Abstract: Change in the concentration of endogenous IAA was monitored with enzyme-linked immunosorbent assays (ELISA), and IAA localization in the tissues was demonstrated by means of immunogold-silver microscopy, with authors modification, during the regeneration after girdling in Broussonetia papyrifera (L.) Vent.. The stimulation of girdling induced a rapid increase of about 100% of the endogenous IAA concentration. However, the concentration decreased during differentiation of the vascular tissues. Although removal of the tree crown and wrapping up in a black plastic sheet inhibited the regeneration of vascular tissues, but the change tendency in the concentration of endogenous IAA during the regeneration remained the same as if the tree crown was intact and the girdled trunk was wrapped up in a transparent plastic sheet. This suggested that rapid increase of endogenous IAA induced by wounding could result from a release of the combined form into free IAA. The tissue-localization showed that there were more silver-grains labelled in the ray, callus and regenerated differentiating vascular tissue cells than that in other tissues. It further suggested that the high concentration of endogenous IAA triggered the dedifferentiation of the immature vascular tissues after girdling, and the lower concentrated IAA flow could promote the initiation and activity of the regenerated cambium.

Key words: Broussonetia papyrifera, differentiation of vascular tissue, regeneration after girdling, endogenous IAA

摘要： 用酶联免疫吸附法研究了构树(Broussonetia papyrifera (L.)Vent.)剥皮后维管组织再生过程中内源IAA浓度的变化，并用改进的免疫金银法测定了此过程中内源IAA在不同组织中的分布。结果表明，剥皮后内源IAA浓度迅速升高，升高幅度近100%。去除树冠和遮光抑制了维管组织的再生，但却没有影响内源IAA浓度的变化趋势。这似表明，剥皮刺激诱导的内源IAA浓度的快速升高可能是束缚态IAA的快速释放，而不是芽和幼叶新合成的结果。内源IAA组织定位的结果表明射线细胞、愈伤组织和新生维管组织内均有较多的银颗粒标记。这些似可表明，高浓度的内源IAA可启动未成熟维管组织细胞的脱分化，而较低浓度的内源IAA流则可诱导再生形成层的发生和活动。

关键词: 构树, 组织定位, 剥皮再生, 内源IAA