The Effects of Growth Substances on the Growth of Tapinanthus bangwensis (Loranthaceae) in vitro

Abstract

The growth response of Tapinanthus bangwensis (Engler and K. Krause) Danser to exogenous growth substances, indole-3yl-acetic acid (IAA), kinetin, and gibberellic acid (GA3), not only varies with the concentrations of each of these substances in the medium but follows a similar trend in each case. Kinetin, IAA, and GA3 were found to enhance growth but not by very appreciable amounts, kinetin being the most effective growth promoter. High concentrations of these substances (5.0 and 10.0 ppm) except GA3 were toxic to the parasite. Gibberellic acid induced the production of accessory leaves at all the concentrations used. Kinetin was also effective in inducing accessory leaves but only at a concentration of 1.0 ppm. Some of the lower concentrations of the growth substances affected significantly some aspects of the parasite's growth and development. Nevertheless, the growth in vitro was still slower than that in vivo.