Morpho-anatomical traits of halophytic species.

Abstract Some aspects of plant tolerance to salt stress are based on morphological and anatomical traits. Halophytes with different preferences for increased salinity conditions show differences in anatomical features, as a consequence of evolving adaptive responses to salt stress. In this chapter we discuss the general morphological and anatomical structure of plants of saline habitats, aiming to provide a detailed review of literature on typical and special morphological and anatomical characteristics of halophytes. Species in the group most tolerant to saline conditions develop two main strategies for avoiding the toxic effect of salt uptake: dilution of salts by increasing leaf or stem succulence (such as Cakile maritima, Salsola soda, Suaeda maritima, Salicornia fruticosa); and/or or by excreting excess salts from specialized secretory structures such as bladders and salt glands (e.g. Halimione portulacoides, Limonium gmelinii). In addition to succulent and salt-excreting halophytes, other species exhibit various xeromorphic characteristics, similar to plants of drought conditions (thick epidermis covered with cuticle and wax, abundant trichomes, small leaves, presence of bulliform cells, etc.). The latter species have usually developed various salt-exclusion adaptive mechanisms, and are a common flora of saline steppe in Europe (Puccinellia distans, Camphorosma annua, Artemisia santonicum, etc.).