In vitro regeneration from protocorms in Dendrobium aqueum Lindley – An imperiled orchid

An efficient in vitro plant regeneration protocol from protocorms of Dendrobium aqueum was developed. The uniformly developed protocorms (in vitro origin) having shoot initials were cultured on half macro strength MS medium (1/2 MS) supplemented with cytokinins (BA, 2iP, KIN and TDZ) at 1, 3, 5, 7, 10 mg l−1, natural additives (BP and CW) at 1%, 3%, 5%, 7%, 10% and auxins (IBA, NAA, 2,4-D) at 1, 3, 5, 7, 10 mg l−1 to study their efficacy on complete plant development. A maximum of 9.4 shoots per explant were generated on 3 mg l−1 of NAA followed by 3% of BP (7.0 shoots). Shoot elongation (1.52 cm) was achieved on 1/2 MS medium fortified with NAA 7 mg l−1 followed by TDZ 7 mg l−1 (1.37 cm). Shoots cultured on 1/2 MS medium supplemented with IBA 5 mg l−1 produced an average of 8.75 roots per shoot, however the lengthiest roots (1.48 cm) were noted in NAA 7 mg l−1. Healthy rooted plantlets successfully acclimatized in ex vitro condition. The role of complete plantlet production by natural additives could be useful for conservation and cost effective commercial production of orchids

Organogenesis from in vitro-derived leaf and internode explants of Hoya wightii ssp. palniensis -a vulnerable species of Western Ghats

An efficient system was developed for indirect plant regeneration from in vitro-derived leaf and internode explants of Hoya wightii ssp. palniensis. Maximum percentage of the organogenic callus was obtained on MS medium supplemented with NAA (1.0 mg/l) and 2,4-D (2.0 mg/l). The best shoot bud induction was observed on MS medium with BA (1.0 mg/l) +IBA (0.5 mg/l). The coconut water (15%) was better, resulting in a differentiation of the shoot initials in to well-developed shoots. The elongated shoots (› 3cm long) were rooted on a full strength MS basal medium, supplemented with 0.2 mg/l of IBA. Finally, the rooted plants were transferred to the soil with 80% success rate. This protocol was utilized for the in vitro propagation of this endangered plant species