亚精胺对镉胁迫下杞柳生长和生理特性的影响

Effects of spermidine on growth and physiological characteristics of Salix integra under cadmium stress

为研究外源亚精胺对镉胁迫下杞柳生长和生理特性的影响,采用营养液培养试验,通过不同浓度(0、10、20、30、40mg·L^-1)的Cd2+胁迫处理,探明Cd2+对杞柳的半抑制浓度;研究在半抑制浓度下施用外源亚精胺(0、0.1、0.2、0.4、0.8、1.6mmol·L^-1)对镉胁迫的缓解效应。结果表明:镉胁迫对杞柳的半抑制浓度为24.50mg·L^-1;施用外源亚精胺可以有效缓解镉胁迫对杞柳生长的抑制作用,外源亚精胺处理相对生长率较对照增加44.97%~102.76%,过氧化氢含量下降54.08%~67.39%;其中0.4mmol·L^-1亚精胺处理下相对生长率、根系节点数、连接数、分叉数的增长幅度均为最高,分别增加102.76%、50.33%、25.20%和25.42%,其总蛋白含量上升43.43%,产生超氧阴离子活力单位与过氧化氢含量分别下降46.35%和67.39%。研究表明,喷施亚精胺能有效缓解杞柳幼苗镉胁迫,其最佳施用浓度为0.4mmol·L^-1。

To study the effects of exogenous spermidine on the growth and physiological characteristics of S. integra exposed to cadmium stress, a hydroponic nutrient solution experiment with different Cd( 0, 10, 20, 30, 40mg·L^-1)concentrations was carried out to determine the semi-inhibitory concentration of Cd for S. integra. Subsequently, the effects of exogenous addition of spermidine( 0, 0.1, 0.2, 0.4, 0.8, 1.6 mmol·L^-1)on the mitigation of Cd stress were investigated using the semi-inhibitory concentration of Cd on S. integra. The results showed that the semi-inhibitory concentration was 24.50mg·L^-1, and the addition of spermidine effectively alleviated the inhibiting effects of Cd stress on S. integra growth. Compared with control plants, the increased relative growth rate of S. integra in spermidine treatment ranged from 44.97% to 102.76%, and the reduction in hydrogen peroxide content ranged from 54.08% to 67.39%. The relative growth rate, root node number, connection number and bifurcation number increased by 102.76%, 50.33%, 25.20%, and 25.42%, respectively, when treated with 0.4 mmol·L^-1 spermidine. Total protein content increased by 43.43%, the activity unit of superoxide anion and the content of hydrogen peroxide decreased by 46.35% and 67.39% that exposed to 0.4mmol·L^-1 spermidine regime. These results suggest that spraying spermidine can effectively alleviate cadmium stress in S. integra var. mandshurica seedlings and the optimum application concentration is 0.4mmol·L^-1.