Anther development, microsporogenesis and microgametogenesis in Heliconia (Heliconiaceae, Zingiberales)

Anther development, micro sporogenesis and microgametogenesis in several species of Heliconia were investigated as part of a complementary embryological study of the Heliconiaceae. All studied Heliconia species present bithecate and tetrasporangiate anthers with fertile pollen grains; only H. rivularis, a natural hybrid, presented sterile pollen grains of variable size and no content. The anther wall has an uniseriate epidermis and endothecium, the latter with helicoidal thickenings, although some cells of the middle layers also showed thickenings; the biseriate tapetum is of amoeboid non-syncytial type, since the tapetum cells did not fuse together forming a true plasmodium. The microsporogenesis is successive leading to isobilateral tetrads. The inaperturate pollen grains had a very reduced exine consisting of a thin, more or less continuous layer with small spines upon; the pollen grain shape is variable among the species, all of them presenting heteropolar pollen, except H. angusta with isopolar ones. Most of these characteristics were shared with other studied Zingiberales, although more studies need to be done. (c) 2006 Elsevier GmbH. All rights reserved.

Embryology and seed development of Blastocaulon scirpeum and Paepalanthus scleranthus (Eriocaulaceae)

The embryology and seed structure of Blastocaulon scirpeum (Mart.) Giul. and Paepalanthus scleranthus Ruhland were studied in order to contribute to the embryology of Eriocaulaceae and supply data for future taxonomic studies. Both species present: anther with 4-layered wall; conspicuous endothecium with fibrous thickenings; secretory tapetum with uninucleate cells; successive microsporogenesis forming isobilateral microspore tetrads; bicellular pollen grains; orthotropous, bitegmic and tenuinucellate ovule; micropyle formed by the inner integument alone; megagametophyte of the Polygonum type, with a conspicuous antipodal cyst; nuclear and starchy endosperm; reduced, undifferentiated, and bell-shaped embryo; operculate and endotestal seed; seed coat derived from the two ovule integuments; and tanniniferous endotegmen. In addition, Blastocaulon scirpeum shows a bisporangiate anther and a 3-layered ovary wall, while P. scleranthus presents a tetrasporangiate anther that becomes bisporangiate at maturity, and a 2-layered ovary wall. This investigation shows that the bisporangiate condition does not suffice to separate Blastocaulon from Paepalanthus, since it is common to both. It also indicates, based on several embryological aspects, the proximity of Eriocaulaceae and Xyridaceae, which comply mainly with the features presented by the other commelinid families. These results may be used in future cladistic analysis of the family, and contribute to a better understanding of its phylogeny.

Polimorfismo floral em Valeriana scandens L. (Valerianaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O gênero sulamericano Gynocraterium Bremek. (Acanthaceae, Nelsonioideae)

Gynocraterium Bremek. é um gênero monotípico descrito para a Guiana e só recentemente citado para outros países sulamericanos. Com base na análise das coleções de 52 herbários nacionais e estrangeiros, verificou-se a ocorrência do táxon em novas localidades, inclusive na Amazônia brasileira. Uma revisão do gênero nos neotrópicos é apresentada, incluindo ratificações nas descrições do mesmo e de Gynocraterium guianense Bremek. Aspectos morfológicos desta espécie são ilustrados pela primeira vez, assim como os grãos de pólen descritos e fotografados através de microscopia eletrônica de varredura. São ainda apresentados aspectos diagnósticos, fenológicos e atualizações sobre a distribuição de G. guianense, que é restrita a região amazônica.

Embryology and seed development of Syngonanthus caulescens (Poir.) Ruhland (Eriocaulaceae-Poales)

The embryology and the seed development of Syngonanthus caulescens are presented. This species possesses: a bithecous and tetrasporangiate anther, with a four-layered wall, a conspicuous endothecium of the baseplate type, a secretory tapetum formed by uninucleate cells, successive microsporogenesis resulting in isobilateral microspore tetrads, spiraperturate and binucleate pollen grains, an orthotropous, pendulous, bitegmic and terminucellate ovule, with a micropyle formed only by the inner integument, a megagametophyte of the Polygonum type, with formation of an antipodal cyst, free-nuclear and starchy endosperm, a broad and bell-shaped embryo, operculate and endotestal seeds, a seed coat derived from the inner layers of both integuments, and tanniniferous endotegmen. These embryological aspects are characteristic not only for Syngonanthus, but for the whole family, with few differences between genera. Furthermore, the pollen grain of the spiraperturate type and the cystic arrangement of the antipodals in the megagametophyte are peculiar and very distinctive features of Eriocaulaceae within the other Poales (commelinids). (c) 2006 Elsevier B.V. All rights reserved.

