TDZ-INDUCED MULTIPLICATION OF Disanthus cercidifolius MAXIM

Disanthus cercidifolius Maxim. (Hamamelidaceae) is an endemic deciduous species native to forests of China and Japan cultivated as an ornamental plant as a result of fall foliage colors. To improve clonal micropropagation of the species a potent synthetic growth regulator TDZ was tested using two application methods: addition of various concentrations (1.1, 2.2, 3.3 µМ) to MS nutrient medium and liquid pulse treatment. The highest multiplication rate (5.8 shoots per explant) was achieved with 30 μM TDZ pulse treatment for 4 h followed by cultivation on MS supplemented with 2.2 μM BA for 6 weeks. Morphological abnormalities associated with TDZ application were analyzed by histological and stereo microscopic methods. The present study revealed both development of axillary shoots from two-node explants and regeneration of adventitious shoots from secondary buds formed on axillary shoots. Observed morphological disorders were overcome successfully by cultivation on TDZ-free medium for 6 weeks.