渗透胁迫对玉米幼苗根尖线粒体ATPase活性与结合态多胺含量的影响

目的]探讨线粒体膜上结合态多胺与渗透胁迫的关系。方法]以抗旱性不同的玉米(Zea maysL.)品种农大108(抗旱性较强)和掖单13(抗旱性较弱)幼苗为材料,研究在聚乙二醇(PEG)-6000渗透胁迫下,幼苗根线粒体ATPase水解活性与膜上非共价结合态亚精胺(Spd)含量的关系。结果]渗透胁迫条件下,抗性强的农大108的ATPase活性下降的幅度明显小于抗性弱的品种掖单13,而农大108的线粒体膜上非共价结合亚精胺的上升幅度明显大于掖单13。外源Spd处理,明显促进了掖单13在胁迫条件下非共价结合Spd含量的增加,同时抑制其在胁迫条件下ATPase活性的降低,从而提高了掖单13幼苗的抗性;Spd生物合成的专一性抑制剂——甲基乙二醛-双(鸟嘌呤腙)(MGBG)处理,显著抑制了农大108在胁迫条件下膜上非共价结合Spd的增加,同时促进其在胁迫条件下ATPase活性的降低,从而明显降低了农大108幼苗的抗性。结论]线粒体膜上的非共价结合的Spd可能通过维持ATPase活性的稳定来提高玉米幼苗的抗渗透胁迫能力。

Effect of Osmotic Stress on ATPase Activity and Conjugated Bound Spermidine Content in Mitochondria from Maize Seedling Root Tip

Objective] The purpose was to discuss the relationship of conjugated polyamines and osmotic stress on mitochondria membrane.Method] With the seedlings of different maize cultivars Nongda 108 with strong drought-tolerance and Yedan 13 with weak drought-tolerance as materials,the relationship of the hydrolytic activity of mitochondria ATPase in seedling roots and noncovalent conjugated spermidine(Spd) content on mitochondria membrane under the osmotic stress of polyethylene glycol(PEG)-6000 was studied.Result] Under the osmotic stress,the ATPase activity decreased more in Yedan 13 than that in Nongda 108 obviously,while the content of non-covalent conjugated Spd increased more in Nongda 108 than that in Yedan 13 obviously.Under the osmotic stress,the exogenous Spd treatment improved the increment of noncovalent conjugated Spd content and inhibited the decrease in ATPase activity in Yedan 13,which enhanced the tolerance of Yedan 13 seedlings.The treatment with methylglyoxal-bis(guanine hydrazone)(MGBG),which was a specific inhibitor of Spd biosynthesis,remarkably inhibited the increment of noncovalent conjugated Spd and improved the decrease of ATPase activity in Nongda 108 under the osmotic stress,which decreased the tolerance of Nongda 108 seedlings.Conclusion] The non-covalent conjugated Spd on mitochondria membrane might enhance the resistance of maize seedling to osmotic stress via maintaining stable ATPase activity.