Department of Botany, Randse Afrikaanse Universiteit, P.O. Box 524, 2000, Johannesburg, Republic of South Africa.
Planta. 1992 Nov;188(4):478-83. doi: 10.1007/BF00197038.
Senescence of Petunia hybrida L. flowers is accompanied by a climacteric pattern in ethylene production and a rapid decline in the levels of putrescine and spermidine during the preclimacteric phase. The decrease in spermidine is caused by the decline in the availability of putrescine which is initially synthesized from L-arginine via agmatine and N-carbamoylputrescine. Inhibition of putrescine and polyamine synthesis resulted in a rapid drop in the levels of putrescine and spermidine without resulting in a concomitant increase in ethylene production. These results indicate that polyamine synthesis is not involved in the control of ethylene synthesis through its effect on the availability of S-adenosylmethionine, and is confirmed by the results obtained with pollinated flowers. Treatment with polyamines may stimulate or suppress ethylene production in the corolla, depending on the concentrations applied. In unpollinated flowers the onset of the climacteric rise in ethylene production was accelerated after treatment with polyamines. However, in pollinated flowers this process was delayed as a result of treatment with low concentrations of polyamines. The effects of exogenous polyamines on ethylene production in both pollinated and unpollinated flowers indicate that ethylene synthesis in these flowers is not regulated by a feedback control mechanism. Although polyamines do not play a key role in the control of ethylene production during the early stages of senescence through their effect on the availability of S-adenosylmethionine, it appears that they play an important role in some of the other processes involved in senescence.
矮牵牛花朵的衰老伴随着乙烯生成的跃变型模式，以及在衰老前期，腐胺和亚精胺水平迅速下降。亚精胺的减少是由于腐胺可用性的下降所致，腐胺最初是通过胍氨酸和 N-碳酰腐胺从 L-精氨酸合成的。腐胺和多胺合成的抑制导致腐胺和亚精胺水平迅速下降，而不会导致乙烯生成的同时增加。这些结果表明，多胺合成不通过其对 S-腺苷甲硫氨酸可用性的影响参与乙烯合成的控制，并通过授粉花朵获得的结果得到证实。多胺处理可能会根据施加的浓度刺激或抑制花瓣中的乙烯生成。在未授粉的花朵中，用多胺处理后，乙烯生成的跃变上升开始加速。然而，在授粉的花朵中，由于低浓度多胺的处理，这个过程被延迟了。外源多胺对授粉和未授粉花朵中乙烯生成的影响表明，这些花朵中的乙烯合成不受反馈控制机制的调节。尽管多胺通过其对 S-腺苷甲硫氨酸可用性的影响在衰老早期的乙烯生成控制中不起关键作用，但它们似乎在衰老过程中涉及的某些其他过程中发挥重要作用。
