title: Salt tolerance during germination and seedling growth of wild wheat Aegilops tauschii and its impact on the species range expansion.
abstract: Adaptation to edaphic stress may have a key role in plant species range expansion. Aegilops tauschii Coss., the common wheat's D-genome progenitor native to the Transcaucasus-Middle East region, is a good model to study the relationships between soil salinity and plant distributions: one of its intraspecific sublineages, TauL1b, drove the long-distance eastward expansion of this species range reaching semi-arid-central Asia. Salt tolerance during germination and seedling growth was evaluated in 206 Ae. tauschii accessions by treating seeds with NaCl solutions differing in concentrations. Differences in natural variation patterns were analyzed between sublineages and associated with natural edaphic condition variables, and then compared with reproductive trait variation patterns. The natural variations observed in NaCl-induced-stress tolerance had clear geographic and genetic structure. Seedling growth significantly increased in the TauL1b accessions that were collected from salt-affected soil habitats, whereas germinability did not. Principal component analysis suggested that the NaCl-induced-stress tolerances and reproductive traits might have had a similar degree of influence on Ae. tauschii's eastward range expansion. Adaptation to salt-affected soils through increased seedling growth was an important factor for the species' successful colonization of the semi-arid central Asian habitats. TauL1b accessions might provide useful genetic resources for salt-tolerant wheat breeds.
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Saisho
authors.affiliation: Laboratory of Plant Genetics, Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Takumi
authors.affiliation: Fukui Prefectural University, Matsuoka, Eiheiji, Yoshida, Fukui 910-1195, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsuoka
mesh_terms: D017753:Ecosystem; D060146:Ecotype; D014644:Genetic Variation; D005843:Geography; D018525:Germination / Q000187:drug effects / Q000502:physiology*; D058507:Host Specificity; D010641:Phenotype; D006109:Poaceae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D025341:Principal Component Analysis; D012098:Reproduction / Q000187:drug effects; D055049:Salt Tolerance / Q000187:drug effects / Q000502:physiology*; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development*; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D012965:Sodium Chloride