Influence of carbon source, MS medium strength and pH on in vitro regeneration of the endangered psammophyte Dianthus giganteiformis subsp. kladovanus from different explant types

Abstract

The goal of this study was to investigate the effect of medium pH and the influence of different graded concentrations of sucrose, fructose and glucose on the regeneration and development of Dianthus giganteiformis subsp. kladovanus grown on media with MS and half-strength MS salts, using different explant types. The results showed that the mean number of axillary buds and the number and length of shoots were significantly influenced by medium pH change and explant type, but the reduced concentration of MS salts did not have effect on those parameters. However, the significant interactions between the explant type and MS salt concentration or medium pH, which affected the mean number of axillary buds and shoots were recorded. The sugar type and its concentration significantly affected shoot development, and the highest number of shoots and axillary buds were obtained on the media containing 10 g L-1 or 30 g L-1 sucrose or 30 g L-1 glucose, while fructose showed poorer results. The longest shoots were developed on media with lower concentrations of sugars, and the best results were obtained on the media with 10 g L-1 and 30 g L-1 glucose. The concentration of NAA neither affected the rooting rate nor the number and length of roots, but explant type and MS salt concentration influenced rooting. For the optimal results, shoot cuttings with 1 to 4 nodes should be rooted on half-strength MS medium without auxine, and the obtained microplants should be acclimatized in a 4:1 mixture of peat and sand. When this protocol of propagation was used, the rooting rate was 95% and the acclimatization rate reached 90%.