Morpho-anatomical plasticity of Stylosanthes viscosa (Fabaceae) in response to different soil and light conditions of Restinga environments

摘要

Structural plasticity is an important ability of plants to acclimate to different environmental conditions, especially in limiting environments such as restingas. The objective of this study was to evaluate the morpho-anatomical plasticity of Stylosanthes viscosa (L.) Sw. (Fabaceae) populations based on the hypothesis that edaphic and luminous factors cause different structural adjustments, such that, in the restinga , herbaceous plants would be more xeromorphic than shrub-tree plants. The study area included formations of herbaceous and shrub-arboreal restinga of Acaraí State Park, located in S?o Francisco do Sul, Santa Catarina, Brazil. Morpho-anatomical attributes of 10 individuals per formation were compared with the t-test. Principal components analysis was used to evaluate the influence of environmental factors on S. viscosa (L.) Sw. populations. In both formations, organic matter content had the greatest influence on adjustments exhibited by the species, with greater emphasis on plant height, stem diameter, fresh mass, dry mass, leaf area and specific leaf area. Morphological attributes exhibited greater plasticity than anatomical attributes. The population of the herbaceous restinga was observed to be more xeromorphic, exhibiting greater investment in mechanical tissues, as opposed to the shrub-arboreal restinga population, which exhibited greater investment in photosynthetic tissues. The results demonstrate the strong influence that soil and light have on the morpho-anatomical plasticity of S. viscosa (L.) Sw. in restinga environments.