Studies on in vitro regeneration competence of pseudobulb cultures in Changnienia amoena Chien

An efficient procedure is outlined for rapid and mass propagation through in vitro culture of pseudobulbs collected in different seasons of an endangered orchid, Changnienia amoena Chien. Axillary buds formed on intact pseudobulbs (collected in April) after a 12-week incubation on half-strength Murashige and Skoog (1/2 MS) medium supplemented with 1 mg L⁻¹ N ⁶-benzyl-adenine (6-BA), 0.5 mg L⁻¹ α-naphthaleneacetic acid (NAA), 100 ml L⁻¹ coconut water and 0.8 g L⁻¹ polyvinylpyrrolidone; no buds were observed on segmentalized pseudobulbs incubated on the same medium. The axillary buds obtained from pseudobulbs growing in the natural habitat in June were detached and incubated for 7 weeks on the same medium leading to 1.4 shoot buds per explant. With repeated subculturing of the shoots on 1/2 MS medium supplemented with 2 mg L⁻¹ 6-BA and 0.5 mg L⁻¹ NAA, a mean of 3.3 shoot buds per explant were observed on successive shoot cultures. A mean of 4.5 roots per shoot were induced on the optimal root induction medium with 1/2 MS medium plus 1.0 mg L⁻¹ NAA and 0.1 mg L⁻¹ 6-BA and the highest rooting percentage was 88.9%. Plantlets 4–5 cm in height were transplanted into pots containing a 1:1 humus and sand mixture and grown for 7 weeks in a greenhouse before being transferred to the field. The survival rate of these transplants was about 75% after two months of growth in the wild.