Regulation of growth of Lilium plantlets in liquid medium by application of paclobutrazol or ancymidol, for its amenability in a bioreactor system: growth parameters.

Effect of growth retardants (paclobutrazol or ancymidol) was studied in Lilium plantlets growing in liquid culture. A significant increase in leaf chlorophyll, epicuticular wax, plant dry weight and bulb starch contents were found in plantlets treated with growth retardants. A similar increase in the number of leaves, roots and bulbs was also noted. However, total leaf area and the fresh weight increased only marginally. These features resulted in robust plantlets that showed significantly improved ex vitro survival. Based on these features, a comprehensive index (CI) was calculated as a measure of quality of the plantlets, and it correlated well with their ex vitro survival. Treatment of plantlets with 3.4 microM paclobutrazol was found to be the best and its carry over effects were also minimal.