Resumo

GUARNASCHELLI, Ana B.; MANTESE, Anita I.  e  BATTAGLIA, Anabela. Anatomical and morphological changes in Eucalyptus sp. seedlings in response to different levels of light. Bol. Soc. Argent. Bot. [online]. 2009, vol.44, n.3-4, pp.273-285. ISSN 1851-2372.

Responses in the anatomy and morphology of Eucalyptus globulus subsp. globulus, Eucalyptus grandis and Eucalyptus camaldulensis seedlings, growing under different levels of light were evaluated. Seedlings were submitted to three levels of irradiance: full sun (C), 50% (S₅₀) and 75% of light restriction (S₇₅) and irrigated daily. Morphological and anatomical characteristics were measured; foliar coefficients and indexes of plasticity were calculated. As light availability diminished, plants showed changes associated with shade acclimation. Increases in leaf area and in leaf coefficients were observed. At the same time, decreases in the thickness of leaves, epidermis, palisade parenchyma, and in the stomatal density were detected. Leaf dry mass and total dry mass decreased under the level S₇₅. The increase in the level of light restriction produced proportional changes in leaf thickness and in leaf area ratio. Irrespective of the level of shade, some differences among the three species were observed, which could be associated with the environmental conditions of their native areas. Although some differences in the plasticity indexes were observed, average values for the three species were similar. This suggests that, for the characteristics considered in this study, the degree of shade acclimation was similar.

Palavras-chave : Eucalyptus; Shade; Acclimation; Plasticity; Morphology; Leaf anatomy.

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