关键词: 构树, 组织定位, 剥皮再生, 内源IAA

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