Kuwabara Asuka, Ikegami Keiichi, Koshiba Tomokazu, Nagata Toshiyuki
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan.
Planta. 2003 Oct;217(6):880-7. doi: 10.1007/s00425-003-1062-z. Epub 2003 Jul 3.
In this study, we examined the effects of ethylene and abscisic acid (ABA) upon heterophyllous leaf formation of Ludwigia arcuata Walt. Treatment with ethylene gas resulted in the formation of submerged-type leaves on terrestrial shoots of L. arcuata, while treatments with ABA induced the formation of terrestrial-type leaves on submerged shoots. Measurement of the endogenous ethylene concentration of submerged shoots showed that it was higher than that of terrestrial ones. In contrast, the endogenous ABA concentration of terrestrial shoots was higher than that of submerged ones. To clarify interactions of ethylene and ABA, simultaneous additions of these two plant hormones were examined. When L. arcuata plants were treated with these two plant hormones, the effects of ABA dominated that of ethylene, resulting in the formation of terrestrial-type leaves. This suggests that ABA may be located downstream of ethylene in signal transduction chains for forming heterophyllous changes. Further, ethylene treatment induced the reduction of endogenous levels of ABA in tissues of L. arcuata, resulting in the formation of submerged-type leaves. Thus the effects of ethylene and ABA upon heterophyllous leaf formation are discussed in relationship to the cross-talk between signaling pathways of ethylene and ABA.
在本研究中，我们研究了乙烯和脱落酸（ABA）对节节菜（Ludwigia arcuata Walt.）异形叶形成的影响。用乙烯气体处理导致节节菜陆生枝条上形成沉水型叶片，而用ABA处理则诱导沉水枝条上形成陆生型叶片。对沉水枝条内源乙烯浓度的测定表明，其高于陆生枝条。相反，陆生枝条的内源ABA浓度高于沉水枝条。为阐明乙烯和ABA的相互作用，我们研究了同时添加这两种植物激素的情况。当用这两种植物激素处理节节菜植株时，ABA的作用占主导，导致形成陆生型叶片。这表明在异形叶变化的信号转导链中，ABA可能位于乙烯的下游。此外，乙烯处理导致节节菜组织中内源ABA水平降低，从而形成沉水型叶片。因此，我们结合乙烯和ABA信号通路之间的相互作用，讨论了乙烯和ABA对异形叶形成的影响。
