Abstract: Some key factors affecting the seed germination, plant growing and rooting of Dendrobium officinale were studied, and the micropropagation system of Dendrobium officinale via seed culture was established. The results showed that 6-benzyladenine (6-BA) in the medium inhibited the development of the protocorm seriously. The suitable seed density for initial germination was 8 000 in the condition that the culture vessel with a diameter of 9 cm was used, and banana powder as organic additives was necessary for seed germination with the suitable amount of 5-10 g·L^-1. The inoculation density was suitable for 100-120 plantlets per bottle in plant growth stage, and inoculation density played a more important role than light quality and medium content. In rooting stage, the plantlet height could be improved greatly when cultured in 3 000 K LED white light than those in fluorescent lamp without reducing the stem diameter, and the proportion of high quality seedlings also improved a lot. The results also showed that banana powder could completely replace fresh banana as organic additives for tissue culture of Dendrobium candidum. During the whole culture process, the temperature was (24±2) ℃. The photoperiod for seed germination was 10 h and the light intensity was 25-30 μmol·m^-2·s^-1, while in the other two stages, the photoperiod kept at 12 h and the light intensity kept around 40 μmol·m^-2·s^-1 were enough.

Key words: Dendrobium officinale, tissue culture, seed culture, optimization