Endodermis with meristematic activity in roots of species of Scleria Berg. (Cyperaceae)

O sistema radicular de Scleria é, como nas demais Cyperaceae, um sistema de raízes adventícias. No estudo anatômico da raiz de sete espécies procedentes do estado de Minas Gerais, Brasil, um aspecto relevante é a presença de um córtex formado por células radialmente dispostas, resultante de uma endoderme com atividade meristemática, formada por células iniciais. Mais da metade da espessura do córtex é resultante dessa atividade, constituindo as Derivadas da Endoderme Meristemática (DEM). Após cessarem as divisões das iniciais endodérmicas, esse tecido sofre diferenciação, primeiro formando estrias de Caspary, apresentando posteriormente, em níveis mais distantes do ápice, espessamentos secundários das paredes das células. O córtex interno exibe espessamento das paredes das células no nível em que a endoderme já apresenta estrias de Caspary.The root system of Scleria is, as in the remaining Cyperaceae, a system of adventitious roots. In the study of root anatomy of seven species from Minas Gerais state, Brazil, one relevant aspect is the presence of a cortex, formed by radially placed cells, resulting from an endodermis with meristematic activity, formed by initial cells. More than half the thickness of the cortex is the result of this activity, constituting the Derivatives of the Meristematic Endodermis (DME). After endodermal initials divisions ceases, this tissue undergoes differentiation, first forming casparian strip, proceeding to, and at the farthest levels from the apex, secondary thickening of these cell walls. The internal cortex presents thickening of cell walls at the level whereat the endodermis denotes casparian strip

Morpho-Anatomical Analysis of the Rhizome in Species of Scleria Berg. (Cyperaceae) from Serra do Cipó (MG)

Aspects related to the nature of stem thickening in monocotyledons have been the subject of many studies. Primary thickening has been attributed to the Primary Thickening Meristem (PTM). According to most authors, it gives rise, besides the adventitious roots, to the vascular tissues and part of the cortex. In other words, it has centripetal and centrifugal activity. For some authors, however, it gives rise only to the vascular system, and for others, only to part of the cortex. However, this work demonstrated that PTM corresponds to the pericycle in the meristematic phase or to the pericycle associated with the endodermis, also with meristematic activity. It was observed that the pericycle was responsible for the formation of the vascular system of the rhizome and of the adventitious roots; the endodermis gave rise to cell layers with radial disposition which comprised the inner portion of the stem cortex, and which corresponded to the region known as the derivatives of the meristematic endodermis (DME). A continuity was also demonstrated between the tissues of the stem and root in species of Scleria Berg. (Cyperaceae).Aspectos relacionados à natureza do espessamento em caules de monocotiledôneas têm sido objeto de estudo de muitos pesquisadores. O espessamento primário vem sendo atribuído ao meristema de espessamento primário (MEP). Segundo a maioria dos autores origina, além das raízes adventícias, os tecidos vasculares e parte do córtex. Para alguns autores, no entanto, origina apenas o sistema vascular e para outros, apenas parte do córtex. Entretanto, demonstra-se neste trabalho, que o MEP corresponde ao periciclo em fase meristemática ou ao periciclo associado à endoderme, também com atividade meristemática. Verificou-se que o periciclo é responsável pela formação do sistema vascular do rizoma e pela formação das raízes adventícias; a endoderme origina fileiras radiais de células que constituem a porção interna do córtex caulinar e que correspondem à região denominada derivadas da endoderme meristemática (DEM). Demonstra-se também, a continuidade entre os tecidos do caule e da raiz nas espécies de Scleria Berg. (Cyperaceae).Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Aspectos micromorfológicos da epiderme das brácteas em espécies de Scleria Berg. - Cyperaceae da Serra do Cipó

Resumo As microestruturas da epiderme foliar são consideradas de grande valor na taxonomia de vários grupos de Cyperaceae e a deposição da sílica é um dos aspectos considerados de maior relevância. Uma proporção variável das células epidérmicas apresenta corpos silicosos, quase sempre com formato cônico e, relacionados, às regiões costais da folha. Os corpos silicosos podem ter formatos diferentes, como os conglomerados de sílica. Nas espécies aqui analisadas, a sílica é observada formando cones, conglomerados e também, impregnando as paredes das células epidérmicas, inclusive, dos estômatos e dos tricomas. Com base nas informações obtidas conclui-se que os caracteres anatômicos da epiderme das brácteas em espécies de Scleria ocorrentes na Serra do Cipó oferecem alguns subsídios, como o formato dos corpos silicosos, a distribuição dos estômatos e a presença ou ausência de tricomas (curtos e longos), que podem ser utilizados como caracteres diagnósticos para delimitação taxonômica

Estudo anatômico da folha de duas espécies de Solanaceae ocorrentes no Núcleo Cabuçu (Guarulhos, SP). Leaf anatomic study in two species of Solanaceae occurring in Núcleo Cabuçu (Guarulhos, SP).

O Núcleo Cabuçu é o quarto e o maisrecente núcleo do Parque Estadual da Cantareira,situado dentro da região metropolitana de SãoPaulo. Plantas invasoras apresentam algumascaracterísticas típicas, como a capacidade decolonização rápida em ambientes abertos,inclusive por ação antrópica e a reprodução,predominantemente autogâmica, o que lhes conferealta uniformidade genética em nível populacional.Dentre as famílias de plantas invasoras queocorrem no Núcleo Cabuçu, cita-se a famíliaSolanaceae. No presente trabalho foi realizada aanálise anatômica da folha em exemplares de duasespécies invasoras de Solanaceae – Solanum variabileMart. e Aureliana fasciculata(Vell.)Sendtn., ambas nativas da flora brasileira. Para osestudos anatômicos foram obtidas secções amão livre da porção mediana da lâmina foliar,da nervura principal e do pecíolo e também,a dissociação da epiderme. Em seguida, o materialfoi submetido às técnicas convencionais deanatomia vegetal para o preparo de lâminas.Concluiu-se que as duas espécies apresentamcaracterísticas anatômicas que, possivelmente,justificam a condição de invasoras, como a amplacobertura de tricomas em Aureliana fasciculata,as drusas de oxalato de cálcio em Solanum variabilee a presença de idioblastos comsubstâncias fenólicas em Solanum variabile.Núcleo Cabuçu is the fourth and latest“núcleo” of the Parque Estadual da Cantareira,situated inside of the metropolitan region ofSão Paulo. Invasive plants present some typicalcharacteristics, as the capacity of fast openedenvironment settling, also for antropic action andthe reproduction, predominantly autogamic, whatconfers them a high genetic uniformity inpopulation level. Amongst the families of invasiveplants that occur in the Núcleo Cabuçu,Solanaceae family is cited. In the present work it wasmade the anatomical analysis of the leaf in units oftwo invasive populations of Solanaceae – Solanum variabileMart. and Aureliana fasciculata(Vell.)Sendtn., both of them, native species of theBrazilian flora. For the anatomical study, sectionsby free hand from the medium portion of the foliarblade, main ribbing and petiole were obtained andalso the dissociation of the epidermis. After that,all the material was submitted to the conventionaltechniques of plant anatomy for blades preparation.It was concluded, by the present study, that thetwo species present anatomical characteristics thatmay justify its invasive condition, such as thegreat covering of trichomes in Solanum variabile,the druses of calcium oxalate in Aureliana fasciculataand the presence of idioblasts with phenolicsubstances in Solanum variabile

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved

Neotropical freshwater fisheries : A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora