HISTOCHEMICAL LOCALIZATION OF ALCOHOL DEHYDROGENASE IN DEVELOPING BEAN SEEDS

Alcohol dehydrogenase activity can be readily localized within bean seeds using the tetrazolium method. In the seed coat, prior to the cotyledon stage of embryo development, staining was seen throughout, especially in the branched parenchyma cells and the integumentary tapetum. As the embryo entered the maturation stage, a gradual decrease in the staining intensity was observed throughout the seed coat. Embryos stained well at all stages of development. In the course of this investigation, a high activity of “nothing dehydrogenase” was observed. Since its activity could be inhibited by methylpyrazole, an ADH inhibitor, it is concluded that the nothing dehydrogenase activity is caused by alcohol dehydrogenase.