Studies on the in vitro regenerative competence of aerial roots of two horticultural important Cymbidium species

In the present study aerial roots were successfully used as explants source for in vitro propagation of Cymbidium aloifolium and Cymbidium iridioides. Aerial roots of ~5?C6?week old from axenic cultures were cultured on MS medium adjuncts with different additives. In C. aloifolium within 20?days of culture ~60% of explants responded positively on MS medium containing sucrose (3%, w/v) and Kn (3???M) and formed PLBs. While in C. iridioides ~50% root explants responded positively on medium enriched with sucrose (3%), AC (0.1%) and IAA (3???M) after 40?days of culture. The shoot buds/PLBs converted into plantlets when maintained on regeneration medium. Of the three basal media tested, MS medium supported optimum regeneration and culture proliferation in both the species. In C. aloifolium ~12 shoot buds developed on medium nourished with sucrose (3%) and BA (3???M) but in C. iridioides optimum regeneration was achieved when medium supplemented with sucrose (3%), CW (15%), CH (100?mg?L^?1) and ~20 shoot buds formed per subculture. The well rooted plantlets were acclimatized for 3?C4?week in 1/10th MS salt solution containing sucrose (1%), charcoal pieces, brick pieces and chopped mosses as support under normal laboratory conditions. The hardened plants were transferred to potting mix where 80 and 75% of transplants survived in C. aloifolium and C. iridioides respectively after 2?months of transfer.     

Asymbiotic seed germination and in vitro seedling development of Cymbidium aloifolium (L.) Sw.: a multipurpose orchid

Cymbidium aloifolium is a multipurpose economically important epiphytic orchid grows on tree trunk in the primary forests. Its population in natural habitat is downsized due to different anthropogenic activities. A successful attempt was made for asymbiotic immature embryo culture and in vitro mass scale production of plantlets. For successful culture initiation seed pods of various developmental ages, various nutrient media, sucrose concentrations, different quality and quantity of plant growth regulators were surveyed. Immature embryos of 9 months after pollination was successfully germinated on MS medium containing sucrose (2%) (w/v) and α-naphthalene acetic acid (NAA) and benzyl adenine (BA) (3 and 6 μM respectively in combination) within 45 days of culture where 90% germination was recorded. The germinated seeds formed PLBs on the optimum germination medium within two passages. The protocorm like bodies (PLBs) differentiated into rooted plantlets within 3 weeks on regeneration medium containing sucrose (3%), casein-hydrolysate (0.1 gl^?1) and BA 3 μM. Amongst the three media studied, optimum regeneration was registered on MS medium where as many as 12 shoot buds developed per explants per subculture of 4 weeks duration. The well rooted plantlets of 6–7 cm long with 3–4 roots were hardened in vitro 3–4 weeks before they were transferred to potting mix. The potted plants were exposed to full sunlight periodically and watered at regular interval. About 70–80% transplants survived after 2 months of potting.