Hildeberto Caldas de Sousa

Astra Blue and Basic Fuchsin Double Staining of Plant Materials

Methods for double staining plant materials using astra blue and basic fuchsin are described here. These methods can be applied to free hand and microtome sections embedded in paraffin, paraplast or historesin. Also, they can be used to study isolated epidermal peels and pollen preparations. Temporary, semipermanent and permanent preparations were studied. Astra blue stained polysaccharides of the cell wall such as cellulose and pectins. Basic fuchsin showed an affinity for lignified, suberized or cutinized walls. The easy preparation of the reagents, excellent color contrast of the histological preparations, and brief staining times of some methods makes them useful for both routine research and didactic purposes. Also, excellent color or black and white photomicrography can be obtained after the double staining described here.

Métodos de coloração de Roeser (1972): modificado - e Kropp (1972) visando a substituição do azul de astra por azul de alcião 8GS ou 8GX

foram testados metodos de coloracao baseados em Roeser (1972) modificado e Kropp (1972), visando a substituicao do corante azul de astra por azul de alciao 8GS ou 8GX. As amostras foram fixadas em FAA, desidratadas em serie butilica terciaria e incluidas em parafina. Os cortes histologicos transversais foram corados segundo diferentes baterias de coloracao, modificadas quanto ao tipo de corante usado, diferenciador e serie de desidratacao. As lâminas permanentes foram preparadas com balsamo-do-canada sintetico. Os resultados obtidos evidenciaram que o metodo de Roeser (1972) modificado e melhor que o de Kropp (1972), nas condicoes deste experimento. O azul de astra pode ser substituido por azul de alciao 8GX e a desidratacao pode ser em serie isopropilica ou etilica, sem grande diferenca entre elas. Sao discutidos os resultados provenientes das di ferentes coloracoes. Palavras-chave: metodo de coloracao, azul de astra. azul de alciao, fucsina basica, safranina, histologia vegetal ABSTRACT - (Staining methods of modified Roeser (1972) and Kropp (1972), aiming at substituing the astra blue by aleian blue 8GS or 8GX). Staining methods based on modified Roeser (1972) as well as that of Kropp (l972) were done with leaves of

Produção, decomposição e qualidade nutricional da serapilheira foliar em uma floresta paludosa de altitude

Florestas paludosas sao ecossistemas com ocorrencia restrita a solos hidromorficos, sujeitos a presenca superficial de agua devido ao afloramento do lencol freatico, onde a diversidade e o estabelecimento da vegetacao dependem de sua adaptabilidade as condicoes de saturacao hidrica e baixa oxigenacao do solo. Este estudo teve como objetivo caracterizar aspectos da ciclagem de N e P em uma floresta paludosa no Parque Estadual do Itacolomi, MG, atraves de mensuracoes da producao, qualidade nutricional e decomposicao da serapilheira foliar durante o periodo de outubro de 2006 a setembro de 2007. A producao anual media de serapilheira nao apresentou variacoes espaciais e foi de 5.7 t ha-1, com pico de producao em setembro. A fracao foliar foi responsavel por 57% da producao total de serapilheira e apresentou concentracoes de N, P e K de 12,6; 0,616 e 3,07 g kg-1, respectivamente. A porcentagem de perda de massa durante a decomposicao de serapilheira foi inversamente correlacionada com o conteudo de agua no solo, variando de 29,2% a 46,2%. A razao N:P da serapilheira foliar sugere que a vegetacao cresca sob limitacao por P. Considerando-se os parâmetros avaliados, a floresta paludosa apresentou um taxa de ciclagem de nutrientes lenta, principalmente em razao da baixa qualidade nutricional da serapilheira e sua lenta decomposicao, em comparacao com valores obtidos em outros estudos em ecossistemas florestais tropicais umidos.

Microscopic variability in mechanical defence and herbivory response in microphyllous leaves of tropical herb species from Serra do Cipó, Brazil

Campos de altitude tropicais apresentam varias especies com folhas microfilas e altamente esclerofilas que co-ocorrem em manchas de solo especificas e, portanto, expostas a ambientes identicos. Neste artigo, foi descrita a herbivoria entre especies microfilas co-ocorrendo em um ecossistema tropical de campos de altitude na Serra do Cipo, Minas Gerais, e testado o efeito de caracteres anatomicos variaveis no padrao de herbivoria foliar. Os caracteres anatomicos das folhas foram investigados em Baccharis imbricata Heering, Lavoisiera imbricata DC. e L. subulata Triana (especies em foco). A herbivoria foi medida nos ramos e nas folhas de cada planta coletada e comparada entre as especies estudadas em uma mancha multiespecifica e entre os individuos de L. subulata da mesma mancha e de uma mancha monoespecifica adjacente. Para todas as especies e individuos foi estimada a proporcao de folhas com diferentes niveis de area perdida. Para as especies em foco, seis folhas foram sorteadas e submetidas a cortes histologicos com o objetivo de realizar medidas precisas das possiveis estruturas anatomicas de defesa. A media relativa de area foliar perdida diferiu significativamente entre as seis especies encontradas na mancha multiespecifica. Individuos de L. subulata foram mais atacados na mancha multiespecifica que na mancha monoespecifica. Os caracteres anatomicos de protecao marginal tanto em B. imbricata quanto em L. imbricata apresentaram um efeito significativo contra a herbivoria. Os resultados sugerem o fato de alguns caracteres anatomicos terem efeito direto contra a herbivoria, mas seu efeito nao e claramente perceptivel entre os ramos de uma mesma planta ou entre plantas de uma mesma especie.

