Influence of Plant Growth Regulators on Callogenesis and the Biomass of Cell Suspensions in Lily (Lilium ledebourii and Lilium regal)

Lily is often described as one of the most widespread, commercial crops in the floriculture industry. Commercially grown cultivars are mostly propagated by bulb scales which it cost effective and uniformity in tissue culture conditions. Plant tissue culture techniques can effectively provide far-reaching implications in micro-propagation.

This study was conducted to investigate the effects of various concentrations of cytokines and auxins on callogenesis and Biomass under in vitro conditions. In this experiment, the evaluations were aimed at measuring different characteristics in two lily cultivars, namely, Lilium ledebourii and Lilium regal. 

The results showed significant values in all of the measured characteristics. The highest percentage of callogenesis was caused by 2 µm PIC plus 1 µm KIN in L. ledebourii (88.66%) and L. regal (88.66%). Also, the callus weight in both cultivars was obtained by applying the same combination of treatments. In the second experiment, the highest fresh biomass of the cell suspension occurred by applying 2 µm PIC plus 4 µm KIN. The maximum amount of fresh biomass in L. ledebourii (88.93 g/L) and L. regal (41 g/L) occurred on the 24th and 20th day of the culture, respectively.

 An efficient and fragile callus induction was developed by NAA, which nonetheless made the condition more suitable for cell suspension culture. These lily cultivars need high amounts of PIC as auxin to grow well in cell suspensions. By increasing the PIC level, the biomass accumulates more. These results can moderately optimize large-scale production of both fragile calli and cell suspension biomass.