Meera Chettri Das

A simple and efficient protocol for the mass propagation of Cymbidium mastersii: an ornamental orchid of Northeast India

The present investigation was undertaken to mass propagate Cymbidium mastersii, an ornamental orchid of Northeast India by in vitro propagation method. This approach could also help for the conservation as well as commercialization of C. mastersii and other threatened and ornamental orchids.

Storage and high conversion frequency of encapsulated protocorm-like bodies ofCymbidium devonianum(orchid)

Summary A method for the storage and high frequency conversion of Cymbidium devonianum protocorm-like bodies (PLBs) is reported. To study the effect of nutrient level on storage, PLBs were encapsulated in calcium alginate beads supplemented with 1.0×, 0.5×, 0.25×, or 0.125× Murashige and Skoog (MS) basal medium containing 0.3% (w/v) sucrose, without agar in the encapsulating matrix, and stored at room temperature (25º ± 2ºC) in the dark. Beads containing 0.25× MS were also kept at different temperatures (0ºC, 4ºC, 8ºC, or room temperature) in the dark to ascertain the optimal temperature for storage. One set of controls (i.e., non-encapsulated PLBs) was maintained for each treatment. The survival and subsequent percentage conversion values of PLBs were assessed at 30 d storage intervals after culturing on MS regeneration medium. Compared to the controls, all encapsulated PLBs showed improved storage at room temperature. In all treatments, non-encapsulated PLBs did not survive, but turned brown and died. Encapsulated PLBs in 0.25× MS medium could be stored for 90 d at room temperature without any significant loss in viability. However, a significant decrease in the survival percentage was recorded after longer storage times. Encapsulated PLBs containing 0.25× medium could be stored at 4ºC and 8ºC for 120 d and 180 d, respectively, without loss of viability. As storage times increased beyond 180 d, the survival percentage of encapsulated PLBs decreased. The conversion of encapsulated PLBs led to the emergence of regenerated plantlets. Initially, small green globular outgrowths from the PLBs were observed on the surface of the beads. These outgrowths multiplied to form clusters of PLBs which then regenerated into plantlets. In both studies, more prolonged storage of encapsulated PLBs increased the time interval for germination and plantlet regeneration on MS regeneration medium. Similarly, decreases in both basal MS strength in the matrix, and in storage temperature, resulted in an increase in the time required for germination and plantlet regeneration. Plantlets that regenerated from stored, encapsulated PLBs were hardened-off, and a high survival percentage (90%) was obtained in a glasshouse.

Plant Resources of India: Potentials for Future Development

The plant resources form an integral part of a huge inter-dependent system that encompasses the physical components and the biological community of life. These resources have enormous prospective benefits to humankind. The ever-increasing population and climate change over the years have contributed substantially to the pressure on plant resources leading to their decline or loss in nature. Hence, there is an immediate need to develop suitable conservation strategies for proper utilization and sustainability of these important resources.

In Vitro Propagation and Conservation of Dendrobium lituiflorum Lindl Through Protocorm-Like Bodies

Axillary buds obtained from 5-month-old in vitro growing plants of Dendrobium lituiflorum Lindl were cultured in Murashige and Skoog (MS) medium supplemented with different concentrations of 2,4-D. Fastest initiation (13.3 days) of protocormlike bodies (PLBs) was observed in cultures containing MS medium supplemented with 0.5 mg l−1 2,4-D. Maximum explant response of 83% was also observed in the same medium. PLBs obtained in MS medium containing 0.5 mg l−1 2,4-D showed maximum regeneration potential of seedlings (19 explant−1) when subcultured in MS medium. Well developed shoots and roots of the seedlings were obtained in the medium containing 0.5 mg l−1 each of NAA and BAP, in combination. Encapsulated PLBs of D. lituiflorum could be stored at 8°C for 90 days with 80% regeneration. However, it was observed that regeneration potential of encapsulated PLBs reduced with further storage. Seventy seven per cent hardened plants survived and bloomed after 2.5 years of hardening.