Edaphically distinct habitats shape the crown architecture of Lychnophora ericoides Mart. (Asteraceae) on tropical mountaintops

Different architectural arrangements may represent contrasting morphological solutions to different environmental pressures. This work aims to elucidate whether the crown architecture of Lychnophora ericoides (Asteraceae) modifies in response to harsh soil conditions (nutrient poor and heavy metal rich) and how its crown architecture affects its reproduction. One hundred and sixty L. ericoides individuals were randomly sampled from eight populations, four on quartzite and four on iron canga rocky complexes in the Iron Quadrangle, southeastern Brazil. We performed soil analyses to characterize edaphic differences and used eight morphometric parameters to describe the crown architecture of the plants. We calculated the population density and reproductive potential to verify the relationship between habitat, architecture, and fitness. Canga soils were more nutrient rich than quartzite soils and plants were architecturally distinct in each habitat. Plants established on canga soils were shorter, had a thinner main branch, and a smaller leaf than those established on quartzite soils. Moreover, plants on canga soils had a larger crown diameter and a greater number of branches and inflorescences. There was no difference in population density but the reproductive potential varied among populations and habitats. The crown architecture of L. ericoides closely relates to reproductive potential and may favor the reproduction of more architectonically complex plants, regardless of habitat.

Structure and floristic composition as indicators of restoration success in an urban riparian forest along the Das Velhas river in Southeastern Brazil

ABSTRACT This study evaluated a 5-year-old riparian forest in an anthropogenically affected region along the Das Velhas River in southeastern Brazil, restored with the purposes of erosion control and other ecosystem functions and to monitor indicators of structure and composition. The forest was monitored via data collection of the diameter and height of trees for phytosociological analysis, including the identification of species and their classification with regard to life form, origin, weed-status, and successional stage. The forest was not very structurally developed and, overall, 111 species were recorded consisting of 65.8% herbs, 24.3% trees, and 9.9% other types of life forms. About 70.9% of species were natives, 29.1% exotics, and 65% weeds. The high abundance of exotic species and weed species (some aggressive such as Leucaena leucocephala) of various life forms may negatively affect the restoration success in terms of seedling recruitment and diversity of native species, but may constitute a neutral or even positive accomplishment for erosion control (with species composition as a secondary effect). Results also reinforce the knowledge that choice of species for restoration must be in accordance with major local filters (e.g., floods), and areas within urban matrices may deserve special attention, including periodic management actions to control undesirable species.

Crown architecture and leaf anatomic traits influencing herbivory on Clethra scabra Pers.: comparing adaptation to wetlands and drained habitats

We tested the hypothesis that tree species adapted to ecotones between forest-swamps have leaf structures varying in response to land water saturation (drained and wetland), which could further influence their resistance against insect herbivory. The hypothesis was tested at the crown and leaf scale. We assessed differences in the plant architecture (height, circumference at breast height, trunk height, and crown) and leaf traits (sclerophylly and anatomy) of tree species inhabiting wetland and drained soils and investigated which variables explained variance in leaf herbivory rates. The study was conducted in Montane and wetland Forests in the Itacolomi State Park, in Southern Brazil, focusing on the Clethra scabra Pers., which inhabits both habitats, and also Myrcia amazonica DC. and Myrcia laruotteana Cambess (congeneric) which inhabit Montane forest and wetland forest, respectively. It was found that C. scabra individuals in wetland areas had simpler crown structure and higher leaf sclerophylly rates than those individuals of this species in the drained habitat. However, the two C. scabra populations did not differ regarding overall foliage thickness and damage by herbivory between drained and wetland habitats. Variables that were related to herbivory in this species were adaxial epidermis thickness and circumference at breast height. Myrcia individuals from wetland areas had less damaged leaves but thinner epidermis than in drained soils, but no variable correlated to herbivory at the leaf scale. Our hypothesis was partially corroborated and suggests that C. scabra is more influenced by soil saturation than Myrcia, and its herbivory is related with structural and anatomic parameters.

ASSESSMENT OF A 5-YEAR-OLD REHABILITATED RIPARIAN FOREST: IS IT ALREADY SUSTAINABLE?

As important as the establishment of projects of ecological restoration is its assessment post- implementation to know whether the area is becoming self-sustainable or need to be redirected. In this way, this study aimed to know the current situation of a 5-year-old rehabilitated riparian forest,inserted in an anthropogenic impacted region,at the das Velhas River, Minas Gerais State, studying the canopy openness and recruitment of seedlings as plant indicators. 15 plots were allocated in the forest, where hemispherical photographs were taken to analyze the canopy openness and evaluate all seedlings from 0.30 m to 1.30 m height.Canopy openness ranged from 23.7% to 38.8% between seasons and only 192 seedlings were found,from 13 species, five of them exotic and aggressive. Although canopy openness was low, it seems that lateral penetration of light has been favoring the development and dominancy of plants from invasive species, whereas few native ones have been recruited. The exotic/invasive plants may compromise the success of restoration mainly by competition with native planted species. The outcomes evidenced an unsustainability of the riparian forest and the requirement of some management actions to control exotic and invasive plants and ensure the preservation of the area and its ecological roles over time.