INFLUENCE OF DIFFERENT MACRONUTRIENT SOLUTIONS AND GROWTH-REGULATORS ON MICROPROPAGATION OF JUVENILE ACACIA-MANGIUM AND PARASERIANTHES FALCATARIA EXPLANTS

The influence of five different macronutrient formulations and various growth regulators on micropropagation of single node explants from Ac acia mangium and Paraserianthes falcataria seedlings was examined afte r 4 weeks and 8 weeks in vitro. The experiment was repeated 4 months l ater. On media lacking growth regulators, growth and development were significantly influenced by the different macronutrient solutions test ed, although morphogenic responses could vary according to the species . For instance, P. falcataria displayed a greater ability for adventit ious rooting than A. mangium. Overall, Knop macronutrient solution ind uced the weakest responses. Explant responsiveness was significantly i nfluenced by the addition of 2.2 or 4.4 mu M 6-benzyladenine combined with either 1.4 or 2.3 mu M kinetin, 1.5 or 2.5 mu M indolebutyric aci d or 1.6 or 2.7 mu M naphthaleneacetic acid. The various combinations of growth regulators tested were shown to inhibit the rooting ability of the explants, while stimulating the production of basal shoots for both species, and of axillary shoots only for A. mangium. In such expe rimental conditions, A. mangium displayed overall a greater potential for micropropagation than P. falcataria.