外源亚精胺对盐胁迫下黄瓜(Cucumis sativus L.)叶绿体活性氧清除系统和结合态多胺含量的影响

采用营养液水培,研究了外源亚精胺(Spd)对NaCl胁迫下抗盐能力不同的两个黄瓜品种幼苗生长、叶绿体中活性氧清除系统、转谷酰胺酶(TGase)活性、结合态多胺含量及植株光合速率的影响.结果表明,外源Spd能提高NaCl胁迫下叶绿体中TGase活性、叶绿体结合态腐胺(Put)、Spd、精胺(Spm)及总多胺含量;提高超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,提高抗坏血酸(AsA)、类胡萝卜素(Car)、还原型谷胱甘肽(GSH)含量及还原型谷胱甘肽/氧化型谷胱甘肽(GSH/ GSSG)比值,降低脱氢抗坏血酸/抗坏血酸(DAsA/AsA)比值;同时显著降低叶绿体过氧化氢(H2O2)和丙二醛(MDA)含量,提高植株净光合速率,缓解NaCl胁迫对幼苗生长的抑制.表明Spd对黄瓜盐害的缓解作用之一可能是通过提高叶绿体结合态多胺含量和叶绿体活性氧清除能力,从而缓解盐胁迫对叶绿体膜的伤害.

Effects of exogenous spermidine on active oxygen scavenging system and bound polyamine contents in chloroplasts of cucumber under salt stress

The objective of this study was to investigate the effects of exogenous application of spermidine on the growth, active oxygen scavenging system and bound polyamine contents in chloroplasts of cucumber under salt stress. The results showed that under salt stress, exogenous spermidine increased TGase activity and bound putrescine, spermidine, spermine and total polyamine contents in chloroplasts. The activities of SOD, APX and GR, the contents of AsA, Car and GSH, and the ratios of GSH/GSSG in chloroplasts were increased, while the ratios of DAsA/AsA and the contents of H2O2 and MDA decreased. Furthermore, exogenous spermidine increased net photosynthetic rates, as well as alleviated the salt-induced plant growth inhibition. These results suggest that exogenous application of spermidine could alleviate salt-induced membrane injury of chloroplast by increasing the active oxygen scavenging ability and the bound polyamine contents in chloroplast.