外源Spd对盐胁迫下黄瓜幼苗生长和活性氧代谢的影响

Effects of exogenous spermidine on cucumber seedling growth and reactive oxygen metabolism under salt stress

以黄瓜品种津春2号为材料,采用营养液栽培,研究了外源亚精胺(Spd)对NaCl胁迫下黄瓜幼苗生长、活性氧代谢和抗氧化酶基因表达的影响。结果表明,NaCl胁迫下,黄瓜幼苗超氧阴离子自由基(O.2-)产生速率、H2O2含量、丙二醛(MDA)含量和电解质渗透率显著升高,而株高、茎粗和生物量显著下降;盐胁迫下喷施Spd明显上调了Cu/Zn-超氧化物歧化酶(SOD)和过氧化物酶(POD)基因的表达,提高了SOD、POD活性,显著降低了黄瓜幼苗O.2-产生速率、H2O2含量、MDA含量和电解质渗透率,且植株株高、茎粗和干鲜重下降幅度降低。表明外源Spd可通过上调盐胁迫下Cu/Zn-SOD和POD基因的表达,使SOD和POD酶活性升高,有效清除活性氧,从而缓解膜脂过氧化伤害,进而缓解盐胁迫对植株生长的抑制。

The experiment was carried out to study the effects of exogenous spermidine（Spd） on cucumber seedling growth and reactive oxygen metabolism and antioxidant enzymes gene expression in cucumber（Cucumis sativus L.cv.Jinchun No.2） seedlings under salt stress with solution culture.The plant height,stem diameter,fresh and dry weight were significantly decreased under salt stress,while the O2 ·-production rate,H2O2 content,MDA contents and electrolyte leakage were increased significantly.However,the inhibition of seedling growth could be alleviated by spraying Spd,and the gene expression of Cu/Zn-superoxide dismutase（SOD） and peroxidase（POD） were up-regulated.The activities of SOD,POD enzymes were also increased,meanwhile the O2 ·-production rate,H2O2 content,MDA content and electrolyte leakage were decreased significantly.The results indicated that gene expression of Cu/Zn-SOD and POD could be up-regulated by exogenous Spd,which could increase the SOD and POD enzymes activities and reduce O2 ·-production rate,H2O2 content,MDA content and electrolyte leakage,and alleviate the inhibition of plant growth in salt stress finally.