Os novelos de fibras do abrigo rupestre Santa Elina (Jangada, MT, Brasil): anatomia vegetal e paleoetnobotânica.

O Abrigo Rupestre Santa Elina rica em Jangada, MT, Brasil, é formado por uma dobra calcária da Bacia do Paraguai e apresenta sedimentos de sucessivas ocupações humanas nos últimos 6.000 anos. Esses sedimentos possuem vestígios vegetais bem conservados em quantidade, como carvões, madeiras, macro-restos vegetais, fibras e artefatos de fibras vegetais, principalmente nas camadas mais recentes. Artefatos de fibras enroladas semelhantes a ninhos de pássaros, referidos como novelos ou maranhas foram estudados histológicamente por meio de técnicas de anatomia vegetal e identificados com base em uma coleção de referência de material lenhoso da região e materiais de herbários. As fibras foram identificadas como sendo de caules de lianas lenhosas do gênero Aristolochia, provavelmente da espécie A. esperanzae O. Kuntze, família Aristolochiaceae. Diversas espécies de Aristolochia, conhecidas como papo-de-peru ou milhome, são usadas como plantas medicinais em várias partes do mundo para muitas finalidades, sendo que também são apontados os usos como repelentes ou amuletos contra cobras. Os novelos arqueológicos podem ter tido algum desses usos e são indicadores de ocorrência de formações florestais, provavelmente indicando condições ecológicas semelhantes às atuais.Santa Elina shelter is located at Jangada County, Mato Grosso State at the North of Paraguay basin, Western Brazil. It is formed by a limestone folding and reveals sediments from the last 6,000 years. Those sediments are very rich in plant vestiges very well preserved comprising wood pieces, charcoal, plant organs and fibers. Ravel like artifacts formed by plant fibers were analyzed by standard plant anatomy methods and identified by comparison to a reference collection and stems from herbaria. The fibers have been identified as stem parts from Aristolochia, probably A. esperanzae O. Kuntze, Aristolochiaceae. Many species of Aristolochia, called “snakeroof ’ are referred as medicinal plants all around the world. They are used for many medical purposes and suggested as snake repellents and snake bites remedy. The occurrence of Aristolochia in the archaeological site suggests presence of forests and palaeoecological conditions similar to our tim

Aroeira’s firebrand in an archaeological context: anthracology contribution to understanding the relationship between man and his environment

The anthracology provides different information about use of plant resources by prehistoric Holocene populations either in the diet or in the use of raw material as a fuel for daily activities (lighting, kitchen, heat). A charred firebrand, a rarely found residue vegetal, was discovered in archaeological sediments dated to 2820±30 years BP (2914±40 years cal.BP) associated with the material vestige of the first ceramic people of Mato Grosso region, in the rock shelter Ferraz Egreja (Rondonópolis, Mato Grosso). Anthracological analysis of this firebrand allowed the identification of the Aroeira tree. The ecological and paleobotanical approach of this result allowed discussing on the taxonomic identification of this sample, and the use, selection and place of procurement of this plant resource by human groups.A antracologia fornece diferentes informações sobre a utilização de recursos vegetais pelas populações pré-históricas do Holoceno seja na dieta alimentar ou no uso da matéria prima como combustível, para as atividades cotidianas (luz, cozinha, calor). Um tição carbonizado, resto vegetal raramente encontrado, foi descoberto em sedimentos arqueológicos datados de 2820±30 anos AP (2914±40 anos cal. AP) associado aos vestígios materiais dos primeiros povos ceramistas da região do Mato Grosso, no abrigo rupestre Ferraz Egreja (Rondonópolis, Mato Grosso). A análise antracológica do tição permitiu a identificação da aroeira. A abordagem ecológica e paleobotânica desse resultado permitiu discutir sobre a identificação desta amostra e sobre o uso, a seleção e o lugar de coleta deste recurso vegetal pelos grupos humanos

Millenial-scale climatic and vegetation changes in a northern Cerrado (Northeast, Brazil) since the Last Glacial Maximum.

