Root Buds and the Development of Root Suckers in Sweetgum

Sweetgum ( Liquidambar styratiflua L.) reproduces prolifically from root suckers in the Georgia Piedmont. Histological observations of lateral root segments without visible buds or suckers reveal numerous suppressed buds embedded in the periderm with vascular traces extending either to the stele of the primary root or to a point of previous root injury. Clusters of adventitious buds are often found embedded in the periderm in swellings associated with aborted lateral roots, and the vascular traces of these buds become continuous with those of the previously formed lateral roots. The exposure of lateral roots to light resulted in the immediate release of numerous suppressed buds all along their surface. Complete girdling of exposed lateral roots had a similar but more restricted effect. The released buds were always concentrated on the side of the girdle away from the parent tree, indicating that some type of inhibition was removed. Histological observations of released buds and their later formed root suckers confirmed the suckers' origin from previously formed suppressed buds.