In vitro propagation and anthraquinone quantification in Gynochthodes umbellata (L.) Razafim. & B. Bremer (Rubiaceae)—A dye yielding plant

Abstract

In vitro propagation techniques have been standardized for axillary shoot multiplication through nodal and shoot tip explant for the first time in Gynochthodes umbellata, a natural dye yielding plant. Single nodes and shoot tip obtained from young top shoots were cultured on Murashige and Skoog agar medium (MS) fortified with different concentrations of different cytokinins like BA, KIN, 2ip and TDZ and its combinations. The positions of nodes from the young shoots have some influence in the percentage axillary shoot induction and multiple shoot formation. Of the different position of the nodes used, the 4th node from the shoot tip showed maximum percentage (85%) response and multiple shoot formation in presence of BA. Of the different cytokinine used, BA had a dominant role in promoting multiple shoot proliferation in the nodal explant. An average of 6.8270±0.28 shoots/node was obtained in MS medium containing 2mg/l BA. The optimal medium for rooting was half strength MS medium (in dark) fortified with 1.5mg/l IAA (17.20±7.55 roots/shoot) with basal callusing, where 1.5mg/l NAA gave maximum of roots (7.90±3.25 roots/shoot) without any basal callus formation and showed highest establishment rate in community pots as well as in the field (90%).The roots of one year old established in vitro derived plants showed higher amount of anthraquinone (8.330mg/g fw) than the in vivo plants (4.567mg/g fw). The described protocol can be effectively used for the large scale propagation, exploitation of active compound and conservation of this important dye yielding plant.