Morphological and anatomical traits of halophytes: Adaptative versus phylogenetic value

Abstract

The halophytes are plant species that have particular morpho-anatomical characteristics that allow them to complete their biological cycles in an environment that has very stringent conditions. In general, in these species, morpho-anatomical adaptations, or morpho-anatomical functional traits, are related to preventing the loss of water by evapotranspiration, with the dilution of salts absorbed in excess and, in some cases, with the excretion of salts. These characters are mostly foundin leaves and stems, since they are the plant organs that are most rigorously exposed to environmental conditions. Specifically among the most important characters are reduced leaves or their absence, large number of eglandular and/or glandular trichomes, presence of salt glands, greater development of support tissues, presence of aqueous tissue, and development of atypical secondary growth, among others. Beyond these generalizations, it should be taken into account that there are not morpho-anatomical characters that define all the halophytes; each species has achieved adaptation to the environment from thecharacteristics that developed within the evolutionary lineage to which it belongs.