Histochemical localization of acetylcholinesterase in leguminous plant, siratro (Macroptilium atropurpureum)

Acetylcholine (ACh) and acetylcholinesterase (AChE) have previously been demonstrated to occur in leguminous plant, Siratro (Macroptilium atropurpureum). In the present work, the localization of acetylcholinesterase (AChE) within selected organs of Siratro is described. Histochemical techniques have been employed to show the presence of acetylcholinesterase activity in petiole, stem, root and the primary and secondary pulvini. No histochemical evidence was observed in petiole, stem and root segments. The enzyme was only present in the primary and secondary pulvini. The AChE in tissues of the primary and secondary pulvini appeared to be in the endodermal cells around the vascular system. Particularly,l after the cytochemical reaction dark spots of copper sulfide strongly stained the endodermal cells that circled around the vascular system in the primary pulvinus. The results confirmed a high ACh content and a high enzyme activity was present in the primary and secondary pulvini of Siratro. In addition, it is demonstrated that the primary pulvinus is associated with ACh function in Siratro plants