Rhizome Segments Form Shoots, Whereas Leaf Cuttings Form Shoots and Rhizomes in Eucodonia ‘Adele’ Treated with Benzyladenine

Abstract

Eucodonia ‘Adele’ initiates seasonal shoot growth from a scaly rhizome. Larger rhizome segments (>2.5 cm) produced shoots at a greater percentage compared with smaller rhizome segments. Shoots produced on larger segments were initiated sooner and had a longer length. However, when shoot formation efficiency was calculated as the number of potential shoots per original stock rhizome, smaller rhizome segments were more efficient, producing three to four times as many shoots. Rhizome segments (2.5 cm) soaked overnight in benzyladenine (BA) produced three to four times more shoots per rhizome (four shoots) compared with untreated or water-soaked rhizomes (0.3 and 0.7 shoot, respectively). The scaly rhizome consists of a central stem-like core surrounded by numerous leaf-like scales. Scales appear to be storage leaf tissue based on anatomy and presence of numerous amyloplasts. New shoots initiate as axillary shoots formed from the central core at the scale attachment. Isolated individual scales also have the capacity for adventitious shoot formation, but only form in about 25% of isolated scales. Leaf cuttings were capable of producing adventitious shoots, roots, and rhizomes. Untreated petiole and lamina cut leaf cuttings formed approximately three rhizomes per leaf cutting compared with less than one adventitious shoot per leaf cutting. Benzyladenine-treated leaf cuttings did not show an increase in rhizome initiation, but soaking lamina cut leaf cuttings in water or BA increased shoot formation to ∼1.5 shoots per cutting. This work with isolated rhizome segments and leaf cuttings presents efficient systems for regenerating rhizomes that can be used to produce stock plants for a stem cutting system for Eucodonia ‘Adele’ as a seasonal pot plant.