Comparison of adventitious shoot formation from node and leaf explants of various carnation (Dianthus caryophyllus L.) cultivars

Abstract

SummaryShoot regeneration of leaf explants from in vitro plants of 35 carnation cultivars, and node explants from greenhouse plants of 38 cultivars was compared. First to third node explants cultured on medium containing 1.0 mg l–1 TDZ for 10.d and subcultured onto medium contain 1.0 mg l–1 BA showed a high shoot regeneration percentage, while the upper node showed higher shoot regeneration ability than the lower node. In contrast, there was no difference in regeneration ability among the first to sixth in vitro leaves (cultured on medium with 0.5 mg l–1 IBA and 0.22 mg l–1 TDZ). In both node and leaf explants regeneration ability was different depending on the cultivar, and there was no difference between standard and spray types. The correlation coefficients between regeneration percentage and the number of shoots per regenerating node and leaf explants were significantly positive (r=0.536** and 0.720**, respectively P<0.01). The correlation coefficient between shoot regeneration percentage of node and leaf explants was significantly positive (r=0.213*; P<0.05). Histological observations on adventitious shoot organogenesis by SEM and light microscopy showed that in both node and leaf explants, shoot primordia were regenerated from the transition zone between the leaf base and the stem. In both node and leaf explants shoot primordia regenerated in the cortex tissue near the wound surface.