Abstract In the Southern Hemisphere, lacustrine sediments started to be deposited with the beginning of the deglaciation at ca 19,000 cal yr BP. At this time the region of Lake Cac -o was dominated by sparse and shrubby vegetation with dominance of steppic grasses in a poor sandy soil. The landscape did not present any ecological characteristics of a modern Cerrado. However single pollen grains of two Cerrado indicators, Byrsonima and Mimosa, suggest that some Cerrado species were able to survive under the prevailing arid climate, probably as small shrubs. After 15,500 cal yr BP, a sudden increase in the moisture rates is evidenced with the progressive expansion of rainforest showing successive dominance of various associations of taxa. The development of the forest stopped abruptly at the end of the Pleistocene between 12,800 and 11,000 cal yr BP, as attested by strong fires and the expansion of Poaceae. In the early Holocene an open landscape with a relatively high level of water in the lake preceded the progressive expansion of Cerrado species towards a denser forested landscape; fires are recorded from then on, resulting in the physiognomy of the Cerrado we know today. Late Pleistocene paleoenvironmental records from northern Brazil reflect the interplay between insolation forcing of two hemispheres with the local components represented by the interannual shift of the Inter Tropical Convergence Zone and the influence of seasonal equatorwards polar air incursions.

THE ENDOPARASITE PILOSTYLES ULEI (APODANTHACEAE - CUCURBITALES) INFLUENCES WOOD STRUCTURE IN THREE HOST SPECIES OF MIMOSA

Pilostyles species (Apodanthaceae) are endoparasites in stems of the plant family Fabaceae. The body comprises masses of parenchyma in the host bark and cortex, with sinkers, comprising groups of twisted tracheal elements surrounded by parenchyma that enter the secondary xylem of the host plant. Here we report for the first time the effects of Pilostyles parasitism on host secondary xylem. We obtained healthy and parasitized stems from Mimosa foliolosa, M. maguirei and M. setosa and compared vessel element length, fiber length, vessel diameter and vessel frequency, measured through digital imaging. Also, tree height and girth were compared between healthy and parasitized M. setosa. When parasitized, plant size, vessel diameter, vessel element length and fiber length are all less than in healthy plants. Also, vessel frequency is greater and vessels are narrower in parasitized stems. These responses to parasitism are similar to those observed in stressed plants. Thus, hosts respond to the parasite by changing its wood micromorphology in favour of increased hydraulic safety.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Research Support Foundation of Sao Paulo State - FAPESP[05/55172-4]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Research Support Foundation of Sao Paulo State - FAPESP[03/10277-8]Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Brazilian Council for Superior Education - CAPE

Flora da Serra do Cipó, Minas Gerais: Apodanthaceae (Rafflesiaceae s.l.), e notas sobre a anatomia de Pilostyles

O estudo da família Apodanthaceae (Rafflesiaceae s.l.) é parte do levantamento da Flora da Serra do Cipó, Minas Gerais, Brasil. Esta família está representada na área pelo gênero Pilostyles, com apenas uma espécie, P. ulei. São apresentadas descrição e ilustrações da espécies, comentários sobre sua distribuição geográfica, fenologia e variabilidade. Figuras e comentários sobre a anatomia da espécie e da interação hospedeiro-parasita saõ também fornecidos

Flora da Serra do Cipó, Minas Gerais: Apodanthaceae (Rafflesiaceae s.l.), e notas sobre a anatomia de Pilostyles

O estudo da família Apodanthaceae (Rafflesiaceae s.l.) é parte do levantamento da Flora da Serra do Cipó, Minas Gerais, Brasil. Esta família está representada na área pelo gênero Pilostyles, com apenas uma espécie, P. ulei. São apresentadas descrição e ilustrações da espécies, comentários sobre sua distribuição geográfica, fenologia e variabilidade. Figuras e comentários sobre a anatomia da espécie e da interação hospedeiro-parasita saõ também fornecidos

Anatomia foliar de Copaifera langsdorffii Desf. (Leguminosae): interpretações ecológicas em diferentes condições edáficas de Cerrado

http://dx.doi.org/10.5007/2175-7925.2012v25n4p29 Copaifera langsdorffii Desf. (Caesalpinioideae, Leguminosae) é uma espécie arbórea de ampla distribuição no Brasil, conhecida como copaíba. O presente trabalho objetiva discutir, numa perspectiva ecológica, alterações estruturais foliares em populações de copaíba em três substratos distintos no Cerrado: neossolo flúvico em margem de rio, afloramento arenítico e latossolo vermelho em campo cerrado. Atributos foliares qualitativos e quantitativos foram observados por meio de preparações histológicas permanentes. Diferenças estatisticamente significativas foram verificadas em todos os parâmetros ecológicos analisados, como área específica foliar, espessura de tecidos e densidade estomática. A presença mais acentuada de características escleromórficas foi constatada nas plantas de arenito e neossolo flúvico, embora o latossolo também seja pobre em bases trocáveis. As alterações estruturais encontradas sejam o resultado da combinação de fatores edáficos, hídricos, microclimáticos e da interação planta/herbívoros existente em cada substrato, porém percebe-se claramente que houve prevalência dos fatores nutricionais do solo em detrimento da disponibilidade de água.

