Rapid clonal propagation of Zygophyllum xanthoxylon (Bunge) Maxim., an endangered desert forage species

This study describes a reliable protocol for callus induction and rapid mass propagation of the ecologically important plant, Zygophyllum xanthoxylon (Bunge) Maxim. The optimum callus induction medium was Murashige and Skoog (MS) supplemented with 4.4 μM 6-benzylaminopurine (BAP) and 2.7 μM α-naphthalene–acetic acid (NAA), on which the callus induction frequencies from different seedling explants were all 100%. However, seedling-derived callus did not form regenerated shoots. In order to achieve shoot multiplication, shoots were developed from cultured plumules, at an average of 3.1 shoots per explant, and the regenerated shoot tips were further multiplied by subculture. The best shoot multiplication from shoot tips was achieved on MS supplemented with 5.4 μM NAA and 22.2 μM BAP after 40 d of culture. Seventy-three percent of regenerated shoots formed roots when cultured on MS supplemented with 8.6 μM IAA after 4 wk of culture. The plants that acclimatized successfully in sand flourished the following year, with normal morphology and growth characteristics.