Micropropagation and histological analysis of Calla lily

Abstract

The expansion of floriculture in Brazil indicates that producers need to specialize and find strategies to reduce production costs and improve the quality of commercial ornamental plants. Calla lily is considered as one of the most appreciated flowers in Brazil. However, there are problems mainly related to bacterial infection caused by Pectobacterium carotovorum. Thus, this study aimed to assess the in vitro propagation of Calla lily. Culture induction was performed transferring the leaf, nodal and root (1 cm2) explants to Murashige and Skoog medium (MS) supplemented with 6-benzyladenine (BA) (0.0, 0.25, 0.5, 1.0, 1.5, 2.0, 4.0 and 6.0 mg L-1) combined with 0.1 mg L-1 naphthalene-1-acetic acid (NAA), 3% sucrose and 0.7% agar. CTT dye was used for quantifying cell viability of calli from nodal explants. Plantlets were individualized and inoculated with different concentrations of NAA and indol-3yl-butyric acid (IBA) (0.0, 1.0, 2.0 and 3.0 mg L-1) for in vitro rooting. Plants were acclimatized in Plantmax® substrate and leaf histological analyses were performed in vitro and ex vitro. The formation of calli was observed in all explants subjected to the BA and NAA concentrations tested. The viability test using CTT showed that the calli should be subcultured 20 days after inoculation due to the increased absorbance. The highest shoot recovery occurred with 4.0 mg L-1 BA combined with 0.1 mg L-1 NAA. The highest percentage of rooted shoots (85%) was found in the culture medium with 2.0 mg L-1 IBA. The acclimatization of rooted shoots in Plantmax® was successfully accomplished and 100% survival of plant material was observed during this stage. Our results demonstrate that micropropagation of Calla lily is successful using nodal explants.