Tissue Culture in Terrestrial Orchid Achieves Success in SCBG

Cymbidium nanutum is a terrestrial orchid endemic to Yunnan, Southwest China. It is of great horticultural value as an ornamental plant because of its beautiful and fragrant flowers. This popular species is endangered due to illegal collection and its habitat destruction. Currently, the propagation of C. nanutum is done mostly through separation of bulbs, which is too inefficient for commercial production. C. nanutum seeds are tiny with no endosperm, and germinate poorly under natural conditions. Tissue culture is known for a rapid and efficient means for commercial production and, therefore, is a crucial step for further biotechnological research, without exploiting the natural populations.

Compared with other orchids, in vitro regeneration from seeds or tissues of terrestrial Cymbidium species is difficult. Dr FANG Zhongming, directed by Prof. ZENG Songjun and DUAN Jun, from Biotechnology Research Group of South China Botanical Garden, CAS, has developed an efficient micropropagation system for C. nanutum using immature seeds. 100ml l^-1 coconut milk (CM) and half-strength Murashige and Skoog (？ MS) medium were best for seed germination. An average proliferation rate of 4.4 was obtained on ？ MS medium containing 0.5 mg l-1 NAA and 1 g l^-1 activated charcoal. Rhizomes produced on an average of 3.7 shoot buds on ？ MS differentiation medium supplemented with 0.1 mg l^-1 thidiazuron (TDZ) and 1.0 g l^-1 citric acid (CA). Hyponex medium supplemented with 100 ml l^-1 CM and 100 g l^-1 banana homogenate (BH) was best for shoot bud growth and the rooting induction. The regeneration protocol in this study provides a basis for germplasm conservation and large-scale multiplication of C. nanutum.

The relative research results have been published by the international journal, Propagation of Ornamental Plants. (http://www.journal-pop.org/2011_11_3_149-155.html)

Rhizome differentiation on medium with TDZ and CA of Cymbidium nanutum

Hardened plant growing in plots filled with sand, sieved peat and perlite in green house of Cymbidium nanutum

In vitro flowering of Cymbidium nanutum