Reproductive biology in the primitive relic Angiosperm Drimys brasiliensis (Winteraceae)

From field observations on Drimys brasiliensis, principally in the Botucatu region of São Paulo State, Brazil, new data on the reproductive biology, the rhythm of growth, and the development of lateral cymose inflorescences, flowers and fruits are presented. Pollination accelerates the rate of flower-development for about 4-6 days. Pollination experiments show that D. brasiliensis is not self-sterile; because of mechanical devices the sticky pollen grains do not normally come into contact with the stigmata unless an animal pollen vector is involved. The pollinators are diurnal Coleoptera, Diptera and Thysanoptera which eat from the pollen, lick from the stigmatic exudates and (in case of the flies) probably also from the staminal glands. Fruit- and seedeaters are birds which seem to be the main dispersal agents. Establishment of new individuals normally is through seedlings, but also by vegetative propagation through plagiotropous branches which may root and separate from the mother plant. The morphological, developmental and reproductive aspects in D. brasiliensis are discussed in a wider context, compared with data from other Magnoliidae, and related to aspects of early Angiosperm evolution. © 1980 Springer-Verlag.

Oral toxicity of chemical substances found in Dimorphandra mollis (Caesalpiniaceae) against honeybees (Apis mellifera) (Hymenoptera: Apidae)

Dimorphandra mollis is a characteristic plant from Brazilian saP vanna-like vegetation. The pollen of this species could be toxic to bees and the objective of the present investigation was to study the toxicity of methanolic extracts obtained from the flowers, peduncles and stem bark of D. mollis to Apis mellifera workers. For the study, the extracts were incorporated into the diet of the bees for later evaluation of mortality rates. The substances isolated: neoisoastilbin, catechin, astilbin and tannins were tested on adult workers and only catechin did not cause toxic effects. The data obtained in the toxicity bioassays were analyzed statistically by Log Rank test and all methanolic extracts showed significant (p<0.0001) toxic effects. Astilbin is also the major component of pollen grains, and is probably responsible for honeybee mortality during blooming periods.

Morphological evolution in the graminid clade: Comparative floral anatomy of the grass relatives Flagellariaceae and Joinvilleaceae

New comparative data are presented on the reproductive morphology and anatomy of two genera closely related to grasses, Flagellaria and Joinvillea, in which the flowers are superficially similar, especially in stamen morphology. This investigation demonstrates some anatomical differences between the two genera. For example, both genera depart from the 'typical' condition of tepal vasculature (three-traced outer tepals and one-traced inner tepals): in Flagellaria, each tepal receives a single vascular bundle and, in Joinvillea, each tepal is supplied by three vascular bundles. Joinvillea possesses supernumerary carpel bundles, as also found in the related family Ecdeiocoleaceae, but not in Flagellaria or grasses. In the anther, the tapetum degenerates early in Flagellaria, and is relatively persistent in Joinvillea, in which the pollen grains remain closely associated with the tapetum inside the anther locule, indicating a correlation between peripheral pollen (a feature that is common in grasses) and a persistent tapetum. This study highlights the presence of a pollen-tube transmitting tissue (PTTT) or solid style in the gynoecium of Flagellaria, as also in many Poaceae, but not in Joinvillea or Ecdeiocoleaceae. We speculate that the presence of a PTTT could represent one of the factors that facilitated the subsequent evolution of the intimately connected gynoecia that characterize grasses. © 2012 The Linnean Society of London.

Ontogenia do óvulo e da Antera de Cybistax antisyphilitica (Mart.) Mart. (Bignoniaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A formação Irati (Grupo Passa Dois, Permiano, Bacia do Paraná) no furo de sondagem FP-01-PR (Sapopema, PR)

Pós-graduação em Geologia Regional - IGCE

Estudo palinológico das formações Serra Alta, Teresina e Rio do Rasto nos furos de sondagem SP-23-PR e SP-58-PR, centro-norte do Paraná (Permiano, Bacia do Paraná)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Embriologia e desenvolvimento de frutos e sementes de Eriocaulaceae e Cyperaceae (Poales)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Embriologia e desenvolvimento pós-seminal de espécies de Poaceae (Poales)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morfologia e desenvolvimento floral em Croton L. e Astraea Klotzsch (Euphorbiaceae sensu stricto)

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

Polinização de dendezeiro por Elaeidobius subvittatus Faust e Elaeidobius kamerunicus Faust (Coleoptera, Curculionidae) no sul do Estado da Bahia

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV