Gelatinous fibretracheids as an escape mechanism for the physiological drought phenomenon

Abstract

Abstract Alchornea sidifolia is a tree species used in the regeneration of degraded forest environments and which grows in both non-flooded and flooded soils. We compared the wood anatomy of trees growing under both conditions in Atlantic Forest remnants in the state of Rio de Janeiro, Brazil, to understand intraspecific aspects of the adaptation of tropical woody species to these conditions. Trees from permanently flooded soils showed wider, shorter, and less frequent vessel elements; wider fibretracheids, with a greater proportion of the gelatinous type; and a lower frequency of radial parenchyma, but with longer strands of axial parenchyma. These results indicate that A. sidifolia trees growing in permanently flooded sites do not show water deficit and that the species is capable of maximizing water use in this growth condition. This conclusion may be directly related to the greater proportion of gelatinous fibretracheids in flooded trees and is contrary to what was expected for wood anatomy of trees under physiological drought.