São Paulo, diferem quanto à estrutura foliar, de exemplares encontrados em área rural, isenta de poluentes aéreos urbanos. Foram avaliadas, comparativamente, as dimensões da folha e, em microscopia de luz, a espessura dos tecidos foliares, a densidade de estômatos e de cristais da espécie, coletada em área rural e em dois pontos da cidade de São Paulo: canteiro central da Avenida dos Bandeirantes, com tráfego veicular intenso, portanto com alta carga de poluentes primários, e no Parque Estadual das Fontes do Ipiranga (PEFI) submetido a altas concentrações de poluentes secundários. Buscaram-se variações que possam ser decorrentes da poluição urbana. As folhas coletadas no meio urbano mostraram menores dimensões, menor espessura do mesofilo, maior densidade estomática e maior quantidade de cristais. A espessura do parênquima lacunoso sofreu redução, quando se comparam as plantas do ambiente rural e urbano; observou-se a menor espessura nas folhas submetidas a poluentes secundários. Não foram observadas variações qualitativas entre as folhas dos três locais avaliados. Considerando que folhas coletadas no meio urbano variaram menos entre si, quando comparadas àquelas de área rural, acredita-se que a poluição aérea da cidade possa ser responsável, pelo menos em parte, pelas variações observadas. Exposições padronizadas, em ambiente monitorado, devem ser realizadas para comprovar tal hipótese.Palavras-chave: anatomia foliar, Eugenia uniflora, poluição aérea, ambiente urbano, pitanga ABSTRACT -(Leaf anatomy of Eugenia uniflora L. (Myrtaceae) in urban and rural environments, São Paulo State, Brazil). The aim of this study was to compare leaves of Eugenia uniflora from the city of São Paulo with leaves of plants from a rural site. Leaf size, tissue thickness, and stomatal and crystal density of E. uniflora growing at two sites in the city of São Paulo were investigated by light microscopy and compared with samples from a rural area. The level and types of air pollutants varied at the urban sites. Primary pollutants were present on Bandeirantes Avenue and secondary ones in the park (Parque Estadual das Fontes do Ipiranga -PEFI). Urban leaves were smaller, thinner and with higher stomatal and crystal density. We observed greater spongy parenchyma thickness in leaves from the avenue when compared to those from the park. No qualitative differences were observed between urban and rural leaves. Leaves from the two urban sites showed similarities, but were different from rural leaves, so we believe that the differences observed may be attributed to the polluted environment of São Paulo. In order to confirm this hypothesis, control experiments should be done.Key words: leaf anatomy, Eugenia uniflora, air pollution, urban environment, "pitanga" IntroduçãoAs plantas que vivem no meio urbano, numa grande metrópole como São Paulo, sofrem os efeitos da poluição do ar oriunda, principalmente, da grande frota automotiva, que produz uma carga elevada de poluentes gasosos e particulados (CETESB 2004). A observação de troncos de árvores q...

The anatomy and the physical, mechanical, acoustical and chemical properties of pernambuco wood (Caesalpinia echinata Lam.) were investigated to determine factors that could explain the different quality of sticks used in bow manufacture. Eighteen sticks were classified into four classes (A to D with A being the best) according to their potential quality for bow manufacture. Selection of samples was based on the experience of a bow maker and on some nondestructive tests. The A-class sticks had a lower frequency of vessels and rays and a higher percentage of fibers when compared to the other classes. They also had higher values of density, speed of sound propagation, modulus of elasticity and modulus of rupture. Klason lignin content was higher in the A-class sticks but the quantity of hydrosoluble and ethanol/benzene soluble extractives was lower. The values of density and speed of sound propagation obtained by nondestructive and destructive methods were similar showing the applicability of the former in the prior selection process of the sticks.

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Caesalpinia echinata Lam. (pau-brasil) is a Brazilian tree with symbolic character for Brazilian forestry, which is at risk of extinction because of illegal logging activities and exportation as raw material for bows of string instruments. Additional studies are required to select substitutes for pau-brasil, i.e., other wood species are being sought with potentially suitable characteristics for bow manufacture. The present paper is dedicated to the evaluation of six native Brazilian woods by comparing their anatomical features, specific gravity, speed of sound propagation, and dynamic modulus of elasticity in relation to the corresponding properties of C. echinata that are considered as standard for bow manufacture. The results showed that length, diameter, lumen diameter, and wall thickness of fibers are the most important variables contributing to specific gravity. Additionally, ray dimensions influenced sonic velocity. The values of dynamic modulus of elasticity are directly related to dimensions of rays and fibers. Among the six woods included in this study, Dipteryx spp., Handroanthus spp., and Hymenaea spp. were considered as the best alternatives to C. echinata wood as sources of bow construction. The bows from the first two woods were already tested by professional musicians and their suitability was certified. The Diplotropis spp. wood also showed promising characteristics. Mezilaurus itauba and Astronium lecointei do not have the necessary properties for bows.

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