anatomia do lenho e dendrocronologia de lianas da família ...

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ever present in all samples from each species and in all growth rings from each sample. The
macroscopic observation provides the distinction by the same features of microscopic
observation; with exception of radially flattened latewood cells that is only possible to detect
in microscopic view. Generally, the macroscopic view facilitates the detection of growth rings
boundaries because of a broad field view.
The features that distinguish the growth ring boundaries observed in this study are frequently
associated to a great number of the tropical tree species (Boninsegna et al. 1989; Détienne,
1989; Worbes, 1989; Heinrich et al., 2006; Marcati et al., 2006), and may be viewed in
several combinations within Leguminosae family, e.g.: marginal parenchyma bands
(Boninsegna et al., 1989; Détienne, 1989; Worbes, 1989; Gourlay, 1995a, 1995b; Eshete &
Stahl, 1999; Roig et al., 2005); radially flattened and thick-walled latewood fibres (Barros &
Callado, 1997; Barros et al., 2001); marginal parenchyma bands and thick-walled fibres in the
latewood (Callado et al., 2001a); marginal parenchyma, radially flattened and thick-walled
latewood fibres (Vetter & Botosso, 1989, Tomazello Filho et al., 2004); marginal parenchyma
bands, and pattern of concurring parenchyma and fibre tissue (fibrous zone) (Worbes, 2002),
change in vessel diameter and marginal parenchyma (Villalba & Boninsegna, 1989; Richter &
Dallwitz, 2000)
Wood anatomy studies related to Leguminosae systematic show that many species present
diffuse porosity and only few species have ring-porous or semi-ring-porous (Wheeler & Baas,
1992; Gasson, 1994, 2000; Höhn, 1999). Some African Caesalpinioideae and Mimosoideae
species when grouped by wood anatomy produce eighteen groups all having diffuse porous,
among them, seven show distinct growth rings and have marginal parenchyma (Höhn, 1999).
The occurrence of mainly diffuse porous was not verified in this study, which one half of
species shows diffuse porosity and other half shows semi-ring-porous.
Studies with African Acacia species show that they have growth rings distinguished mainly
by marginal parenchyma, many times represent one year (Gourlay, 1995a, 1995b; Eshete &
Stahl, 1999) and abundant prismatic crystals of calcium oxalate are related to marginal
parenchyma (Gourlay, 1995a, 1995b). In present study S. tenuifolia and the other three
species with distinct growth rings have abundant calcium oxalate prismatic crystals related to
marginal parenchyma. The others Senegalia species with growth rings of sporadic occurrence
also show calcium oxalate prismatic crystals related to marginal parenchyma in distinct
boundaries. The Senegalia species in the present study before belonged to Acacia genus.
Recently the New World taxa from Acacia subgenus Aculeiferum Vassal were relocated to
Senegalia genus (Seigler et al., 2006).