摘要： 为了研究不同K⁺吸收途径在小麦耐盐机理中的作用，以小麦耐盐品种沧6005（C6005）和敏感品种矮抗58（AK58）为材料，通过K⁺吸收相关抑制剂和NaCl对幼苗进行根系处理，测定并分析了根系K⁺、Na⁺含量、比值和质膜K⁺转运相关蛋白活性的变化。结果表明：与正常条件生长小麦相比，250 mmol/L NaCl处理7 d后，2种耐盐性不同的小麦根系中的K⁺/Na⁺比明显降低，同时与敏感品种相比，耐盐品种能保持较高的K⁺/Na⁺比；NaCl胁迫下，通过3种抑制剂处理对K⁺含量及K⁺/Na⁺比值的影响发现，与钾离子通道和非选择性阳离子通道途径相比，小麦根系K⁺吸收主要通过钾载体途径；当该途径被抑制时，沧6005的K⁺/Na⁺比下降幅度明显高于矮抗58，表明耐盐品种更依赖该途径；NaCl胁迫下，钾载体途径被抑制时，小麦根系质膜质子泵H⁺-ATPase和H⁺-PPase活性明显降低，且沧6005降低幅度相对更大；NaCl胁迫下，钾载体抑制剂处理，对沧6005质膜K⁺/H⁺转运蛋白的抑制作用明显强于矮抗58，进一步证明上述结果。研究表明，盐胁迫下小麦主要通过钾载体途径吸收K⁺，耐盐品种沧6005对钾转运载体的依赖程度更高；高NaCl环境中，细胞质膜质子泵活性和钾载体活性的提高对于维持K⁺/Na⁺比具有重要作用。为深入解析小麦耐盐机理提供了理论依据。

关键词: 小麦, 盐胁迫, K⁺/Na⁺比, 质膜蛋白, K⁺抑制剂

Abstract: In order to examine the effects of different K⁺ uptake pathways on the mechanism of salt-tolerance of wheat. Winter wheat cultivars salt-tolerant C6005 and salt-sensitive AK58 were used to investigate the contents of K⁺ and Na⁺and K⁺/Na⁺ ratios and plasma membrane proteins activities under NaCl stress and co-treatments with TEA (Tetraethylammonium chloride,K⁺passway inhibitor),NEM (N-Ethylmaleimide,transporter inhibitor) and Ba (NO₃)₂(NSCCs inhibitor)respectively in the study.The major results were as follows:250 mmol/L NaCl treatment for 7 days significantly (P <0.05) decreased the K⁺/Na⁺ ratios of root both salt-tolerant and sensitive cultivars compared with their controls,and C6005 could retain higher K⁺/Na⁺ ratios than AK58 under NaCl stress. Comparatively,NEM had greater inhibition on both K⁺ contents and K⁺/Na⁺ ratios than TEA and Ba(NO₃)₂ in both salt-tolerant and sensitive cultivars. Under NaCl stress,when K⁺ transporters were inhibited,K⁺/Na⁺ ratios of C6005 were decreased more obviously than that of AK58,the activities of plasma membrane H⁺-ATPase and H⁺-PPase in both cultivars were decreased,and the change extend was larger in C6005. Meanwhile,the activities of K⁺/H⁺ transporters in C6005 were inhibited more violently than that in AK58 when pretreated with NEM under stress. The results suggested that K⁺ transporters were the primary approach for K⁺ absorption under salt stress in wheat,especially in salt-tolerant cultivar,and the energy mainly came from H⁺-ATPase and H⁺-PPase of proton pump of plasma membranes under salt stress. This work will provide theoretical basis for further analyzing the mechanism of salt-tolerance of wheat.

Key words: Wheat, Salt stress, K⁺/Na⁺, Plasma membrane proteins, K⁺ absorption

中图分类号: 

• S512.01