Optimisation of in vitro propagation in liquadamber (Liquidambar orientalis)

Liquidambar orientalis, a relict endemic species dating back to ancient times, has been used for its balsam for thousands of years. Today, it naturally occurs in a limited area in Southwestern Anatolia. Although its share in the balsam market has recently been overtaken by American sweetgum (L. styraciflua), Cleopatra used Anatolian sweetgum balsam as a perfume thousands of years ago. The species is also utilized in landscaping and holds economic importance. In addition to propagation through seeds and cuttings, studies are being conducted to achieve faster and clonal propagation in tissue culture, aiming to produce more efficient and higher-quality plant material. In this study, the aim was to determine the most suitable sterilization method for Liquidambar orientalis, establish optimal shoot proliferation and rooting media, and carry out acclimatization. For sterilization, various combinations of NaClO (20%) and fungicide (Captan, 0.3%) were tested. The highest sterilization success rate (89.29%) was obtained using 24-hour Captan (0.3%) treatment followed by 20 minutes in NaClO (20%). To investigate the effects of benzyl adenine (BA) and indole butyric acid (IBA) on plant development, different combinations of BA and IBA were tested. The best shoot proliferation was observed in Woody Plant Medium (WPM) containing 1 mg/L BA and 0.5 mg/L IBA. Studies on rooting media showed that optimal root development occurred in the medium supplemented with 1.0 mg/L IBA. When the shoot lengths of rooted cuttings were evaluated, the most satisfactory growth was observed in the 1.0 mg/L IBA treatment. Rooted shoots were subsequently transferred to a sterile peat–perlite mixture and acclimatized under greenhouse conditions for four weeks, achieving an approximate success rate of 90%.