Induced Polyploid in Lindernia sp. by Colchicine In Vitro

Abstract

Lindernia is an herbaceous plant in the family Linderniaceae with small leaves and flowers. It resembles the popular ornamental plant Torenia. Colchicine is a substance that has been reported to cause various mutations in plants. The objective of this research was to determine if colchicine would cause changes in the growth habit or morphology of Linderniaceae. Lindernia nodes were surface sterilized and cultured in vitro on half-strength semisolid MS medium. After subculturing, new nodes were excised and submerged in liquid ½ MS medium with colchicine added at concentrations of 0, 5, 10, 15 and 20 ppm for 1, 2 and 3 days, after which they were cultured on semisolid medium with no colchicine for another 30 days. The survival rate and growth of new shoots was clearly affected by exposure to colchicine. At the concentration of 15 ppm and duration of 3 days, the survival rate was only 15% and the mean number of new shoots was only 5. Plant height, internode length, and leaf length were also reduced in every colchicine treatment. The mean leaf width of Lindernia exposed to 5 ppm and 20 ppm colchicine was less than the control. The number of roots was less than control in the 10 ppm and 15 ppm colchicine treatment groups, and mean root length was less than control in the 5 ppm and 10 ppm groups. In screening for putative polyploids, it was observed that plants from the colchicine treatments tended to be shorter, with thicker stems and smaller, curled leaves compared to the control. A tetraploid plant (2n = 4x) was found in the 5 ppm colchicine for 2 days treatment group.