Gemperlová Lenka, Nováková Marie, Vanková Radomíra, Eder Josef, Cvikrová Milena
Institute of Experimental Botany, Academy of Sciences of Czech Republic, Rozvojová 135, 165 02 Prague 6, Czech Republic.
J Exp Bot. 2006;57(6):1413-21. doi: 10.1093/jxb/erj121. Epub 2006 Mar 23.
Changes in the contents of polyamines (PAs) in tobacco leaves (Nicotiana tabacum L. cv. Wisconsin 38) grown under 16 h photoperiod were correlated with arginine and ornithine decarboxylase (EC 4.1.1.19 and EC 4.1.1.17) and diamine oxidase (EC 1.4.3.6) activities. The maximum of free and soluble conjugated forms of PAs occurred 1-2 h after the middle of the light period and was followed by two distinct peaks at the end of the light and at the beginning of the dark phase. Putrescine was the most abundant and cadaverine the least abundant PA in both free and PCA-soluble forms. However, cadaverine was predominant in PCA-insoluble conjugates, followed by putrescine, spermidine, and spermine. Both arginine and ornithine decarboxylases are involved in putrescine biosynthesis in tobacco leaves. Light dramatically stimulated the activity of ornithine decarboxylase, while no photoinduction of arginine decarboxylase activity was observed. Ornithine decarboxylase was found mainly in the particulate fraction. Only one peak, just after light induction, occurred in the cytosolic fraction, with 35% of the total ornithine decarboxylase activity. By contrast, the total arginine decarboxylase activity was equally divided between the soluble and pellet fractions. A sharp increase in diamine oxidase activity occurred 1 h after exposure to light, concomitant with the light-induced increase in ornithine decarboxylase activity. After a decline, diamine oxidase activity increased again, together with the rise in the amount of free Put. The roles of both conjugation of PAs with hydroxycinnamic acids and oxidative degradation of putrescine in maintaining free PA levels during the 24 h light/dark cycle are discussed. The presented results have shown that the parameters studied here followed rhythmical changes and were not only affected by light.
在16小时光周期下生长的烟草叶片（烟草品种Wisconsin 38）中多胺（PAs）含量的变化与精氨酸脱羧酶和鸟氨酸脱羧酶（分别为EC 4.1.1.19和EC 4.1.1.17）以及二胺氧化酶（EC 1.4.3.6）的活性相关。游离态和可溶性结合态PAs的最大值出现在光照期中期后的1 - 2小时，随后在光照结束时和黑暗期开始时出现两个明显的峰值。在游离态和PCA可溶性形式中，腐胺是含量最丰富的多胺，尸胺是含量最少的多胺。然而，在PCA不溶性结合物中，尸胺占主导地位，其次是腐胺、亚精胺和精胺。精氨酸脱羧酶和鸟氨酸脱羧酶都参与烟草叶片中腐胺的生物合成。光照显著刺激鸟氨酸脱羧酶的活性，而未观察到精氨酸脱羧酶活性的光诱导现象。鸟氨酸脱羧酶主要存在于颗粒部分。在胞质部分，仅在光照诱导后出现一个峰值，占鸟氨酸脱羧酶总活性的35%。相比之下，精氨酸脱羧酶的总活性在可溶性部分和沉淀部分中平均分布。光照1小时后，二胺氧化酶活性急剧增加，同时伴随着光照诱导的鸟氨酸脱羧酶活性的增加。在下降之后，二胺氧化酶活性再次增加，同时游离腐胺的量也增加。本文讨论了多胺与羟基肉桂酸的结合以及腐胺的氧化降解在24小时光/暗周期中维持游离多胺水平的作用。所呈现的结果表明，这里研究的参数呈现出节律性变化，并且不仅受光照影响。
