The hormonal regulation of axillary bud growth in Arabidopsis
The hormonal regulation of axillary bud growth in Arabidopsis
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DOI：
10.1046/j.1365-313x.2000.00862.x
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发表时间：
2000-10-01
期刊：
影响因子：
7.2
通讯作者：
Leyser, O
中科院分区：
文献类型：
--
作者：
Chatfield, SP;Stirnberg, P;Leyser, O
长期以来，人们都知道顶端来源的生长素抑制侧芽生长，但由于它似乎不进入芽，因此有人提出它的抑制作用是由第二信使介导的。候选者包括植物激素乙烯、细胞分裂素和脱落酸。我们已经开发了一种新的方法来研究这种现象，使用模式植物拟南芥。该测定允许研究顶端和基部激素应用对离体节段上芽生长的影响。我们已经表明，顶端生长素可以抑制小芽的生长，但较大的芽被发现已经失去了能力的反应。我们已经使用的测定与野生型和葡萄糖信号突变体的节点测试乙烯，细胞分裂素和脱落酸在芽抑制顶端生长素的作用。我们的数据消除乙烯作为第二信使生长素介导的芽抑制。同样，脱落酸信号是不需要生长素的行动，虽然基部应用脱落酸可以增强抑制顶端生长素和顶部应用脱落酸可以减少it.By对比，基部应用细胞分裂素被发现释放侧芽抑制顶端生长素，而顶部应用细胞分裂素显着增加抑制的持续时间。这些结果与细胞分裂素独立调节芽的生长，而不是作为生长素的第二信使是一致的。然而，在细胞分裂素信号突变体的情况下，不能排除细胞分裂素作为生长素第二信使的作用。
Apically derived auxin has long been known to inhibit lateral bud growth, but since it appears not to enter the bud, it has been proposed that its inhibitory effect is mediated by a second messenger. Candidates include the plant hormones ethylene, cytokinin and abscisic acid. We have developed a new assay to study this phenomenon using the model plant Arabidopsis. The assay allows study of the effects of both apical and basal hormone applications on the growth of buds on excised nodal sections. We have shown that apical auxin can inhibit the growth of small buds, but larger buds were found to have lost competence to respond. We have used the assay with nodes from wild-type and hormone-signalling mutants to test the role of ethylene, cytokinin and abscisic acid in bud inhibition by apical auxin. Our data eliminate ethylene as a second messenger for auxin-mediated bud inhibition. Similarly, abscisic acid signalling is not to be required for auxin action, although basally applied abscisic can enhance inhibition by apical auxin and apically applied abscisic acid can reduce it. By contrast, basally applied cytokinin was found to release lateral buds from inhibition by apical auxin, while apically applied cytokinin dramatically increased the duration of inhibition. These results are consistent with cytokinin acting independently to regulate bud growth, rather than as a second messenger for auxin. However, in the absence of cytokinin-signalling mutants, a role for cytokinin as a second messenger for auxin cannot be ruled out.