Studies of the rooting of cuttings of Hydrangea macrophylla: enzyme changes

Abstract

Enzyme changes in root initials of Hydrangea macrophylla during adventitious root formation are described. Extensive changes in enzyme activity were demonstrated by histochemical staining and all enzymes investigated showed increased activity in the tissue responsible for root initiation.The earliest change observed was that of peroxidase in the phloem and xylem ray cells. This was followed by a change in the activity of cytochrome oxidase and succinic dehydrogenase. Alpha-amylase was localized by the substrate film method. The highest amylase activity was demonstrated in the epidermal tissues and vascular bundles. As the root primordia developed, enzyme activity shifted from the vascular bundles to the periphery of the bundles. A positive correlation was found between the starch content and root number of cuttings.