title: Sodium instead of potassium and chloride is an important macronutrient to improve leaf succulence and shoot development for halophyte Sesuvium portulacastrum.
abstract: Soil salinity is contributed largely by NaCl but some halophytes such as Sesuvium portulacastrum have evolved to adapt salinity environment and demonstrate optimal development under moderate salinity. To elucidate the detail mechanisms of the great salt tolerance and determine the respective contributions of Na(+), K(+) and Cl(-) on the development of S. portulacastrum, morphological and physiological analysis were performed using plants supplied with 200 mM of different ions including cations (Na(+), K(+), Li(+)) and anions (Cl(-), NO(3)(-), Ac(-)) respectively. The results revealed that the salt-treated plants accumulated large amounts of sodium in both leaf and stem. There was a greater shoot growth in presence of external Na(+) compared to K(+) and Cl(-). Na(+) was found more effective than K(+) and Cl(-) in cell expansion, leaf succulence, and shoot development. Flame emission and X-Ray microanalysis revealed the relative Na(+) content was much higher than K(+) and Cl(-) in both leaf and stem of well developed S. portulacastrum, leading to a higher Na(+)/K(+) ratio. The effects of different ions on the development of S. portulacastrum were listed as the following: Na(+) > NO(3)(-) > CK > Cl(-) > K(+) > Ac(-) > Li(+). These results demonstrated NaCl toxicity is attributable largely to the effect of Cl(-) but rarely to Na(+), and thus sodium is concluded as a more important macronutrient than potassium and chloride for improving leaf succulence and shoot development of halophyte S. portulacastrum.
authors.affiliation: Institute of Tropical Biosciences and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China.
authors.forename: Dongyang
authors.initials: D
authors.lastname: Wang
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Bing
authors.initials: B
authors.lastname: Han
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Anping
authors.initials: A
authors.lastname: Guo
authors.forename: Dong
authors.initials: D
authors.lastname: Zheng
authors.forename: Chongjing
authors.initials: C
authors.lastname: Liu
authors.forename: Lili
authors.initials: L
authors.lastname: Chang
authors.forename: Ming
authors.initials: M
authors.lastname: Peng
authors.forename: Xuchu
authors.initials: X
authors.lastname: Wang
mesh_terms: D035722:Aizoaceae / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D002712:Chlorides / Q000378:metabolism*; D004577:Electron Probe Microanalysis; D007477:Ions / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D018520:Plant Shoots / Q000187:drug effects / Q000502:physiology*; D018547:Plant Stems / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D011188:Potassium / Q000378:metabolism*; D055051:Salt-Tolerant Plants / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology; D014867:Water / Q000378:metabolism
chemical_list: D002712:Chlorides; D007477:Ions; D014867:Water; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium