不同盐胁迫下胀果甘草(Glycyrrhiza inflates Bat.)Na+吸收的共质体途径初步研究

摘要

In order to provide the basis for the study the molecular mechanisms of salt tolerance in Glycyrrhiza inflates,the symplast pathway of Na+ uptake was investigated using different ion channel inhibitors in this study.The results indicated that Ca2+ (inhibitors of low-affinity cation transporter and nonselective cation channels) did not have significant effect on the Na+ absorption when plants were treated with 50 or 150 mmol/L NaCl.The inhibitors of K+ channels,TEA+ (10 mmol/L) and Cs+ (10 mmol/L) didn't significantly reduce Na+ uptake,however Ba2+(10 mmol/L) significantly reduced Na+ uptake under 50 mmol/L NaCl treatment.In contrast,under 150 mmol/L NaCl treatment,Ba2+ (10 mmol/L) didn't significantly reduce Na+ uptake,TEA+ (10 mmol/L) and Cs+ (10 mmol/L) significantly reduced Na+ uptake under 150 mmol/L NaCl treatment.The data suggested that nonselective cation channels (NSCCs) and a low-affinity cation transporter (LCT1) were not the major pathways of sodium ion influx.We proposed that two distinct low-affinity Na+ uptake pathways exist in Glycyrrhiza inflates:'Pathway 1'is insensitive to TEA+ or Cs+,but is sensitive to Ba2+ and mediates Na+ uptake under low salinities (50 mmol/L NaCl);'pathway 2'is insensitive to Ba2+,but is sensitive to TEA+ and Cs2+ and mediates Na+ uptake under high salinities (150 mmol/L NaCl).%本实验通过不同离子通道抑制剂对胀果甘草钠离子吸收的影响分析,探讨了其钠离子吸收的共质体途径,为其耐盐分子机制的研究提供基础.结果表明:在低盐浓度(50 mmol/L NaCl)和高盐浓度(150 mmol/L NaCl)下,Ca2+(低亲和阳离子载体和无选择阳离子通道的抑制剂)均无显著的影响胀果甘草对Na+的吸收;然而当加入钾离子通道抑制剂时,Ba2+显著地降低了低盐胁迫(50 mmol/L NaCl)下胀果甘草对钠离子的吸收;TEA+、Cs+显著的降低了在高盐胁迫(150mmol/L NaCl)下胀果甘草对钠离子的吸收.由此得出,无选择阳离子通道NSCCs和低亲和阳离子载体LCT1不是钠离子流入的主要途径,钠离子通过2条低亲和性的Na+吸收途径流入:途径1对Ba2+敏感,对TEA+、Cs+不敏感,介导低盐浓度(50 mmol/L NaCl)下的Na+吸收;途径2对TEA+、Cs+敏感,对Ba2+不敏感,介导高盐浓度(150 mmol/L NaCl)下的Na+吸收.