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

The embryology and the seed development of Eriocaulaceae and Cyperaceae were studied here in order to contribute to the taxonomy and phylogeny of both families. The results given by different genera of Eriocaulaceae allowed us to strengthen the embryological uniformity of the family. The endothecial thickenings of the baseplate-type, the spiraperturate pollen grains, the antipodal cyst closely associated to the hypostase, and the operculated endotestal seeds are synapomorphies of Eriocaulaceae within Poales. The use of the character number of microsporangia of anthers in genera delimitation is not consistent, while those related to the seed coat seem to be more stable in establishing relationships between genera. The overall embryological features pointed out the necessity of a taxonomic revision in Eriocaulaceae, aiming at a more natural classification of its taxa. In Cyperaceae, the embryology and the fruit development were investigated in species of Hypolytrum and Rhynchospora, showing that most of these aspects are also uniform within the family. The endothecial thickenings of the spiral type, the Cyperaceous-type of simultaneous microsporogenesis, the trinucleate pollen grain of the pseudomonad type, the formation of a funicular obturator closely associated with the hypostase of the ovule, the Onagrad-Juncus variation embryogeny, and the fruit of the achene type with silica deposition clearly distinguish this family amongst the other Poales. Hypolytrum differs from Rhynchospora as well as from the other genera of Cyperaceae already studied for the spherical pseudomonads, with reticulate exine and central arrangement in the microsporangia, the micropyle formed by both the integuments, and the conspicuous parietal tissue which indicate its position as a basal group in the family. Moreover, the number and the ...(Complete abstract, click electronic address below).Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Confirmação da ocorrência de Abolboda poarchon Seub. (Xyridaceae) no Estado de São Paulo, Brasil

A ocorrência de Abolboda poarchon Seub. é documentada para o Estado de São Paulo, com base em coletas realizadas no município de Itirapina. O trabalho apresenta a descrição detalhada de A. poarchon e A. pulchella, espécies simpátricas, com características diagnósticas e distintivas para o reconhecimento das mesmas no campo.The occurrence of Abolboda poarchon in São Paulo State is documented, based on collections from Itirapina municipality. This paper presents a detailed description of the sympatric species, A. poarchon and A. pulchella, emphasizing some diagnostic features for field identification

Seed morphology and post-seminal development of Tillandsia L. (Bromeliaceae) from the Campos Gerais, Paraná, Southern Brazil

Foi estudada a morfologia da semente e do desenvolvimento pós-seminal de Tillandsia gardneri Lindl., T. streptocarpa Baker, e T. stricta Sol. ex Sims (Bromeliaceae), que ocorrem nos Campos Gerais do Paraná, Brasil. As sementes apresentaram cerca de 2,0 mm de comprimento e testa com apêndices plumosos na região micropylar. A presença desses apêndices é um caráter importante na taxonomia da família e garante sucesso na dispersão anemocórica das sementes. Após a embebição, as sementes levaram cerca de 20 dias para germinar. A primeira estrutura que emergiu durante a germinação foi o cotilédone haustorial, que é responsável pela nutrição da plântula. Eram ausentes catafilo e raiz primária. Na plântula ocorreu a formação de um pequeno tanque, que é constituído pela base da bainha da folha primária superposta à base da bainha da folha secundária. Esse pequeno tanque permaneceu na posição vertical e armazenou água e detritos orgânicos para a nutrição da plântula. As raízes adventícias emergiram tardiamente.This work studied the morphology and post-seminal development of seeds of Tillandsia gardneri Lindl., T. streptocarpa Baker, and T. stricta Sol. ex Sims (Bromeliaceae) from the Campos Gerais, State of Paraná, Southern Brazil. The seeds (ca. 2.0 mm long) presented plumose appendages at their micropylar end, an important structure in the taxonomy of the family since it represented an elaborate apparatus allowing effective wind-dispersal. Seeds germinated after circa twenty days. The haustorial cotyledon, responsible for the seedling nutrition, appeared first during the germination process. No cataphyll or primary roots developed. A small tank came along in the seedling, formed by the base of the sheath of the first leaf, which overlapped that of the second leaf. This tank can store water and litter. The adventitious roots developed later.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Anatomia de algumas espécies aquáticas de Eriocaulaceae brasileiras

