真盐生植物盐地碱蓬根系边缘细胞在耐盐中的作用初探

以黄河三角洲潮间带盐地碱蓬种子生成的幼苗为材料,研究了NaCl胁迫对盐地碱蓬生长与根系边缘细胞的影响。盐地碱蓬的第一个边缘细胞几乎与根尖同步产生,当根长达到13mm时,边缘细胞数目达到最大值。NaCl胁迫抑制边缘细胞的活性,但低浓度的NaCl处理增加边缘细胞的数目。低浓度NaCl处理时果胶甲基酯酶（PME）的活性比对照有明显增加,超氧化物歧化酶（SOD）活性随着NaCl浓度的增加呈现先上升后下降的趋势,低浓度NaCl可以增加盐地碱蓬根内过氧化氢酶（CAT）的活性,NaCl处理时间和处理浓度都对过氧化物酶（POD）活性的影响不明显。这些结果表明,盐地碱蓬至少部分通过增加调控活性氧（ROS）水平增加PME活性及根系边缘细胞数目来抵抗NaCl胁迫。

Preliminary Study on the Role of Root Border Cells in Salt Tolerance of Euhalophytte Suaeda salsa L.

The seedlings generated from the seeds of Suaeda salsa L.from intertidal zones of Yellow River Delta were used to examine the effect of NaCl stress on the growth,number and activity of the root border cells（BC）.The primal border cells occurred nearly synchronously with primary root tip of S.salsa.The number of root border cells reached maximum value when root length reached 13 mm.Activity of BC was inhibited by NaCl stress.However,low concentration of NaCl treatment（200-400 mmol·L-1） significantly increased the number of BC,high concentration of NaCl decreased the BC number.Similar to the number of BC,activity of pectin methylesterase（PME） under low concentration of NaCl increased but declined under high concentration of NaCl.Interestingly,activities of superoxide dismutase（SOD） and catalase（CAT） were also increased by low concentration of NaCl treatment,but inhibited by high concentration of NaCl.NaCl stress did not affect peroxidase activity.These results suggest that S.salsa adapts to high salinity partly via regulating ROS level to increase of the number of BC and activity of PME.