Prospects of increasing the presence of Helianthemum kahiricum Dell. pastoral North African plant by means of micropropagation
Helianthemum kahiricum has great potential in forage, in traditional medicine, for halting desert encroachment and stabilizing sand dunes through their excellent root systems development, and in the improvement of soil organic matter content. H. kahiricum is threatened with extinction because of overgrazing abuse and increasing human disturbance. For these reasons, in vitro propagation is essential for developing efficient conservation program. Several cytokinins: indole-3-acetic acid (IAA) ratios and a range of zeatin concentrations were evaluated for their effect on shoot multiplication from apical shoots and nodal segments. The type of cytokinin and the origin of the explants were the most important factors affecting shoot multiplication. The highest shoot multiplication rate was obtained from single-nodal explants on medium hormone free. Increasing zeatin concentrations promotes decreased shoot multiplication independently of explants type, although this effect tends to decrease with higher zeatin concentration. Shoot growth was higher in apical shoots and it was not stimulated by the presence of auxin. A number of experiments were conducted to identify suitable procedures for rooting of in vitro produced shoots. Although, rooting frequency rose to 98% by in vitro culture on an auxin-free medium, the survival of the plants after 6 months of acclimatization was good (90%).
Keywords: Biotechnology conservation, pastoral species, ex vitro rooting, Helianthemum kahiricum, in vitro culture.