Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 956, Buenos Aires (1113), Argentina.
Plant Physiol. 1991 Oct;97(2):778-85. doi: 10.1104/pp.97.2.778.
When the polyamine content of soybean (Glycine max) seeds was examined during the early stages of germination, the major polyamine in the cotyledons was found to be spermidine, followed by spermine; while very low concentrations of cadaverine were found. In the embryonic axes, however, cadaverine was the main polyamine and its content markedly increased 24 hours after the start of germination. When the germination of the seeds was performed in the presence of 1 millimolar alpha-difluoromethylornithine (DFMO), a marked decrease in the cadaverine content was found, while the other polyamines were not affected. This decrease of the cadaverine content was already noticeable after the first hours of germination. In the presence of DFMO, a pronounced elongation in the roots of the seedlings and a marked decrease in the appearance of secondary roots as compared with controls, was observed. This abnormal rooting of the seedlings caused by DFMO was almost completely reverted by the addition of 1 millimolar cadaverine. The latter also increased the appearance of secondary roots in the seedlings. The decrease in the cadaverine content produced by DFMO could be traced to a strong inhibition of lysine decarboxylase. A temporal correlation between the increase in cadaverine content and the increase in lysine decarboxylase activity was found. Both reached a maximum at the second day of germination. The activity of diamine oxidase, the cadaverine degrading enzyme, started to increase at the third day and reached a maximum between the fourth and fifth day of germination. DFMO increased the activity of diamine oxidase by about 25%. Hence, the large decrease in cadaverine content produced by DFMO has to be attributed to the in vivo suppression of lysine decarboxylase activity. Ornithine decarboxylase activity was also suppressed by DFMO, but putrescine and spermidine contents were not affected, except in the meristematic tissues. The obtained results suggest an important role for cadaverine in the normal rooting process of soybean seedlings.
当研究大豆（Glycine max）种子在萌发早期的多胺含量时，发现子叶中的主要多胺是腐胺，其次是精胺；而尸胺的浓度非常低。然而，在胚胎轴中，尸胺是主要的多胺，其含量在萌发开始后 24 小时内显著增加。当种子在 1 毫摩尔α-二氟甲基鸟氨酸（DFMO）存在下萌发时，发现尸胺含量明显下降，而其他多胺不受影响。这种尸胺含量的下降在萌发后的头几个小时就已经很明显了。在 DFMO 的存在下，观察到幼苗的根明显伸长，与对照相比，次级根的出现明显减少。DFMO 引起的幼苗异常生根几乎可以完全被添加 1 毫摩尔尸胺逆转。后者也增加了幼苗次级根的出现。DFMO 导致的尸胺含量下降可归因于赖氨酸脱羧酶的强烈抑制。发现尸胺含量的增加与赖氨酸脱羧酶活性的增加之间存在时间相关性。两者都在萌发的第二天达到最大值。腐胺降解酶二胺氧化酶的活性在第三天开始增加，并在萌发的第四至第五天达到最大值。DFMO 将二胺氧化酶的活性提高了约 25%。因此，DFMO 产生的尸胺含量大量减少必须归因于赖氨酸脱羧酶活性的体内抑制。DFMO 还抑制鸟氨酸脱羧酶的活性，但精氨酸和腐胺的含量不受影响，除了在分生组织中。所得结果表明尸胺在大豆幼苗正常生根过程中起着重要作用。
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