In vivo labeling of sunflower embryonic tissues by fluorescently labeled phenylalkylamine

A fluorescently labeled phenylalkylamine. DM-Bodipy PAA, was used as a prob e for the in vivo detection of ion channels in embryonic and nonembryonic t issues of sunflower. Zygotic embryos, somatic embryos, callus leaves, roots , and shoots were analysed. Fluorescence intensity in the tissues was deter mined with cytofluorometry and confocal microscopy. DM-Bodipy PAA intensive ly labeled the protoderm and epidermis cells in both zygotic and somatic em bryos Callus cultures exhibited labeling on sites where somatic embryos dev eloped. Labeling was, however, very weak in leaves. shoots, and roots, exce pt in the root cap and in the epidermis of the root. Considering that the l ocation of phenylalkylamine binding sites is related to the distribution of ion channels in both animal and plant cells, the high intensity of labelin g observed in the protoderm and epidermis of zygotic and somatic embryos as well as in protoderm, epidermis and caps of root tips, is consistent with the role these tissues may play in ion exchange with the environment.