Vol. 2, Issue 1 (2017)
In vitro seed germination and rhizome based micropropagation of Calanthe densiflora Lindl: An indigenous terristerial orchid of Bangladesh
Author(s): TK Bhowmik, MM Rahman
Abstract: In vitro seed germination and rhizome based micropropagation protocol was established in Calanthe densiflora an indigenous terrestrial orchid of Bangladesh. The seeds were germinated on different media with three different sources of carbohydrates viz. sucrose, glucose and lactose. The germination rate was found to be better on PM medium. Among three carbon sources, the percentage of seed germination was higher in sucrose containing medium than glucose and lactose containing media. The germinated seedlings were cultured on solid & liquid medium. In liquid and solid culture the highest rate of elongation was achieved on MS + 3% (w/v) sucrose + 1.0 mg/l IAA + 1.0 mg/l BAP and 0.8% (w/v) agar solidified MS medium supplemented with 3% (w/v) sucrose + 1.0 mg/l NAA + 1.0 mg/l BAP respectively. Elongation of shoot system was better in liquid media than 0.8% (w/v) agar solidified medium. It also proved that MS was better than PM for elongation of shoot system. Rhizome segments of aseptic seedlings were used for rapid micropropagation. Rhizome segments underwent direct organogenesis to produce multiple shoot buds and maximum average number of shoot buds (6.45 ± 0.41/segment) induced on MS medium supplemented with 3% (w/v) sucrose + 1.0 mg/l IAA + 2.0 mg/l BAP followed by 6.02 ± 0.35 shoot buds/segment on MS + 3% (w/v) sucrose + 1.0 mg/l NAA + 2.0 mg/l BAP. Liquid media were more effective in SPSs induction than agar solidified medium. MS medium supplemented with 3% (w/v) sucrose and 0.5 mg/l IBA was best for induction of strong and stout root system. The rooted seedlings were finally transferred to outside natural environment by successive phases of acclimatization.