CONTROLLED IN VITRO ENVIRONMENT FOR STAGE II MiCROPROPAGATION OF BUDDLEIA ALTERNIFOLIA (BUTTERFLY BUSH)
ABSTRACT Optimal light, sucrose, and CO2 levels were determined for Stage II micropropagation of Buddleia alternifolia (Butterfly Bush). Five levels each of light (50, 75, 100, 125, 150 ixmol m-2s-l PPF), of sucrose (0, 1, 2, 3, and 4%), and of force-ventilated CO2 (0, 350, 600, 900, 1200 ppm) were compared through one-way factorial experiments. Three levels of each factor were then selected for a 3x3x4 factorial experiment of the same culture. Free-ventilated CO2 of 350 ppm, serving as control, constituted the fourth level of CO2. The results showed that the observed optimum points were 2% sucrose, 125 |xmol m-2s-l PPF, and 600 ppm force-ventilated CO2. Based on the lack of interactive effects between the factors, the general absence of statistical differences between the levels within each optimum factor range, and considerations of economic benefits, the preferred factor levels were chosen to be 3% sucrose, 350 ppm free-ventilated CO2, and 75 |imol m-2s-i PPF. The study also revealed that elevated in vitro light and CO2 levels, in the absence of sucrose, did not promote the growth of the culture.