In Vitro Regeneration and Hardening of Plantlets through Seed Culture in Spathoglottis plicata Blume

摘要

Spathoglottis plicata Blume, a vegetatively propagating ground orchid growing well in the tropical plains, is important for its attractive long inflorescence with blight pinkish-purple flowers. Commercial potentiality of this orchid has not been properly explored, possibly due to its slow rate of growth and multiplication, delayed flowering and lack of seed germinability in vivo, and chance variation through recombination, ruling out the scope of a desirable modificaiion of these constraints. Considering all these aspects, in the present investigation protocols for in vitro regeneration and hardening for mass propagation were developed through seed culture. Seeds from mature green pods were inoculated in the Vacin and Went medium with different concentrations of adjuncts. Extracts of tomato, banana (ripe and unripe), Amaranthus and sugarcane, yoghurt water were used as additives in the medium. The effective concentration was 0.2% in case of tomato juice, ripe and unripe banana pulp and Amaranthus extract; while it was 0.4% in case of yoghurt water and sugarcane extract. The most effective adjunct was yoghurt water (0.4%), which reduced the time required for germination by 8 days. When the seeds treated with the chemical mutagen sodium azide (1%) were inoculated in the VW medium enriched with the additives and with 0.4% yoghurt water the time required for germination was found to be reduced further. Roots developed, in the plantlets obtained from untreated seeds, within 100 days, while in the seeds treated with sodium azide, rooting occurred within 90 days. The plantlets thus obtained were hardened, maintaining humidity and were finally transferred to soil.