用高压液相色谱法，研究了玉米品种农大108（抗旱性较强）和掖单13（抗旱性较弱）幼苗叶片中游离态(free, f)、酸可溶性共价结合态(AS-conjugated)和酸不溶性共价结合态(AIS-bound) 多胺（polyamine, PA）与渗透胁迫的关系。结果发现，渗透胁迫7 d，农大108的fSpd和fSpm的含量显著(P＜0.05)上升，而掖单13的fPut的升幅显著(P＜0.05)。用S-腺苷蛋氨酸脱羧酶（SAMDC）抑制剂甲基乙二醛-双（鸟嘌呤腙）（MGBG）处理农大108，显著抑制了渗透胁迫诱导的fSpd和fSpm的增加，并且加重了渗透胁迫伤害，用外源Spd处理掖单13，则显著促进了渗透胁迫诱导的fSpd和fSpm的增加，并且减缓了渗透胁迫的伤害。渗透胁迫下，农大108幼苗叶片中AS-conjugated-PA和AIS-bound-PA的上升幅度都显著大于掖单13。用转谷氨酰胺酶（TGase）抑制剂菲咯啉(o-Phen)处理，则抑制了渗透胁迫诱导的AIS-bound-PA含量的上升，并加重了渗透胁迫的伤害。上述结果说明，玉米幼苗叶片中的fSpd、fSpm、AS-conjugated-PA和AIS-bound-PA的升高有利于增强幼苗的抗渗透性。
The changes in contents and forms of polyamines (PAs) in seedling leaves of two maize (Zea mays L.) cultivars, Nongda 108 (drought-tolerant) and Yedan 13 (drought-sensitive), were investigated under osmotic stress. On the 8th day after polyethylene glycol (PEG) -6 000 treatment, free spermidine (fSpd) and free spermine (fSpm) content in leaves increased significantly（P＜0.05）in Nongda 108, while Yedan 13 showed a significant increase of free putrescine (fPut) content. Thus Nongda 108 gave a higher ratio of (fSpd + fSpm)/fPut than Yedan 13 in leaves under osmotic stress. Exogenous methylglyoxal-bis (guanylhydrazone) (MGBG), which is a S-adenosylmethionine decarboxylase (SAMDC) inhibitor, resulted in reduction of fSpd and fSpm contents and aggravation of PEG-induced injury to Nongda 108 leaves, while exogenous Spd treatment resulted in an increase of fSpd + fSpm in leaves, in concert with an alleviation of PEG-induced injury to seedlings of Yedan 13. Osmotic stress induced significant increases of acid soluble conjugated PA (AS-conjugated PA) and acid insoluble bound PA (AIS-bound PA) contents in leaves of Nongda 108, and osmotic stress affected slightly in Yedan 13 leaves. Exogenous phenanthrolin (o-Phen), an inhibitor of transglutaminase (TGase), aggravated PEG-induced injury to Nongda 108, coupled with decreases of AIS-bound PA content. The results suggest that fSpd, fSpm, AS-conjugated-PA and AIS-bound PA facilitate the osmotic stress tolerance of maize seedlings.
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