Abstract

FIGUEROA, María E et al. Ecological wood anatomy of Allenrolfea vaginata (Griseb.) Kuntze (Chenopodiaceae) in saline environments in Santiago del Estero. Ecol. austral [online]. 2011, vol.21, n.3, pp.339-352. ISSN 1667-782X.

This paper aimed to analyze the variability of wood anatomical features of Allenrolfea vaginata (Griseb.) Kuntze (Chenopodiaceae) under different salinity conditions in three vegetation types. Wood samples from 15 individuals in total were collected from three different sites, namely halophyte vegetation and Haplic Epi Hypersalic Fluvisol (Endohyposodic, Siltic) soil over a low brine (site I), xerophytic shrub vegetation and Haplic Endo Hypersalic Fluvisol (Siltic) soil over a paleoplain (site II), and tree xerophyte vegetation and Haplic Endo Hypersalic Solonchak (Endohyposodic, Siltic) soil over a dorsal (site III). The quantitative parameters compared among individuals were: vessel diameter, vessel element length, and vessel frequency, ray height, fiber-tracheid diameter and length. Soil samples were taken from each site for their characterization. Wood anatomy of A. vaginata shows xeromorphic features that allow for its adaptation to water stress which is worsened because of the high soil salinity. The variables with significative differences were: diameter and length of vessel element, fiber-tracheid diameter, and ray height. The main anatomical variables of conduction (i.e., vessel elements diameter and length) help more in explaining the total variability among sites being those with major ecological significance. Thus the individuals under study showed differences in their conducting capacity as a response to the variability in soil water availability of the sites given by the electric conductivity and the hypersaline horizon depth realized in the different types of vegetation. The smaller and shorter vessels of the halophyte vegetation with higher soil electric conductivity and less soil water availability provide higher security for water conduction than those bigger and longer of the xerophytic shrub vegetation with lower electric conductivity. This eco-anatomical study allowed for the completion of an exploratory analysis on the behavior of a set of quantitative anatomical variables and contributes to the understanding of the wood anatomical-structural mechanisms of a halophyte from the Semiarid Chaco assuring its survival under different soil salinity conditions.

Keywords : Anatomy; Xylem; Adaptation; Salinity.

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