cGMP和Ca^2+通过提升PM H^+-ATPase活性降低Na^+/K^+比维持苔草愈伤组织离子稳态  

cGMP and Ca^2+maintain ion homeostasis by enhancing PM H^+-ATPase activity and reducing Na^+/K^+ratio in salt-stressed calluses of Carex moorcroftii

作　　者：贾红磊 马佩云 JIA Hong-lei;MA Pei-yun(School of Environmental Science and Engineering,Shaanxi University of Science&Technology,Xi′an 710021,China)

机构地区：[1]陕西科技大学环境科学与工程学院,陕西西安710021

出　　处：《陕西科技大学学报》2020年第6期54-59,74,共7页Journal of Shaanxi University of Science & Technology

基　　金：国家自然科学基金项目(31700445)。

摘　　要：两种生态型苔草Carex morcroftii(C.moorcroftii)植物沙生型(DC)和水生型(SC)的愈伤组织对盐度具有不同的敏感性.本研究对这两种生态类型苔草愈伤组织进行盐胁迫处理.在100 mM NaCl处理下,Na^+百分比显著增加而K^+百分比降低,导致SC愈伤组织Na^+/K^+比值急剧增加,但DC中Na^+/K^+比值与对照相比无显著性差异.8-Br-cGMP(cGMP的一种类似物)以浓度依赖性的方式影响DC和SC的元素比值.6-苯胺-5,8-喹啉二酮(Ly83583,cGMP抑制剂)可降低内源性cGMP的浓度,通过降低K+百分比、增加Na+百分比和Na^+/K^+比来消除8-Br-cGMP的作用.DC愈伤组织中,Ly83583能够降低由于NaCl导致的PM H^+-ATPase活性的增加.然而,乙二醇-双-(2-氨基乙基醚)四乙酸(EGTA,Ca^2+螯合剂)不能改变cGMP的内源性浓度.以上结果表明,Ca^2+作为cGMP的下游信号通过降低Na^+/K^+比率和提升PM H^+-ATPase活性增强苔草愈伤组织的耐盐性.Calluses from two ecotypes of Carex moorcroftii plant(dune C.moorcroftii[DC]and swamp C.moorcroftii[SC])display different sensitivity to salinity.Salt stress treatment of these two ecological types of plants in this study.Under 100 mM NaCl treatment Na^+percentage significantly increased and K+percentage decreased leading to a sharp increase in Na^+/K^+ratio in the SC calluses but Na^+/K^+ratio showed no significant difference in the DC calluses compared to the control.Application of 8-Br-cGMP(an analog of cGMP)revealed that cGMP affected element ratios in both DC and SC calluses in a concentration-dependent manner.6-Anilino-5,8-quinolinedione(Ly83583 a guanylate cyclase inhibitor)could decrease the concentration of endogenous cGMP which counteracted the effect of 8-Br-cGMP by decreasing K^+percentage increasing Na^+percentage and Na^+/K^+ratio.The increased activity of plasma membrane(PM)H^+-ATPase caused by NaCl treatment in the DC callus was reversed by treatment with Ly83583.However Glycol-bis-(2-amino ethyl ether)-N′,N′,N′,N′-tetraacetic acid(EGTA,a Ca^2+chelator)could not change endogenous concentration of cGMP.These results indicate that Ca^2+as a downstream signal of cGMP enhances salt resistance by decreasing the Na^+/K^+ratio and increasing PM H^+-ATPase activity in C.moorcroftii calluses.

关 键 词：CGMP Carex morcroftii 离子稳态 PM H+-ATPase活性 盐胁迫 

分 类 号：X173[环境科学与工程—环境科学]