Estudou-se a anatomia de raízes, caules, folhas e escapos de Eriocaulon elichrysoides, Leiothrix fluitans, Paepalanthus obtusifolius, Philodice hoffmannseggii, Syngonanthus caulescens e Tonina fluviatilis,espécies aquáticas de Eriocaulaceae que ocorrem em diferentes ecossistemas brasileiros, visando a caracterização anatômica das mesmas e também a interpretação das adaptações ao ambiente. Essas plantas caracterizam-se por apresentarem raízes com aspecto esponjoso e esbranquiçado; acúmulo de ar no córtex; epiderme unisseriada, de paredes finas; córtex externo, mediano e interno; endoderme unisseriada e periciclo unisseriado ou multisseriado. em L. fluitans, P. obtusifolius e T. fluviatilis foram observadas raízes absorventes com aerênquima e raízes fixadoras sem aerênquima. Caules aéreos ou rizomatosos, com ou sem espessamentos causados pelo periciclo. Folhas e escapos com células epidérmicas de paredes finas, estômatos somente na face abaxial, parênquima clorofiliano frouxo, tecido de sustentação pouco desenvolvido e feixes vasculares colaterais. Essas estruturas anatômicas são típicas de plantas de ambientes úmidos ou aquáticos, e ocorrem de forma convergente em diferentes gêneros de Eriocaulaceae.The anatomy of roots, stems, leaves, and scapes of Eriocaulon elichrysoides, Leiothrix fluitans, Paepalanthus obtusifolius, Philodice hoffmannseggii, Syngonanthus caulescens, and Tonina fluviatilis were studied. All species are aquatic Eriocaulaceae that occur in Brazilian ecosystems. This paper aims to describe the anatomical characterization as well as the interpretation of the adaptations related to the environment. These species present roots with spongy and whitish aspect; air storage in the cortex; thin-walled uniseriate epidermal cells; differentiated cortex; uniseriate endodermis, and uniseriate or multiseriate pericycle. L. fluitans, P. obtusifolius, and T. fluviatilis present roots that store and roots that do not store air in the cortex. The stems are aerial or rhizomatous, with or without thickening resulted from the activity of the pericycle. Leaves and scapes present thin-walled epidermal cells, stomata on the abaxial surface, loosely aggregated chlorenchyma, reduced collenchyma, and collateral vascular bundles. The anatomical features observed are those typical of plants of aquatic or wet habitats. They are convergent and occur in different genera of Eriocaulaceae

Evidence of pseudomonad pollen formation in Hypolytrum (Mapanioideae, Cyperaceae)

Cyperaceae are characterised by typical simultaneous microsporogenesis that results in the formation of pseudomonad pollen. Morphological studies indicate the occurrence of a distinct pollen type in Mapanioideae, the spherical and monoporate Mapania-type pollen, found in representatives of Hypolytreae. This study investigates anther and pollen development in species of Hypolytrum for a better understanding of the mapanioid pollen type. Stages in microsporogenesis and microgametogenesis were analysed in both Hypolytrum (Mapanioideae, Hypolytreae; five species sampled) and Rhynchospora (Cyperoideae; two species studied). The latter was used as a comparator, known for the occurrence of pseudomonads. The results presented here confirm those already reported for the family, regardless of genus. The most important differences are morphological, not developmental. All species sampled of both genera had Cyperaceae-type simultaneous microsporogenesis resulting in pseudomonad pollen. Predictions that Mapania-type pollen in Hypolytrum would be monad are refuted. Anthers examined of Rhynchospora showed phenolic idioblasts, while those of species of Hypolytrum did not. There is need for ontogenetic studies on the other genera of Hypolytreae, such as Mapania and Scirpodendron, to extend and test the generality of our observations across the Hypolytreae.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP