Synthesis of New Indolic Plant Hormones and Their Application to Plant Tissue Cultures

在我们以前从豌豆种子中分离得到4-氯吲哚乙酸及其甲酯的基础上，我们合成了吲哚乙酸二氯衍生物的全部十种区域异构体，并测定了它们的生长素活性。其中，5，6-二氯吲哚-乙酸（5，6-Cl_2-IAA）表现出最强的生长素活性，且这种活性强于已知的所有天然和人工合成的生长素。它能诱导绿豆幼苗产生大量侧根，并能抵抗过氧化物酶催化的分解。而5，7-二氯吲哚乙酸（5，7-Cl_2-IAA）的生长素活性远低于其它二氯吲哚衍生物。有趣的是，当小麦和水稻种子用5，7-Cl_2-IAA萌发时，根明显向上卷曲。这种负向地性显然是一种抗生长素活性。为了消除其弱的生长素样活性，我们将AA的侧链从乙酰基改变为异丁酰基，这已知会改变2，4 ...更多信息 -D为抗生长素。由此合成的α-（5，7-二氯吲哚-3-）异丁酸（5，7-Cl_2-IIBA）对生长素介导的燕麦胚芽鞘伸长有抑制作用。5，6-Cl_2-IAA在0.01mg/L浓度下诱导海柏杂种根培养中产生托品烷类生物碱，与0.5mg/LIAA相当。用5，6-Cl_2-IAA法，不仅在根组织中，而且在培养基中也能检测到生物碱。以烟草（Nicotiana tabacum）花梗为外植体，在含有过量生长素（IAA）和抗生长素（5，7-Cl_2-IIBA）的改良Murashige-Skoog培养基上培养，建立了一个离体花芽形成的生物测定体系。在该体系中，5，7-Cl_2-IIBA是非常有效的：短日照处理植株的叶片分泌物刺激花芽形成。此外，产生的芽生长成大的，发育良好的，形状类似于那些完整的烟草植物的天然花蕾。少

Based on our success in the previous isolation of 4-chloroindole--acetic acid and its methyl ester from immature seeds of Pisum sativum, we synthesized all ten regioisomers of dichloro-derivatives of indole--acetic acid, and measured their auxin activity. Among them, -dichloroindole--acetic acid (5, 6-Cl_2-IAA) showed the strongest auxin activity, and this activity was stronger than all the known natural and synthetic auxins. It induced many lateral roots in mung bean seedlings, and resisted peroxi-dase-catalyzed decomposition. In contrast, 5, 7-dichloroindole--acetic acid (5, 7-Cl_2-IAA) showed much weaker auxin activity than the other dichloro-indole derivatives. Interestingly, when wheat and rice seeds were germinated with 5, 7-Cl_2-IAA their roots curled markedly upwards. This negative geotropism is clearly an antiauxin activity. To eliminate its weak auxinlike activity, we changed the side chain of AA from acetyl to isobutyryl group, which is known to change auxin activity of 2, 4 … More -D to antiauxin of PCIB. alpha-(5, 7-Dichloroindole-3-)isobutyric acid (5, 7-Cl_2-IIBA) thus synthesized showed to inhibit auxin-mediated elongation of avena coleoptiles. Its activity is stronger than that of alpha-(pchlorophenoxy)isobutyric acid and is comparable to that of 2, 3, 5-triiodobenzoic acid, which are typical antiauxins.5, 6-Cl_2-IAA induced tropane alkaloid production in root cultures of a Duboisia hybrid at 0.01mg/L, which was comparable to 0.5mg/L IAA. By using 5, 6-Cl_2-IAA, the alkaloids were detected not only in the root tissue but also in the medium. An in vitro bioassay system for floral bud formation was established using Nicotiana tabacum explants excised from floral stalks cultured on modified Murashige-Skoog medium containing excess auxin (IAA) and antiauxin (5, 7-Cl_2-IIBA). In this system, 5, 7-Cl_2-IIBA was very effective : leaf exudate from short day-treated plants stimulated floral bud formation. Moreover, the buds produced grew into large, well-developed ones with shapes similar to those of the natural floral buds of intact tobacco plants. Less