多胺对小麦离体叶片衰老的调节

THE RELATIONSHIP BETWEEN POLYAMINES AND SENESCENCE OF DETACHED WHEAT LEAVES

Spm、Spd 和 Put 可延缓叶片喑诱导衰老时叶绿素的损失和蛋白质水解。根据对多胺处理后叶片中 MDA 含量及 SOD 和 POD 的分析证明,多胺能延缓衰老与它们维持组织清除自由基的能力有关。叶片衰老时 ADC 和 ODC 活性下降,以及多胺生物合成的前身和抑制剂都可以调节衰老的事实,进一步证明组织衰老与多胺的直接关系。DFMO 可逆转 KT 的防衰效应,准测 KT 的作用有多胺介入。

The role of polyamines in the regulation of senescence was examined in excised wheat leaves.The polyamines——putrescine (Put) spermidine (Spd) and spermine (Spm) prevented the loss of chlorophyll normally associated with senescence of leaf tissue maintained in dar- kness.Polyamines were also highly effective in retarding earlier event——the rise in protease activity of leaf senescence,prior to chlorophyll loss. A good quantitative correlation was found between chlorophyll and MDA content.After 0.5 m mol/l Spd was applied,SOD activity was stabilized and POD activity was hardly chang- ed.On the contrary,SOD activity dedlined and POD activity increased in the control.The analysis of isozyme showed that a new band of POD isozyme was found after incubation for 48 hours,but it was not observed at the same time after the treatment with 0.5 m mol/l Spd. On the other hand,SOD isozyme had no change in senescing process or after the treatment.In the dark-induced senescence,ADC and ODC activity decreased.The kinetin promoted ADC and ODC activity compared with that of the control.The antisenescence function of kinetin was reversed partially by DFMO.A possible reason for polyamines antisenescence function and their relation to the plant hormones is discussed.