THE EFFECT OF ETHEPHON ON THE GROWTH AND DEVELOPMENT OF LIATRIS-SPICATA

The first experiment studied the effect of applying ethylene biosynthe sis regulating compounds (ethephon 1000 ppm, silver thiosulphate 0.4 m M and cobalt chloride 5 mM) on the growth and development of Liatris s picata cv. Callilepis. The results pointed to the important growth ret ardant properties of ethephon and the increased number of flowering st ems per corm which could be obtained by pre-planting application. A se cond experiment aimed to optimize ethephon treatment in Liatris by app lying the growth retardant in different concentrations (100, 700, 1300 , 1900 and 2500 ppm) at three stages of development: stage I (pre-plan ting), stage II (immediately after the formation of basal leaf rosette ) and stage III (when the main shoot began its rapid longitudinal grow th). Besides confirming the effects produced by ethephon in the first experiment, the results suggested that the application of high ethepho n concentrations (1900 and 2500 ppm) during stage II of growth produce d many miniature flowering stems coming from the principal or secondar y shoot.