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

Abstract

SummaryThe 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 a-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 mM) and NAA (2.15 mM) 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. Key wordsThe species of Gloriosa of Colchicaceae (formerly under Liliaceae), distributed throughout tropical and sub-tropical regions of Asia and Africa, are medicinally important for treatment of chronic ulcers, hemorrhoids, leprosy and for inducing labor pains (Chopra et al. 1969). These plants contain the valuable alkaloids, the colchicine and colchicosides like another genus, Iphigenia under this family (Mukhopadhyay and Mukhopadhyay 2008a, b). The plants of Gloriosa are being overexploited for long time by the rural people for their medicinal purpose and that has caused its distribution very limited and so designated as threatened. Moreover, Gloriosa shows a very poor rate of vegetative propagation and one plant produces only one bi-forked tuber with one growing bud on top of each fork. The seed-grown plants, on the other hand, also take three to four years to flower and therefore, it is also not usually favored by the growers. In order to maintain different germplasms of these species of Gloriosa, suitable measures for rapid mass propagation and conservation are of much importance. Several

Kembang sungsang (Gloriosa superba L.): A potential plant as a source of biomutagens

“…Colchicine which is antimitotic, interferes with microtubule organization, causing abnormal metaphase to form cells with multiple chromosomes. Indirectly, colchicine affects the membrane structure by inhibiting the synthesis of the constituent elements of the membrane [9,34].…”

“…Besides inducing polyploidy initiation it can also cause low frequency chlorophyll mutations. The specific problem of ploidy induction due to colchicine, especially in plants that are propagated vegetatively is chimerism which is caused by a network with different levels of ploidy in one plant or part of the plant [9,34].…”