title: Genotypic difference in salinity tolerance in quinoa is determined by differential control of xylem Na(+) loading and stomatal density.
abstract: Quinoa is regarded as a highly salt tolerant halophyte crop, of great potential for cultivation on saline areas around the world. Fourteen quinoa genotypes of different geographical origin, differing in salinity tolerance, were grown under greenhouse conditions. Salinity treatment started on 10 day old seedlings. Six weeks after the treatment commenced, leaf sap Na and K content and osmolality, stomatal density, chlorophyll fluorescence characteristics, and xylem sap Na and K composition were measured. Responses to salinity differed greatly among the varieties. All cultivars had substantially increased K(+) concentrations in the leaf sap, but the most tolerant cultivars had lower xylem Na(+) content at the time of sampling. Most tolerant cultivars had lowest leaf sap osmolality. All varieties reduced stomata density when grown under saline conditions. All varieties clustered into two groups (includers and excluders) depending on their strategy of handling Na(+) under saline conditions. Under control (non-saline) conditions, a strong positive correlation was observed between salinity tolerance and plants ability to accumulate Na(+) in the shoot. Increased leaf sap K(+), controlled Na(+) loading to the xylem, and reduced stomata density are important physiological traits contributing to genotypic differences in salinity tolerance in quinoa, a halophyte species from Chenopodium family.
authors.affiliation: School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart, Tas 7001, Australia. Sergey.Shabala@utas.edu.au
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
authors.forename: Yuda
authors.initials: Y
authors.lastname: Hariadi
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Jacobsen
mesh_terms: D027465:Chenopodium quinoa / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D002734:Chlorophyll / Q000378:metabolism; D017753:Ecosystem; D005453:Fluorescence; D005838:Genotype; D017440:Photoperiod; D054046:Plant Stomata / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics*; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D052584:Xylem / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002734:Chlorophyll; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium