THE INFLUENCE OF ETHYLENE ON PROLIFERATION AND GROWTH OF ROSE SHOOT CULTURES

Ethylene accumulation in four different rose in vitro culture containers was evaluated. Multiplication rate was the highest, and axes most elongated, in the two containers where ethylene accumulation was limited. Pulse treatments of ethylene at various concentrations enhanced proliferation depending on concentration (5 ppm generally was the most favourable) and time of application, while reducing elongation of the shoots. An ethylene trap in the flask atmospheres of the cultures reduced rose shoot proliferation rate but increased elongation of the axes. Inhibitors of ethylene biosynthesis, aminoethoxyvinylglycine (AVG) and cobalt chloride (CoCl2), increased multiplication rate by providing a higher number of axes of a suitable size for subculture. The ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) had a beneficial effect on multiplication rate, although reducing longitudinal growth of the axes.