-1 Cr(VI concentration or higher. Considering the pollution from Cr(VI in some areas of R. diphyllum natural occurrence, these data indicate that low reproductive rates and disappearance of populations are likely to occur in these situations.Regnellidium diphyllum Lindman é uma filicínea heterosporada que se desenvolve em ambientes aquáticos e áreas úmidas circundantes, sendo considerada ameaçada pelo aumento da poluição e desaparecimento dos seus hábitats naturais. Entre os contaminantes, o cromo hexavalente - Cr(VI - é conhecido por estar presente nos efluentes de algumas indústrias de curtimento de couro. Testes de germinação foram realizados em meio líquido de Meyer, com concentrações de 0(controle; 0,1; 0,5; 1; 5; 10; 15; 20; 30; 50; e 80 mg.L-1 de Cr(VI, a partir de uma solução padrão de Titrisol® a 1000 mg.L-1. O desenvolvimento primário dos esporófitos apom
Popular among young American readers since the early 1930s, Maj Lindman's two series of children's books--"Snipp, Snapp, Snurr and Flicka, Ricka, Dicka"--continue their long publishing histories in the U.S. These nostalgia-filled adventures about the Swedish triplet boys and girls construct positive values of childhood independence and…
Ambush 23 Vignette 7 - Two Convoys in the Kill Zone 27 Vignette 8 - Ambush Near Abdullah-e Burj 31 Vignette 9 - Deh-Khwaja Ambush 35 Vignette 10...Although Arab leaders and the West supplied arms and material to the Mujahideen, they did so with the hope of creat- ing a permanent, bleeding ulcer on...and Major Ray Finch. Robert Love helped with translation support and Linda Pride and Al Lindman provided computer assistance. The Combined Arms
Full Text Available Lectotypes, neotypes or epitypes are confirmed or designated here for 16 of the 22 names coined by Martín Sessé y Lacasta and José Mariano Mociño that were described as members of the large genus Solanum (Solanaceae: Solanum bifidum, S. cordovense, S. declinatum, S. dichotomum, S. diphyllum, S. lanceifolium, S. lanceolatum, S. lineatum (both homonyms, S. longifolium, S. mexicanum, S. nutans, S. sarmentosum, S. scandens, S. tlacotalpense and S. uniflorum. A brief introduction assesses the importance of the Sessé & Mociño expedition (the Real Expedición Botánica a Nueva España to the botany of their time, and identifies difficulties in identifying and neotypifying or lectotypifying names coined by them. More than half of the names coined by Sessé and Mociño have no material associated with them. The currently accepted name for each taxon is given, and taxa of uncertain status are indicated. Each typification is accompanied by a discussion of the reasoning behind the choice of specimen, and all newly designated types are illustrated.Se confirman o designan los lectótipos, neótipos o epítipos de 16 de los 22 nombres acuñados por Martín de Sessé y Lacasta y José Mariano Mociño que o bien fueron descritos dentro del género Solanum (Solanaceae o son actualmente reconocidos como parte del mismo: Solanum bifidum, S. cordovense, S. declinatum, S. dichotomum, S. diphyllum, S. lanceifolium, S. lanceolatum, S. lineatum (ambos homónimos, S. longifolium, S. mexicanum, S. nutans, S. sarmentosum, S. scandens, S. tlacotalpense y S. uniflorum. Se incluye una breve introducción explicando la importancia de la Real Expedición Botánica a Nueva España (expedición de Sessé y Mociño para la botánica de su tiempo, así como las dificultades que entraña neotipificar o lectotipificar los nombres acuñados por éllos. Se incluye el nombre aceptado para cada taxon cuando es posible y cada tipificación se acompaña de una discusión explicando
Recent phylogenetic studies have provided compelling evidence that confirms the once disputed hypothesis of monophyly for heterosporous leptosporangiate ferns (Marsileaceae and Salviniaceae). Hypotheses for relationships among the three genera of Marsileaceae (Marsilea, Regnellidium, and Pilularia), however, have continued to be in conflict. The phylogeny of Marsileaceae is investigated here using information from morphology and rbcL sequence data. In addition, relationships among all heterosporous ferns, including the whole-plant fossil Hydropteris pinnata are reconsidered. Data sets of 71 morphological and 1239 rbcL characters for 23 leptosporangiate ferns, including eight heterosporous ingroup taxa and 15 homosporous outgroup taxa, were subjected to maximum parsimony analysis. Morphological analyses were carried out both with and without the fossil Hydropteris, and it was excluded from all analyses with rbcL data. An annotated list of the 71 morphological characters is provided in the appendix. For comparative purposes, the Rothwell and Stockey (1994) data set was also reanalyzed here. The best estimate of phylogenetic relationships for Marsileaceae in all analyses is