Department of Vegetable Crops, University of California, Davis, California 95616.
Plant Physiol. 1978 Jan;61(1):68-71. doi: 10.1104/pp.61.1.68.
The suggestion that indole-3-acetic acid (IAA)-stimulated ethylene production is associated with oxidative degradation of IAA and is mediated by 3-methyleneoxindole (MOI) has been tested in mung bean (Phaseolus aureus Roxb.) hypocotyl segments. While IAA actively stimulated ethylene production, MOI and indole-3-aldehyde, the major products of IAA oxidation, were inactive. Tissues treated with a mixture of intermediates of IAA oxidation, obtained from a 1-hour incubation of IAA with peroxidase, failed to stimulate ethylene production. Furthermore, chlorogenic acid and p-coumaric acid, which are known to interfere with the enzymic oxidation of IAA to MOI, had no effect on IAA-stimulated ethylene production. Other oxidation products of IAA, including oxindole-3-acetic acid, indole-3-carboxylic acid, (2-sulfoindole)-3-acetic acid, and dioxindole-3-acetic acid, were all inactive. 1-Naphthaleneacetic acid was as active as IAA in stimulating ethylene production but was decarboxylated at a much lower rate than IAA, suggesting that oxidative decarboxylation of auxins is not linked to ethylene production. These results demonstrate that IAA-stimulated ethylene production in mung bean hypocotyl tissue is not mediated by MOI or other associated oxidative products of IAA.
吲哚-3-乙酸（IAA）刺激乙烯生成与 IAA 的氧化降解有关，并由 3-亚甲基氧吲哚（MOI）介导的这一假说，已经在绿豆（Phaseolus aureus Roxb.）下胚轴段中得到了检验。虽然 IAA 能积极地刺激乙烯生成，但 MOI 和 IAA 氧化的主要产物吲哚-3-醛却没有活性。用酶促氧化 IAA 1 小时获得的 IAA 氧化中间产物混合物处理组织，未能刺激乙烯生成。此外，已知会干扰 IAA 氧化成 MOI 的酶促反应的绿原酸和对香豆酸，对 IAA 刺激的乙烯生成没有影响。IAA 的其他氧化产物，包括吲哚-3-乙酸、吲哚-3-羧酸、（2-磺基吲哚）-3-乙酸和二氧吲哚-3-乙酸，都没有活性。1-萘乙酸在刺激乙烯生成方面与 IAA 一样有效，但比 IAA 脱羧的速度要低得多，这表明生长素的氧化脱羧与乙烯生成无关。这些结果表明，在绿豆下胚轴组织中，IAA 刺激的乙烯生成不是由 MOI 或其他相关的 IAA 氧化产物介导的。
