In Vitro Shoot Formation and Elongation of Dwarf Pomegranate

Abstract

Fig. 1. Effect of BA (A) and NAA (B) concentration on in vitro shoot formation and elongation of Punica granatum ‘Nana’ on MS medium supplemented with either 2.0 μM NAA (A) or 2.0 μM BA (B). Each data point represents the mean ± 1 SE of 20 cultures. Dwarf pomegranate (Punica granatum L. ‘Nana’) is used for landscape, indoor culture, and bonsai. Adventitious shoot formation has been reported in anther and leaf callus cultures of tree pomegranate (Moriguchi et al., 1987; Omura et al., 1987). In vitro propagation has also been reported for tree pomegranate (Mascarenhas et al., 1981). However, we found no information on in vitro propagation of dwarf pomegranate. In this paper, we report in vitro shoot formation from nodal sections of dwarf pomegranate. Terminal shoots with seven to 10 nodes were excised from actively growing plants of dwarf pomegranate maintained in a greenhouse. Shoots were surface-disinfected as described previously (Zhang et al., 1987) and then cut to provide nodal sections (≈ 5 mm long). The explants were placed vertically in 25 × 100 mm culture tubes each containing 10 ml modified MS medium (Murashige and Skoog, 1962; Zhang et al., 1987). For shoot formation and elongation, the medium was supplemented with the following combinations of plant growth regulators: 1) with the NAA (1-naphthaleneacetic acid) level fixed at 2.0 μM, BA [ N -(phenylmethyl)-l H purin6-amine] levels were 0, 0.5, 1.0, 2.0, 4.0, 8.0, or 16.0 μM; and 2) with the BA level fixed at 2 μM, NAA levels were 0, 0.5, 1.0,