Ecological wood anatomy and cambial activity of Roupala rhombifolia (Proteaceae) in Serra do Cipó (MG) / Anatomia ecológica do lenho e atividade cambial de Roupala rhombifolia (Proteaceae) na Serra do Cipó (MG)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The intensity of environmental variations is smaller on tropical than temperate regions. Therefore, tropical species were considered for years as evergrowing. In addition, environmental variations can exist in small and big scales and species should respond differently depending on each environmental stimulus. By these reasons, the aim of the study was to analyze the growth pattern of Roupala rhombifolia, considering phenology, cambial activity and anatomical wood features changes, concerning the micro-scale with edaphic differences emphasis. Phenological results showed that R. rhombifolia is an evergreen specie with periodical flushes, continuous leaf fall and not annual flowering, that weakly happened only in November 2007 after a fire event. The fruiting event was not seen during the observation period, except by the maintenance of fruits and seeds from previous fruiting period. Seasonal cambial activity was found positively associated with bud break and leaf expansion, which were related with water soil restoration after the first rain in June 2006, during seasonal drought end. Cambial activity decreased, reaching minimal values, between flush and expansion periods. Xylem and phloem differentiation were found all over the year, but seasonal phloem differentiation was not evaluated due to the absence of growth markers. In comparative wood anatomy the variance (ANOVA) and cluster analysis showed that the specimens of the areas compared had clear differences and were grouped in each physiognomy. The best distinctiveness was found in the field specimens, which had the lowest values for vessel area, vessel density, ray height, fiber length and conductive area percentage, and the highest values for vessel element length. Riparian forest specimens showed higher values compared to mountain top forest specimens, except by vessel density. Therefore, mountain top forest specimens had intermediated values. Most of those anatomical differences are associated with each physiognomy characteristics like water body distance and essentially physical and chemical soil differences. In conclusion, R. rhombifolia can respond to environmental stimulus presenting seasonal growth pattern, concerning rain and photoperiod, and anatomical wood changes, concerning edaphic differences.

ASSUNTO(S)

atividade cambial roupala rhombifolia anatomia ecológica ecological anatomy roupala rhombifolia cambial activity

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