Dark-induced hormone changes coincide with the resumption of light-inhibited shoot growth in Catasetum fimbriatum (Orchidaceae)

Catasetum fimbriatum plants cultivated in the absence of light exhibit continuous shoot growth leading to the formation of nodes and internodes. On the other hand, when these plants are incubated in the presence of light, shoot longitudinal growth is inhibited and pseudobulbs develop just below the shoot apical meristem. These facts provide evidence of a possible influence of light on mitotic cell division in the shoot apex as well as on pseudobulb initiation. The effects of light and dark on the interruption and/or maintenance of shoot apex mitotic activity and the subsequent formation of pseudobulbs in the sub-meristematic regions were investigated by means of histological and hormonal studies. The interruption of shoot apex development occurred around the 150th d of light incubation and seems to have resulted from the establishment of a strong storage sink in the region of the future pseudobulb, in detriment to the continuous activity of the shoot apical meristem. The reduced total cytokinins/IAA ratio in the apex, mainly due to high levels of IAA, could be a key factor in the interruption of cell divisions. Transfer to the dark brings about the resumption of shoot apex development of plants through the re-entrance of cells in the cell cycle which coincides with a significant increase in the total cytokinins/IAA ratio. (C) 2009 Elsevier GmbH. All rights reserved.FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Evaluating the annual nature of juvenile rings in Bolivian tropical rainforest trees

Knowledge on juvenile tree growth is crucial to understand how trees reach the canopy in tropical forests. However, long-term data on juvenile tree growth are usually unavailable. Annual tree rings provide growth information for the entire life of trees and their analysis has become more popular in tropical forest regions over the past decades. Nonetheless, tree ring studies mainly deal with adult rings as the annual character of juvenile rings has been questioned. We evaluated whether juvenile tree rings can be used for three Bolivian rainforest species. First, we characterized the rings of juvenile and adult trees anatomically. We then evaluated the annual nature of tree rings by a combination of three indirect methods: evaluation of synchronous growth patterns in the tree- ring series, (14)C bomb peak dating and correlations with rainfall. Our results indicate that rings of juvenile and adult trees are defined by similar ring-boundary elements. We built juvenile tree-ring chronologies and verified the ring age of several samples using (14)C bomb peak dating. We found that ring width was correlated with rainfall in all species, but in different ways. In all, the chronology, rainfall correlations and (14)C dating suggest that rings in our study species are formed annually

Parasites on parasites AJB paper

All organisms engage in parasitic relations, as either parasites or hosts. Some species may even play both roles simultaneously. Among flowering plants, parasitism is characterized by the development of an intrusive organ called a haustorium, which absorbs water and nutrients from host plants. Despite this functionally unifying feature, haustoria are not homologous structures, as parasitic plants have evolved at least 12 times independently. These plants represent ca. 1% of all extant flowering species and show a wide diversity of life histories. A great variety of plants may also serve as hosts, including other parasitic plants. This phenomenon of parasitic exploitation of another parasite, broadly known as hyper- or epi- parasitism, is well described among bacteria, fungi, and animals, but remains poorly understood among plants. Here, we review empirical evidence of plant hyperparasitism, including variations of self-parasitism, and discuss the diversity and ecological importance of these interactions, and suggest possible evolutionary mechanisms. Hyperparasitism may provide benefits in terms of improved nutrition and enhanced host-parasite compatibility if partners are related. Different forms of self-parasitism may facilitate nutrient sharing among and within parasitic plant individuals, while also offering potential for the evolution of hyperparasitism. Cases of hyperparasitic interactions between parasitic plants may affect the ecology of individual species and modulate their ecosystem impacts. Parasitic plant phenology and disperser feeding behavior are considered to play a major role in the occurrence of hyperparasitism, especially among mistletoes. There is also potential for hyperparasites to act as biological control agents of invasive primary parasitic host species