In vitro Microtuberization and Enhanced Colchicine Accumulation in Two Species of Gloriosa

抄録

The present article describes an efficient technique for micropropagation and microtuberization of two species of Gloriosa, G. orangea and G. rothschildiana of Colchicaceae, the colchicine yielding plants. The plants were propagated in culture through apical shoot bud multiplication using modified Murashige and Skoog's nutrient medium (MS) supplemented with 6-benzylaminopurine (BAP) and α-naphthaleneacetic acid (NAA) in presence of two different concentrations of sucrose (3 and 6%). The process of microtuberization was found to be quite efficient in MS containing 3% sucrose, producing about 180–240 tubers per culture vessel within 6 months or less. On the other hand, the medium with 6% sucrose level induced microtuberization 2 weeks earlier with reduced rate of regeneration. The microtubers from 3% media showed 97% germination rate. The best result was obtained in a medium containing BAP (17.76 μM) and NAA (2.15 μM) with about 18–24 shoots and 14–21 microtubers/shoot. A 1.7 fold increase in colchicine accumulation in G. rothschildiana and a 2.0 fold increase in G. orangea estimated through High Pressure Liquid Chromatography (HPLC) were observed as compared to in vivo tubers. The extracted colchicine showed better efficacy than standard colchicine from Sigma Chemical Co. in treated root tip cells of Allium sativum L. and Mucuna pruriens L. In both these test plant systems, the extracted colchicine induced both polyploidy and diplochromatid formation at variable rates and the values were little higher in G. orangea than in G. rothschildiana. Moreover, G. orangea responded better than G. rothschildiana against the same concentrations of plant growth regulators and showed better colchicine accumulation as well.