title: The coordinated regulation of Na+and K+in Hordeum brevisubulatum responding to time of salt stress.
abstract: Hordeum brevisubulatum, called as wild barley, is a useful monocotyledonous halophyte for soil improvement in northern China. Although previously studied, its main salt tolerance mechanism remained controversial. The current work showed that shoot Na+concentration was increased rapidly with stress time and significantly higher than in wheat during 0-168h of 100mM NaCl treatment. Similar results were also found under 25 and 50mM NaCl treatments. Even K+was increased from 0.01 to 50mM in the cultural solution, no significant effect was found on tissue Na+concentrations. Interestingly, shoot growth was improved, and stronger root activity was maintained in H. brevisubulatum compared with wheat after 7days treatment of 100mM NaCl. To investigate the long-term stress impact on tissue Na+, 100mM NaCl was prolonged to 60 days. The maximum values of Na+concentrations were observed at 7th in shoot and 14th day in roots, respectively, and then decreased gradually. Micro-electrode ion flux estimation was used and it was found that increasing Na+efflux while maintaining K+influx were the major strategies to reduce the Na+concentration during long-term salt stress. Moreover, leaf Na+secretions showed little contribution to the tissue Na+decrease. Thereby, the physiological mechanism for H. brevisubulatum to survive from long-term salt stress was proposed that rapid Na+accumulation occurred in the shoot to respond the initial salt shock, then Na+efflux was triggered and K+influx was activated to maintain a stable K+/Na+ratio in tissues.
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China.
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystem, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, People's Republic of China.
authors.forename: Zeng-Run
authors.initials: ZR
authors.lastname: Xia
authors.affiliation: School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, People's Republic of China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Wu
authors.affiliation: School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, People's Republic of China.
authors.forename: Hui-Jun
authors.initials: HJ
authors.lastname: Yuan
authors.affiliation: College of Animal Science, South China Agricultural University, Guangzhou 510642, People's Republic of China.
authors.forename: Xin-Rui
authors.initials: XR
authors.lastname: Wang
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China.
authors.forename: Jin-Hua
authors.initials: JH
authors.lastname: Li
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China.
authors.forename: Fu-Ping
authors.initials: FP
authors.lastname: Tian
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China.
authors.forename: Xin-Qiang
authors.initials: XQ
authors.lastname: Zhu
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China.
authors.forename: Jiong-Jie
authors.initials: JJ
authors.lastname: He
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystem, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, People's Republic of China.
authors.forename: Tanweer
authors.initials: T
authors.lastname: Kumar
authors.affiliation: Lanzhou Institute of Husbandry and Pharmaceutical Science, Chinese Academy of Agricultural Sciences, Lanzhou 730050, People's Republic of China. Electronic address: 13609381223@139.com.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Grassland Agro-ecosystem, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, People's Republic of China. Electronic address: jlzhang@lzu.edu.cn.
authors.forename: Jin-Lin
authors.initials: JL
authors.lastname: Zhang
mesh_terms: D001467:Hordeum / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D011188:Potassium / Q000737:chemistry / Q000378:metabolism*; D055049:Salt Tolerance; D012964:Sodium / Q000737:chemistry / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium
keywords: Coordinated ion regulation; K(+) influx; Na(+) efflux; Na(+) secretion; Rapid Na(+) accumulation