that Pilularia and Regnellidium are sister taxa and Marsilea is sister to that clade. Morphological synapomorphies for various nodes are discussed. Analyses that included Hydropteris resulted in two most-parsimonious trees that differ only in the placement of the fossil. One topology is identical to the relationship found by Rothwell and Stockey (1994), placing the fossil sister to the Azolla plus Salvinia clade. The alternative topology places Hydropteris as the most basal member of the heterosporous fern clade. Equivocal interpretations for character evolution in heterosporous ferns are discussed in the context of these two most-parsimonious trees. Because of the observed degree of character ambiguity, the phylogenetic placement of Hydropteris is best viewed as unresolved, and recognition of the
Full Text Available Abstract Background Bocconia and Macleaya are the only genera of the poppy family (Papaveraceae lacking petals; however, the developmental and genetic processes underlying such evolutionary shift have not yet been studied. Results We studied floral development in two species of petal-less poppies Bocconia frutescens and Macleaya cordata as well as in the closely related petal-bearing Stylophorum diphyllum. We generated a floral transcriptome of B. frutescens to identify MADS-box ABCE floral organ identity genes expressed during early floral development. We performed phylogenetic analyses of these genes across Ranunculales as well as RT-PCR and qRT-PCR to assess loci-specific expression patterns. We found that petal-to-stamen homeosis in petal-less poppies occurs through distinct developmental pathways. Transcriptomic analyses of B. frutescens floral buds showed that homologs of all MADS-box genes are expressed except for the APETALA3-3 ortholog. Species-specific duplications of other ABCE genes in B. frutescens have resulted in functional copies with expanded expression patterns than those predicted by the model. Conclusions Petal loss in B. frutescens is likely associated with the lack of expression of AP3-3 and an expanded expression of AGAMOUS. The genetic basis of petal identity is conserved in Ranunculaceae and Papaveraceae although they have different number of AP3 paralogs and exhibit dissimilar floral groundplans.
Cúneo, N. Rubén; Gandolfo, María A.; Zamaloa, María C.; Hermsen, Elizabeth
In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America. PMID:25148081
N Rubén Cúneo
Full Text Available In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla and a monocot (Araceae. Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae. Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form and the eudicot angiosperm Nelumbo (Nelumbonaceae are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae, ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.
J. C. Manning
Full Text Available The species of Ornithogalum L. subgenus Aspasia section Aspasia are revised. Section Aspasia is defined by a rosette of lanceolate to oblong leaves; large, boat-shaped, ± petaloid bracts; moderately-sized white, yellow or orange flowers, sometimes with dark central markings; thin-textured, ellipsoid capsules that are enclosed by and concealed within the persistent, papery perianth; and angular, colliculate to echinulate seeds. Twelve species are recognized in the section, separable into three series based on seed morphology. O. conicum is redefined to exclude specimens from the Eastern Cape, which are recognized as O. synanthifolium, and O. conicum subsp. strictum is raised to species status as O. strictum. The circumscription of O. duhium is expanded to include O.fimbrimarginatum and O. subcoriaceum, previously distinguished on account of their longer styles.Collections from the Roggeveld Escarpment and Klein Roggeveld that were previously included in O. fimbrimaiginatum are recognized as the new species O. corticatum Mart.-Azarin, on the basis of their unusual, thick, cartilaginous outer tunics and puberulous adaxial leaf surface. O. ceresianum is removed from the synonomy of O. thyrsoides and recognized as a distinct species on account of its extensive glossy black tepal markings, winged inner filaments, and glossy black ovary. The poorly known O. puberuhim is more ftilly described based on several recent collections, and O. leeupoortense is neotypified in the absence of any original type material. O. rupestre and O. multifolium are regarded as colour forms of the same species, for which O. rupestre is the older name. Similarly, O. roussouwii is a depauperate, pale form of O. maculatum and is thus included in the synonomy of that species. The circumscription of O. pruinosum remains unchanged. The species O. haurii, O. diphyllum and O. sephtonii from the Drakensberg Mountains of Eastern Cape and KwaZulu-Natal are excluded from