Water deficit affects wood vessels of Croton floribundus Spreng. in different vegetation types, São Paulo State, Brazil

Abstract

-(Water defi cit affects wood vessels of Croton fl oribundus Spreng. in different vegetation types, São Paulo State, Brazil). In this paper we showed that water defi cit affects the wood vessels of Croton fl oribundus in fi ve areas with different vegetation types: Rain Forest, Semi-deciduous Forest and Woody Savanna. We concluded that variations in the vessels are due especially to water defi cit and the number of months with water defi cit. Larger diameter vessels occurred in areas with higher water defi cit, which may represent a strategy to optimize the water transport in favorable periods. Vessels with smaller diameters occur in areas with lower defi cit, which may be related to lower minimum temperatures and frost occurrence, which like drought can cause vessel embolism. In Caetetus Ecological Station, a Semi-deciduous Forest (area of highest water defi cit), we observed investments in effi ciency and safety, with the occurrence of larger diameter vessels associated with one of the lowest vulnerability indexes and highest proportions of multiple vessels of four or more elements. Key words: Ecological anatomy, mesomorphy, vulnerability, water availability RESUMO -(Défi cit hídrico interfere nos vasos do lenho de Croton fl oribundus Spreng. em diferentes tipos de vegetação, SP, Brasil). O défi cit hídrico infl uenciou na formação dos vasos da madeira de Croton fl oribundus ocorrentes em cinco áreas com as seguintes vegetações: Floresta Ombrófi la, Floresta Estacional Semidecidual e Cerradão. As variações dos vasos devem-se especialmente ao défi cit hídrico e número de meses com défi cit hídrico. Vasos de maior diâmetro ocorreram em áreas com maior défi cit hídrico, o que pode indicar uma estratégia para otimizar o transporte de água em épocas favoráveis. Vasos com menores diâmetros ocorreram em áreas com menor défi cit hídrico, possivelmente infl uenciados pelas menores temperaturas mínimas e a ocorrência de geadas, que semelhante a seca, causa a embolia dos vasos. Na Estação Ecológica de Caetetus, Floresta Estacional Semidecidual (área com maior défi cit de água) observaram-se investimentos em efi ciência e segurança, com a ocorrência de vasos de maior diâmetro associados a um dos menores índices de vulnerabilidade e maior proporção de vasos múltiplos de quatro ou mais elementos. Palavras-chave: Anatomia ecológica, disponibilidade hídrica, mesomorfi a, vulnerabilidade

WOOD AXIAL CHARACTERIZATION OF 32-YEAR-OLD Croton piptocalyx Müll. Arg. EUPHORBIACEAE

“…Thus, comparisons are made with other species of the genus. Using that basis of comparison, the wood anatomy of Croton piptocalyx generally agrees with that of other species of the genus such as described in the literature, including Croton urucurana (Luchi, 2004), some other 159 species of the genus (Wiedenhoeft, 2008) and Croton floribundus (Longui et al, 2012). However, as a result of tree age and species differences, the quantitative data do vary.…”

“…The wood of some species of this genus have already been studied (Luchi, 2004;Wiedenhoeft, 2008;Wiedenhoeft et al, 2009;Longui et al, 2012;Novello et al, 2012;Siegloch et al, 2012). However, no studies in the literature have reported on C. piptocalyx wood.…”