盐胁迫下宁夏枸杞根系Na+、K+平衡及抑制剂对其影响的研究

摘要

以宁夏枸杞为试验材料,利用非损伤微测技术及原子吸收分光光度法,研究NaCl胁迫下枸杞根系中Na+、K+吸收转运及质膜Na+/H+逆向转运蛋白抑制剂阿米洛利和质膜H+-ATPase抑制剂矾酸钠对宁夏枸杞根系离子平衡的影响.结果表明:随着NaCl胁迫浓度的增加,枸杞根系中Na+含量总体升高,与对照差异不显著;K+含量呈先升后降趋势;Na+/K+呈先降后升趋势,且低于对照;Na+外排先增加后减少,K+外排降低,且显著高于对照.随着胁迫时间的延长,枸杞根系中Na+、K+含量增加,Na+外排逐渐减慢,K+外排增加;阿米洛利与矾酸钠均显著降低了盐诱导下的Na+和H+内流.NaCl胁迫下宁夏枸杞根系借助于其质膜上的Na+/H+逆向运输系统,将胞内过量的Na+排出胞外,同时抑制K+外排,保持细胞内较低的Na+/K+,维持胞内Na+、K+平衡,从而表现出较强的耐盐性.%We detected absorption and transportation of Na+,K+in the root of Ningxia Lycium barbarum L.under NaCl stress by using non-invasive micro-test technology and atomic absorption spectrophotometry.The results showed that the root exhibited a higher capacity to induce the Na+efflux compared with that of control.The higher the concentration of NaCl,the more Na+accumulated in the root,but have no significant difference with CK.The K+content increased first and then declined,and the Na+/K+ratio showed the opposite trend.The longer duration of NaCl treatment,the more Na+and K+accumulated.At the mean time,the lower Na+efflux and higher K+efflux were also observed in the root compared with that of control.These results suggested that initial salt stress enhanced the salt-elicited Na+efflux but inhibited K+efflux to maintain the lower Na+/K+ratio and cellular Na+/K+homeostasis.The NaCl-induced Na+ef-flux and H+influx were inhibited by amiloride(a Na+/H+antiporter inhibitor)or sodium orthovanadate(a plasma membrane H+-ATPase inhibitor),indicating that Na+extrusion in the root of Ningxia Lycium barbarum L.arises from the active Na+/H+antiporter across the plasma membrane.