摘要
The present study aimed to determine the mechanism of cation-selective secretion by multicellular salt glands.Using a hydroponic culture system,the secretion and accumulation of Na+ and K+ in Tamarix ramosissima and T.laxa under different salt stresses (NaCl,KCl and NaCl+KCl) were studied.Additionally,the effects of salt gland inhibitors (orthovanadate,Ba2+,ouabain,tetraethylammonium (TEA) and verapamil) on Na+ and K+ secretion and accumulation were examined.Treatment with NaCl (at 0-200 mmol L 1 levels) significantly increased Na+ secretion,whereas KCl treatment (at 0-200 mmol L 1 levels) significantly increased K+ secretion.The ratio of secretion to accumulation of Na+ was higher than that of K+.The changes in Na+ and K+ secretion differed after adding different ions into the single-salt solutions.Addition of NaCl to the KCl solution (at 100 mmol L 1 level,respectively) led to a significant decrease in K+ secretion rate,whereas addition of KCl to the NaCl solution (at 100 mmol L 1 level,respectively) had little impact on the Na+ secretion rate.These results indicated that Na+ secretion in Tamarix was highly selective.In addition,Na+ secretion was significantly inhibited by orthovanadate,ouabain,TEA and verapamil,and K+ secretion was significantly inhibited by ouabain,TEA and verapamil.The different impacts of orthovanadate on Na+ and K+ secretion might be the primary cause for the different Na+ and K+ secretion abilities of multicellular salt glands in Tamarix.
The present study aimed to determine the mechanism of cation-selective secretion by multicellular salt glands.Using a hydroponic culture system,the secretion and accumulation of Na^＋ and K^＋ in Tamarix ramosissima and T.laxa under different salt stresses （NaCl,KCl and NaCl^＋KCl） were studied.Additionally,the effects of salt gland inhibitors （orthovanadate,Ba^2＋,ouabain,tetraethylammonium （TEA） and verapamil） on Na^＋ and K^＋ secretion and accumulation were examined.Treatment with NaCl （at 0-200 mmol L 1 levels） significantly increased Na^＋ secretion,whereas KCl treatment （at 0-200 mmol L 1 levels） significantly increased K^＋ secretion.The ratio of secretion to accumulation of Na＋ was higher than that of K^＋.The changes in Na^＋ and K^＋ secretion differed after adding different ions into the single-salt solutions.Addition of NaCl to the KCl solution （at 100 mmol L 1 level,respectively） led to a significant decrease in K＋ secretion rate,whereas addition of KCl to the NaCl solution （at 100 mmol L 1 level,respectively） had little impact on the Na^＋ secretion rate.These results indicated that Na^＋ secretion in Tamarix was highly selective.In addition,Na^＋ secretion was significantly inhibited by orthovanadate,ouabain,TEA and verapamil,and K^＋ secretion was significantly inhibited by ouabain,TEA and verapamil.The different impacts of orthovanadate on Na^＋ and K^＋ secretion might be the primary cause for the different Na^＋ and K^＋ secretion abilities of multicellular salt glands in Tamarix.
基金
supported by the Special Fund for Public Welfare Industrial(Agriculture) Research of China(Grant No. 200903001)
Chinese Academy of Sciences Innovation Base Project for Agriculture(Grant No. KSCX1-YW-09-10),the Chinese Academy of Sciences Agricultural Projects (Grant No. KSCX2-YW-N-41)
