Abstract:

Since the transplanting seedlings are difficult to adapt to rooting culture and domestication due to the tenuous stems in medium, the rejuvenation research was conducted using test-tube plantlets of Bletilla striata by optimizing the conditions of the medium. Based on the proliferative and rhizogenic formulas established in our previous study, the single factor and L₉(3⁴) orthogonal experiment were carried out using different subculture plantlets, different concentrations of plant growth retardant (PP₃₃₃ and CCC) and carbon source, aiming to investigate the impact of different types and concentrations of plant growth retardant and explants on rejuvenation, multiplication, rooting culture and transplanting. L₉(3⁴) orthogonal test exhibited that the optimal rejuvenation medium was MS+ 1.0 g/L AC+ 50 g/L banana puree+ 0.5 mg/L 6-BA+ 0.01 mg/L NAA+ 0.5 mg/L PP₃₃₃+ 0.1 mg/L CCC+ 40 g/L sucrose for the fourth generation. After 70 d, the diameter of the plantlets’ basal part of stem, the growth coefficient and the occurrence rate was (0.26±0.06) cm, 2.13 and 100%, respectively. The pseudobulbs and roots were sent forth from rejuvenation plantlets after 60 d on the 1/2MS medium containing 1.0 g/L AC, 80 g/L banana puree, 0.1 mg/L 6-BA, 1.0 mg/L NAA and 15 g/L sucrose. The survival rate of transplant seedlings was 100%. High-efficiency regeneration system of B. striata with optimal rejuvenation condition was established.

Key words: Bletilla striata, rejuvenation cultivation, plant growth retardant, pseudobulb, acclimatization transplant