盐胁迫下不同K^+吸收抑制剂对小麦根系K^+/Na^+比和质膜相关蛋白活性的影响

Effects of K^+ Absorption Inhibitors on K^+/Na^+ Ratios and Activities of Plasma Membrane Proteins under Salt Stress in Triticum aestivum L.

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。

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（NO_3）_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（NO_3）_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.