Adventitious rooting of apple microcuttings in vitro: an anatomical study

Abstract

In view of the lack of information on the anatomy of rooting in vitro, the time course of adventitious rooting was followed in an apple rootstock. Microcuttings raised on Murashige–Skoog medium were transferred to medium containing indolebutyric acid, then fixed at 0, 1.5, 3, 5, 7, and 10 days. A variety of tissues in close proximity to the cut stem surface exhibited an "activation" response over the first 3 days. Root meristemoids consisting of densely staining cells with enlarged nucleoli formed outside the xylem by day 5. Considerable variation in meristemoid development was noted within single stems and among stems. Meristemoids transformed into root primordia, some of which established a vascular connection with the stem by day 10.