Micropropagation and ex vitro rooting of three ZZ plant (Zamioculcas zamiifolia Engl.) cultivars

Abstract

Zamioculcas zamiifolia Engl. is an ornamental indoor plant from the Araceae family. The usual method to propagate this ornamental plant is dividing the rhizome or leaf, although the production rate is too low. Therefore, plant tissue culture can be the best method for the rapid propagation of this plant. In this study, the in vitro culture of three Zamioculcas zamiifolia Engl. plant cultivars was investigated. For this purpose, two types of explants were used (apical part of the leaflet and basal part of the leaflet with petiolule). In order to obtain the best protocol for protocorm-like bodies (PLB) formation, the explants were cultured on Murashige and Skoog (MS) and ½MS basal medium containing different hormonal compositions. After 120 d, MS culture media containing four hormonal compositions, namely 0.2 mg L⁻¹ 6-benzyl aminopurine (BA) with 4 mg L⁻¹ 1-naphthaleneacetic acid (NAA), 2 mg L⁻¹ BA with 1 mg L⁻¹ NAA, 8 mg L⁻¹ BA with 1 mg L⁻¹ NAA, and 8 mg L⁻¹ BA with 4 mg L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D), were selected. Then, two types of explants (apical part of the leaflet and basal part of the leaflet with petiolule) of three ZZ plant cultivars (Raven, Supernova, and Regular) were cultured on selected media. Results showed that the highest callus induction was obtained on MS medium with 0.2 mg L⁻¹ BA and 4 mg L⁻¹ NAA. Then, calluses were transferred onto MS medium with 2 mg L⁻¹ BA and 1 mg L⁻¹ NAA for PLB formation. After the formation of eye buds on the PLBs, the explants were transferred to light:dark (16:8) conditions with two hormonal compositions (8 mg L⁻¹ BA and 1 mg L⁻¹ NAA or 8 mg L⁻¹ BA and 4 mg L⁻¹ 2,4-D). The MS medium supplemented with 8 mg L⁻¹ BA and 1 mg L⁻¹ NAA was selected for regeneration of the eye buds. During the rooting stage, regenerated plantlets were transferred into the two hormonal treatments (2 mg L⁻¹ indole-3-butyric acid (IBA) and 5 mg L⁻¹ IBA). Results showed that a small number of roots with inappropriate length were produced during in vitro conditions, so the rooting was re-evaluated under in vivo conditions. Root development was improved during the acclimatization phase. Finally, the highest acclimatization percentage was obtained on peat moss:perlite substrate. This developed protocol can be used for the commercial production of ZZ plant on a large scale.